AS 1012.11-2000_R2014

AS 1012.11—2000 (Reconfirmed) 2014-10-24STANDARDS AUSTRALIARECONFIRMATIONOFAS 1012.11—2000Methods of testing concreteMethod 11: Determination of the modulus of ruptureRECONFIRMATION NOTICETechnical Co mmittee BD-042 has reviewed the co ntent o f this publicatio n and in accordance with Standards Australia procedures for reconfirmation, it has been determined that the publication is still valid and does not require change.Certain documents referenced in the publication may have been amended since the original date o f publicatio n. Users are advised to ensure that they are using the latest versio ns o f such documents as appropriate, unless advised otherwise in this Reconfirmation Notice.Appro ved fo r reco nfirmatio n in acco rdance with Standards Australia pro cedures fo r reconfirmation on 9 September 2014.The following are represented on Technical Committee BD-042:AUSTROADSAustralian Chamber of Commerce and IndustryCement Concrete and Aggregates—ConcreteConcrete Institute of AustraliaNational Association of Testing Authorities AustraliaThe University of New South WalesUniversity of Technology SydneyVictorian Construction Materials LaboratoryNOTESAS 1012.11—2000.au © Standards Australia 1Australian StandardTM Methods of testing concrete Method 11: Determination of the modulus of rupture 1 SCOPE This Standard sets out a method for determining the modulus of rupture of concrete test specimens prepared in accordance with AS 1012.8.2 tested as simple beams with third-point loading.NOTES: 1 This Standard may involve hazardous materials, operations and equipment. This Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before use. Relevance of this Standard to fibre-reinforced concrete is to be further mittee BD/42 is seeking information from all interested parties.2 REFERENCED DOCUMENTS The following documents are referred to in this Standard:AS 1012Methods of testing concrete 1012.1Method 1:Sampling of fresh concrete 1012.8.2Method 8.2:Method for making and curing concrete — Flexure test specimen concrete specimens 1012.9Method 9:Determination of the compressive strength of concrete specimens 2193Methods for the calibration and grading of force-measuring systems of testing machines 3 ACCEPTANCE OF TEST SPECIMENS Moulded flexure test specimens shall be accepted for testing if they have been moulded in accordance with the provisions of AS 1012.8.2, and if they are free from defects likely to affect their strength.Where specimens liable to rejection are tested, all apparent defects shall be noted in accordance with Clauses 9 and 10 of this Standard.Specimens shall be liable to rejection if any of the following conditions exist:(a) Chipped edges, surface cracking or honeycombing are apparent anywhere in the tested span.(b) The surfaces of the specimen are out of plane such that any of the lines of contact between the bearing surfaces on which the rollers bear are out of plane by more than 0.1 mm.AS 1012.11Reconfirmed 2014AS 1012.11—2000© Standards Australia .au24 APPARATUS4.1 Testing machinesThe testing machine shall comply with the following requirements:(a) It shall meet the requirements for Grade A machines, as defined in AS 2193 for therelevant range of compressive forces.NOTE: The machine needs to be suitable for the range required since this test is normallycarried out at a lower range of force than AS 1012.9.(b)It shall be power operated and capable of applying compressive forces increasing continuously at the rate of loading and in the manner specified in Clause 6.(c) The machine shall be fitted with a device for controlling rate of loading which canoperate at a rate of loading specified in Clause 6.4.2 Flexure testing apparatusThe force shall be applied to the specimen through a frame containing two supportingrollers and two loading rollers. The frame shall consist of two parts (upper and lower) eachof which shall be precisely located in the testing machine so that loading is applied evenlyand precisely at the third points of the span. This frame may be incorporated either in thetesting machine or in an accessory that can be used with, or between, the platens of asuitable compression-testing machine.The application of the force shall be through the spherical seat or a loading ball (seeFigure 1) that is centrally placed between the loading rollers.The rollers shall be suitably articulated to ensure that—(a)the force is divided equally between the loading rollers;(b)the force is applied normal to the specimen surface; and (c) the specimen is not restrained or subject to torsion.NOTE: This may be achieved by incorporating a suitable system of transverse rollers and either aspherical seat or a ball in both the supporting group and loading group of rollers.A suitable arrangement of the loading apparatus is illustrated in Figure 1.The dimensions and spacing of the rollers shall comply with the following requirements:(i) Two hardened steel rollers of 38 mm to 40 mm nominal diameter shall be provided tosupport the specimen. The centre-to-centre distance of the supporting rollers (L ) shallbe in accordance with Table 1.(ii)Two hardened steel rollers of 38 mm to 40 mm nominal diameter shall be used toapply the load at the third points of the supporting span. The centre-to-centre distanceof the loading rollers (l ) shall be in accordance with Table 1.(iii) The length of both the supporting and loading rollers shall be at least equal to thewidth of the specimen being tested.To ensure that the rollers bear uniformly on the width of the specimen, the surface ofthe rollers along any contact edge shall not deviate from a straight line by more than±0.02 mm in 150 mm.4.3 Measuring apparatusVernier calliper or ruler readable to at least 1 mm.AS 1012.11—2000.au © Standards Australia 35 CONDITIONING OF TEST SPECIMENS PRIOR TO TESTThe specimen shall be cured in accordance with AS 1012.8.2 to ensure that the surface ofthe specimen has been maintained wet for 48 h prior to testing and that they are saturatedand kept wet immediately prior to testing.At the end of the conditioning period, the specimen shall be kept wet and shall be testedpromptly. The surfaces of the specimens that are loaded shall be free from grit, and allsurfaces shall be wiped, if necessary, to remove surplus water.TABLE 1CENTRE-TO-CENTRE DISTANCES OF THE SUPPORTINGAND LOADING ROLLERSFIGURE 1 DIAGRAMMATIC VIEW OF A SUITABLE FLEXURE TESTING APPARATUS6 PROCEDUREThe procedure shall be as follows:AS 1012.11—2000© Standards Australia.au 4(a)Remove grit from the surface of the specimen that is loaded and, if necessary, wipe to remove the surplus water.(b) Turn the specimen on its side with respect to its position as moulded and then centreit on the supporting rollers. Although it is necessary to locate the specimen centrallywith respect to its width, it is neither necessary nor always desirable that it be locatedcentrally with respect to its length. The position of the specimen may be arrangedsuch as to avoid any defects that may occur near one end.(c) Bring the loading rollers into contact with the top, apply a seating load not exceeding100 N, check the uniformity of bearing of the rollers, and mark their position on thesides of the specimen before proceeding with the loading.(d) Apply the force without shock and increase continuously at a rate equivalent to1 ±0.1 MPa/min extreme fibre stress until no increase in force can be sustained.Record the maximum force applied to the specimen as indicated by the testingmachine.(e) Determine the average width and average depth of the specimen at the section offailure to the nearest 1 mm.(f) Note the appearance of the concrete and the type of fracture, if the fracture is unusual.(g) If the fracture occurs outside the middle third of the span length, do not calculate themodulus of rupture but measure and record the distance from the nearest supportingroller to the section of failure.7CALCULATION When the fracture occurs within the middle third of the specimen, the modulus of rupture shall be calculated as follows:BD PL f 2cf )1000(= wheref cf=modulus of rupture, in megapascals P=maximum applied force indicated by the testing machine, in kilonewtons L=span length, in millimetres B=average width of the specimen at the section of failure, in millimetres D =average depth of specimen at the section of failure, in millimetres 8 PRECISION STATEMENTFor pairs of beams made from the same sample, cured in similar conditions and tested inaccordance with this standard, the repeatability expressed as a percentage of the mean ofthe two strengths obtained, is 18 percent at the 95 percent probability level.NOTE: This statement on repeatability is based on limited Australian data and may be amendedwhen more data is collected.9 RECORDSThe following information shall be recorded for each test specimen:(a)Identification of the concrete.(b) Job site or laboratory where tested.AS 1012.11—2000.au © Standards Australia 5(c)Date and time of test.(d)Moisture condition of specimen, as received.(e)Any apparent defects of the specimen, as received.(f)Age of specimen at the date of test, if known.(g)Failure load.(h)Span length.(i)Average width and depth of the specimen at the section of failure.(j)Modulus of rupture, calculated to the nearest 0.1 MPa, or the position of the fracture,if it occurs outside the middle third of the span length.(k)Appearance of the concrete in the fracture surface and the type of fracture, if these are unusual.(l)Any other significant factors noted before, during or after testing.(m) Identification of the testing operator.(n) Reference to this Standard, i.e. AS 1012.11.10 REPORTThe following information shall be reported:(a)Identification of the concrete.(b)Date and location of test.(c)Age of specimen at the date of test, if known.(d)Nominal size of specimen.(e)Modulus of rupture, calculated to the nearest 0.1 MPa, or the position of the fracture if it occur outside the middle third of the span length.(f) Any apparent defects, any relevant comments on the moisture condition of thespecimen, as received, or any other significant factor(s) noted before, during or aftertesting.(g) Reference to this Standard, i.e. AS 1012.11.(h)Such other information contained in the sampling records (see AS 1012.1) as may berequested.This Australian Standard was prepared by Technical Committee BD/42, Methods of Testing Concrete. It was approved on behalf of the Council of Standards Australia on 28 April 2000 and published on 18 May 2000.The following interests are represented on Committee BD/42:Association of Consulting Engineers AustraliaAUSTROADSAustralian Chamber of Commerce and IndustryAustralian Pre-mixed Concrete AssociationCSIRO—Building, Construction and EngineeringCement and Concrete Association of AustraliaConcrete Institute of AustraliaNational Association of Testing Authorities AustraliaUniversity of New South WalesUniversity of Technology, SydneyKeeping Standards up-to-dateStandards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased.Detailed information about Standards can be found visiting the Standards Australia web site at .au and looking up the relevant Standard in the on-line catalogue.Alternatively, the printed Catalogue provides information current at 1 January each year, and the monthly magazine, The Australian Standard, has a full listing of revisions and amendments published each month.We also welcome suggestions for the improvement in our Standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Contact us via email at mail@.au, or write to the Chief Executive, Standards Australia International Ltd, PO Box 1055, Strathfield, NSW 2135.Originated as AS A106—1985.Previous edition AS 1012.11—1985.Third edition 2000.This Standard was issued in draft form for comment as DR 98462.COPYRIGHT© Standards Australia InternationalAll rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher.Published by Standards Australia International LtdPO Box 1055, Strathfield, NSW 2135, AustraliaISBN 0 7337 3392 1Printed in AustraliaThis page has been left intentionally blank.。