Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens

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混凝土材料强度检测标准

混凝土材料强度检测标准一、前言混凝土是一种常用的建筑材料，其强度是衡量其质量的重要指标之一。

因此，在建筑工程中进行混凝土强度检测是非常必要的。

本文将详细介绍混凝土材料强度检测标准，包括相关的国家标准和行业规范。

通过本文的学习，读者可以了解混凝土强度检测的基本知识和标准要求，从而更好地进行混凝土强度检测工作。

二、混凝土材料强度检测标准概述混凝土的强度是指混凝土在受力作用下所能承受的最大应力。

混凝土的强度检测是建筑工程中非常重要的一个环节，其结果直接影响到工程质量和安全。

因此，混凝土强度检测需要按照一定的标准进行，以确保检测结果的准确性和可靠性。

目前，国内外对混凝土强度检测的标准有很多，其中包括国家标准、行业规范和国际标准等，下面将逐一介绍。

三、国家标准1. GB/T 50080-2016《混凝土结构设计规范》GB/T 50080-2016《混凝土结构设计规范》是我国目前最新的混凝土结构设计规范，其中包括了混凝土强度检测的相关内容。

该标准规定了混凝土强度检测的试验方法、检测设备和检测结果的评定等方面的要求。

2. GB/T 50081-2002《混凝土强度检验标准及其修订》GB/T 50081-2002《混凝土强度检验标准及其修订》是我国混凝土强度检测的基本标准，该标准规定了混凝土强度检测的试验方法、检测设备和检测结果的评定等方面的要求。

该标准适用于混凝土强度检测的所有阶段，包括施工前、施工中和施工后的检测。

3. GB/T 50107-2010《混凝土强度检测规程》GB/T 50107-2010《混凝土强度检测规程》是我国混凝土强度检测的具体规程，该标准规定了混凝土强度检测的试验方法、检测设备和检测结果的评定等方面的要求，并对混凝土强度检测的质量控制和质量保证进行了详细的规定。

四、行业规范1. JGJ/T 70-2009《混凝土强度检验规程》JGJ/T 70-2009《混凝土强度检验规程》是中国建筑行业标准化技术委员会发布的混凝土强度检测规范，该规范主要针对混凝土强度检测进行了详细的规定，包括试验方法、检测设备和检测结果的评定等方面的要求，并对检测质量的控制和保证进行了详细的规定。

uhpc检测标准

uhpc检测标准超高性能计算（UHPC）是一种新型的混凝土材料，具有高强度、高耐久性和优异的工作性能。

为了确保UHPC的质量，需要进行一系列的质量检测。

本文将介绍UHPC的检测标准和相关参考内容，以帮助读者更好地了解UHPC的检测方法和要求。

1. 抗压强度测试抗压强度是评价混凝土材料质量的重要指标之一，也是UHPC 的核心性能指标。

常见的UHPC抗压强度测试标准包括GB/T 50081-2002《混凝土力学性能试验方法标准》和ASTMC39/C39M-18a《Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens》。

此外，还可以参考国际放射性核素标准组织（IRSN）的技术规范T 201-07《Ultra high performance concrete for prestressed applications》，其中有关UHPC抗压强度测试的要求和方法。

2. 抗拉强度测试与抗压强度类似，抗拉强度是评价混凝土材料性能的重要指标之一。

通常采用拉伸试验测定混凝土的抗拉强度。

常用的UHPC抗拉强度测试标准包括GB/T 50081-2002和ASTMC496/C496M-17a《Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens》。

此外，还可以参考法国规范NF EN 12390-6:2020《Testing hardened concrete Part 6: Tensile splitting strength of test specimens》。

3. 自流平性测试UHPC具有良好的自流平性能，可以流动到较小的空隙中，并通过自重充实。

自流平性测试可以通过测量混凝土物料在倾斜平面上的流动性能来评估。

ASTM - C39-C39M - Standard Test Methods for Compressive Strength of Cylindrical Concrete Specimens

N OTE1—The testing laboratory performing this test method should be evaluated in accordance with Practice C1077.5.Apparatus5.1Testing Machine—The testing machine shall be of a type having sufficient capacity and capable of providing the rates of loading prescribed in7.5.5.1.1Veriﬁcation of calibration of the testing machines in accordance with Practices E4is required under the following conditions:5.1.1.1After an elapsed interval since the previous veriﬁ-cation of18months maximum,but preferably after an interval of12months,5.1.1.2On original installation or relocation of the machine, 5.1.1.3Immediately after making repairs or adjustments that affect the operation of the force applying system of the machine or the values displayed on the load indicating system, except for zero adjustments that compensate for the mass of bearing blocks,or specimen,or both,or5.1.1.4Whenever there is reason to doubt the accuracy of the results,without regard to the time interval since the last veriﬁcation.5.1.2Design—The design of the machine must include the following features:5.1.2.1The machine must be power operated and must apply the load continuously rather than intermittently,and without shock.If it has only one loading rate(meeting the requirements of7.5),it must be provided with a supplemental means for loading at a rate suitable for veriﬁcation.This supplemental means of loading may be power or hand oper-ated.N OTE2—High-strength concrete cylinders rupture more intensely than normal strength cylinders.As a safety precaution,it is recommended that the testing machines should be equipped with protective fragment guards.5.1.2.2The space provided for test specimens shall be large enough to accommodate,in a readable position,an elastic calibration device which is of sufficient capacity to cover the potential loading range of the testing machine and which complies with the requirements of Practice E74.N OTE3—The types of elastic calibration devices most generally avail-able and most commonly used for this purpose are the circular proving ring or load cell.5.1.3Accuracy—The accuracy of the testing machine shall be in accordance with the following provisions:5.1.3.1The percentage of error for the loads within the proposed range of use of the testing machine shall not exceed 61.0%of the indicated load.5.1.3.2The accuracy of the testing machine shall be veriﬁed by applyingﬁve test loads in four approximately equal increments in ascending order.The difference between any two successive test loads shall not exceed one third of the differ-ence between the maximum and minimum test loads.5.1.3.3The test load as indicated by the testing machine and the applied load computed from the readings of the veriﬁcation device shall be recorded at each test point.Calculate the error, E,and the percentage of error,E p,for each point from these data as follows:E5A2B(1)E p5100~A2B!/Bwhere:A5load,lbf[kN]indicated by the machine being veriﬁed, andB5applied load,lbf[kN]as determined by the calibrating device.5.1.3.4The report on the veriﬁcation of a testing machine shall state within what loading range it was found to conform to speciﬁcation requirements rather than reporting a blanket acceptance or rejection.In no case shall the loading range be stated as including loads below the value which is100times the smallest change of load estimable on the load-indicating mechanism of the testing machine or loads within that portion of the range below10%of the maximum range capacity. 5.1.3.5In no case shall the loading range be stated as including loads outside the range of loads applied during the veriﬁcation test.5.1.3.6The indicated load of a testing machine shall not be corrected either by calculation or by the use of a calibration diagram to obtain values within the required permissible variation.5.2The testing machine shall be equipped with two steel bearing blocks with hardened faces(Note4),one of which is a spherically seated block that will bear on the upper surface of the specimen,and the other a solid block on which the specimen shall rest.Bearing faces of the blocks shall have a minimum dimension at least3%greater than the diameter of the specimen to be tested.Except for the concentric circles described below,the bearing faces shall not depart from a plane by more than0.001in.[0.02mm]in any6in.[150mm]of blocks6in.[150mm]in diameter or larger,or by more than 0.001in.[0.02mm]in the diameter of any smaller block;and new blocks shall be manufactured within one half of this tolerance.When the diameter of the bearing face of the spherically seated block exceeds the diameter of the specimen by more than0.5in.[13mm],concentric circles not more than 0.03in.[0.8mm]deep and not more than0.04in.[1mm]wide shall be inscribed to facilitate proper centering.N OTE4—It is desirable that the bearing faces of blocks used for compression testing of concrete have a Rockwell hardness of not less than 55HRC.5.2.1Bottom bearing blocks shall conform to the following requirements:5.2.1.1The bottom bearing block is speciﬁed for the pur-pose of providing a readily machinable surface for mainte-nance of the speciﬁed surface conditions(Note5).The top and bottom surfaces shall be parallel to each other.If the testing machine is so designed that the platen itself is readily main-tained in the speciﬁed surface condition,a bottom block is not required.Its least horizontal dimension shall be at least3% greater than the diameter of the specimen to be tested. Concentric circles as described in5.2are optional on the bottom block.N OTE5—The block may be fastened to the platen of the testing machine.5.2.1.2Final centering must be made with reference to the upper spherical block.When the lower bearing block is usedtoassist in centering the specimen,the center of the concentricrings,when provided,or the center of the block itself must bedirectly below the center of the spherical head.Provision shallbe made on the platen of the machine to assure such a position.5.2.1.3The bottom bearing block shall be at least 1in.[25mm]thick when new,and at least 0.9in.[22.5mm]thick afterany resurfacing operations.5.2.2The spherically seated bearing block shall conform tothe following requirements:5.2.2.1The maximum diameter of the bearing face of thesuspended spherically seated block shall not exceed the valuesgiven below:Diameter of Maximum DiameterTest Specimens,of Bearing Face,in.[mm]in.[mm]2[50]4[105]3[75]5[130]4[100] 6.5[165]6[150]10[255]8[200]11[280]N OTE 6—Square bearing faces are permissible,provided the diameterof the largest possible inscribed circle does not exceed the above diameter.5.2.2.2The center of the sphere shall coincide with thesurface of the bearing face within a tolerance of 65%of theradius of the sphere.The diameter of the sphere shall be at least75%of the diameter of the specimen to be tested.5.2.2.3The ball and the socket must be so designed by themanufacturer that the steel in the contact area does notpermanently deform under repeated use,with loads up to12000psi [85MPa]on the test specimen.N OTE 7—The preferred contact area is in the form of a ring (describedas preferred“bearing”area)as shown on Fig.1.5.2.2.4The curved surfaces of the socket and of the spheri-cal portion shall be kept clean and shall be lubricated with apetroleum-type oil such as conventional motor oil,not with apressure type grease.After contacting the specimen and appli-cation of small initial load,further tilting of the sphericallyseated block is not intended and is undesirable.5.2.2.5If the radius of the sphere is smaller than the radius of the largest specimen to be tested,the portion of the bearing face extending beyond the sphere shall have a thickness not less than the difference between the radius of the sphere and radius of the specimen.The least dimension of the bearing face shall be at least as great as the diameter of the sphere (see Fig.1).5.2.2.6The movable portion of the bearing block shall be held closely in the spherical seat,but the design shall be such that the bearing face can be rotated freely and tilted at least 4°in any direction.5.3Load Indication :5.3.1If the load of a compression machine used in concrete testing is registered on a dial,the dial shall be provided with a graduated scale that is readable to at least the nearest 0.1%of the full scale load (Note 8).The dial shall be readable within 1%of the indicated load at any given load level within the loading range.In no case shall the loading range of a dial be considered to include loads below the value that is 100times the smallest change of load that can be read on the scale.The scale shall be provided with a graduation line equal to zero and so numbered.The dial pointer shall be of sufficient length to reach the graduation marks;the width of the end of the pointer shall not exceed the clear distance between the smallest graduations.Each dial shall be equipped with a zero adjust-ment located outside the dialcase and easily accessible from the front of the machine while observing the zero mark and dial pointer.Each dial shall be equipped with a suitable device that at all times until reset,will indicate to within 1%accuracy the maximum load applied to the specimen.N OTE 8—Readability is considered to be 0.02in.[0.5mm]along the arc described by the end of the pointer.Also,one half of a scale interval is readable with reasonable certainty when the spacing on the load indicating mechanism is between 0.04in.[1mm]and 0.06in.[2mm].When the spacing is between 0.06and 0.12in.[2and 3mm],one third of a scale interval is readable with reasonable certainty.When the spacing is 0.12in.[3mm]or more,one fourth of a scale interval is readable with reasonable certainty.5.3.2If the testing machine load is indicated in digital form,the numerical display must be large enough to be easily read.The numerical increment must be equal to or less than 0.10%of the full scale load of a given loading range.In no case shall the veriﬁed loading range include loads less than the minimum numerical increment multiplied by 100.The accuracy of the indicated load must be within 1.0%for any value displayed within the veriﬁed loading range.Provision must be made for adjusting to indicate true zero at zero load.There shall be provided a maximum load indicator that at all times until reset will indicate within 1%system accuracy the maximum load applied to the specimen.6.Specimens 6.1Specimens shall not be tested if any individual diameter of a cylinder differs from any other diameter of the same cylinder by more than 2%.N OTE 9—This may occur when single use molds are damaged or deformed during shipment,when ﬂexible single use molds are deformed during molding or when a core drill deﬂects or shifts during drilling.6.2Neither end of compressive test specimens whentestedN OTE 1—Provision shall be made for holding the ball in the socket andfor holding the entire unit in the testing machine.FIG.1Schematic Sketch of a Typical Spherical BearingBlockshall depart from perpendicularity to the axis by more than0.5°(approximately equivalent to0.12in12in.[3in300mm]).The ends of compression test specimens that are not plane within 0.002in.[0.050mm]shall be sawed or ground to meet that tolerance,or capped in accordance with either Practice C617 or Practice C1231.The diameter used for calculating the cross-sectional area of the test specimen shall be determined to the nearest0.01in.[0.25mm]by averaging two diameters measured at right angles to each other at about midheight of the specimen.6.3The number of individual cylinders measured for deter-mination of average diameter may be reduced to one for each ten specimens or three specimens per day,whichever is greater, if all cylinders are known to have been made from a single lot of reusable or single-use molds which consistently produce specimens with average diameters within a range of0.02in.[0.5mm].When the average diameters do not fall within the range of0.02in.[0.5mm]or when the cylinders are not made from a single lot of molds,each cylinder tested must be measured and the value used in calculation of the unit compressive strength of that specimen.When the diameters are measured at the reduced frequency,the cross-sectional areas of all cylinders tested on that day shall be computed from the average of the diameters of the three or more cylinders representing the group tested that day.6.4The length shall be measured to the nearest0.05D when the length to diameter ratio is less than1.8,or more than2.2, or when the volume of the cylinder is determined from measured dimensions.7.Procedure7.1Compression tests of moist-cured specimens shall be made as soon as practicable after removal from moist storage.7.2Test specimens shall be kept moist by any convenient method during the period between removal from moist storage and testing.They shall be tested in the moist condition.7.3All test specimens for a given test age shall be broken within the permissible time tolerances prescribed as follows: Test Age Permissible Tolerance24h60.5h or2.1%3days2h or2.8%7days6h or3.6%28days20h or3.0%90days2days2.2%7.4Placing the Specimen—Place the plain(lower)bearing block,with its hardened face up,on the table or platen of the testing machine directly under the spherically seated(upper) bearing block.Wipe clean the bearing faces of the upper and lower bearing blocks and of the test specimen and place the test specimen on the lower bearing block.Carefully align the axis of the specimen with the center of thrust of the spherically seated block.7.4.1Zero Veriﬁcation and Block Seating—Prior to testing the specimen,verify that the load indicator is set to zero.In cases where the indicator is not properly set to zero,adjust the indicator(Note10).As the spherically seated block is brought to bear on the specimen,rotate its movable portion gently by hand so that uniform seating is obtained.N OTE10—The technique used to verify and adjust load indicator to zero will vary depending on the machine manufacturer.Consult your owner’s manual or compression machine calibrator for the proper tech-nique.7.5Rate of Loading—Apply the load continuously and without shock.7.5.1For testing machines of the screw type,the moving head shall travel at a rate of approximately0.05in.[1mm]/min when the machine is running idle.For hydraulically operated machines,the load shall be applied at a rate of movement (platen to crosshead measurement)corresponding to a loading rate on the specimen within the range of20to50psi/s[0.15to 0.35MPa/s].The designated rate of movement shall be maintained at least during the latter half of the anticipated loading phase of the testing cycle.7.5.2During the application of theﬁrst half of the antici-pated loading phase a higher rate of loading shall be permitted.7.5.3Make no adjustment in the rate of movement of the platen at any time while a specimen is yielding rapidly immediately before failure.7.6Apply the load until the specimen fails,and record the maximum load carried by the specimen during the test.Note the type of failure and the appearance of the concrete.8.Calculation8.1Calculate the compressive strength of the specimen by dividing the maximum load carried by the specimen during the test by the average cross-sectional area determined as de-scribed in Section6and express the result to the nearest10psi [0.1MPa].8.2If the specimen length to diameter ratio is less than1.8, correct the result obtained in8.1by multiplying by the appropriate correction factor shown in the following table: L/D: 1.75 1.50 1.25 1.00Factor:0.980.960.930.87(Note11)N OTE11—These correction factors apply to lightweight concrete weighing between100and120lb/ft3[1600and1920kg/m3]and to normal weight concrete.They are applicable to concrete dry or soaked at the time of loading.Values not given in the table shall be determined by interpolation.The correction factors are applicable for nominal concrete strengths from2000to6000psi[15to45MPa].9.Report9.1Report the following information:9.1.1Identiﬁcation number,9.1.2Diameter(and length,if outside the range of1.8D to 2.2D),in inches[millimetres],9.1.3Cross-sectional area,in square inches[square milli-metres],9.1.4Maximum load,in pounds-force[kilonewtons],9.1.5Compressive strength calculated to the nearest10psi [0.1MPa],9.1.6Type of fracture,if other than the usual cone(see Fig.2),9.1.7Defects in either specimen or caps,and,9.1.8Age of specimen.10.Precision and Bias10.1Precision—The single operator precision of tests of individual6by12in.[150by300mm]cylinders madefroma well-mixed sample of concrete is given for cylinders made ina laboratory environment and under normal ﬁeld conditions(see 10.1.1).Coefficient ofAcceptable Range of A Variation A2results 3results Single operatorLaboratory conditions2.37% 6.6%7.8%Field conditions2.87%8.0%9.5%A These numbers represent respectively the (1s)and (d2s)limits as describedin Practice C 670.10.1.1The values given are applicable to 6by 12in.[150by300mm]cylinders with compressive strength between 2000and 8000psi [15to 55MPa].They are derived from CCRLconcrete reference sample data for laboratory conditions and a collection of 1265test reports from 225commercial testing laboratories in 1978.5N OTE 12—Subcommittee C09.03will re-examine recent CCRL Con-crete Reference Sample Program data and ﬁeld test data to see if these values are representative of current practice and if they can be extended to cover a wider range of strengths and specimen sizes.10.2Bias —Since there is no accepted reference material,no statement on bias is being made.11.Keywords The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this ers of this standard are expressly advised that determination of the validity of any such patent rights,and the risk of infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ﬁve years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards,100Barr Harbor Drive,West Conshohocken,PA 19428.This standard is copyrighted by ASTM,100Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.Individual reprints (single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585(phone),610-832-9555(fax),or service@ (e-mail);or through the ASTM website ().5Research report RR:C09-1006is on ﬁle at ASTMHeadquarters.Cone(a)Cone and Split (b)Cone and Shear(c)Shear (d)Columnar (e)FIG.2Sketches of Types ofFracture。

ASTM室温压缩试样国际标准

Designation:E9–89a(Reapproved2000)Standard Test Methods ofCompression Testing of Metallic Materials at Room Temperature1This standard is issued under theﬁxed designation E9;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1These test methods cover the apparatus,specimens,and procedure for axial-load compression testing of metallic mate-rials at room temperature(Note1).For additional requirements pertaining to cemented carbides,see Annex A1.N OTE1—For compression tests at elevated temperatures,see Practice E209.1.2The values stated in inch-pound units are to be regarded as the standard.The metric equivalent values cited in the standard may be approximate.1.3This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1ASTM Standards:B557Test Methods for Tension Testing Wrought and Cast Aluminum-and Magnesium-Alloy Products2E4Practices for Force Veriﬁcation of Testing Machines3 E6Terminology Relating to Methods of Mechanical Test-ing3E83Practice for Veriﬁcation and Classiﬁcation of Exten-someter3E111Test Method for Young’s Modulus,Tangent Modulus, and Chord Modulus3E171Speciﬁcation for Standard Atmospheres for Condi-tioning and Testing Flexible Barrier Materials4E177Practice for Use of the Terms Precision and Bias in ASTM Test Methods5E209Practice for Compression Tests of Metallic Materials at Elevated Temperatures with Conventional or Rapid Heating Rates and Strain Rates3E251Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages33.Terminology3.1Deﬁnitions:The deﬁnitions of terms relating to com-pression testing and room temperature in Terminology E6and Speciﬁcation E171,respectively,shall apply to these test methods.3.2Deﬁnitions of Terms Speciﬁc to This Standard:3.2.1buckling—In addition to compressive failure by crushing of the material,compressive failure may occur by(1) elastic instability over the length of a column specimen due to nonaxiality of loading,(2)inelastic instability over the length of a column specimen,(3)a local instability,either elastic or inelastic,over a small portion of the gage length,or(4)a twisting or torsional failure in which cross sections rotate over each other about the longitudinal specimen axis.These types of failures are all termed buckling.3.2.2column—a compression member that is axially loaded and that may fail by buckling.3.2.3radius of gyration—the square root of the ratio of the moment of inertia of the cross section about the centroidal axis to the cross-sectional area:r5~I/A!1/2(1) where:r=radius of gyration,I=moment of inertia of the cross section about centroidal axis(for specimens without lateral support,the smallervalue of I is the critical value),andA=cross-sectional area.3.2.4critical stress—the axial uniform stress that causes a column to be on the verge of buckling.The critical load is calculated by multiplying the critical stress by the cross-section area.3.2.5buckling equations—If the buckling stress is less than or equal to the proportional limit of the material its value may be calculated using the Euler equation:1These test methods are under the jurisdiction of ASTM Committee E28onMechanical Testing and are the direct responsibility of Subcommittee E28.04onUniaxial Testing.Current edition approved March31,1989.Published May1989.Originallypublished as E9–st previous edition E9–89.2Annual Book of ASTM Standards,V ol02.02.3Annual Book of ASTM Standards,V ol03.01.4Annual Book of ASTM Standards,V ol15.09.5Annual Book of ASTM Standards,V ol14.02.1Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.S cr 5C p 2E /~L /r !2(2)If the buckling stress is greater than the proportional limit of the material its value may be calculated from the modiﬁed Euler equation:S cr 5C p 2E t /~L /r !2(3)where:S cr =critical buckling stress,E =Young’s modulus,E t =tangent modulus at the buckling stress,L =column length,and C =end-ﬁxity coefficient.Methods of calculating the critical stress using Eq 3are given in Ref (1).63.2.6end-ﬁxity coeffıcient —There are certain ideal speci-men end-ﬁxity conditions for which theory will deﬁne the value of the constant C (see Fig.1).These values are:Freely rotating ends (pinned or hinged)C =1(a )One end ﬁxed,the other free to rotate C =2(b )Both ends ﬁxed C =4(c )N OTE 2—For ﬂat-end specimens tested between ﬂat rigid anvils,it was shown in Ref (1)that a value of C =3.75is appropriate.3.2.7barreling —restricted deformation of the end regions of a test specimen under compressive load due to friction at the specimen end sections and the resulting nonuniform transverse deformation as shown schematically and in the photograph in Fig.2.Additional theoretical and experimental information on barreling as illustrated in Fig.2is given in Ref (2).4.Summary of Test Methods4.1The specimen is subjected to an increasing axial com-pressive load;both load and strain may be monitored either continuously or in ﬁnite increments,and the mechanical properties in compression determined.5.Signiﬁcance and Use5.1Signiﬁcance —The data obtained from a compression test may include the yield strength,the yield point,Young’s modulus,the stress-strain curve,and the compressive strength (see Terminology E 6).In the case of a material that does not fail in compression by a shattering fracture,compressive strength is a value that is dependent on total strain and specimen geometry.5.2Use —Compressive properties are of interest in the analyses of structures subject to compressive or bending loads or both and in the analyses of metal working and fabrication processes that involve large compressive deformation such as forging and rolling.For brittle or nonductile metals that fracture in tension at stresses below the yield strength,com-pression tests offer the possibility of extending the strain range of the stress-strain data.While the compression test is not complicated by necking as is the tension test for certain metallic materials,buckling and barreling (see Section 3)can complicate results and should be minimized.6.Apparatus6.1Testing Machines —Machines used for compression test-ing shall conform to the requirements of Practices E 4.For universal machines with a common test space,calibration shall be performed in compression.6.1.1The bearing surfaces of the heads of the testing machine shall be parallel at all times with 0.0002in./in.(m/m)unless an alignment device of the type described in 6.3is used.6.2Bearing Blocks :6.2.1Both ends of the compression specimen shall bear on blocks with surfaces ﬂat and parallel within 0.0002in./in.(m/m).Lack of initial parallelism can be overcome by the use of adjustable bearing blocks (Note 3).The blocks shall be made of,or faced with,hard material.Current laboratory practice suggests the use of tungsten carbide when testing steel and hardened steel blocks (55HRC or greater)and when testing nonferrous materials such as aluminum,copper,etc.The specimen must be carefully centered with respect to the testing machine heads or the subpress if used (see 6.3,Alignment Device/Subpress).N OTE 3—It should be remembered that the object of an adjustable bearing block is to give the specimen as even a distribution of initial load as possible.An adjustable bearing block cannot be relied on to compensate for any tilting of the heads that may occur during the test.6.2.2The bearing faces of adjustable bearing blocks that contact the specimen shall be made parallel before the load is applied to the specimen.One type of adjustable bearing block that has proven satisfactory is illustrated in Fig.3.Another arrangement involving the use of a spherical-seated bearing block that has been found satisfactory for testing material other than in sheet form is shown in Fig.4.It is desirable that the spherical-seated bearing block be at the upper end of the test specimen (for specimens tested with the load axis vertical).The spherical surface of the block shall be deﬁned by a radius having its point of origin in the ﬂat surface that bears on the specimen.6.3Alignment Device/Subpress :6The boldface numbers in parentheses refer to the list of references at the end of thisstandard.FIG.1Diagrams Showing Fixity Conditions and ResultingBuckling ofDeformation6.3.1It is usually necessary to use an alignment device,unless the testing machine has been designed speciﬁcally foraxial alignment.The design of the device or subpress is largely dependent on the size and strength of the specimen.It must be designed so that the ram (or other moving parts)does not jam or tilt the device or the frame of the machine as a result of loading.The bearing blocks of the device shall have the same requirements for parallelism and ﬂatness as given in6.2.1.N OTE 1—A cylindrical specimen of AISI 4340steel (HRC =40)was compressed 57%(see upper diagram).The photo macrograph was made of a polished and etched cross section of the tested specimen.The highly distorted ﬂow lines are the result of friction between the specimen ends and the loading ﬁxture.Note the triangular regions of restricted deformation at the ends and the cross-shaped zone of severe shear.FIG.2Illustration ofBarrelingFIG.3Adjustable Bearing Block for CompressionTestingFIG.4Spherical-Seated BearingBlock6.3.2The primary requirements of all alignment devices are that the load is applied axially,uniformly,and with negligible “slip-stick”friction.An alignment device that has been found suitable is shown in Fig.5and described in Ref.(3).Other devices of the subpress type have also been used successfully.6.4Compression Testing Jigs—In testing thin specimens, such as sheet material,some means should be adopted to prevent the specimen from buckling during loading.This may be accomplished by using a jig containing sidesupport plates that bear against the wide sides of the specimen.The jig must afford a suitable combination of lateral-support pressure and spring constant to prevent buckling,but without interfering with axial deformation of the specimen.Although suitable combinations vary somewhat with variations in specimen material and thickness,testing temperatures,and accuracy of alignment,acceptable results can be obtained with rather wide ranges of lateral-support pressure and spring constant.Gener-ally,the higher the spring constant of the jig,the lower the lateral-support pressure that is required.Proper adjustments of these variables should be established during the qualiﬁcation of the equipment(see6.6).6.4.1It is not the intent of these methods to designate speciﬁc jigs for testing sheet materials,but merely to provide a few illustrations and references to jigs that have been used successfully,some of which are cited in Table1.Other jigs are acceptable provided they prevent buckling and pass the quali-ﬁcation test set forth pression jigs generally require that the specimen be lubricated on the supported sides to prevent extraneous friction forces from occurring at the support points.6.5Strain Measurements:6.5.1Mechanical or electromechanical devices used for measuring strain shall comply with the requirements for the applicable class described in Practice E83.The device shall be veriﬁed in compression.6.5.2Electrical-resistance strain gages(or other single-use devices)may be used provided the measuring system has been veriﬁed and found to be accurate to the degree speciﬁed in Practice E83.The characteristics of electrical resistance strain gages have been determined from Test Methods E251.6.6Qualiﬁcation of Test Apparatus—The complete compression-test apparatus,which consists of the testing ma-chine and when applicable,one or more of the following;the alignment device,the jig and the strain-measurement system, shall be qualiﬁed as follows:6.6.1Conduct tests to establish the elastic modulus orﬁve replicate specimens of2024-T3aluminum alloy sheet or 2024-T4aluminum alloy bar in accordance with Test Method E111.These qualiﬁcation specimens shall be machined from sheet or bar in the location speciﬁed in Test Methods B557. The thickness of the sheet or diameter of the bar may be machined to the desired thickness or diameter.It is essential that the extensometer be properly seated on the specimens when this test is performed.When the qualiﬁcation specimens each provide a modulus value of10.73106psi(73.8GPa) 65%,the apparatus qualiﬁes.6.6.2The qualiﬁcation procedure shall be performed using the thinnest rectangular specimen or smallest diameter round specimen to be tested in the apparatus.7.Test Specimens7.1Specimens in Solid Cylindrical Form—It is recom-mended that,where feasible,compression test specimens be in the form of solid circular cylinders.Three forms of solid cylindrical test specimens for metallic materials are recog-nized,and designated as short,medium-length,and long(Note 4).Suggested dimensions for solid compression test specimens for general use are given in Table2.N OTE4—Short specimens typically are used for compression tests of such materials as bearing metals,which in service are used in the form of thin plates to carry load perpendicular to the surface.Medium-length specimens typically are used for determining the general compressive strength properties of metallic materials.Long specimens are best adapted for determining the modulus of elasticity in compression of metallic materials.The specimen dimensions given in Table2have been usedsuccessfully.Specimens with a L/D(length/diameter ratio)of1.5or2.0are best adapted for determining the compressive strength of high-strengthmaterials.7.2Rectangular or Sheet-Type Specimens—Test specimensshall beﬂat and preferably of the full thickness of the material.Where lateral support is necessary,the width and length aredependent upon the dimensions of the jig used to support thespecimen.The length shall be sufficient to allow the specimento shorten the amount required to deﬁne the yield strength,oryield point,but not long enough to permit buckling in the FIG.5Example of Compression Testing Apparatusunsupported portion.Specimen dimensions and the various types of jigs are given in Table 1.7.3Preparation of Specimens —Lateral surfaces in the gage length shall not vary in diameter,width,or thickness by more than 1%or 0.002in.(0.05mm),whichever is less.(If a reduced section is used,this requirement applies only to the surface of the reduced section.)Also,the centerline of all lateral surfaces of the specimens shall be coaxial within 0.01in.(0.25mm).7.3.1Surface Finish —Machined surfaces of specimens shall have a surface ﬁnish of 63µin.(1.6µm)or better.Machined lateral surfaces to which lateral support is to be applied shall be ﬁnished to at least 40microinches (1.0µm)arithmetic average.7.3.2Flatness and Parallelism —The ends of a specimen shall be ﬂat and parallel within 0.0005in./in.(mm/mm)and perpendicular to the lateral surfaces to within 38of arc.In most cases this requirement necessitates the machining or grinding of the ends of the specimen.7.3.3Edges of Rectangular Specimens —A width of mate-rial equal to at least the thickness of the specimen shall be machined from all sheared or stamped edges in order to remove material whose properties may have been altered.(If a reducedsection is used,this requirement applies only to the edges of the reduced section.)Specimens shall be ﬁnished so that the surfaces are free of nicks,grooves,and burrs.7.4Gage Length Location —The ends of the gage length shall not be closer to the ends of the specimen or ends of the reduced section than one half of the width or diameter of the specimen.8.Procedure8.1Specimen Measurement —Measure the width and thick-ness,or thediameter of the specimen with a micrometer along the gage section.Specimen dimensions greater than 0.10in.(2.5mm)should be measured to the nearest 0.001in.(0.02mm),and those less than 0.10in.(2.5mm)should be determined to the nearest 1%of the dimension being mea-sured.Calculate the average cross-sectional area of the speci-men gage section.8.2Cleaning —Clean the ends of the specimen and ﬁxture bearing blocks with acetone or another suitable solvent to remove all traces of grease and oil.8.3Lubrication —Bearing surface friction can affect test results (see section 5.2and Fig.2).Friction has been success-fully reduced by lubricating the bearing surfaces with TFE-ﬂuorocarbon sheet,molybdenum disulﬁde,and other materials summarized in Ref.(3).8.4Specimen Installation —Place the specimen in the test ﬁxture and carefully align the specimen to the ﬁxture to ensure concentric loading.Also,check that the specimen loading/reaction surfaces mate with the respective surfaces of the ﬁxture.If the ﬁxture has side supports,the specimen sides should contact the support mechanism with the clamping pressure recommended by the ﬁxture manufacturer,or as determined during the ﬁxture veriﬁcation tests.If screws are used to adjust side support pressure,it is recommended that a torque wrench be utilized to ensure consistent pressure.8.4.1Transducer Attachment —If required,attach the exten-someter or other transducers,or both,to the specimen gage section.The gage length must be at least one half or preferably one diameter away from the ends of the specimen (see 7.4).8.5Load-Strain Range Selection —Set the load range of the testing machine so the maximum expected load is at least oneTABLE 1Representative Compression Jigs and Specimen Dimensions for Testing of Thin Sheet AType of JigRef ThicknessWidthLengthGage Length in.mmin.mmin.mmin.mmMontgomery-Templin:(4and 5)General use0.016and over 0.40and over 0.62516.0 2.6467.0125Magnesium alloys 0.016and over 0.40and over 0.750B 20.0 2.6467.0125NACA (Kotanchik et al)(6)0.020and over 0.50and over 0.5313.6 2.5364.5125Moore-McDonald (7)0.032and over 0.80and over 0.75C 20.0 2.6467.0125LaTour-Wolford (8)0.010to 0.0200.25to 0.500.5012.5 1.9549.51250.020and over 0.50and over 0.5012.5 2.0051.0125Miller(9-11)0.006to 0.0100.15to 0.250.4812.2 2.2256.51250.010to 0.0200.25to 0.500.5012.5 2.2356.51250.020and over 0.50and over 0.5012.5 2.2557.0125Sandorff-Dillon:(12)General use0.010and over 0.25and over 0.5012.5 4.12104.5250High-strength steel0.010and over0.25and over0.5012.53.1078.5250A See Ref.(13)for additional jigs and specimen dimensions.BReduced to 0.625in.(16.0mm)for 1.25in.(30mm)at the mid-length.CReduced to 0.650in.(16.5mm)for 1.25in.(30mm)at the mid-length.TABLE 2Suggested Solid Cylindrical Specimens AN OTE 1—Metric units represent converted specimen dimensions close to,but not the exact conversion from inch-pound units.Speci-mens DiameterLengthApprox L/D Ra-tio in.mm in.mm Short1.1260.010.5060.0130.060.213.060.2 1.0060.051.0060.0525.61.25.61.0.82.0Medium0.5060.0113.060.2 1.5060.0538.61. 3.00.8060.0120.060.2 2.3860.1260.63. 3.01.0060.0125.060.2 3.0060.1275.63. 3.01.1260.0130.060.23.3860.1285.63.3.0Long0.8060.011.2560.0120.060.232.060.2 6.3860.1212.50min 160.63.320min8.010.0AOther length-to-diameter ratios may be used when the test is for compressive yield strength.third of the range selected.Select the strain or deﬂection scale so that the elastic portion of the load-versus-strain or load-versus-deﬂection plot on the autographic record,is between 30°and60°to the load axis.8.6Strain Measurements—Devices used for measuring strain shall comply with the requirements for the applicable class of extensometer described in Practice E83.Electrical strain gages,if used,shall have performance characteristics established by the manufacturer in accordance with TestMethods E251.8.7Testing Speed—For testing machines equipped with strain-rate pacers,set the machine to strain the specimen at a rate of0.005in./in.·min(m/m·min).For machine with load control or with crosshead speed control,set the rate so the specimen is tested at a rate equivalent to0.005in./in.·min (m/m·min)strain-rate in the elastic portion.A rate of0.003 in./in.·min(m/m·min)can be used if the material is strain-rate sensitive.8.7.1For machines without strain-pacing equipment or automatic feedback control systems,maintain a constant cross-head speed to obtain the desired average strain-rate from the start of loading to the end point of the test.The average strain-rate can be determined from a time-interval-marked load-strain record,a time-strain graph,or from the time of the start of loading to the end point of test as determined from a time-measuring device(for example,stopwatch).It should be recognized that the use of machines with constant rate of crosshead movement does not ensure constant strain rate throughout a test.8.7.2It should also be noted that the free-running crosshead speed may differ from the speed under load for the same machine setting,and that specimens of different stiffnesses may also result in different rates,depending upon the test machine andﬁxturing.Whatever the method,the specimen should be tested at a uniform rate without reversals or sudden changes.The test rate must also be such that the rate of load change on the specimen being tested,will be within the dynamic response of the measuring systems.This is of particu-lar importance when testing short specimens of high-modulus materials.8.8Test Conduct—After the specimen has been installed and aligned,and the strain-or deﬂection-measuring transducer installed,activate the recording device(s)and initiate the test at the prescribed rate.Continue the test at a uniform rate until the test has been completed as stated below.8.8.1Ductile Materials—For ductile materials,the yield strength or yield point,and sometimes the strength at a strain greater than the yield strain,can be determined.The conduct of the test to determine either the onset of yielding or the compressive strength or both is the same.Materials without sharp-kneed stress-strain diagrams will require that the strain or deﬂection at yield be initially estimated,and the specimen tested sufficiently beyond the initial estimation to be sure the yield stress can be determined after the test(see9.3).For materials,exhibiting a sharp-kneed stress-strain curve or a distinctive yield point,the test can be terminated either after a sharp knee or after the drop in load is observed.8.8.2Brittle Materials—Brittle materials that fail by crush-ing or shattering may be tested to failure.8.9Number of Specimens—Specimen blanks shall be taken from bulk materials according to applicable speciﬁcations.The number of specimens to be tested should be sufficient to meet the requirements as determined by the test purpose,or as agreed upon between the parties involved.The larger the sample,the greater the conﬁdence that the sample represents the total population.In most cases,betweenﬁve and ten specimens should be sufficient to determine the compressive properties of a sample with reasonable conﬁdence.8.10Precautions:8.10.1Buckling—In compression tests of relatively long, slender specimens that are not laterally supported,the speci-mens may buckle elastically andﬂy from the test setup.A protective device should be in place to prevent injury.8.10.2Shattering Fracture—Some materials may fail in a shattering manner which will cause pieces to be expelled as shrapnel.A protective device should be in place to prevent injury.9.Calculations9.1Determine the properties of the material from the dimensions of the specimen and the stress-strain diagram as described in the following paragraphs.For testing machines that record load units instead of stress,convert the load-versus-strain diagram to units of stress by dividing the load by the original cross-sectional area of the specimen gage section. 9.2Modulus of Elasticity—Calculate the modulus of elas-ticity as speciﬁed in Test Method E111.If the elastic modulus is the prime quantity to be determined,the procedure given in Test Method E111must be followed.Again,the calculation of the modulus shall be according to Section7of Test Method E111.9.3Yield Strength—To determine the yield strength by the offset method it is necessary to secure data(autographic or numerical)from which a stress-strain diagram may be drawn. Then on the stress-strain diagram(Fig.6)lay off Om equal to the speciﬁed value of offset(conventional offset is0.002in./in. (m/m)),draw mn parallel to OA,and thus locate r,the intersection of mn with the stress-strain diagram.The stress corresponding to the point r is the yield strength for the speciﬁed offset.9.3.1In reporting values of yield strength obtained by these methods,the speciﬁed value of offset used should be stated in parentheses after the term yield strength.Thus:Yield strength~offset50.2%!552.0ksi~359MP a!(4) 9.3.2In using these methods,a Class B-2extensometer,as described in Practice E83,is sufficiently sensitive for most materials.N OTE5—Automatic devices are available that determine offset yield strength without plotting a stress-strain curve.Such devices may be used if their accuracy has been demonstrated to be satisfactory.N OTE6—If the load drops before the speciﬁed offset is reached, technically the material does not have a yield strength(for that offset).In this case,the stress at the maximum load before the speciﬁed offset is reached may be reported instead of the yield strength and shall be designated as the yield point.9.4Yield Point —Materials that exhibit a sharp-kneed stress-strain diagram may exhibit a distinct drop in stress with increasing strain.The yield point is the maximum stress attained just prior to the sudden drop in stress.For testing machines without strain-or deﬂection-recording capabilities,the yield point can be determined by noting the load at which the load dial indicator needle suddenly drops with the testing machine running at a steady rate.9.5Compressive Strength —For a material that fails in compression by crushing or fracturing,the compressive strength is the maximum stress at or before fracture,as determined by dividing the maximum load by the cross-sectional area.For ductile materials,compressive strength may be determined from the stress-strain diagram at a speciﬁed total strain.The strain at which this stress was determined must be speciﬁed.10.Report10.1Include the following information in the test report:10.1.1Specimen Material —Describe the specimen mate-rial,alloy,heat treatment,mill batch number,grain direction,etc.,as applicable.10.1.2Specimen Conﬁguration —Include a sketch of the specimen conﬁguration or reference to the specimen drawing.10.1.3Specimen Dimensions —State the actual measured dimensions for each specimen.10.1.4Test Fixture and Lubricant —Describe the test ﬁxture or refer to ﬁxture drawings,specifying lubricant used if any.10.1.5Testing Machine —Include the make,model,and load range of testing machine.10.1.6Speed of Testing —Record the test rate and mode of control.10.1.7Stress-Strain Diagram —Include,if possible,the stress-strain diagram with scales,specimen number,test data,rate,and other pertinent information.10.1.8Modulus of Elasticity —Report the modulus of elas-ticity when required,as determined according to 9.2.10.1.9Yield Strength —Report the yield stress or yield point when required and the method of determination,as calculated in 9.3and 9.4.10.1.10Compressive Strength —Report the compressive strength for material exhibiting brittle failure.A compressive strength at a speciﬁed total strain may be reported for ductile materials.If so,report the strain at which the compressive stress was determined.10.1.11Type of Failure —When applicable,describe the type of specimen failure.10.1.12Precision and Bias —State the precision and accu-racy of the data reported as applicable in a manner consistent with Practice E 177.10.1.13Anomalies —State any anomalies that occurred dur-ing the test that may have had an effect on the test results.10.2For commercial acceptance testing the following sec-tions of 10.1are considered sufficient:10.1.1and 10.1.2,and 10.1.9and 10.1.11.11.Precision and Bias11.1Precision —The following parameters are reported to impact upon the precision of the test methods:specimen buckling,loading surface friction,specimen barreling,and specimen size.The subcommittee is in the process of quanti-fying these effects.11.2Bias —There are no available reference standards for destructive type tests such as compression.Therefore,the bias of this test method is an unknown.12.Keywords12.1axial compression;barreling;bearing blocks;buckling;compressometer;sheet compression jig;stress-strain diagram;sub-press;testingmachineFIG.6Stress-Strain Diagram for Determination of Yield Strengthby the OffsetMethod。

ASTM D695 塑料压缩

Designation:D695–02An American National Standard Standard Test Method forCompressive Properties of Rigid Plastics1This standard is issued under theﬁxed designation D695;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1This test method covers the determination of the me-chanical properties of unreinforced and reinforced rigid plas-tics,including high-modulus composites,when loaded in compression at relatively low uniform rates of straining or loading.Test specimens of standard shape are employed.1.2The values stated in SI units are to be regarded as the standard.The values in parentheses are for information only. N OTE1—For compressive properties of resin-matrix composites rein-forced with oriented continuous,discontinuous,or cross-ply reinforce-ments,tests may be made in accordance with Test Method D3410. 1.3This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A speciﬁc precau-tionary statement is given in Note11.N OTE2—This test method is technically equivalent to ISO604.2.Referenced Documents2.1ASTM Standards:D618Practice for Conditioning Plastics for Testing2D638Test Method for Tensile Properties of Plastics2D3410Test Method for Compressive Properties of Poly-mer Matrix Composite Materials with Unsupported Gage Section by Shear Loading3D4000Classiﬁcation System for Specifying Plastic Mate-rials4D4066Speciﬁcation for Nylon Injection and Extrusion Materials4E4Practices for Force Veriﬁcation of Testing Machines5 E83Practice for Veriﬁcation and Classiﬁcation of Exten-someters5E691Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method63.Terminology3.1Deﬁnitions:3.1.1compressive deformation—the decrease in length pro-duced in the gage length of the test specimen by a compressive load.It is expressed in units of length.3.1.2compressive strain—the ratio of compressive defor-mation to the gage length of the test specimen,that is,the change in length per unit of original length along the longitu-dinal axis.It is expressed as a dimensionless ratio.3.1.3compressive strength—the maximum compressive stress(nominal)carried by a test specimen during a compres-sion test.It may or may not be the compressive stress (nominal)carried by the specimen at the moment of rupture.3.1.4compressive strength at failure(nominal)—the com-pressive stress(nominal)sustained at the moment of failure of the test specimen if shattering occurs.3.1.5compressive stress(nominal)—the compressive load per unit area of minimum original cross section within the gage boundaries,carried by the test specimen at any given moment. It is expressed in force per unit area.3.1.5.1Discussion—The expression of compressive proper-ties in terms of the minimum original cross section is almost universally used.Under some circumstances the compressive properties have been expressed per unit of prevailing cross section.These properties are called“true”compressive prop-erties.3.1.6compressive stress-strain diagram—a diagram in which values of compressive stress are plotted as ordinates against corresponding values of compressive strain as abscis-sas.3.1.7compressive yield point—theﬁrst point on the stress-strain diagram at which an increase in strain occurs without an increase in stress.3.1.8compressive yield strength—normally the stress at the yield point(see also section3.113.1.11).3.1.9crushing load—the maximum compressive force ap-plied to the specimen,under the conditions of testing,that produces a designated degree of failure.3.1.10modulus of elasticity—the ratio of stress(nominal)to1This test method is under the jurisdiction of ASTM Committee D20on Plasticsand is the direct responsibility of Subcommittee D20.10on Mechanical Properties.Current edition approved April10,2002.Published June2002.Originallypublished as D695–st previous edition D695–96.2Annual Book of ASTM Standards,V ol08.01.3Annual Book of ASTM Standards,V ol15.03.4Annual Book of ASTM Standards,V ol08.02.5Annual Book of ASTM Standards,V ol03.01.6Annual Book of ASTM Standards,V ol14.02.1Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.corresponding strain below the proportional limit of a material. It is expressed in force per unit area based on the average initial cross-sectional area.3.1.11offset compressive yield strength—the stress at which the stress-strain curve departs from linearity by a speciﬁed percent of deformation(offset).3.1.12percent compressive strain—the compressive defor-mation of a test specimen expressed as a percent of the original gage length.3.1.13proportional limit—the greatest stress that a material is capable of sustaining without any deviation from propor-tionality of stress to strain(Hooke’s law).It is expressed in force per unit area.3.1.14slenderness ratio—the ratio of the length of a col-umn of uniform cross section to its least radius of gyration.For specimens of uniform rectangular cross section,the radius of gyration is0.289times the smaller cross-sectional dimension. For specimens of uniform circular cross section,the radius of gyration is0.250times the diameter.4.Signiﬁcance and Use4.1Compression tests provide information about the com-pressive properties of plastics when employed under conditions approximating those under which the tests are made.For many materials,there may be a speciﬁcation that requires the use of this test method,but with some procedural modiﬁcations that take precedence when adhering to the speciﬁcation.Therefore, it is advisable to refer to that material speciﬁcation before using this test method.Table1in Classiﬁcation D4000lists the ASTM materials standards that currently exist.4.2Compressive properties include modulus of elasticity, yield stress,deformation beyond yield point,and compressive strength(unless the material merelyﬂattens but does not fracture).Materials possessing a low order of ductility may not exhibit a yield point.In the case of a material that fails in compression by a shattering fracture,the compressive strength has a very deﬁnite value.In the case of a material that does not fail in compression by a shattering fracture,the compressive strength is an arbitrary one depending upon the degree of distortion that is regarded as indicating complete failure of the material.Many plastic materials will continue to deform in compression until aﬂat disk is produced,the compressive stress(nominal)rising steadily in the process,without any well-deﬁned fracture pressive strength can have no real meaning in such cases.4.3Compression tests provide a standard method of obtain-ing data for research and development,quality control,accep-tance or rejection under speciﬁcations,and special purposes. The tests cannot be considered signiﬁcant for engineering design in applications differing widely from the load-time scale of the standard test.Such applications require additional tests such as impact,creep,and fatigue.4.4Before proceeding with this test method,reference should be made to the speciﬁcation of the material being tested. Any test specimen preparation,conditioning,dimensions,and testing parameters covered in the materials speciﬁcation shall take precedence over those mentioned in this test method.If there is no material speciﬁcation,then the default conditions apply.5.Apparatus5.1Testing Machine—Any suitable testing machine capable of control of constant-rate-of-crosshead movement and com-prising essentially the following:5.1.1Drive Mechanism—A drive mechanism for imparting to the cross-head movable member,a uniform,controlled velocity with respect to the base(ﬁxed member),with this velocity to be regulated as speciﬁed in Section9.5.1.2Load Indicator—A load-indicating mechanism ca-pable of showing the total compressive load carried by the test specimen.The mechanism shall be essentially free from inertia-lag at the speciﬁed rate of testing and shall indicate the load with an accuracy of61%of the maximum indicated value of the test(load).The accuracy of the testing machine shall be veriﬁed at least once a year in accordance with Practices E4.5.2Compressometer—A suitable instrument for determin-ing the distance between twoﬁxed points on the test specimen at any time during the test.It is desirable that this instrument automatically record this distance(or any change in it)as a function of the load on the test specimen.The instrument shall be essentially free of inertia-lag at the speciﬁed rate of loading and shall conform to the requirements for a Class B-2 extensometer as deﬁned in Practice E83.N OTE3—The requirements for extensometers cited herein apply to compressometers as well.5.3Compression Tool—A compression tool for applying the load to the test specimen.This tool shall be so constructed that loading is axial within1:1000and applied through surfaces that areﬂat within0.025mm(0.001in.)and parallel to each other in a plane normal to the vertical loading axis.Examples of suitable compression tools are shown in Fig.1and Fig.2. 5.4Supporting Jig—A supporting jig for thin specimens is shown in Fig.3and Fig.4.5.5Micrometers—Suitable micrometers,reading to0.01 mm or0.001in.for measuring the width,thickness,and length of the specimens.6.Test Specimens6.1Unless otherwise speciﬁed in the materials speciﬁca-tions,the specimens described in6.2and6.7shall be used. These specimens may be prepared by machining operations from materials in sheet,plate,rod,tube,or similar form,or they may be prepared by compression or injection molding of the material to be tested.All machining operations shall be done carefully so that smooth surfaces result.Great care shall be taken in machining the ends so that smooth,ﬂat parallel surfaces and sharp,clean edges,to within0.025mm(0.001in.) perpendicular to the long axis of the specimen,result.6.2The standard test specimen,except as indicated in 6.3-6.7,shall be in the form of a right cylinder or prism whose length is twice its principal width or diameter.Preferred specimen sizes are12.7by12.7by25.4mm(0.50by0.50by 1in.)(prism),or12.7mm in diameter by25.4mm(cylinder). Where elastic modulus and offset yield-stress data are desired, the test specimen shall be of such dimensions that the slender-ness ratio is in the range from11to16:1.In this case,preferred specimen sizes are12.7by12.7by50.8mm(0.50by0.50by2in.)(prism),or 12.7mm in diameter by 50.8mm (cylinder).6.3For rod material,the test specimen shall have a diameter equal to the diameter of the rod and a sufficient length to allow a specimen slenderness ratio in the range from 11to 16:1.6.4When testing tubes,the test specimen shall have a diameter equal to the diameter of the tube and a length of 25.4mm (1in.)(Note 4).For crushing-load determinations (at right angles to the longitudinal axis),the specimen size shall be the same,with the diameter becoming the height.N OTE 4—This specimen can be used for tubes with a wall thickness of1mm (0.039in.)or over,to inside diameters of 6.4mm (0.25in.)or over,and to outside diameters of 50.8mm (2.0in.)or less.6.5Where it is desired to test conventional high-pressure laminates in the form of sheets,the thickness of which is less than 25.4mm (1in.),a pile-up of sheets 25.4mm square,with a sufficient number of layers to produce a height of at least 25.4mm,may be used.6.6When testing material that may be suspected of anisot-ropy,duplicate sets of test specimens shall be prepared having their long axis respectively parallel with and normal to the suspected direction of anisotropy.6.7Reinforced Plastics,Including High-Strength Compos-ites and High-Strength Composites and Highly Orthotropic Laminates —The following specimens shall be used for rein-forced materials,or for other materials when necessary to comply with the slenderness ratio requirements or to permit attachment of a deformation-measuring device.6.7.1For materials 3.2mm (1⁄8in.)and over in thickness,a specimen shall consist of a prism having a cross section of 12.7mm (1⁄2in.)by the thickness of the material and a length such that the slenderness ratio is in the range from 11to 16:1(Note 5).6.7.2For materials under 3.2mm (1⁄8in.)thick,or where elastic modulus testing is required and the slenderness ratio does not provide for enough length for attachment of a compressometer or similar device,a specimen conforming to that shown in Fig.5shall be used.The supporting jig shown in Fig.3and Fig.4shall be used to support the specimen during testing (Note 6).N OTE 5—If failure for materials in the thickness range of 3.2mm (1⁄8in.)is by delamination rather than by the desirable shear plane fracture,the material may be tested in accordance with 6.7.2.N OTE 6—Round-robin tests have established that relatively satisfactory measurements of modulus of elasticity may be obtained by applying a compressometer to the edges of the jig-supported specimen.6.8When testing syntactic foam,the standard test specimen shall be in the form of a right cylinder 25.4mm (1in.)in diameter by 50.8mm (2in.)in length.7.Conditioning7.1Conditioning —Condition the test specimens at 2362°C (73.463.6°F)and 5065%relative humidity for not less than 40h prior to test in accordance with Procedure AofN OTE 1—Devices similar to the one illustrated have been successfully used in a number of different laboratories.Details of the device developed at the National Institute for Standards and Technology are given in the paper by Aitchinson,C.S.,and Miller,J.A.,“A Subpress for Compressive Tests,”National Advisory Committee for Aeronautics,Technical Note No.912,1943.FIG.1Subpress for CompressionTestsFIG.2CompressionToolFIG.3Support Jig for ThisSpecimenPractice D 618unless otherwise speciﬁed by contract or the relevant ASTM material speciﬁcation.Reference pre-test con-ditioning,to settle disagreements,shall apply tolerances of 61°C (1.8°F)and 62%relative humidity.7.2Test Conditions —Conduct the tests at 2362°C (73.463.6°F)and 5065%relative humidity unless otherwise speciﬁed by contract or the relevant ASTM material speciﬁca-tion.Reference testing conditions,to settle disagreements,shall apply tolerances of 61°C (1.8°F)and 62%relative humidity.8.Number of Test Specimens8.1At least ﬁve specimens shall be tested for each sample in the case of isotropic materials.8.2Ten specimens,ﬁve normal to and ﬁve parallel with the principal axis of anisotropy,shall be tested for each sample in the case of anisotropic materials.8.3Specimens that break at some obvious fortuitous ﬂow shall be discarded and retests made,unless such ﬂaws consti-tute a variable,the effect of which it is desired to study.9.Speed of Testing9.1Speed of testing shall be the relative rate of motion of the grips or test ﬁxtures during the test.Rate of motion of the driven grip or ﬁxture when the machine is running idle may be used if it can be shown that the resulting speed of testing is within the limits of variation allowed.9.2The standard speed of testing shall be 1.360.3mm (0.05060.010in.)/min,except as noted in 10.5.4.10.Procedure10.1Measure the width and thickness of the specimen to the nearest 0.01mm (0.001in.)at several points along its length.Calculate and record the minimum value of the cross-sectional area.Measure the length of the specimen and record the value.10.2Place the test specimen between the surfaces of the compression tool,taking care to align the center line of its long axis with the center line of the plunger and to ensure that the ends of the specimen are parallel with the surface of the compression tool.Adjust the crosshead of the testing machine until it just contacts the top of the compression toolplunger.N OTE 1—Cold rolled steel.N OTE 2—Furnished four steel machine screws and nuts,round head,slotted,length 31.75mm (11⁄4in.).N OTE 3—Grind surfaces denoted “Gr.”FIG.4Support Jig,DetailsFIG.5Compression Test Specimen for Materials Less than 3.2mmThickN OTE7—The compression tool may not be necessary for testing of lower modulus(for example,100000to500000psi)material if the loading surfaces are maintained smooth,ﬂat,and parallel to the extent that buckling is not incurred.10.3Place thin specimens in the jig(Fig.3and Fig.4)so that they areﬂush with the base and centered(Note8).The nuts or screws on the jig shall beﬁnger tight(Note9).Place the assembly in the compression tool as described in5.3.N OTE8—A round-robin test,designed to assess the inﬂuence of specimen positioning in the supporting jig(that is,ﬂush versus centered mounting),showed no signiﬁcant effect on compressive strength due to this variable.However,ﬂush mounting of the specimen with the base of the jig is speciﬁed for convenience and ease of mounting.7N OTE9—A round-robin test on the effect of lateral pressure at the supporting jig has established that reproducible data can be obtained with the tightness of the jig controlled as indicated.10.4If only compressive strength or compressive yield strength,or both,are desired,proceed as follows:10.4.1Set the speed control at1.3mm/min(0.050in./min) and start the machine.10.4.2Record the maximum load carried by the specimen during the test(usually this will be the load at the moment of rupture).10.5If stress-strain data are desired,proceed as follows: 10.5.1Attach compressometer.10.5.2Set the speed control at1.3mm/min(0.050in./min) and start the machine.10.5.3Record loads and corresponding compressive strain at appropriate intervals of strain or,if the test machine is equipped with an automatic recording device,record the complete load-deformation curve.10.5.4After the yield point has been reached,it may be desirable to increase the speed from5to6mm/min(0.20to 0.25in./min)and allow the machine to run at this speed until the specimen breaks.This may be done only with relatively ductile materials and on a machine with a weighing system with response rapid enough to produce accurate results. 11.Calculation11.1Compressive Strength—Calculate the compressive strength by dividing the maximum compressive load carried by the specimen during the test by the original minimum cross-sectional area of the specimen.Express the result in megapas-cals or pounds-force per square inch and report to three signiﬁcantﬁgures.11.2Compressive Yield Strength—Calculate the compres-sive yield strength by dividing the load carried by the specimen at the yield point by the original minimum cross-sectional area of the specimen.Express the result in megapascals or pounds-force per square inch and report to three signiﬁcantﬁgures.11.3Offset Yield Strength—Calculate the offset yield strength by the method referred to in3.1.11.11.4Modulus of Elasticity—Calculate the modulus of elas-ticity by drawing a tangent to the initial linear portion of the load deformation curve,selecting any point on this straight line portion,and dividing the compressive stress represented by this point by the corresponding strain,measure from the point where the extended tangent line intersects the strain-axis. Express the result in gigapascals or pounds-force per square inch and report to three signiﬁcantﬁgures(see Annex A1).11.5For each series of tests,calculate to three signiﬁcant ﬁgures the arithmetic mean of all values obtained and report as the“average value”for the particular property in question. 11.6Calculate the standard deviation(estimated)as follows and report to two signiﬁcantﬁgures:s5=~(X22nX¯2!/~n21!(1) where:s=estimated standard deviation,X=value of single observation,n=number of observations,andX¯=arithmetic mean of the set of observations.N OTE10—The method for determining the offset compressive yield strength is similar to that described in the Annex of Test Method D638.12.Report12.1Report the following information:12.1.1Complete identiﬁcation of the material tested,includ-ing type,source,manufacturer’s code number,form,principal dimensions,previous history,etc.,12.1.2Method of preparing test specimens,12.1.3Type of test specimen and dimensions,12.1.4Conditioning procedure used,12.1.5Atmospheric conditions in test room,12.1.6Number of specimens tested,12.1.7Speed of testing,12.1.8Compressive strength,average value,and standard deviation,12.1.9Compressive yield strength and offset yield strength average value,and standard deviation,when of interest, 12.1.10Modulus of elasticity in compression(if required), average value,standard deviation,12.1.11Date of test,and12.1.12Date of test method.13.Precision and Bias813.1Table1and Table2are based on a round-robin test conducted in1987in accordance with Practice E691,involv-ing three materials tested by six laboratories for Test Method D695M.Since the test parameters overlap within tolerances and the test values are normalized,the same data are used for both test methods.For each material,all of the samples were prepared at one source.Each test result was the average ofﬁve individual determinations.Each laboratory obtained two test results for each material.N OTE11—Caution:The following explanations of r and R(13.2-13.2.3)are only intended to present a meaningful way of considering the approximate precision of this test method.The data in Table1and Table 2should not be rigorously applied to acceptance or rejection of material, as those data are speciﬁc to the round robin and may not be representative7Supporting data are available from ASTM Headquarters.Request RR:D20-1061.8Supporting data are available from ASTM Headquarters,Request RR:D20-1150.of other lots,conditions,materials,or ers of this test method should apply the principles outlined in Practice E 691to generatedata speciﬁc to their laboratory and materials or between speciﬁc laboratories.The principles of 13.2-13.2.3would then be valid for such data.13.2Concept of r and R —If S (r )and S (R )have been calculated from a large enough body of data,and for test results that were averages from testing ﬁve specimens:13.2.1Repeatability,r —Comparing two test results for the same material,obtained by the same operator using the same equipment on the same day.The two test results should be judged not equivalent if they differ by more than the r value for that material.13.2.2Reproducibility,R —Comparing two results for the same material,obtained by different operators using different equipment on different days.The two test results should be judged not equivalent if they differ by more than R value for that material.13.2.3Any judgement in accordance with 13.2.1and 13.2.2would have an approximate 95%(0.95)probability of being correct.13.3There are no recognized standards by which to esti-mate the bias of this test method.14.Keywords14.1compressive properties;compressive strength;modu-lus of elasticity;plasticsANNEX(Mandatory Information)A1.TOE COMPENSATIONA1.1In a typical stress-strain curve (Fig.A1.1)there is a toe region,AC ,that does not represent a property of the material.It is an artifact caused by a takeup of slack,and alignment or seating of the specimen.In order to obtain correct values of such parameters as modulus,strain,and offset yield point,this artifact must be compensated for to give the corrected zero point on the strain or extension axis.A1.2In the case of a material exhibiting a region of Hookean (linear)behavior (Fig.A1.1),a continuation of the linear (CD )region of the curve is constructed through the zero-stress axis.This intersection (B )is the corrected zero-strain point from which all extensions or strains must be measured,including the yield offset (BE ),if applicable.The elastic modulus can be determined by dividing the stress at any point along the line CD (or its extension)by the strain at the same point (measured from Point B ,deﬁned as zero-strain).A1.3In the case of a material that does not exhibit any linear region (Fig.A1.2),the same kind of toe correction of the zero-strain point can be made by constructing a tangent to the maximum slope at the inﬂection point (H 8).This is extended to intersect the strain axis at Point B 8,the corrected zero-strainTABLE 1Precision,Compressive Strength(Values in Units of Megapascals )Material Average S r A S R B r C R D Acetal100 1.1 2.1 3.1 5.9Polystyrene106 1.4 3.5 3.99.8Linen-ﬁlled phenolic1583.77.510.421.0AS r is the within-laboratory standard deviation for the indicated material.It is obtained by pooling the within-laboratory standard deviations of the test results from all of the participating laboratories:S r =[[(S 1)2+(S 2)2+...+(S n )2]/n ]1/2.BS R is the between-laboratories reproducibility,expressed as a standard deviation,for the indicated material.Cr is the within-laboratory repeatability limit,r =2.83S r .DR is the between-laboratory reproducibility limit,R =2.83S R .TABLE 2Precision,Compressive Modulus(Values in Units of Megapascals )Material Average S r A S R B r C R D Acetal3.280.140.250.390.70Polystyrene3.880.070.740.20 2.07Linen-ﬁlled phenolic6.820.230.900.642.52AS r is the within-laboratory standard deviation for the indicated material.It is obtained by pooling the within-laboratory standard deviations of the test results from all of the participating laboratories:S r =[[(S 1)2+(S 2)2+...+(S n )2]/n ]1/2.BS R is the between-laboratories reproducibility,expressed as a standard deviation,for the indicated material.Cr is the within-laboratory repeatability limit,r =2.83S r .DR is the between-laboratory reproducibility limit,R =2.83S R.N OTE 1—Some chart recorders plot the mirror image of this graph.FIG.A1.1Material with HookeanRegioning Point B 8as zero strain,the stress at any point (G 8)on the curve can be divided by the strain at that point to obtaina secant modulus (slope of line B 8G 8).For those materials with no linear region,any attempt to use the tangent through the inﬂection point as a basis for determination of an offset yield point may result in unacceptable error.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this ers of this standard are expressly advised that determination of the validity of any such patent rights,and the risk of infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ﬁve years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Individual reprints (single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585(phone),610-832-9555(fax),or service@ (e-mail);or through the ASTM website().N OTE 1—Some chart recorders plot the mirror image of this graph.FIG.A1.2Material with No HookeanRegion。

铁路混凝土强度检验评定标准英文版

铁路混凝土强度检验评定标准英文版全文共3篇示例，供读者参考篇1Title: Standard for Testing and Evaluation of Concrete Strength in Railway ConstructionIntroductionIn railway construction, concrete plays a crucial role in ensuring the stability and durability of tracks, bridges, tunnels, and other structures. Therefore, it is essential to have standardized procedures for testing and evaluating the strength of concrete used in railway construction projects. This article will discuss the standard methods and criteria for testing and evaluating the strength of concrete in railway construction.1. ScopeThis standard applies to the testing and evaluation of the compressive strength of concrete used in railway construction projects. It covers the procedures for preparing test specimens, conducting compression tests, and determining the compressive strength of concrete.2. Test Specimens PreparationTest specimens shall be prepared in accordance with ASTM C31/C31M-17 Standard Practice for Making and Curing Concrete Test Specimens in the Field. The specimens shall be cast in steel moulds of the required dimensions and cured under specified conditions.3. Compression TestingCompression tests shall be conducted in accordance with ASTM C39/C39M-16a Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. The tests shall be performed using a hydraulic testing machine with a capacity of at least 120% of the expected maximum load.4. Determination of Compressive StrengthThe compressive strength of concrete shall be determined by dividing the maximum load applied during the test by the cross-sectional area of the specimen. The results shall be reported in megapascals (MPa) or pounds per square inch (psi).5. Evaluation CriteriaThe compressive strength of concrete shall be evaluated based on the following criteria:- Minimum Strength Requirement: The minimum compressive strength of concrete shall meet the specified design requirements for railway construction projects.- Quality Control: The average compressive strength of concrete specimens shall not deviate by more than 15% from the specified design strength.- Acceptance Criteria: At least 95% of the test specimens shall meet or exceed the specified design strength.6. ReportingThe test results shall be recorded in a standardized format, including the details of specimen preparation, testing procedures, and results. The report shall be signed by the testing laboratory and submitted to the project engineer for review and approval.ConclusionStandardized testing and evaluation of concrete strength are essential for ensuring the safety and reliability of railway construction projects. By following the procedures outlined in this standard, engineers and contractors can determine the strength of concrete with accuracy and confidence, leading to successful and durable railway structures.篇2Railway Concrete Strength Inspection and Evaluation StandardsIntroductionIn the construction of railway infrastructure, concrete is one of the most commonly used materials due to its durability and high compressive strength. It is essential to ensure that the concrete used in railway construction meets the required standards for strength in order to guarantee the safety and durability of the railway track. This document outlines the inspection and evaluation standards for determining the strength of concrete used in railway construction.Methods of TestingThere are several methods used to test the strength of concrete, with the most common being compressive strength testing. The most widely used standard for this test is the ASTM C39/C39M – 18 Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. This method involves casting cylindrical specimens of concrete and subjecting them to a compressive force until failure occurs. The maximum load atwhich the specimen fails is used to calculate the compressive strength of the concrete.Another method of testing concrete strength is the ASTM C856 – 11 Standard Practice for Petrographic Examination of Hardened Concrete. This method involves examining thin sections of concrete under a microscope to assess the presence of any defects or weaknesses that could affect the strength of the concrete.Evaluation StandardsThe evaluation of concrete strength in railway construction is typically measured in terms of compressive strength. The minimum compressive strength required for concrete used in railway construction is usually specified in the project design documents or by relevant standards. For example, the American Concrete Institute (ACI) recommends a minimum compressive strength of 4000 psi for concrete used in railway construction.In addition to compressive strength, other factors that may affect the strength of concrete in railway construction include the water-cement ratio, curing methods, and the presence of any admixtures. It is important to carefully monitor these factors during the construction process to ensure that the concrete meets the required standards for strength.Inspection ProceduresDuring the construction of railway infrastructure, it is important to conduct regular inspections of the concrete to ensure that it meets the required standards for strength. This can be done through the use of non-destructive testing methods such as ultrasonic testing or rebound hammer testing. These methods provide a quick and effective way to assess the strength of the concrete without damaging the structure.In addition to non-destructive testing, it is also important to conduct regular destructive testing of concrete specimens to verify the compressive strength of the concrete. This can be done by casting specimens of concrete at regular intervals during the construction process and subjecting them to compressive strength testing in a laboratory.ConclusionEnsuring the strength of concrete used in railway construction is essential for guaranteeing the safety and durability of the railway track. By following the testing, evaluation, and inspection standards outlined in this document, railway construction companies can ensure that the concrete meets the required standards for strength and reliability. By carefully monitoring the construction process and conductingregular inspections, it is possible to identify any issues with the concrete and take corrective action before they result in failures or accidents on the railway track.篇3Railway Concrete Strength Inspection and Assessment StandardsIntroductionRailway concrete structures, such as bridges, culverts, and retaining walls, play a crucial role in the safety and stability of railway tracks. It is essential to ensure the strength and durability of these structures to maintain the smooth operation of railway transportation. The inspection and assessment of concrete strength are critical in determining the structural integrity and safety of railway infrastructure.Standard Testing Methods1. Compressive Strength Testing: Compressive strength testing is the most common method used to evaluate the strength of concrete. The test involves applying a compressive force to a concrete cylinder or cube until it fails. The compressive strength is then calculated based on the maximum force applied and the cross-sectional area of the concrete sample.2. Ultrasonic Testing: Ultrasonic testing is a non-destructive method used to assess the quality and integrity of concrete structures. It involves sending high-frequency sound waves through the concrete and measuring the time it takes for the waves to bounce back. This method is used to detect voids, cracks, and other defects that may affect the strength of the concrete.3. Rebound Hammer Testing: Rebound hammer testing is another non-destructive method used to evaluate the strength of concrete. The test involves striking the concrete surface with a spring-loaded hammer and measuring the rebound velocity. The rebound value is then correlated with the compressive strength of the concrete.Assessment CriteriaThe assessment of concrete strength in railway structures is typically based on the following criteria:1. Compressive Strength: The compressive strength of concrete should meet the minimum requirements specified in the design standards. The concrete strength is usually expressed in megapascals (MPa) and should be checked against the design specifications to ensure structural stability.2. Ultrasonic Pulse Velocity: The ultrasonic pulse velocity (UPV) of concrete is an indicator of its quality and uniformity. A lower UPV value indicates the presence of defects or deterioration in the concrete structure. The UPV should be measured at various points along the structure to identify any areas of concern.3. Rebound Hammer Value: The rebound hammer value is used to assess the surface hardness and strength of concrete structures. A higher rebound value indicates a stronger and more durable concrete. The rebound value should be within the acceptable range specified by the design standards.ConclusionThe inspection and assessment of concrete strength are essential for ensuring the safety and stability of railway structures. By following the standard testing methods and assessment criteria, railway operators can identify and address any weaknesses in the concrete structures before they pose a risk to the transportation system. It is crucial to conduct regular inspections and testing to maintain the integrity of railway infrastructure and ensure the smooth operation of the railway network.。

混凝土强度检验的国际标准对比

混凝土强度检验的国际标准对比一、引言混凝土是广泛应用于建筑和基础设施工程中的一种常用材料。

为了确保混凝土工程的质量和安全性，强度检验是必不可少的一环。

本文旨在对比不同国际标准对混凝土强度检验的要求和方法，以期促进标准化和互通有无。

二、美国标准在美国，混凝土的强度检验主要依据ASTM C39标准，即“混凝土立方体抗压强度试验”。

根据该标准，混凝土样品采用标准尺寸，经过一定养护时间后，在试验机上进行加载，以确定其抗压强度。

ASTM C39标准详细规定了试验机的要求、加载速率、取样方法等。

三、欧洲标准在欧洲，混凝土强度检验的相关标准主要有EN 12390-3和EN 206-1。

EN 12390-3标准规定了混凝土立方体和圆柱体抗压强度试验的具体要求，特别强调试验前的养护条件和试样的尺寸。

而EN 206-1则是欧洲对混凝土的整体性能要求的集成标准，对强度检验的方法也有所涉及。

四、中国标准中国国内对混凝土强度检验的标准则主要包括GB/T 50081和GB/T 50082标准。

GB/T 50081标准规定了混凝土抗压强度试验的方法和要求，包括试样制备、试验机的使用、加载速率等方面。

GB/T 50082标准则进一步细化了混凝土制样和试验工作的具体指导，以确保检验结果的准确性和可靠性。

五、对比分析从以上对不同国际标准的介绍可见，混凝土强度检验的方法和要求在各个标准中有所差异，但总体上保持了一定的统一性。

主要差异体现在对试样尺寸、试样养护条件、试验机使用等方面的规定上。

例如，美国标准更注重试验机的要求和加载速率的确定，而欧洲标准则更强调试验前的养护条件，以及总体性能要求的细化。

中国标准则在制样和试验工作方面有更为详细的规定，以确保检验结果的准确性。

六、标准化与互通混凝土强度检验的国际标准对比表明，各个标准在方法和要求上的一致性尚可，但仍存在一些差异。

为了推动全球混凝土行业的标准化和互通有无，建议各国之间加强交流与合作，共同制定更加统一的标准。

回弹法现场检测技术标准

回弹法现场检测技术标准
目前关于回弹法（Schmidt击针法）现场检测技术的标准有以
下几个：
1. GB/T 50315-2018《建筑物室外墙体工程质量验收规范》：
该标准规定了墙体回弹法检测的技术要求和检测方法，包括回弹仪的型号选择、表面处理、检测点布置、重复回弹次数、数据处理等内容。

2. ASTM C170-09(2015)《Standard Test Method for Compressive Strength of Dimension Stone》：该标准规定了回弹法测定天然
石材抗压强度的方法，包括回弹仪的校准、试样制备、回弹测试等内容。

3. EN 12504-2:2012《Testing concrete in structures - Part 2: Non-destructive testing - Determination of rebound number》：该标准
是欧洲非破坏性检测领域的相关标准之一，规定了回弹法测定混凝土抗压强度的方法和技术要求。

当然，还有其他一些国家和地区制定的相关标准，但以上三个是较为常用的回弹法现场检测技术标准。

在进行回弹法检测时，可以参考并遵守这些标准，以确保测试结果的准确性和可比性。

ASTM D695-2010

Designation:D695–10Standard Test Method forCompressive Properties of Rigid Plastics1This standard is issued under theﬁxed designation D695;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(´)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope*1.1This test method covers the determination of the me-chanical properties of unreinforced and reinforced rigid plas-tics,including high-modulus composites,when loaded in compression at relatively low uniform rates of straining or loading.Test specimens of standard shape are employed.This procedure is applicable for a composite modulus up to and including41,370MPa(6,000,000psi).1.2The values stated in SI units are to be regarded as the standard.The values in parentheses are for information only. N OTE1—For compressive properties of resin-matrix composites rein-forced with oriented continuous,discontinuous,or cross-ply reinforce-ments,tests may be made in accordance with Test Method D3410/ D3410M.1.3This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A speciﬁc precau-tionary statement is given in13.1.N OTE2—This test method is technically equivalent to ISO604.2.Referenced Documents2.1ASTM Standards:2D618Practice for Conditioning Plastics for TestingD638Test Method for Tensile Properties of PlasticsD883Terminology Relating to PlasticsD3410/D3410M Test Method for Compressive Properties of Polymer Matrix Composite Materials with Unsupported Gage Section by Shear LoadingD4000Classiﬁcation System for Specifying Plastic Materi-alsD5947Test Methods for Physical Dimensions of Solid Plastics SpecimensE4Practices for Force Veriﬁcation of Testing MachinesE83Practice for Veriﬁcation and Classiﬁcation of Exten-someter SystemsE691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2ISO Standard:3ISO604Plastics—Determination of Compressive Proper-ties3.Terminology3.1General—The deﬁnitions of plastics used in this test method are in accordance with Terminology D883unless otherwise indicated.3.2Deﬁnitions:3.2.1compressive deformation—the decrease in length pro-duced in the gage length of the test specimen by a compressive load.It is expressed in units of length.3.2.2compressive strain—the ratio of compressive defor-mation to the gage length of the test specimen,that is,the change in length per unit of original length along the longitu-dinal axis.It is expressed as a dimensionless ratio.3.2.3compressive strength—the maximum compressive stress(nominal)carried by a test specimen during a compres-sion test.It may or may not be the compressive stress (nominal)carried by the specimen at the moment of rupture.3.2.4compressive strength at failure(nominal)—the com-pressive stress(nominal)sustained at the moment of failure of the test specimen if shattering occurs.3.2.5compressive stress(nominal)—the compressive load per unit area of minimum original cross section within the gage boundaries,carried by the test specimen at any given moment. It is expressed in force per unit area.1This test method is under the jurisdiction of ASTM Committee D20on Plastics and is the direct responsibility of Subcommittee D20.10on Mechanical Properties.Current edition approved April1,2010.Published April2010.Originally approved st previous edition approved in2008as D695-08.DOI: 10.1520/D0695-10.2For referenced ASTM standards,visit the ASTM website,,or contact ASTM Customer Service at service@.For Annual Book of ASTMStandards volume information,refer to the standard’s Document Summary page on the ASTM website.3Available from American National Standards Institute(ANSI),25W.43rd St., 4th Floor,New York,NY10036,.*A Summary of Changes section appears at the end of this standard. Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.3.2.5.1Discussion—The expression of compressive proper-ties in terms of the minimum original cross section is almost universally used.Under some circumstances the compressive properties have been expressed per unit of prevailing cross section.These properties are called“true”compressive prop-erties.3.2.6compressive stress-strain diagram—a diagram in which values of compressive stress are plotted as ordinates against corresponding values of compressive strain as abscis-sas.3.2.7compressive yield point—theﬁrst point on the stress-strain diagram at which an increase in strain occurs without an increase in stress.3.2.8compressive yield strength—normally the stress at the yield point(see also section3.2.11).3.2.9crushing load—the maximum compressive force ap-plied to the specimen,under the conditions of testing,that produces a designated degree of failure.3.2.10modulus of elasticity—the ratio of stress(nominal)to corresponding strain below the proportional limit of a material. It is expressed in force per unit area based on the average initial cross-sectional area.3.2.11offset compressive yield strength—the stress at which the stress-strain curve departs from linearity by a speciﬁed percent of deformation(offset).3.2.12percent compressive strain—the compressive defor-mation of a test specimen expressed as a percent of the original gage length.3.2.13proportional limit—the greatest stress that a material is capable of sustaining without any deviation from propor-tionality of stress to strain(Hooke’s law).It is expressed in force per unit area.3.2.14slenderness ratio—the ratio of the length of a col-umn of uniform cross section to its least radius of gyration.For specimens of uniform rectangular cross section,the radius of gyration is0.289times the smaller cross-sectional dimension. For specimens of uniform circular cross section,the radius of gyration is0.250times the diameter.4.Signiﬁcance and Use4.1Compression tests provide information about the com-pressive properties of plastics when employed under conditions approximating those under which the tests are made.4.2Compressive properties include modulus of elasticity, yield stress,deformation beyond yield point,and compressive strength(unless the material merelyﬂattens but does not fracture).Materials possessing a low order of ductility may not exhibit a yield point.In the case of a material that fails in compression by a shattering fracture,the compressive strength has a very deﬁnite value.In the case of a material that does not fail in compression by a shattering fracture,the compressive strength is an arbitrary one depending upon the degree of distortion that is regarded as indicating complete failure of the material.Many plastic materials will continue to deform in compression until aﬂat disk is produced,the compressive stress(nominal)rising steadily in the process,without any well-deﬁned fracture pressive strength can have no real meaning in such cases.4.3Compression tests provide a standard method of obtain-ing data for research and development,quality control,accep-tance or rejection under speciﬁcations,and special purposes. The tests cannot be considered signiﬁcant for engineering design in applications differing widely from the load-time scale of the standard test.Such applications require additional tests such as impact,creep,and fatigue.4.4Before proceeding with this test method,reference should be made to the ASTM speciﬁcation for the material being tested.Any test specimen preparation,conditioning, dimensions,and testing parameters covered in the materials speciﬁcation shall take precedence over those mentioned in this test method.If there is no material speciﬁcation,then the default conditions apply.Table1in Classiﬁcation D4000lists the ASTM materials standards that currently exist.5.Apparatus5.1Testing Machine—Any suitable testing machine capable of control of constant-rate-of-crosshead movement and com-prising essentially the following:5.1.1Drive Mechanism—A drive mechanism for imparting to the movable cross-head member,a uniform,controlled velocity with respect to the base(ﬁxed member),with this velocity to be regulated as speciﬁed in Section9.5.1.2Load Indicator—A load-indicating mechanism ca-pable of showing the total compressive load carried by the test specimen.The mechanism shall be essentially free from inertia-lag at the speciﬁed rate of testing and shall indicate the load with an accuracy of61%of the maximum indicated value of the test(load).The accuracy of the testing machine shall be veriﬁed at least once a year in accordance with Practices E4.5.2Compressometer—A suitable instrument for determin-ing the distance between twoﬁxed points on the test specimen at any time during the test.It is desirable that this instrument automatically record this distance(or any change in it)as a function of the load on the test specimen.The instrument shall be essentially free of inertia-lag at the speciﬁed rate of loading and shall conform to the requirements for a Class B-2 extensometer as deﬁned in Practice E83.N OTE3—The requirements for extensometers cited herein apply to compressometers as well.5.3Compression Tool—A compression tool for applying the load to the test specimen.This tool shall be so constructed that loading is axial within1:1000and applied through surfaces that areﬂat within0.025mm(0.001in.)and parallel to each other in a plane normal to the vertical loading axis.Examples of suitable compression tools are shown in Fig.1and Fig.2. 5.4Supporting Jig—A supporting jig for thin specimens is shown in Fig.3and Fig.4.5.5Micrometers—Suitable micrometers,reading to0.01 mm or0.001in.for measuring the width,thickness,and length of the specimens.6.Test Specimens6.1Unless otherwise speciﬁed in the materials speciﬁca-tions,the specimens described in6.2and6.7shall be used. These specimens may be prepared by machiningoperationsfrom materials in sheet,plate,rod,tube,or similar form,or they may be prepared by compression or injection molding of the material to be tested.All machining operations shall be done carefully so that smooth surfaces result.Great care shall be taken in machining the ends so that smooth,ﬂat parallel surfaces and sharp,clean edges,to within 0.025mm (0.001in.)perpendicular to the long axis of the specimen,result.6.2The standard test specimen,except as indicated in 6.3-6.7,shall be in the form of a right cylinder or prism whoselength is twice its principal width or diameter.Preferred specimen sizes are 12.7by 12.7by 25.4mm (0.50by 0.50by 1in.)(prism),or 12.7mm in diameter by 25.4mm (cylinder).Where elastic modulus and offset yield-stress data are desired,the test specimen shall be of such dimensions that the slender-ness ratio is in the range from 11to 16:1.In this case,preferred specimen sizes are 12.7by 12.7by 50.8mm (0.50by 0.50by 2in.)(prism),or 12.7mm in diameter by 50.8mm (cylinder).6.3For rod material,the test specimen shall have a diameter equal to the diameter of the rod and a sufficient length to allow a specimen slenderness ratio in the range from 11to 16:1.6.4When testing tubes,the test specimen shall have a diameter equal to the diameter of the tube and a length of 25.4mm (1in.)(Note 4).For crushing-load determinations (at right angles to the longitudinal axis),the specimen size shall be the same,with the diameter becoming the height.N OTE 4—This specimen can be used for tubes with a wall thickness of 1mm (0.039in.)or over,to inside diameters of 6.4mm (0.25in.)or over,and to outside diameters of 50.8mm (2.0in.)or less.6.5Where it is desired to test conventional high-pressure laminates in the form of sheets,the thickness of which is less than 25.4mm (1in.),a pile-up of sheets 25.4mm square,with a sufficient number of layers to produce a height of at least 25.4mm,may be used.6.6When testing material that may be suspected of anisot-ropy,duplicate sets of test specimens shall be prepared having their long axis respectively parallel with and normal to the suspected direction of anisotropy.6.7Reinforced Plastics,Including High-Strength Compos-ites and High-Strength Composites and Highly Orthotropic Laminates —The following specimens shall be used for rein-forced materials,or for other materials when necessary to comply with the slenderness ratio requirements or to permit attachment of a deformation-measuring device.6.7.1For materials 3.2mm (1⁄8in.)and over in thickness,a specimen shall consist of a prism having a cross section of 12.7mm (1⁄2in.)by the thickness of the material and a length such that the slenderness ratio is in the range from 11to 16:1(Note 5).6.7.2For materials under 3.2mm (1⁄8in.)thick,or where elastic modulus testing is required and the slenderness ratio does not provide for enough length for attachment of a compressometer or similar device,a specimen conformingtoN OTE 1—Devices similar to the one illustrated have been successfully used in a number of different laboratories.Details of the device developed at the National Institute for Standards and Technology are given in the paper by Aitchinson,C.S.,and Miller,J.A.,“A Subpress for Compressive Tests,”National Advisory Committee for Aeronautics,Technical Note No.912,1943.FIG.1Subpress for CompressionTestsFIG.2CompressionToolFIG.3Support Jig for ThinSpecimenthat shown in Fig.5shall be used.The supporting jig shown in Fig.3and Fig.4shall be used to support the specimen during testing (Note 6).N OTE 5—If failure for materials in the thickness range of 3.2mm (1⁄8in.)is by delamination rather than by the desirable shear plane fracture,the material may be tested in accordance with 6.7.2.N OTE 6—Round-robin tests have established that relatively satisfactory measurements of modulus of elasticity may be obtained by applying a compressometer to the edges of the jig-supported specimen.6.8When testing syntactic foam,the standard test specimen shall be in the form of a right cylinder 25.4mm (1in.)in diameter by 50.8mm (2in.)in length.7.Conditioning7.1Conditioning —Condition the test specimens in accor-dance with Procedure A of Practice D618unless otherwise speciﬁed by contract or relevant ASTM material speciﬁcation.Conditioning time is speciﬁed as a minimum.Temperature and humidity tolerances shall be in accordance with Section 7of Practice D618unless speciﬁed differently by contract or material speciﬁcation.7.2Test Conditions —Conduct the tests at the same tempera-ture and humidity used for conditioning with tolerances in accordance with Section 7of Practice D618unless otherwise speciﬁed by contract or the relevant ASTM material speciﬁca-tion.8.Number of Test Specimens8.1At least ﬁve specimens shall be tested for each sample in the case of isotropic materials.8.2Ten specimens,ﬁve normal to and ﬁve parallel with the principal axis of anisotropy,shall be tested for each sample in the case of anisotropic materials.8.3Specimens that break at some obvious ﬂaw shall be discarded and retests made,unless such ﬂaws constitute a variable,the effect of which it is desired to study.9.Speed of Testing9.1Speed of testing shall be the relative rate of motion of the grips or test ﬁxtures during the test.Rate of motion of the driven grip or ﬁxture when the machine is running idle may be used if it can be shown that the resulting speed of testing is within the limits of variation allowed.9.2The standard speed of testing shall be 1.360.3mm (0.05060.010in.)/min,except as noted in 10.5.4.10.Procedure10.1Measure the width and thickness of the specimen to the nearest 0.01mm (0.001in.)at several points along its length.Calculate and record the minimum value of the cross-sectional area.Measure the length of the specimen and record the value.10.2Place the test specimen between the surfaces of the compression tool,taking care to align the center line of its long axis with the center line of the plunger and to ensure that the ends of the specimen are parallel with the surface of the compression tool.Adjust the crosshead of the testing machine until it just contacts the top of the compression tool plunger.N OTE 7—The compression tool may not be necessary for testing of lower modulus (for example,700MPa to 3500MPa (100,000psi to 500,000psi))material if the loading surfaces are maintained smooth,ﬂat,and parallel to the extent that buckling is not incurred.10.3Place thin specimens in the jig (Fig.3and Fig.4)so that they are ﬂush with the base and centered (Note 8).The nuts or screws on the jig shall be ﬁnger tight (Note 9).Place the assembly in the compression tool as described in 5.3.N OTE 8—A round-robin test,designed to assess the inﬂuenceofN OTE 1—Cold rolled steel.N OTE 2—Furnished four steel machine screws and nuts,round head,slotted,length 31.75mm (11⁄4in.).N OTE 3—Grind surfaces denoted “Gr.”FIG.4Support Jig,Detailsspecimen positioning in the supporting jig (that is,ﬂush versus centered mounting),showed no signiﬁcant effect on compressive strength due to this variable.However,ﬂush mounting of the specimen with the base of the jig is speciﬁed for convenience and ease of mounting.4N OTE 9—A round-robin test on the effect of lateral pressure at the supporting jig has established that reproducible data can be obtained with the tightness of the jig controlled as indicated.10.4If only compressive strength or compressive yield strength,or both,are desired,proceed as follows:10.4.1Set the speed control at 1.3mm/min (0.050in./min)and start the machine.10.4.2Record the maximum load carried by the specimen during the test (usually this will be the load at the moment of rupture).10.5If stress-strain data are desired,proceed as follows:10.5.1Attach compressometer.10.5.2Set the speed control at 1.3mm/min (0.050in./min)and start the machine.10.5.3Record loads and corresponding compressive strain at appropriate intervals of strain or,if the test machine is equipped with an automatic recording device,record the complete load-deformation curve.10.5.4After the yield point has been reached,it may be desirable to increase the speed from 5to 6mm/min (0.20to 0.25in./min)and allow the machine to run at this speed until the specimen breaks.This may be done only with relatively ductile materials and on a machine with a weighing system with response rapid enough to produce accurate results.11.Calculation11.1Compressive Strength —Calculate the compressive strength by dividing the maximum compressive load carried by the specimen during the test by the original minimum cross-sectional area of the specimen.Express the result in megapas-cals or pounds-force per square inch and report to three signiﬁcant ﬁgures.11.2Compressive Yield Strength —Calculate the compres-sive yield strength by dividing the load carried by the specimen at the yield point by the original minimum cross-sectional areaof the specimen.Express the result in megapascals or pounds-force per square inch and report to three signiﬁcant ﬁgures.11.3Offset Yield Strength —Calculate the offset yield strength by the method referred to in 3.2.11.11.4Modulus of Elasticity —Calculate the modulus of elas-ticity by drawing a tangent to the initial linear portion of the load deformation curve,selecting any point on this straight line portion,and dividing the compressive stress represented by this point by the corresponding strain,measure from the point where the extended tangent line intersects the strain-axis.Express the result in gigapascals or pounds-force per square inch and report to three signiﬁcant ﬁgures (see Annex A1).11.5For each series of tests,calculate to three signiﬁcant ﬁgures the arithmetic mean of all values obtained and report as the “average value”for the particular property in question.11.6Calculate the standard deviation (estimated)as follows and report to two signiﬁcant ﬁgures:s 5=~(X 22nX¯2!/~n 21!(1)where:s =estimated standard deviation,X =value of single observation,n =number of observations,andX¯=arithmetic mean of the set of observations.N OTE 10—The method for determining the offset compressive yield strength is similar to that described in the Annex of Test Method D638.12.Report12.1Report the following information:12.1.1Complete identiﬁcation of the material tested,includ-ing type,source,manufacturer’s code number,form,principal dimensions,previous history,etc.,12.1.2Method of preparing test specimens,12.1.3Type of test specimen and dimensions,12.1.4Conditioning procedure used,12.1.5Atmospheric conditions in test room,12.1.6Number of specimens tested,12.1.7Speed of testing,12.1.8Compressive strength,average value,and standard deviation,12.1.9Compressive yield strength and offset yield strength average value,and standard deviation,when of interest,4Supporting data have been ﬁled at ASTM International Headquarters and may be obtained by requesting Research ReportRR:D20-1061.FIG.5Compression Test Specimen for Materials Less than 3.2mmThick12.1.10Modulus of elasticity in compression(if required), average value,standard deviation,12.1.11Date of test,and12.1.12Date of test method.13.Precision and Bias13.1Table1and Table2are based on a round-robin test conducted in1987in accordance with Practice E691,involving three materials tested by six laboratories for Test Method D695M.Since the test parameters overlap within tolerances and the test values are normalized,the same data are used for both test methods.For each material,all of the samples were prepared at one source.Each test result was the average ofﬁve individual determinations.Each laboratory obtained two test results for each material.(Warning—The following explana-tions of r and R(13.2-13.2.3)are only intended to present a meaningful way of considering the approximate precision of this test method.The data in Table1and Table2should not be rigorously applied to acceptance or rejection of material,as these data apply only to the materials tested in the round robin and are unlikely to be rigorously representative of other lots, formulations,conditions,materials,or ers of this test method should apply the principles outlined in Practice E691to generate data speciﬁc to their laboratory and materials or between speciﬁc laboratories.The principles of13.2-13.2.3 would then be valid for such data.)13.2Concept of r and R in Table1and Table2—If S(r)and S(R)have been calculated from a large enough body of data, and for test results that were averages from testing ofﬁve specimens for each test result,then:13.2.1Repeatability—Two test results obtained within one laboratory shall be judged not equivalent if they differ by more than the“r”for that the material.“r”is the interval represent-ing the critical difference between two test results for the same material,obtained by the same operator using the same equipment on the same day in the same laboratory.13.2.2Reproducibility,R—Two test results obtained by different laboratories shall be judged not equivalent if they differ by more than the“R”value for that material.“R”is the interval representing the critical difference between the two test results for the same material,obtained by different operators using different equipment in different laboratories.13.2.3Any judgement in accordance with13.2.1and13.2.2 would have an approximate95%(0.95)probability of being correct.13.3There are no recognized standards by which to esti-mate the bias of this test method.14.Keywords14.1compressive properties;compressive strength;modu-lus of elasticity;plasticsANNEX (Mandatory Information) A1.TOE COMPENSATIONA1.1In a typical stress-strain curve(Fig.A1.1)there is a toe region,AC,that does not represent a property of the material.It is an artifact caused by a takeup of slack,and alignment or seating of the specimen.In order to obtain correct values of such parameters as modulus,strain,and offset yield point,this artifact must be compensated for to give the corrected zero point on the strain or extension axis.A1.2In the case of a material exhibiting a region of Hookean(linear)behavior(Fig.A1.1),a continuation of the linear(CD)region of the curve is constructed through the zero-stress axis.This intersection(B)is the corrected zero-strain point from which all extensions or strains must be measured,including the yield offset(BE),if applicable.The elastic modulus can be determined by dividing the stress at any point along the line CD(or its extension)by the strain at the same point(measured from Point B,deﬁned as zero-strain). A1.3In the case of a material that does not exhibit any linear region(Fig.A1.2),the same kind of toe correction of the zero-strain point can be made by constructing a tangent to the maximum slope at the inﬂection point(H8).This is extended to intersect the strain axis at Point B8,the corrected zero-strain ing Point B8as zero strain,the stress at any point(G8)TABLE1Precision,Compressive Strength(Values in Units of Megapascals)Material Average S r A S R B r C R D Acetal100 1.1 2.1 3.1 5.9 Polystyrene106 1.4 3.5 3.99.8 Linen-ﬁlled phenolic158 3.77.510.421.0A Sris the within-laboratory standard deviation for the indicated material.It is obtained by pooling the within-laboratory standard deviations of the test results from all of the participating laboratories:S r=[[(S1)2+(S2)2+...+(S n)2]/n]1/2.B SRis the between-laboratories reproducibility,expressed as a standard deviation,for the indicated material.C r is the within-laboratory repeatability limit,r=2.83Sr .D R is the between-laboratory reproducibility limit,R=2.83SR .TABLE2Precision,Compressive Modulus(Values in Units of Gigapascals)Material Average S r A S R B r C R DAcetal 3.280.140.250.390.70Polystyrene 3.880.070.740.20 2.07Linen-ﬁlled phenolic 6.820.230.900.64 2.52A Sris the within-laboratory standard deviation for the indicated material.It is obtained by pooling the within-laboratory standard deviations of the test resultsfrom all of the participating laboratories:S r=[[(S1)2+(S2)2+...+(S n)2]/n]1/2.B SRis the between-laboratories reproducibility,expressed as a standard deviation,for the indicated material.C r is the within-laboratory repeatability limit,r=2.83Sr.D R is the between-laboratory reproducibility limit,R=2.83SR.on the curve can be divided by the strain at that point to obtain a secant modulus (slope of line B 8G 8).For those materials withno linear region,any attempt to use the tangent through the inﬂection point as a basis for determination of an offset yield point may result in unacceptable error.SUMMARY OF CHANGESCommittee D20has identiﬁed the location of selected changes to this standard since the last issue (D695-08)that may impact the use of this standard.(April 1,2010)(1)Revised Section 7.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this ers of this standard are expressly advised that determination of the validity of any such patent rights,and the risk of infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ﬁve years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Individual reprints (single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585(phone),610-832-9555(fax),or service@ (e-mail);or through the ASTM website ().Permission rights to photocopy the standard may also be secured from the ASTM website (/COPYRIGHT/).N OTE 1—Some chart recorders plot the mirror image of this graph.FIG.A1.1Material with HookeanRegionN OTE 1—Some chart recorders plot the mirror image of this graph.FIG.A1.2Material with No HookeanRegion。

ASTM粘性土的无侧向抗压强度标准试验方法D 2166-00

Designation: D 2166-00Standard Test Method forUnconfined Compressive Strength of Cohesive Soil粘性土的无侧限抗压强度标准试验方法1.范围1.1 该试验方法适用于确定原状、重塑、或击实的粘性土的无侧限抗压强度，使用在轴向加载的控制应变法。

1.2 根据总应力，该试验方法提供粘性土强度的大约值。

1.3 该试验方法仅适用于粘性材料，其在加载试验期间不排出或放出水（由于变形或压缩，水从土中排出），并将在卸掉限制压力后保持固有强度，像粘土或是胶结土。

干和易脆的土，裂隙的或冲积的材料，粉土，泥炭土，和砂不能用该试验方法测试有效的无侧限抗压强度值。

1.4 该试验方法不是测试方法D 2850的替代测试方法。

1.5 所有观察和测试值应满足在操作规程D 6026中确定的有效数字和取整的指导纲领。

1.5.1 在该试验方法中用于说明怎样收集/记录数据和计算的程序被认为是行业标准。

此外，代表性有效数字应保留。

该程序没有考虑材料变化、获取数据的目的、特殊研究目的、或是任何使用则的客观考虑；增加或是减少报告的有效数位以与这些考虑相当是很平常的。

在分析方法里考虑用于工程的有效数位超出了本试验方法范围。

1.6 数值单位以SI单位制被认为是标准的。

数值单位为英寸-英镑的是近似值。

1.7该标准试验方法没有包含所有的安全问题，即便要，也应联系实际需要。

在试验前确定合适的安全、健康守则和决定其规章制度适用的局限性是试验者的责任。

2. 参考文件3. 术语3.1 定义：标准术语参见术语D 653。

3.2 该标准中特定的定义：3.2.1 无侧限抗压强度（u q ）-在简单的压缩试验里作用在无侧限圆柱形土试样上的应力变弱。

在该试验方法里，无侧限抗压强度取单位面积上的最大荷载或者轴向应变为15%时的单位面积上的荷载，在进行试验期间，以最先取得的值为无侧限抗压强度。

混凝土无侧限抗压强度试验试件尺寸

混凝土无侧限抗压强度试验试件尺寸英文回答：Concrete Unconfined Compressive Strength Test Specimen Dimensions.The dimensions of concrete unconfined compressive strength test specimens are crucial in ensuring the accuracy and reliability of the test results. The American Society for Testing and Materials (ASTM) and the International Organization for Standardization (ISO) have established standardized specimen sizes and shapes for unconfined compressive strength testing of concrete.ASTM C39/C39M: Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens.Type: Cylindrical.Diameter: 150 mm (6 in)。

Height: 300 mm (12 in)。

ISO 1920-1: Testing of Concrete Part 1: Determination of Compressive Strength of Test Specimens.Type: Cylindrical.Diameter: 150 mm (6 in)。

Height: 300 mm (12 in) or 100 mm (4 in)。

Variations in Specimen Dimensions.Cube: While not as common as cylindrical specimens, cube-shaped specimens can also be used for unconfined compressive strength testing. The standard cube dimensions are 150 mm x 150 mm x 150 mm (6 in x 6 in x 6 in).Size Requirements: The minimum specimen size required for unconfined compressive strength testing depends on the maximum aggregate size used in the concrete. Specimens mustbe large enough to ensure that the failure plane is not influenced by the specimen boundaries.Height-to-Diameter Ratio: The height-to-diameter ratio (H/D) of cylindrical specimens is typically maintained within a range of 2:1 to 3:1. This ratio ensures uniform stress distribution and minimizes the effects of end restraint.Surface Preparation and Testing Procedure.Surface Preparation: The ends of the specimen should be flat and perpendicular to the loading axis.Testing Procedure: The specimen is placed in a compression testing machine and compressed axially at a constant rate of strain. The maximum load sustained by the specimen before failure is recorded as the unconfined compressive strength.Importance of Specimen Dimensions.Maintaining the specified specimen dimensions is essential for several reasons:Consistency and Repeatability: Standardized specimen sizes ensure consistency in testing procedures and allowfor the comparison of results from different laboratories.Representative Failure Mode: The appropriate specimen dimensions promote a failure mode that is representative of the actual behavior of concrete under unconfined compressive loads.Accurate Strength Measurement: The dimensions and shape of the specimen influence the stress distribution and failure mechanisms, which directly affect the measured compressive strength.中文回答：混凝土无侧限抗压强度试验试件尺寸。

ASTM D1621-2010

Designation:D1621–10Standard Test Method forCompressive Properties of Rigid Cellular Plastics1This standard is issued under theﬁxed designation D1621;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(´)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope*1.1This test method describes a procedure for determining the compressive properties of rigid cellular materials,particu-larly expanded plastics.1.2The values stated in SI units are to be regarded as the standard.The values in parentheses are for information only.1.3This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.N OTE1—This test method and ISO844are technically equivalent.2.Referenced Documents2.1ASTM Standards:2D618Practice for Conditioning Plastics for TestingE4Practices for Force Veriﬁcation of Testing MachinesE83Practice for Veriﬁcation and Classiﬁcation of Exten-someter SystemsE691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2ISO Standard:ISO844Cellular Plastics—Compression Test of Rigid Ma-terials33.Terminology3.1Deﬁnitions:3.1.1compliance—the displacement difference between test machine drive system displacement values and actual specimen displacement.3.1.2compliance correction—an analytical method of modifying test instrument displacement values to eliminate the amount of that measurement attributed to test instrument compliance.3.1.3compressive deformation—the decrease in length pro-duced in the gage length of the test specimen by a compressive load expressed in units of length.3.1.4compressive strain—the dimensionless ratio of com-pressive deformation to the gage length of the test specimen or the change in length per unit of original length along the longitudinal axis.3.1.5compressive strength—the stress at the yield point if a yield point occurs before10%deformation(as in Fig.1a)or, in the absence of such a yield point,the stress at10% deformation(as in Fig.1b).3.1.6compressive stress(nominal)—the compressive load per unit area of minimum original cross section within the gage boundaries,carried by the test specimen at any given moment, expressed in force per unit area.3.1.7compressive stress-strain diagram—a diagram in which values of compressive stress are plotted as ordinates against corresponding values of compressive strain as abscis-sas.3.1.8compressive yield point—theﬁrst point on the stress-strain diagram at which an increase in strain occurs without an increase in stress.3.1.9deﬂectometer—a device used to sense the compres-sive deﬂection of the specimen by direct measurement of the distance between the compression platens.3.1.10displacement—compression platen movement after the platens contact the specimen,expressed in millimetres or inches.3.1.11gage length—the initial measured thickness of the test specimen expressed in units of length.1This test method is under the jurisdiction of ASTM Committee D20on Plasticsand is the direct responsibility of Subcommittee D20.22on Cellular Materials-Plastics and Elastomers.Current edition approved April1,2010.Published April2010.Originallyapproved st previous edition approved in2004as D1621-04a.DOI:10.1520/D1621-10.2For referenced ASTM standards,visit the ASTM website,,orcontact ASTM Customer Service at service@.For Annual Book of ASTMStandards volume information,refer to the standard’s Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25W.43rd St.,4th Floor,New York,NY10036,.*A Summary of Changes section appears at the end of this standard. Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.3.1.12modulus of elasticity —the ratio of stress (nominal)to corresponding strain below the proportional limit of a material expressed in force per unit area based on the minimum initial cross-sectional area.3.1.13proportional limit —the greatest stress that a material is capable of sustaining without any deviation from propor-tionality of stress-to-strain (Hooke’s law)expressed in force per unit area.4.Signiﬁcance and Use4.1This test method provides information regarding the behavior of cellular materials under compressive loads.Test data is obtained,and from a complete load-deformation curve it is possible to compute the compressive stress at any load (such as compressive stress at proportional-limit load or compressive strength at maximum load)and to compute the effective modulus of elasticity.4.2Compression tests provide a standard method of obtain-ing data for research and development,quality control,accep-tance or rejection under speciﬁcations,and special purposes.The tests cannot be considered signiﬁcant for engineering design in applications differing widely from the load -time scale of the standard test.Such applications require additional tests such as impact,creep,and fatigue.4.3Before proceeding with this test method,reference shall be made to the speciﬁcation of the material being tested.Any test specimen preparation,conditioning,dimensions,or testing parameters,or a combination thereof,covered in the materials speciﬁcation shall take precedence over those mentioned in this test method.If there are no material speciﬁcations,then the default conditions apply.5.Apparatus5.1Testing Machine —A testing instrument that includes both a stationary and movable member and includes a drivesystem for imparting to the movable member (crosshead),a uniform,controlled velocity with respect to the stationary member (base).The testing machine shall also include the following:5.1.1Load Measurement System —A load measurement sys-tem capable of accurately recording the compressive load imparted to the test specimen.The system shall be indicate the load with an accuracy of 61%of the measured value or better.The accuracy of the load measurement system shall be veriﬁed in accordance with Practices E4.5.2Compression Platens —Two ﬂat plates,one attached to the stationary base of the testing instrument and the other attached to the moving crosshead to deliver the load to the test specimen.These plates shall be larger than the specimen loading surface to ensure that the specimen loading is uniform.It is recommended that one platen incorporate a spherical seating mechanism to compensate for non-parallelism in the specimen’s loading surfaces or non-parallelism in the base and crosshead of the testing instrument.5.3Displacement Measurement System —A displacement measurement system capable of accurately recording the com-pressive deformation of the test specimen during testing to an accuracy of 61%of the measured value or better.This measurement is made through use of the test machine cross-head drive system or using a direct measurement of compres-sion platen displacement.5.3.1Direct Compression Platen Displacement —This sys-tem shall employ a deﬂectometer that directly reads the distant between the upper and lower compression platens.The accu-racy of the displacement measurement transducer shall be veriﬁed in accordance with Practices E83and shall be classi-ﬁed as a Class C or better.5.3.2Test Machine Crosshead Drive System —This system shall employ the position output from the crosshead drive system as a indicator of compression platen displacement.ThisX 1=10%CORE DEFORMATIONX 2=DEFLECTION (APPROXIMATELY 13%)FIG.1a Compressive Strength (See 3.1.5and Section 9)FIG.1b Compressive Strength (See 3.1.5and Section 9)method is only appropriate when it is demonstrated that the effects of drive system compliance result in displacement errors of less than1%of the measurement or if appropriate compliance correction methods are employed to reduce the measurement error to less than1%.5.3.2.1Determining Drive System Compliance—Testing in-strument drive systems always exhibit a certain level of compliance that is characterized by a variance between the reported crosshead displacement and the displacement actually imparted to the specimen.This variance is a function of load frame stiffness,drive system wind-up,load cell compliance andﬁxture compliance.This compliance can be measured then, if determined to be signiﬁcant and empirically subtracted from test data to improve test accuracy.The procedure to determine compliance follows:(1)Conﬁgure the test system to match the actual test conﬁguration.(2)Position the two compression platens very close to each other simulating a zero thickness specimen in place.(3)Start the crosshead moving at12.5mm(0.5in.)/min in the compression direction recording crosshead displacement and the corresponding load values.(4)Increase load to a point exceeding the highest load expected during specimen testing.Stop the crosshead and return to the pre-test location.(5)The recorded load-deﬂection curve,starting when the compression platens contact one another,is deﬁned as test system compliance5.3.2.2Performing Compliance Correction—Using the load-deﬂection curve created in5.3.2.1,measure the system compliance at each given load value.On each specimen test curve at each given load value,subtract the system compliance from each recorded displacement value.This will be the new load-deﬂection curve for use in calculations starting in Section 9.5.4Micrometer Dial Gage,caliper,or steel rule,suitable for measuring dimensions of the specimens to61%of the measured values.6.Test Specimen6.1The test specimen shall be square or circular in cross section with a minimum of25.8cm2(4in.2)and maximum of 232cm2(36in.2)in area.The minimum height shall be25.4 mm(1in.)and the maximum height shall be no greater than the width or diameter of the specimen.Care should be taken so that the loaded ends of the specimen are parallel to each other and perpendicular to the sides.N OTE2—Cellular plastics are not ideal materials,and the compressive modulus may appear signiﬁcantly different,depending on the test condi-tions,particularly the test thickness.All data that are to be compared should be obtained using common test conditions.6.2All surfaces of the specimen shall be free from large visibleﬂaws or imperfections.6.3If the material is suspected to be anisotropic,the direction of the compressive loading must be speciﬁed relative to the suspected direction of anisotropy.6.4A minimum ofﬁve specimens shall be tested for each sample.Specimens that fail at some obviousﬂaw should be discarded and retests made,unless suchﬂaws constitute a variable the effect of which it is desired to study.7.Conditioning7.1Conditioning—Condition the test specimens at236 2°C(73.463.6°F)and50610%relative humidity for not less than40h prior to test in accordance with Procedure A of Practice D618,unless otherwise speciﬁed in the contract or relevant material speciﬁcation.In cases of disagreement,the tolerances shall be61°C(61.8°F)and65%relative humid-ity.7.2Test Conditions—Conduct tests in the standard labora-tory atmosphere of2362°C(73.463.6°F)and50610% relative humidity,unless otherwise speciﬁed.In cases of disagreement,the tolerances shall be61°C(61.8°F)and 65%relative humidity.8.Procedure8.1Measure the dimensions of the specimen to a precision of61%of the measurement as follows:8.1.1Thicknesses up to and including25.4mm(1in.)shall be measured using a dial-type gage having a foot with minimum area of6.45cm2(1in.2).Hold the pressure of the dial foot to0.1760.03kPa(0.02560.005psi).8.1.2Measure dimensions over25.4mm(1in.)with a dial gage,a sliding-caliper gage,or a steel scale.When a sliding-caliper gage is employed,the proper setting shall be that point at which the measuring faces of the gage contact the surfaces of the specimen without compressing them.8.1.3Record each dimension as an average of three mea-surements.8.2Place the specimen between the compression platens ensuring that the specimen center-line is aligned with the center-line of the compression platens and the load will be distributed as uniformly as possible over the entire loading surface of the specimen.It will expedite the testing process if, when the specimen is in place,the upper platen is positioned close to,but not touching,the specimen.8.2.1If following5.3.2.1,attach the deﬂectometer or com-pression extensometer to the compression platens.8.3Start the crosshead moving in the direction to compress the specimen with the rate of crosshead displacement of2.56 0.25mm(0.160.01in.)/min for each25.4mm(1in.)of specimen thickness.8.4Record compression platen displacement and the corre-sponding load data.This recorded curve will be used directly if following5.3.2.1or could be modiﬁed following5.3.2.2. 8.5Continue until a yield point is reached or until the specimen has been compressed approximately13%of its original thickness,whichever occursﬁrst.8.5.1When speciﬁed,a deformation other than10%may be used as the point at which stress shall be calculated.In such a case,compress the specimen approximately3%more than the deformation speciﬁed.Substitute the speciﬁed deformation wherever“10%deformation”is cited in Sections9and10.9.Calculation9.1Using a straightedge or through the use of computer software,carefully extend to the zero load line thesteepeststraight portion of the load-deﬂection curve examining only the lower portion of the load-deﬂection curve.This establishes the “zero deformation”or“zero strain”point(Point O in Fig.1a and Fig.1b).Measure all distances for deformation or strain calculations from this point.9.2Measure from Point O along the zero-load line a distance representing10%specimen deformation.At that point(Point M in Fig.1a and Fig.1b),draw a vertical line intersecting the load-deﬂection or load-strain curve at Point P.9.2.1If there is no yield point before Point P(as in Fig.1b),read the load at Point P.9.2.2If there is a yield point before Point P(as Point L in Fig.1),read the load and measure the percent core deformation or strain(Distance O-R)at the yield point.9.2.3Calculate the compressive strength by dividing the load(9.2.1or9.2.2)by the initial horizontal cross-sectional area of the specimen.9.3If compressive modulus is requested,choose any con-venient point(such as Point S in Fig.1b)along the steepest straight line portion of the load-deﬂection or load-strain curve. Read the load and measure the deformation or strain(Distance O-T)at that point.9.3.1Calculate the apparent modulus as follows:E c5WH/AD(1) where:E c=modulus of elasticity in compression,Pa(psi),W=load,N(lbf),H=initial specimen height,m(in.),A=initial horizontal cross-sectional area,m2(in.2),and D=deformation,m(in.).9.3.2Calculate the estimated standard deviation as follows:s5=~(x22nX¯2!/~n21!(2) where:s=estimated standard deviation,x=value of a single observation,n=number of observations,andX¯=arithmetic mean of the set of observations.10.Report10.1Report the following information:10.1.1Complete identiﬁcation of the material tested,includ-ing type,source,code numbers,form,principal dimensions, previous history,and so forth.10.1.2Number of specimens tested if different from that speciﬁed in6.4.10.1.3Conditioning procedure used if different from that speciﬁed in Section7.10.1.4Atmospheric conditions in test room if different from those speciﬁed in Section7.10.1.5Values for each specimen,plus averages and standard deviations,of modulus(if requested)and compressive strength.10.1.6Deformation at maximum load to two signiﬁcant ﬁgures.10.1.7Date of test.11.Precision11.1Table1is based on a round robin4conducted in1998 in accordance with Practice E691,involving three materials tested by seven laboratories.For each material,all of the samples were prepared at one source,but the individual specimens were prepared at the laboratories that tested them. Each test result was the average of seven individual determi-nations.Each laboratory obtained six test results for each material.Precision,characterized by repeatability(S r and r) and reproducibility(S R and R)has been determined as shown in Table1.(Warning—The explanation of r and R are only intended to present a meaningful way of considering the approximate precision of this test method.The data in Table1 should not be applied to acceptance or rejection of materials,as these data apply only to the materials tested in the round robin and are unlikely to be rigorously representative of other lots, formulations,conditions,materials,or ers of this test method should apply the principles outlined in Practice E691to generate data speciﬁc to their materials and labora-tory.)N OTE3—The precision data presented in Table1was obtained using the test conditions deﬁned in this test method.If a material speciﬁcation deﬁnes other test conditions,this precision data shall not be assumed to apply.12.Keywords12.1cellular plastics;compressive modulus;compressive strength4Supporting data are available from ASTM Headquarters.Request RR:D20-1201.TABLE1Precision DataMaterials Average,psi S r A S R B r C R D A13.6307 1.1491 1.6078 3.2174 4.5019B31.3183 1.0944 1.1213 3.0642 3.1398C10.39810.9796 1.0764 2.7430 3.0141A Sr=within-laboratory standard deviation for the indicated material.It is obtained by pooling the within-laboratory standard deviations of the test results from all of the participating laboratories.B SR=between-laboratories reproducibility,expressed as standard deviation.C r=within-laboratory critical interval between two test results=2.83Sr.D R=between-laboratories critical interval between two test results=2.83SR.SUMMARY OF CHANGESCommittee D20has identiﬁed the location of selected changes to this standard since the last issue (D1621-04a)that may impact the use of this standard.(April1,2010)(1)Revised Section7.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this ers of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed everyﬁve years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959, United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the aboveaddress or at610-832-9585(phone),610-832-9555(fax),or service@(e-mail);or through the ASTM website().Permission rights to photocopy the standard may also be secured from the ASTM website(/COPYRIGHT/).。

混凝土材料耐久性测试标准

混凝土材料耐久性测试标准一、引言混凝土是建筑中最常用的材料之一，它的性能直接影响到建筑物的使用寿命和安全性。

为了保证混凝土的耐久性，需要对其进行耐久性测试。

本文将介绍混凝土材料耐久性测试的标准。

二、耐久性测试的目的混凝土材料在使用过程中受到多种因素的影响，如水分、氧气、氯离子、二氧化碳等，这些因素会导致混凝土的性能发生变化，最终影响混凝土的耐久性。

因此，耐久性测试的目的在于评估混凝土材料在不同环境下的耐久性，以便确定混凝土的使用寿命和质量。

三、耐久性测试的内容1. 抗压强度测试抗压强度是评估混凝土性能的重要指标之一，它可以反映混凝土的质量和强度。

抗压强度测试是通过在规定的时间内施加压力来测试混凝土的强度。

测试结果可以用来评估混凝土的质量和强度，以及它在不同环境下的耐久性。

2. 吸水性测试混凝土的吸水性是它的另一个重要性能指标。

吸水性测试是通过将混凝土浸泡在水中一段时间后，测量混凝土吸收水分的能力来测试混凝土的吸水性。

测试结果可以用来评估混凝土的抗渗性和耐久性。

3. 抗冻性测试混凝土在低温环境下容易发生冻融损伤，因此抗冻性是评估混凝土耐久性的重要指标之一。

抗冻性测试是通过将混凝土暴露在低温环境下一段时间，然后测量混凝土的强度和质量变化来测试混凝土的抗冻性。

测试结果可以用来评估混凝土在低温环境下的耐久性。

4. 抗碱性测试混凝土中含有的氢氧化钙会和水反应产生氢氧化钙，进而引起混凝土的碱性变化。

抗碱性测试是通过将混凝土暴露在高碱环境下一段时间，然后测量混凝土的强度和质量变化来测试混凝土的抗碱性。

测试结果可以用来评估混凝土在高碱环境下的耐久性。

5. 抗氯离子渗透性测试氯离子是混凝土中的一种常见有害物质，它会进入混凝土内部并与混凝土中的钙离子反应，从而引起混凝土的变质和开裂。

抗氯离子渗透性测试是通过将混凝土暴露在含氯环境下一段时间，然后测量混凝土中氯离子的渗透深度来测试混凝土的抗氯离子渗透性。

测试结果可以用来评估混凝土在含氯环境下的耐久性。

混凝土抗压试验参考文献

混凝土抗压试验参考文献混凝土抗压试验是评估混凝土在承受外部压力时的强度和稳定性的关键方法。

通过进行抗压试验，我们能够了解混凝土的力学性能，为工程设计和施工提供可靠的依据。

以下是一些相关的参考文献。

1. ACI 318-14 "Building Code Requirements for Structural Concrete"：这是美国混凝土协会（ACI）发布的混凝土结构设计规范，其中包含了混凝土抗压试验的要求和方法。

2. ASTM C39/C39M-20 "Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens"：这是美国材料和试验协会（ASTM）发布的混凝土抗压试验的标准方法，通过对圆柱形混凝土试样进行压力加载，评估混凝土的抗压强度。

3. ASTM C78/C78M-18 "Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)"：这是ASTM发布的混凝土抗弯强度测试方法，通过对简支梁进行三点弯曲加载，评估混凝土的抗弯强度。

4. BS EN 12390-3:2019 "Testing hardened concrete - Part 3: Compressive strength of test specimens"：这是欧洲标准化组织（CEN）发布的混凝土抗压试验的标准方法，其中包括对试样进行压力加载，评估混凝土的抗压强度。

5. BS EN 12390-5:2019 "Testing hardened concrete - Part 5: Flexural strength of test specimens"：这是CEN发布的混凝土抗弯强度测试方法，通过对试样进行弯曲加载，评估混凝土的抗弯强度。

混凝土试件尺寸标准

混凝土试件尺寸标准一、引言混凝土是一种广泛应用的材料，其性能的好坏直接影响到建筑物的安全性能。

混凝土试件是测试混凝土性能的重要手段之一，而混凝土试件尺寸标准则是保证试件质量和测试结果准确性的重要保障。

本文将对混凝土试件尺寸标准进行详细讲解。

二、试件类型混凝土试件一般分为立方体试件、圆柱试件和棱柱试件。

其中，立方体试件是最常见的试件类型，一般用于强度试验和变形试验。

圆柱试件用于确定混凝土的抗压强度和弹性模量等力学性能，而棱柱试件则用于测定混凝土的抗弯强度和剪切强度等性能。

三、试件尺寸1. 立方体试件尺寸标准立方体试件的尺寸标准主要有以下两种：(1) GB/T 50081-2002《混凝土结构设计规范》规定：立方体试件的边长应为150mm，允许偏差范围为±1.5mm。

(2) ASTM C39/C39M-18a《Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens》规定：立方体试件的边长应为6英寸（152.4mm），允许偏差范围为±0.02英寸（0.5mm）。

2. 圆柱试件尺寸标准圆柱试件的尺寸标准主要有以下两种：(1) GB/T 50081-2002《混凝土结构设计规范》规定：圆柱试件的直径应为150mm，高度应为300mm，允许偏差范围为±1.5mm。

(2) ASTM C39/C39M-18a《Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens》规定：圆柱试件的直径应为4英寸（101.6mm），高度应为8英寸（203.2mm），允许偏差范围为±0.02英寸（0.5mm）。

3. 棱柱试件尺寸标准棱柱试件的尺寸标准主要有以下两种：(1) GB/T 50081-2002《混凝土结构设计规范》规定：棱柱试件的截面尺寸应为150mm×150mm，高度应为300mm，允许偏差范围为±1.5mm。

pdf 混凝土强度检验评定标准

pdf 混凝土强度检验评定标准PDF文件是一种通用的电子文档格式，可以包含各种类型的内容，包括检验评定标准。

混凝土强度检验评定标准通常由独立的标准化机构或相关行业组织制定，并通过电子文档或纸质文档的形式进行发布。

具体的PDF混凝土强度检验评定标准取决于所使用的标准和国家或地区的要求。

以下是一些常用的混凝土强度检验评定标准，可能在PDF格式中提供：
1. ASTM C39/C39M-20 - "Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens"：美国材料和试验协会（ASTM）发布的关于混凝土圆柱体抗压强度测试的标准。

2. EN 12390-3:2019 – "Testing hardened concrete – Part 3: Compressive strength of test specimens"：欧洲标准化委员会（CEN）发布的关于混凝土试样抗压强度测试的标准。

3. ACI 318-19 – "Building Code Requirements for Structural Concrete"：美国混凝土协会（ACI）发布的关
于结构混凝土建筑规范，其中包括有关混凝土强度检验和评定的要求。

要获取具体的PDF混凝土强度检验评定标准的副本，建议您查阅相关标准化机构的网站或联络相应的标准颁布机构（如ASTM、CEN、ACI等）以获取最新版本的标准文件。

这样可以获得最准确、最新的混凝土强度检验评定标准的PDF版本。

混凝土压缩强度检测标准

混凝土压缩强度检测标准一、前言混凝土是建筑中常见的材料之一，它具有强度高、耐久性好、施工方便等优点，因此在建筑中得到广泛应用。

然而，混凝土强度的检测对于保证建筑质量至关重要。

本文将就混凝土压缩强度检测标准进行详细说明。

二、混凝土压缩强度检测标准概述混凝土压缩强度检测旨在评估混凝土的质量，通过测定混凝土的抗压强度来判断其是否符合设计要求。

通常情况下，混凝土的压缩强度检测是在混凝土的成型后进行的。

在混凝土的成型过程中，需要保证混凝土的配合比、水灰比等参数符合设计要求，以确保混凝土的质量。

三、混凝土压缩强度检测方法1. 实验设备混凝土压缩强度检测需要使用压力机，压力机的规格、型号应符合相关标准要求。

同时，还需要使用混凝土试块模具、试块抹光器、试块灰尘刷等实验设备。

2. 试块制备试块制备是混凝土压缩强度检测的重要步骤。

试块制备需要按照相关标准进行，试块模具的尺寸应符合标准要求。

在制备试块的过程中，需要注意保证混凝土的配合比、水灰比等参数符合设计要求。

3. 试块养护试块的养护是混凝土压缩强度检测的另一个重要步骤。

试块养护需要在试块成型后尽快进行，养护的时间应符合相关标准要求。

在试块养护的过程中，需要注意保持试块表面湿润，避免试块表面出现龟裂等情况。

4. 试块检测试块检测是混凝土压缩强度检测的最后一步。

试块检测需要使用压力机进行，检测时需要注意压力机的工作稳定性、试块的位置等因素。

检测时需要记录试块的破坏强度，并进行数据分析。

四、混凝土压缩强度检测标准混凝土压缩强度检测的标准有多个，以下介绍几个常用的标准：1. GB/T 50081-2002《混凝土试验方法标准规程》2. JGJ/T 70-2009《建筑混凝土强度检测与评定规范》3. ASTM C39/C39M-18a《Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens》4. ACI 318-19《Building Code Requirements for Structural Concrete and Commentary》五、混凝土压缩强度检测结果分析混凝土压缩强度检测的结果需要进行数据分析，通常情况下需要计算出试块的平均强度值以及标准偏差等数据。

管型塑料压缩强度检测标准

管型塑料压缩强度检测标准
管型塑料的压缩强度检测通常会遵循特定的标准和测试方法。

以下是一些常见用于管型塑料压缩强度检测的标准：
1. ASTM D695 - Standard Test Method for Compressive Properties of Rigid Plastics
- 用于测定刚性塑料材料的抗压性能。

2. ISO 604 - Plastics - Determination of Compressive Properties
- 用于测定塑料材料的压缩性能。

3. EN 12127 - Plastics - Unplasticized poly (vinyl chloride) (PVC-U) moulding and extrusion materials - Part 3: Preparation of test specimens and determination of properties
- 用于硬质聚氯乙烯（PVC-U）材料的性能测定,包括压缩性能。

这些标准提供了管型塑料材料的压缩强度测试所需的标准测试程序、样品制备、试验设备和数据报告等细节。

不
同的国家或地区可能有自己的相关标准，因此在进行压缩强度测试时，应当根据具体的应用要求和管道材料的类型选择相应的标准进行测试。

在进行管型塑料的压缩强度测试时，应遵循相应的标准操作程序，确保测试结果的准确性和可靠性。

如果需要进行这方面的测试，建议寻求专业的材料测试实验室或工程机构的帮助，以确保测试按照标准进行并得到准确的结果。

混凝土制品的标准硬度

混凝土制品的标准硬度混凝土制品的标准硬度混凝土制品是一种常见的建筑材料，用于制造各种建筑构件，如地基、墙体、楼板等。

混凝土制品的质量直接关系到建筑物的安全性和耐久性，因此，混凝土制品的硬度是一个重要的性能指标。

标准硬度的概念标准硬度是指一种材料在特定条件下的硬度指标，通常使用一定的试验方法进行测试，并将测试结果与相应的标准进行比较，以确定材料的硬度是否符合标准。

标准硬度对于混凝土制品来说，是一个重要的质量控制指标，可以用于检测混凝土制品的硬度是否符合要求。

混凝土制品的标准硬度测试方法混凝土制品的标准硬度测试通常使用压力试验法进行。

该测试方法需要使用一台万能试验机和一组压力板，压力板的尺寸和形状应符合相应的标准。

测试时，将混凝土制品放在压力板上，然后向上施加一定的压力，直到混凝土制品发生破坏。

测试过程中需要记录下压力和位移的变化，并计算出混凝土制品的标准硬度。

混凝土制品的标准硬度标准混凝土制品的标准硬度标准通常由国际标准组织或各国的建筑标准化机构制定。

以下是一些常用的混凝土制品标准硬度标准：1. ASTM C39/C39M-20a Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens该标准规定了用于测试混凝土圆柱体的压力试验法。

标准规定了测试所需的设备、试样制备方法、测试程序和结果计算方法。

2. BS EN 12390-3:2019 Testing hardened concrete - Part 3: Compressive strength of test specimens该标准规定了用于测试混凝土试样（包括立方体、圆柱体和长方体）的压力试验法。

标准规定了测试所需的设备、试样制备方法、测试程序和结果计算方法。

3. GB/T 50081-2002 混凝土强度检验方法标准该标准规定了用于测试混凝土试样（包括立方体、圆柱体和长方体）的压力试验法。

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Designation:C39/C39M–12Standard Test Method forCompressive Strength of Cylindrical Concrete Specimens1 This standard is issued under theﬁxed designation C39/C39M;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(´)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope*1.1This test method covers determination of compressive strength of cylindrical concrete specimens such as molded cylinders and drilled cores.It is limited to concrete having a density in excess of800kg/m3[50lb/ft3].1.2The values stated in either SI units or inch-pound units are to be regarded separately as standard.The inch-pound units are shown in brackets.The values stated in each system may not be exact equivalents;therefore,each system shall be used independently of the bining values from the two systems may result in non-conformance with the standard. 1.3This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.(Warning—Means should be provided to contain concrete fragments during sudden rupture of specimens.Tendency for sudden rupture increases with increasing concrete strength and it is more likely when the testing machine is relativelyﬂexible.The safety precautions given in the Manual of Aggregate and Concrete Testing are recommended.)1.4The text of this standard references notes which provide explanatory material.These notes shall not be considered as requirements of the standard.2.Referenced Documents2.1ASTM Standards:2C31/C31M Practice for Making and Curing Concrete Test Specimens in the FieldC42/C42M Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of ConcreteC192/C192M Practice for Making and Curing Concrete Test Specimens in the LaboratoryC617Practice for Capping Cylindrical Concrete Specimens C670Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsC873Test Method for Compressive Strength of Concrete Cylinders Cast in Place in Cylindrical MoldsC1077Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency EvaluationC1231/C1231M Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Con-crete CylindersE4Practices for Force Veriﬁcation of Testing MachinesE74Practice of Calibration of Force-Measuring Instru-ments for Verifying the Force Indication of Testing Ma-chinesManual of Aggregate and Concrete Testing3.Summary of Test Method3.1This test method consists of applying a compressive axial load to molded cylinders or cores at a rate which is within a prescribed range until failure occurs.The compressive strength of the specimen is calculated by dividing the maxi-mum load attained during the test by the cross-sectional area of the specimen.4.Signiﬁcance and Use4.1Care must be exercised in the interpretation of the signiﬁcance of compressive strength determinations by this test method since strength is not a fundamental or intrinsic property of concrete made from given materials.Values obtained will depend on the size and shape of the specimen,batching,mixing1This test method is under the jurisdiction of ASTM Committee C09onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.61on Testing for Strength.Current edition approved Feb.1,2012.Published March2012.Originallyapproved st previous edition approved in2011as C39/C39M–11a.DOI:10.1520/C0039_C0039M-12.2For referenced ASTM standards,visit the ASTM website,,orcontact ASTM Customer Service at service@.For Annual Book of ASTMStandards volume information,refer to the standard’s Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standard. Copyright.C ASTM International.100Barr Harbor Dr.P.O.box C-700West Conshohocken,Pennsylvania.19428-2959,United Statesprocedures,the methods of sampling,molding,and fabrication and the age,temperature,and moisture conditions during curing.4.2This test method is used to determine compressive strength of cylindrical specimens prepared and cured in accor-dance with Practices C31/C31M,C192/C192M,C617,and C1231/C1231M and Test Methods C42/C42M and C873. 4.3The results of this test method are used as a basis for quality control of concrete proportioning,mixing,and placing operations;determination of compliance with speciﬁcations; control for evaluating effectiveness of admixtures;and similar uses.4.4The individual who tests concrete cylinders for accep-tance testing shall meet the concrete laboratory technician requirements of Practice C1077,including an examination requiring performance demonstration that is evaluated by an independent examiner.N OTE1—Certiﬁcation equivalent to the minimum guidelines for ACI Concrete Laboratory Technician,Level I or ACI Concrete Strength Testing Technician will satisfy this requirement.5.Apparatus5.1Testing Machine—The testing machine shall be of a type having sufficient capacity and capable of providing the rates of loading prescribed in7.5.5.1.1Verify calibration of the testing machines in accor-dance with Practices E4,except that the veriﬁed loading range shall be as required in5.3.Veriﬁcation is required under the following conditions:5.1.1.1At least annually,but not to exceed13months, 5.1.1.2On original installation or immediately after reloca-tion,5.1.1.3Immediately after making repairs or adjustments that affect the operation of the force applying system or the values displayed on the load indicating system,except for zero adjustments that compensate for the mass of bearing blocks or specimen,or both,or5.1.1.4Whenever there is reason to suspect the accuracy of the indicated loads.5.1.2Design—The design of the machine must include the following features:5.1.2.1The machine must be power operated and must apply the load continuously rather than intermittently,and without shock.If it has only one loading rate(meeting the requirements of7.5),it must be provided with a supplemental means for loading at a rate suitable for veriﬁcation.This supplemental means of loading may be power or hand oper-ated.5.1.2.2The space provided for test specimens shall be large enough to accommodate,in a readable position,an elastic calibration device which is of sufficient capacity to cover the potential loading range of the testing machine and which complies with the requirements of Practice E74.N OTE2—The types of elastic calibration devices most generally avail-able and most commonly used for this purpose are the circular proving ring or load cell.5.1.3Accuracy—The accuracy of the testing machine shall be in accordance with the following provisions:5.1.3.1The percentage of error for the loads within the proposed range of use of the testing machine shall not exceed 61.0%of the indicated load.5.1.3.2The accuracy of the testing machine shall be veriﬁed by applyingﬁve test loads in four approximately equal increments in ascending order.The difference between any two successive test loads shall not exceed one third of the differ-ence between the maximum and minimum test loads.5.1.3.3The test load as indicated by the testing machine and the applied load computed from the readings of the veriﬁcation device shall be recorded at each test point.Calculate the error, E,and the percentage of error,E p,for each point from these data as follows:E5A2B(1)E p5100~A2B!/Bwhere:A=load,kN[lbf]indicated by the machine being veriﬁed, andB=applied load,kN[lbf]as determined by the calibrating device.5.1.3.4The report on the veriﬁcation of a testing machine shall state within what loading range it was found to conform to speciﬁcation requirements rather than reporting a blanket acceptance or rejection.In no case shall the loading range be stated as including loads below the value which is100times the smallest change of load estimable on the load-indicating mechanism of the testing machine or loads within that portion of the range below10%of the maximum range capacity. 5.1.3.5In no case shall the loading range be stated as including loads outside the range of loads applied during the veriﬁcation test.5.1.3.6The indicated load of a testing machine shall not be corrected either by calculation or by the use of a calibration diagram to obtain values within the required permissible variation.5.2The testing machine shall be equipped with two steel bearing blocks with hardened faces(Note3),one of which is a spherically seated block that will bear on the upper surface of the specimen,and the other a solid block on which the specimen shall rest.Bearing faces of the blocks shall have a minimum dimension at least3%greater than the diameter of the specimen to be tested.Except for the concentric circles described below,the bearing faces shall not depart from a plane by more than0.02mm[0.001in.]in any150mm[6in.]of blocks150mm[6in.]in diameter or larger,or by more than 0.02mm[0.001in.]in the diameter of any smaller block;and new blocks shall be manufactured within one half of this tolerance.When the diameter of the bearing face of the spherically seated block exceeds the diameter of the specimen by more than13mm[0.5in.],concentric circles not more than 0.8mm[0.03in.]deep and not more than1mm[0.04in.]wide shall be inscribed to facilitate proper centering.N OTE3—It is desirable that the bearing faces of blocks used for compression testing of concrete have a Rockwell hardness of not less than 55HRC.5.2.1Bottom bearing blocks shall conform to the followingrequirements:5.2.1.1The bottom bearing block is speciﬁed for the pur-pose of providing a readily machinable surface for mainte-nance of the speciﬁed surface conditions(Note4).The top and bottom surfaces shall be parallel to each other.If the testing machine is so designed that the platen itself is readily main-tained in the speciﬁed surface condition,a bottom block is not required.Its least horizontal dimension shall be at least3% greater than the diameter of the specimen to be tested. Concentric circles as described in5.2are optional on the bottom block.N OTE4—The block may be fastened to the platen of the testing machine.5.2.1.2Final centering must be made with reference to the upper spherical block.When the lower bearing block is used to assist in centering the specimen,the center of the concentric rings,when provided,or the center of the block itself must be directly below the center of the spherical head.Provision shall be made on the platen of the machine to assure such a position.5.2.1.3The bottom bearing block shall be at least25mm[1 in.]thick when new,and at least22.5mm[0.9in.]thick after any resurfacing operations.5.2.2The spherically seated bearing block shall conform to the following requirements:5.2.2.1The maximum diameter of the bearing face of the suspended spherically seated block shall not exceed the values given below:Diameter of Maximum DiameterTest Specimens,of Bearing Face,mm[in.]mm[in.]50[2]105[4]75[3]130[5]100[4]165[6.5]150[6]255[10]200[8]280[11]N OTE5—Square bearing faces are permissible,provided the diameter of the largest possible inscribed circle does not exceed the above diameter.5.2.2.2The center of the sphere shall coincide with the surface of the bearing face within a tolerance of65%of the radius of the sphere.The diameter of the sphere shall be at least 75%of the diameter of the specimen to be tested.5.2.2.3The ball and the socket shall be designed so that the steel in the contact area does not permanently deform when loaded to the capacity of the testing machine.N OTE6—The preferred contact area is in the form of a ring(described as“preferred bearing area”)as shown on Fig.1.5.2.2.4At least every six months,or as speciﬁed by the manufacturer of the testing machine,clean and lubricate the curved surfaces of the socket and of the spherical portion of the machine.The lubricant shall be a petroleum-type oil such as conventional motor oil or as speciﬁed by the manufacturer of the testing machine.N OTE7—To ensure uniform seating,the spherically seated head is designed to tilt freely as it comes into contact with the top of the specimen. After contact,further rotation is undesirable.Friction between the socket and the spherical portion of the head provides restraint against further rotation during loading.Petroleum-type oil such as conventional motor oil has been shown to permit the necessary friction to develop.Pressure-type greases can reduce the desired friction and permit undesired rotation of the spherical head and should not be used unless recommended by the manufacturer of the testing machine.5.2.2.5If the radius of the sphere is smaller than the radius of the largest specimen to be tested,the portion of the bearing face extending beyond the sphere shall have a thickness not less than the difference between the radius of the sphere and radius of the specimen.The least dimension of the bearing face shall be at least as great as the diameter of the sphere(see Fig.1).5.2.2.6The movable portion of the bearing block shall be held closely in the spherical seat,but the design shall be such that the bearing face can be rotated freely and tilted at least4°in any direction.5.2.2.7If the ball portion of the upper bearing block is a two-piece design composed of a spherical portion and a bearing plate,a mechanical means shall be provided to ensure that the spherical portion isﬁxed and centered on the bearing plate.5.3Load Indication:5.3.1If the load of a compression machine used in concrete testing is registered on a dial,the dial shall be provided with a graduated scale that is readable to at least the nearest0.1%of the full scale load(Note8).The dial shall be readable within 1%of the indicated load at any given load level within the loading range.In no case shall the loading range of a dial be considered to include loads below the value that is100times the smallest change of load that can be read on the scale.The scale shall be provided with a graduation line equal to zero and so numbered.The dial pointer shall be of sufficient length to reach the graduation marks;the width of the end of the pointer shall not exceed the clear distance between the smallest graduations.Each dial shall be equipped with a zero adjust-ment located outside the dialcase and easily accessible from the front of the machine while observing the zero mark and dial pointer.Each dial shall be equipped with a suitable device that at all times,until reset,will indicate to within1%accuracy the maximum load applied to thespecimen.N OTE—Provision shall be made for holding the ball in the socket and for holding the entire unit in the testing machine.FIG.1Schematic Sketch of a Typical Spherical BearingBlockN OTE8—Readability is considered to be0.5mm[0.02in.]along the arc described by the end of the pointer.Also,one half of a scale interval is readable with reasonable certainty when the spacing on the load indicating mechanism is between1mm[0.04in.]and2mm[0.06in.].When the spacing is between2and3mm[0.06and0.12in.],one third of a scale interval is readable with reasonable certainty.When the spacing is3mm [0.12in.]or more,one fourth of a scale interval is readable with reasonable certainty.5.3.2If the testing machine load is indicated in digital form, the numerical display must be large enough to be easily read. The numerical increment must be equal to or less than0.10% of the full scale load of a given loading range.In no case shall the veriﬁed loading range include loads less than the minimum numerical increment multiplied by100.The accuracy of the indicated load must be within1.0%for any value displayed within the veriﬁed loading range.Provision must be made for adjusting to indicate true zero at zero load.There shall be provided a maximum load indicator that at all times until reset will indicate within1%system accuracy the maximum load applied to the specimen.5.4Documentation of the calibration and maintenance of the testing machine shall be in accordance with Practice C1077.6.Specimens6.1Specimens shall not be tested if any individual diameter of a cylinder differs from any other diameter of the same cylinder by more than2%.N OTE9—This may occur when single use molds are damaged or deformed during shipment,whenﬂexible single use molds are deformed during molding,or when a core drill deﬂects or shifts during drilling. 6.2Prior to testing,neither end of test specimens shall depart from perpendicularity to the axis by more than0.5°(approximately equivalent to1mm in100mm[0.12in.in12 in.]).The ends of compression test specimens that are not plane within0.050mm[0.002in.]shall be sawed or ground to meet that tolerance,or capped in accordance with either Practice C617or,when permitted,Practice C1231/C1231M.The diam-eter used for calculating the cross-sectional area of the test specimen shall be determined to the nearest0.25mm[0.01in.] by averaging two diameters measured at right angles to each other at about midheight of the specimen.6.3The number of individual cylinders measured for deter-mination of average diameter is not prohibited from being reduced to one for each ten specimens or three specimens per day,whichever is greater,if all cylinders are known to have been made from a single lot of reusable or single-use molds which consistently produce specimens with average diameters within a range of0.5mm[0.02in.].When the average diameters do not fall within the range of0.5mm[0.02in.]or when the cylinders are not made from a single lot of molds, each cylinder tested must be measured and the value used in calculation of the unit compressive strength of that specimen. When the diameters are measured at the reduced frequency,the cross-sectional areas of all cylinders tested on that day shall be computed from the average of the diameters of the three or more cylinders representing the group tested that day.6.4If the purchaser of the testing services requests measure-ment of density of test specimens,determine the mass of specimens before capping.Remove any surface moisture with a towel and measure the mass of the specimen using a balance or scale that is accurate to within0.3%of the mass being measured.Measure the length of the specimen to the nearest1 mm[0.05in.]at three locations spaced evenly around the pute the average length and record to the nearest1mm[0.05in.].Alternatively,determine the cylinder density by weighing the cylinder in air and then submerged under water at23.062.0°C[73.563.5°F],and computing the volume according to8.3.1.6.5When density determination is not required and the length to diameter ratio is less than1.8or more than2.2, measure the length of the specimen to the nearest0.05D.7.Procedure7.1Compression tests of moist-cured specimens shall be made as soon as practicable after removal from moist storage.7.2Test specimens shall be kept moist by any convenient method during the period between removal from moist storage and testing.They shall be tested in the moist condition.7.3All test specimens for a given test age shall be broken within the permissible time tolerances prescribed as follows: Test Age Permissible Tolerance24h60.5h or2.1%3days2h or2.8%7days6h or3.6%28days20h or3.0%90days2days2.2%7.4Placing the Specimen—Place the plain(lower)bearing block,with its hardened face up,on the table or platen of the testing machine directly under the spherically seated(upper) bearing block.Wipe clean the bearing faces of the upper and lower bearing blocks and of the test specimen and place the test specimen on the lower bearing block.Carefully align the axis of the specimen with the center of thrust of the spherically seated block.7.4.1Zero Veriﬁcation and Block Seating—Prior to testing the specimen,verify that the load indicator is set to zero.In cases where the indicator is not properly set to zero,adjust the indicator(Note10).After placing the specimen in the machine but prior to applying the load on the specimen,tilt the movable portion of the spherically seated block gently by hand so that the bearing face appears to be parallel to the top of the test specimen.N OTE10—The technique used to verify and adjust load indicator to zero will vary depending on the machine manufacturer.Consult your owner’s manual or compression machine calibrator for the proper tech-nique.7.5Rate of Loading—Apply the load continuously and without shock.7.5.1The load shall be applied at a rate of movement(platen to crosshead measurement)corresponding to a stress rate on the specimen of0.2560.05MPa/s[3567psi/s](See Note 11).The designated rate of movement shall be maintained at least during the latter half of the anticipated loading phase. N OTE11—For a screw-driven or displacement-controlled testing ma-chine,preliminary testing will be necessary to establish the required rate of movement to achieve the speciﬁed stress rate.The required rateofmovement will depend on the size of the test specimen,the elastic modulus of the concrete,and the stiffness of the testing machine.7.5.2During application of the ﬁrst half of the anticipated loading phase,a higher rate of loading shall be permitted.The higher loading rate shall be applied in a controlled manner so that the specimen is not subjected to shock loading.7.5.3Make no adjustment in the rate of movement (platen to crosshead)as the ultimate load is being approached and the stress rate decreases due to cracking in the specimen.7.6Apply the compressive load until the load indicator shows that the load is decreasing steadily and the specimen displays a well-deﬁned fracture pattern (Types 1to 4in Fig.2).For a testing machine equipped with a specimen break detector,automatic shut-off of the testing machine is prohibited until the load has dropped to a value that is less than 95%of the peak load.When testing with unbonded caps,a corner fracture similar to a Type 5or 6pattern shown in Fig.2may occur before the ultimate capacity of the specimen has been attained.Continue compressing the specimen until the user is certain that the ultimate capacity has been attained.Record the maximum load carried by the specimen during the test,and note the type of fracture pattern according to Fig.2.If the fracture pattern is not one of the typical patterns shown in Fig.2,sketch and describe brieﬂy the fracture pattern.If the measured strength is lower than expected,examine the frac-tured concrete and note the presence of large air voids,evidence of segregation,whether fractures pass predominantly around or through the coarse aggregate particles,and verify end preparations were in accordance with Practice C617or Practice C1231/C1231M .8.Calculation8.1Calculate the compressive strength of the specimen by dividing the maximum load carried by the specimen during the test by the average cross-sectional area determined as de-scribed in Section 6and express the result to the nearest 0.1MPa [10psi].8.2If the specimen length to diameter ratio is 1.75or less,correct the result obtained in 8.1by multiplying by the appropriate correction factor shown in the following table Note 12:L/D: 1.75 1.50 1.25 1.00Factor:0.980.960.930.87Use interpolation to determine correction factors for L/D values between those given in thetable.FIG.2Schematic of Typical FracturePatternsN OTE12—Correction factors depend on various conditions such as moisture condition,strength level,and elastic modulus.Average values are given in the table.These correction factors apply to low-density concrete weighing between1600and1920kg/m3[100and120lb/ft3]and to normal-density concrete.They are applicable to concrete dry or soaked at the time of loading and for nominal concrete strengths from14to42MPa [2000to6000psi].For strengths higher than42MPa[6000psi]correction factors may be larger than the values listed above3.8.3When required,calculate the density of the specimen to the nearest10kg/m3[1lb/ft3]as follows:Density5WV(2)where:W=mass of specimen,kg[lb],andV=volume of specimen computed from the average diameter and average length or from weighing thecylinder in air and submerged,m3[ft3]8.3.1When the volume is determined from submerged weighing,calculate the volume as follows:V5W–W sg w(3)where:W s=apparent mass of submerged specimen,kg[lb],andg w=density of water at23°C[73.5°F]=997.5kg/m3[62.27lbs/ft3].9.Report9.1Report the following information:9.1.1Identiﬁcation number,9.1.2Average measured diameter(and measured length,if outside the range of1.8D to2.2D),in millimetres[inches], 9.1.3Cross-sectional area,in square millimetres[square inches],9.1.4Maximum load,in kilonewtons[pounds-force],9.1.5Compressive strength calculated to the nearest0.1 MPa[10psi],9.1.6Type of fracture(see Fig.2),9.1.7Defects in either specimen or caps,and,9.1.8Age of specimen.9.1.9When determined,the density to the nearest10kg/ m3[1lb/ft3].10.Precision and Bias10.1Precision10.1.1Within-Test Precision—The following table provides the within-test precision of tests of150by300mm[6by12 in.]and100by200mm[4by8in.]cylinders made from a well-mixed sample of concrete under laboratory conditions and underﬁeld conditions(see10.1.2).Coefficient ofVariation4Acceptable Range4ofIndividual Cylinder Strengths2cylinders3cylinders 150by300mm[6by12in.]Laboratory conditions 2.4% 6.6%7.8% Field conditions 2.9%8.0%9.5%100by200mm[4by8in.]Laboratory conditions 3.2%9.0%10.6% 10.1.2The within-test coefficient of variation represents the expected variation of measured strength of companion cylin-ders prepared from the same sample of concrete and tested by one laboratory at the same age.The values given for the within-test coefficient of variation of150by300mm[6by12 in.]cylinders are applicable for compressive strengths between 2000and15to55MPa[8000psi]and those for100by200 mm[4by8in.]cylinders are applicable for compressive strengths between17to32MPa[2500and4700psi].The within-test coefficients of variation for150by300mm[6by12 in.]cylinders are derived from CCRL concrete proﬁciency sample data for laboratory conditions and a collection of1265 test reports from225commercial testing laboratories in1978.5 The within-test coefficient of variation of100by200mm[4by 8in.]cylinders are derived from CCRL concrete proﬁciency sample data for laboratory conditions.10.1.3Multilaboratory Precision—The multi-laboratory coefficient of variation for compressive strength test results of 150by300mm[6by12in.]cylinders has been found to be 5.0%4;therefore,the results of properly conducted tests by two laboratories on specimens prepared from the same sample of concrete are not expected to differ by more than14%4of the average(See Note13).A strength test result is the average of two cylinders tested at the same age.N OTE13—The multilaboratory precision does not include variations associated with different operators preparing test specimens from split or independent samples of concrete.These variations are expected to increase the multilaboratory coefficient of variation.10.1.4The multilaboratory data were obtained from six separate organized strength testing round robin programs where150x300mm[6x12in.]cylindrical specimens were prepared at a single location and tested by different laborato-ries.The range of average strength from these programs was 17.0to90MPa[2500to13000psi].N OTE14—Subcommittee C09.61will continue to examine recent concrete proﬁciency sample data andﬁeld test data and make revisions to precisions statements when data indicate that they can be extended to cover a wider range of strengths and specimen sizes.10.2Bias—Since there is no accepted reference material,no statement on bias is being made.3Bartlett,F.M.and MacGregor,J.G.,“Effect of Core Length-to-Diameter Ratio on Concrete Core Strength,”ACI Materials Journal,V ol91,No.4,July-August, 1994,pp.339-348.4These numbers represent respectively the(1s%)and(d2s%)limits as described in Practice C670.5Supporting data have beenﬁled at ASTM International Headquarters and may be obtained by requesting Research ReportRR:C09-1006.。

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