外文翻译(中英文word版)废弃混凝土再生新技术探索
混凝土工艺中英文对照外文翻译文献
混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译) Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons,however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials arematerials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends underthe heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cementswhen ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to theconcrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it isembedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable untileventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。
国外再生混凝土的应用前沿及标准
国外再生混凝土的应用前沿及标准一、前言再生混凝土（Recycled Concrete）是将废弃混凝土经过加工后再利用于新的混凝土中的一种可持续发展的建筑材料。
在全球环保意识不断增强的情况下，再生混凝土的应用越来越受到重视。
本文将介绍国外再生混凝土的应用前沿及标准，以期为国内相关产业提供参考。
二、国外再生混凝土的应用前沿1. 混凝土的再生利用率不断提高在欧洲和北美地区，混凝土的再生利用率不断提高。
欧洲的再生混凝土利用率已经达到了70%以上，而在北美地区，再生混凝土的利用率也在逐年增长。
这是由于在这些发达国家，政府对环保的重视程度较高，对建筑废弃物的回收和再利用也有着更严格的要求。
2. 再生混凝土的技术不断创新随着技术的不断发展，再生混凝土的质量也在不断提高。
在欧洲和北美地区，一些研究机构和企业已经开发出了一些高性能的再生混凝土。
这些混凝土不仅可以满足常规混凝土的使用要求，而且还具有更好的性能，如更好的耐久性、更高的承载能力等。
3. 再生混凝土的应用范围不断扩大在国外，再生混凝土已经广泛应用于公路、桥梁、隧道、机场、码头等基础设施建设中。
此外，再生混凝土还可以用于预制构件、地基、填充等领域。
三、国外再生混凝土的标准1. 欧洲标准欧洲标准EN 206：2013规定了混凝土的性能要求和材料性质，包括混凝土的抗压强度、抗拉强度、抗弯强度、耐久性、可加工性等方面。
此外，欧洲标准还要求再生混凝土的性能应满足与常规混凝土相同的要求，并且要求再生混凝土的使用量应不超过混凝土总量的30%。
2. 美国标准美国标准ACI 555R-01规定了再生混凝土的性能要求和应用要求，包括再生混凝土的抗压强度、抗拉强度、抗弯强度、耐久性等方面。
此外，美国标准还要求再生混凝土的使用应符合环保要求，并且需要进行全面的质量控制和检测。
3. 日本标准日本标准JIS A 5021-2003规定了再生混凝土的性能要求和应用要求，包括再生混凝土的抗压强度、抗拉强度、抗弯强度、耐久性等方面。
外文翻译 (自动保存的)
能源和建筑在MWC的热性能和机械性能研究：提高混凝土制品环境可持续性克里斯蒂娜Becchio ，斯特凡诺保罗Corgnati ，安德烈Kindinis ，西莫内塔Pagliolico能量学系（DENER ），都灵理工大学，科索公爵阿布鲁齐24 ，10129都灵，意大利材料科学与工程化学（DISMIC ），都灵理工大学，科索公爵阿布鲁齐24 ，10129意大利都灵系文章信息文章历史：2009年3月13日修改稿2009年5月13日2009年5月29日关键词：木材聚集轻质混凝土热式质量电导率抗压强度摘要本研究以构成一个更可持续的轻质混凝土，矿化木混凝土（MWC）上，由木工生产废料替代天然骨料的可能性。
利用这种类型的聚集体，三重目的已经达到：保存天然原料，节约能源和废物的再利用。
此外，使用木材聚集的性能，试图建立一个可持续的混凝土具有高的热惯量，高耐热性和低体重。
在本文中，对混凝土的机械性能和热性能的添加木聚集体的影响进行了研究。
机械性能进行了调查与抗压强度的测试，而一维热流模型已被用于预测MWC的热导率。
这个方案具有良好的绝缘围护结构的需求，同时具有高的热质量：使用MWC可以用不同的类型学比较重的建筑围护结构的想法有关。
一系列其他的值可以得出：重量轻，环保，易产业化，便于现场浇注。
因此，在建筑结构木器，混凝土的应用程序可能是为了提高可持续性和建筑节能一个有趣的解决方案。
2009爱思唯尔B.V.保留所有权利。
1 、介绍促进可持续发展带来了压力采取适当的方法，以保护环境各个行业，包括建筑。
在建设过程中需要能量的高支出，并导致广泛的可量化的环境影响，包括气体排放，水资源利用和固体和液体废物。
能源消耗的提取，运输，加工和装配的原材料，以及所连接的二氧化碳和温室气体排放占建设[1-3]所有生命周期的多变，但相当大的比率。
还有一系列既通过施工过程和建设的网站上的存在，包括土地的干扰，生态系统改变，植被破坏，占领一个潜在的资源网站的结果，产生不易量化局部环境的影响地下水干扰。
混凝土工艺中英文对照外文翻译文献
混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译)Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons, however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials are materials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends under the heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cements when ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to the concrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it is embedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable until eventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。
钢筋混凝土结构中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)Reinforced ConcreteConcrete and reinforced concrete are used as building materials in every country. In many, including the United States and Canada, reinforced concrete is a dominant structural material in engineered construction. The universal nature of reinforced concrete construction stems from the wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required in concrete construction, and the economy of reinforced concrete compared to other forms of construction. Concrete and reinforced concrete are used in bridges, buildings of all sorts underground structures, water tanks, television towers, offshore oil exploration and production structures, dams, and even in ships.Reinforced concrete structures may be cast-in-place concrete, constructed in their final location, or they may be precast concreteproduced in a factory and erected at the construction site. Concrete structures may be severe and functional in design, or the shape and layout and be whimsical and artistic. Few other building materials off the architect and engineer such versatility and scope.Concrete is strong in compression but weak in tension. As a result, cracks develop whenever loads, or restrained shrinkage of temperature changes, give rise to tensile stresses in excess of the tensile strength of the concrete. In a plain concrete beam, the moments about the neutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beam fails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the concrete in such a way that the tension forces needed for moment equilibrium after the concrete cracks can be developed in the bars.The construction of a reinforced concrete member involves building a from of mold in the shape of the member being built. The form must be strong enough to support both the weight and hydrostatic pressure of the wet concrete, and any forces applied to it by workers, concrete buggies, wind, and so on. The reinforcement is placed in this form and held in place during the concreting operation. After the concrete has hardened, the forms are removed. As the forms are removed, props of shores are installed to support the weight of the concrete until it has reached sufficient strength to support the loads by itself.The designer must proportion a concrete member for adequate strength to resist the loads and adequate stiffness to prevent excessive deflections. In beam must be proportioned so that it can be constructed. For example, the reinforcement must be detailed so that it can be assembled in the field, and since the concrete is placed in the form after the reinforcement is in place, the concrete must be able to flow around, between, and past the reinforcement to fill all parts of the form completely.The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions. The choice of structural system is made by the architect of engineer early in the design, based on the following considerations:1. Economy. Frequently, the foremost consideration is the overall const of the structure. This is, of course, a function of the costs of the materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall construction time since the contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commercial project, the cost of construction financing will be a significant fraction of the total cost. As a result, financial savings due to rapid construction may more than offset increased material costs. For this reason, any measures the designer can take to standardize the design and forming will generally pay off in reduced overall costs.In many cases the long-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are important consideration.2. Suitability of material for architectural and structural function.A reinforced concrete system frequently allows the designer to combine the architectural and structural functions. Concrete has the advantage that it is placed in a plastic condition and is given the desired shape and texture by means of the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearing elements while providing the finished floor and / or ceiling surfaces. Similarly, reinforced concrete walls can provide architecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Finally, the choice of size of shape is governed by the designer and not by the availability of standard manufactured members.3. Fire resistance. The structure in a building must withstand the effects of a fire and remain standing while the building is evacuated and the fire is extinguished. A concrete building inherently has a 1- to 3-hour fire rating without special fireproofing or other details. Structural steel or timber buildings must be fireproofed to attain similar fire ratings.4. Low maintenance.Concrete members inherently require less maintenance than do structural steel or timber members. This is particularly true if dense, air-entrained concrete has been used forsurfaces exposed to the atmosphere, and if care has been taken in the design to provide adequate drainage off and away from the structure. Special precautions must be taken for concrete exposed to salts such as deicing chemicals.5. Availability of materials. Sand, gravel, cement, and concrete mixing facilities are very widely available, and reinforcing steel can be transported to most job sites more easily than can structural steel. As a result, reinforced concrete is frequently used in remote areas.On the other hand, there are a number of factors that may cause one to select a material other than reinforced concrete. These include:1. Low tensile strength.The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly or may allow penetration of water. When this occurs, water or chemicals such as road deicing salts may cause deterioration or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and / of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-place structure involves three steps not encountered in the construction of steel or timber structures. These are ( a ) the construction of the forms, ( b ) the removal of these forms, and (c) propping or shoring the new concrete to support its weight until its strength is adequate. Each of these steps involves labor and / or materials, which are not necessary with other forms of construction.3. Relatively low strength per unit of weight for volume.The compressive strength of concrete is roughly 5 to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable steel structure. As a result, long-span structures are often built from steel.4. Time-dependent volume changes. Both concrete and steel undergo-approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled,and because steel is a better concrete, a steel structure is generally affected by temperature changes to a greater extent than is a concrete structure. On the other hand, concrete undergoes frying shrinkage, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time, possibly doubling, due to creep of the concrete under sustained loads.In almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughout their professional careers. Much of this text is directly concerned with the behavior and proportioning of components that make up typical reinforced concrete structures-beams, columns, and slabs. Once the behavior of these individual elements is understood, the designer will have the background to analyze and design a wide range of complex structures, such as foundations, buildings, and bridges, composed of these elements.Since reinforced concrete is a no homogeneous material that creeps, shrinks, and cracks, its stresses cannot be accurately predicted by the traditional equations derived in a course in strength of materials for homogeneous elastic materials. Much of reinforced concrete design in therefore empirical, i.e., design equations and design methods are based on experimental and time-proved results instead of being derived exclusively from theoretical formulations.A thorough understanding of the behavior of reinforced concrete will allow the designer to convert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete’s desirable characteristics, its high compressive strength, its fire resistance, and its durability.Concrete, a stone like material, is made by mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives ( that modify properties ) into a workable mixture. In its unhardened or plastic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile strength and therefore cracks easily. Because unreinforced concrete is brittle, it cannot undergo large deformations under load and failssuddenly-without warning. The addition fo steel reinforcement to the concrete reduces the negative effects of its two principal inherent weaknesses, its susceptibility to cracking and its brittleness. When the reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforced concrete, is used extensively to construct foundations, structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Two other characteristics of concrete that are present even when concrete is reinforced are shrinkage and creep, but the negative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standards that control important details of design and construction. The purpose of codes it produce structures so that the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originated and controlled by specialists who are concerned with the proper use of a specific material or who are involved with the safe design of a particular class of structures.The second type of code, called a building code, is established to cover construction in a given region, often a city or a state. The objective of a building code is also to protect the public by accounting for the influence of the local environmental conditions on construction. For example, local authorities may specify additional provisions to account for such regional conditions as earthquake, heavy snow, or tornados. National structural codes genrally are incorporated into local building codes.The American Concrete Institute ( ACI ) Building Code covering the design of reinforced concrete buildings. It contains provisions covering all aspects of reinforced concrete manufacture, design, and construction. It includes specifications on quality of materials, details on mixing and placing concrete, design assumptions for the analysis of continuous structures, and equations for proportioning members for design forces.All structures must be proportioned so they will not fail or deform excessively under any possible condition of service. Therefore it is important that an engineer use great care in anticipating all the probableloads to which a structure will be subjected during its lifetime.Although the design of most members is controlled typically by dead and live load acting simultaneously, consideration must also be given to the forces produced by wind, impact, shrinkage, temperature change, creep and support settlements, earthquake, and so forth.The load associated with the weight of the structure itself and its permanent components is called the dead load. The dead load of concrete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately until members have been sized. Since some figure for the dead load must be used in computations to size the members, its magnitude must be estimated at first. After a structure has been analyzed, the members sized, and architectural details completed, the dead load can be computed more accurately. If the computed dead load is approximately equal to the initial estimate of its value ( or slightly less ), the design is complete, but if a significant difference exists between the computed and estimated values of dead weight, the computations should be revised using an improved value of dead load. An accurate estimate of dead load is particularly important when spans are long, say over 75 ft ( 22.9 m ), because dead load constitutes a major portion of the design load.Live loads associated with building use are specific items of equipment and occupants in a certain area of a building, building codes specify values of uniform live for which members are to be designed.After the structure has been sized for vertical load, it is checked for wind in combination with dead and live load as specified in the code. Wind loads do not usually control the size of members in building less than 16 to 18 stories, but for tall buildings wind loads become significant and cause large forces to develop in the structures. Under these conditions economy can be achieved only by selecting a structural system that is able to transfer horizontal loads into the ground efficiently.钢筋混凝土在每一个国家，混凝土及钢筋混凝土都被用来作为建筑材料。
土木工程混凝土论文中英文资料外文翻译文献
土木工程混凝土论文中英文资料外文翻译文献外文资料STUDIES ON IMPACT STRENGTH OF CONCRETESUBJECTED TO SUSTAINEDELEVATED TEMPERATUREConcrete has a remarkable fire resisting properties. Damage in concrete due to fire depends on a great extent on the intensity and duration of fire. Spalling cracking during heating are common concrete behaviour observed in the investigation of the fire affected structures. Plenty of literature is available on the studies of concrete based on time temperature cures. In power, oil sectorsand nuclear reactors concrete is exposed to high temperature for considerable period of time. These effects can be reckoned as exposure to sustained elevated temperature. The sustained elevated temperature may be varying from a few hours to a number of years depending upon practical condition of exposures. The knowledge on properties under such conditions is also of prime importance apart from the structures subjected to high intensity fire. Impact studies of structure subjected to sustained elevated temperature becomes more important as it involves sensitive structures which is more prone to attacks and accidents. In this paper impact studies on concrete subjected to sustained elevated temperature has been discussed. Experiments have been conducted on 180 specimens along with 180 companion cube specimens. The temperatures of 100°C, 200°C and 300°C for a duration of exposure of 2 hours 4 hours and 6 hours has been considered in the experiments. The results are logically analyzed and concluded.1. INTRODUCTIONThe remarkable property of concrete to resist the fire reduces the damage in a concrete structure whenever there is an accidental fire. In most of the cases the concrete remains intact with minor damages only. The reason being low thermal conductivity of concrete at higher temperatures and hence limiting the depth of penetration of firedamage. But when the concrete is subjected to high temperature for long duration the deterioration of concrete takes place. Hence it is essential to understand the strength and deformation characteristics of concrete subjected to temperature for long duration. In this paper an attempt has been made to study the variation in Impact Strength of concrete when subjected to a temperature range 100oC, 200oC and 300oC sustained for a period of 2 hrs, 4 hrs and 6 hrs.The review of the literature shows that a lot of research work [1 – 3] has taken place on the effect of elevated temperature on concrete. All these studies are based on time –temperature curves. Hence an attempt has been made to study the effect of sustained elevated temperature on impact strength of concrete and the results are compared with the compressive strength. The experimental programme has been planned for unstressed residual strength test based on the available facilities. Residual strength is the strength of heated and subsequently cooled concrete specimens expressed as percentage of the strength of unheated specimens.2. EXPERIMENTAL INVESTIGATION2.1. TEST SPECIMEN AND MATERIALSA total of 180 specimens were tested in the present study along with 180 companion cubes. An electric oven capable of reaching a maximum temperature of 300oC has been used for investigation. Fine and coarse aggregates conforming to IS383 has been used to prepare the specimen with mix proportions M1 = 1:2.1:3.95 w/c = 0.58, M2 = 1:1.15:3.56 w/c = 0.53, M3 = 1:0.8:2.4 w/c = 0.4.2.2 TEST VARIABLESThe effects of the following variables were studied.2.2.1 Size sSize of Impact Strength Test Specimen was 150 mm dial and 64 mm thickness and size of companion cube 150 x 150 x 150 mm.2.2.2 Maximum TemperatureIn addition to room temperature, the effect of three different temperatures (100oC, 200oC and 300oC) on the compressive strength was investigated.2.2.3 Exposure Time at Maximum TemperatureThree different exposure times were used to investigate the influence of heat on compressive strength; they are 2 hrs, 4 hrs and 6 hrs.2.2.4 Cooling MethodSpecimens were cooled in air to room temperature.3. TEST PROCEDUREAll the specimens were cast in steel moulds as per IS516 and each layer was compacted. Specimens were then kept in their moulds for 24 hours after which they were decoupled and placed into a curing tank until 28 days. After which the specimens were removed and were allowed to dry in room temperature. These specimens were kept in the oven and the required target temperature was set. Depending on the number of specimen kept inside the oven the time taken to reach the steady state was found to vary. After the steady state was reached the specimens were subjected to predetermined steady duration at the end of which the specimens are cooled to room temperature and tested.ACI drop weight impact strength test was adopted. This is the simplest method for evaluating impact resistance of concrete. The size of the specimen is 150 mm dial and 64 mm thickness. The disc specimens were prepared using steel moulds cured and heated and cooled as. This consists of a standard manually operated 4.54 kg hammer with 457 mm drop. A 64 mm hardened steel ball and a flat base plate with positioning bracket and lugs. The specimen is placed between the four guides pieces (lugs) located 4.8 mm away from the sample. A frame (positioning bracket) is then built in order to target the steel ball at the centre of concrete disc. The disc is coated at the bottom with a thin layer of petroleum jelly or heavy grease to reduce the friction between the specimen and base plate. The bottom part of the hammer unit was placed with its base upon the steel ball and the load was applied by dropping weight repeatedly. The loading was continued until the disc failed and opened up such that it touched three of the four positioning lugs. The number of blows that caused this condition is recorded as the failure strength. The companion cubes were tested for cube compression strength (fake).4. ANALYSIS AND RESULTS4.1 RESIDUAL COMPRESSIVE STRENGTH VS. TEMPERATUREFrom Table 1, at 100°C sustained elevated temperature it is seen that the residual strength of air cooled specimens of mixes M1, M2 and M3 has increased in strength 114% for M1 mix, 109% for M2 mix and 111% for M3 mix for 6 hours duration of exposure. When the sustained elevated temperature is to 200°C for air cooled specimens there is a decrease in strength up to 910% approximately for M1 mix for a duration of 6 hours, but in case of M2 mix it is 82% and for M3 mix it is 63% maximum for 6 hours duration of exposure. When the concrete mixes M1, M2 and M3 are exposed to 300°C sustained temperature there is a reduction in strength up to 78% for M1 mix for 6 hour duration of exposure.4.2 RESIDUAL COMPRESSIVE STRENGTH VS DURATION OF EXPOSUREFrom Table 1, result shows that heating up to 100°C for 2 hours and 4 hours, the residual strength of mix M1 has decreased where as the residual strength of mix M2 and M3 has increased. The residual strength is further increased for 6 hours duration of exposure in all the three mixes M1, M2 and M3 even beyond the strength at room temperature. When the specimens of mixes M1, M2 and M3 are exposed to 200°C for 2,4 and 6 hours of duration, it is observed that the residual strength has decreased below the room temperature and has reached 92% for M1 mix, 82 and 73% for M2 and M3 mix respectively. Concrete cubes of mixes M1, M2 and M3 when subjected to 300°C temperature for 2,4 and 6 hours the residual strength for mix M1 reduces to 92% for 2 hours up to 78% for six hours duration of exposure, for M2 mix 90% for 2 hours duration of exposure up to 76% for six hour duration of exposure, for M3 mix 88% up to 68% between 2 and 6 hours of duration of exposure.5. IMPACT STRENGTH OF CONCRETE5.1 RESIDUAL IMPACT STRENGTH VS TEMPERATUREFrom the table 1, it can be observed that for the sustained elevated temperature of 100°C the residual impact strength of all the specimens reduces and vary between 20 and 50% for mix M1, 15 to 40% for mix M2 and M3. When the sustained elevated temperature is 200°C the residual impact strength of all the mixes further decreases. The reduction is around 60-70% for mix M1, 55 to 65% for M2 and M3 mix. When the sustained elevated temperature is 300°C it is observed that the residual impact strength reduces further and vary between 85 and 70% for mix M1 and 85 to 90% for mix M2 and mix M3.5.2 RESIDUAL IMPACT STRENGTH VS DURATION OF EXPOSUREFrom the Table 1 and Figures 1 to 3, it can be observed that there is a reduction in impact strength when the sustained elevated temperature is 100°C for 2 hrs, 4 hrs and 6 hrs, and its range is 15 to 50% for all the mixes M1, M2 and M3. The influence of duration of exposure is higher for mix M1 which decreases more rapidly as compared to mix M2 and mix M3 for the same duration of exposure. When the specimens are subjected to sustained elevated temperature of 200°C for 2,4 and 6 hour of duration, further reduction in residual impact strength is observed as compared to at 100°C. The reduction is in the range of 55-70% for all the mixes. The six hour duration of exposure has a greater influence on the residual impact strength of concrete. When the sustained elevated temperature is 300°C for 2,4 and 6 hours duration of exposure the residualimpact strength reduces. It can be seen that both temperature and duration of exposure have a very high influence on the residual impact strength of concrete which shows a reduction up to 90% approximately for all the mixes.6. CONCLUSIONThe compressive strength of concrete increases at 100oC when exposed to sustained elevated temperature. The compressive strength of concrete decreases when exposed to 200°C and 300°C from 10 to 30% for 6 hours of exposure. Residual impact strength reduces irrespective of temperature and duration. Residual impact strength decreases at a higher rate of 20% to 85% as compared to compressive strength between 15% and 30 % when subjected to sustained elevated temperature. The impact strength reduces at a higher rate as compared to compressive strength when subjected to sustained elevated temperature.混凝土受持续高温影响的强度的研究混凝土具有显着的耐火性能。
废弃混凝土资源化再生利用的新技术及其应用
废弃混凝土资源化再生利用的新技术及其应用一、背景介绍近年来，城市化进程加快，建设活动频繁，建筑垃圾产生量急剧增加。
其中，废弃混凝土是建筑垃圾中产量最大的一类。
传统处理方式是填埋，但填埋会占用大量土地资源，同时也会对环境造成污染。
因此，废弃混凝土资源化再生利用已成为一个热门话题。
二、废弃混凝土再生利用技术1. 混凝土碎石再生利用技术混凝土碎石再生利用技术是将废弃混凝土进行破碎、筛分等处理后，用于制造再生混凝土、路基、路面等建筑材料。
这种技术能够有效地减少废弃混凝土的填埋量，同时降低了新原材料的使用量，对环境和资源的保护具有重要意义。
2. 水泥混凝土回收技术水泥混凝土回收技术是指将废弃混凝土进行粉碎、筛分、洗涤等处理后，回收其中的水泥和砂石颗粒，用于制造新的混凝土。
这种技术能够有效地降低建筑垃圾的填埋量，同时还可以减少新原材料的使用量，节约资源。
3. 生态混凝土制备技术生态混凝土制备技术是指将废弃混凝土进行处理后，加入一定的生态骨料和其他辅料，制备出新型混凝土。
这种混凝土具有较好的生态环保性能，能够在一定程度上解决城市建设中的生态环保问题。
三、废弃混凝土再生利用应用案例1. 上海环球中心上海环球中心是一座集商业、文化、娱乐等多功能于一体的超高层建筑。
在建设过程中，废弃混凝土资源化再生利用技术得到了广泛应用。
根据统计，此项目共处理了约10万吨废弃混凝土，其中近70%被再生利用。
再生利用后的废弃混凝土被用作路基、路面、基础等建筑材料，有效地减少了建筑垃圾的填埋量，节约了大量的原材料。
2. 北京大兴国际机场北京大兴国际机场是中国首个“四横四纵”民航枢纽和世界上最大的单体航站楼。
在建设过程中，废弃混凝土资源化再生利用技术也得到了广泛应用。
据统计，此项目共处理了约23万吨废弃混凝土，其中近80%被再生利用。
再生利用后的废弃混凝土被用作路基、路面、基础等建筑材料，有效地减少了建筑垃圾的填埋量，节约了大量的原材料。
混凝土结构修复中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)对混凝土修复过程中的真正理解或误解摘要：在最近的一段时间内，在世界的很多地方，早期钢筋的腐蚀而对混凝土结构产生的早期恶化和损坏，已经成为混凝土结构方面的主要问题。
加速这个恶化过程的一个主要因素是混凝土结构所存在的环境和气候状况。
恶劣的环境与低质量的混凝土加上有或无缺陷的设计和建设惯例，这都使结构恶化的过程变得具有交互性，累积得非常迅速，进而形成一种恶性的发展，而且很难被停止。
很多混凝土结构耐久性差的性能正引起结构产生裂缝.而在补救工作的支出，则使物主和社会所不能承担，并且他们也不希望看到悲剧重演。
这篇文章仅提出一些对钢筋腐蚀和保护选择的初步认识，而对混凝土和混凝土修理的抑制混合物腐蚀的影响则进行了详细讨论。
与抑制剂在修理效力有关的复杂论文已经发表，其中主要对基于电化学活动在新结构和修复结构方面之间差别进行了分析。
随着盲目的对需要修理的混凝土使用那些适用于新建筑的保护方法，文章断定："修复混凝土"的生意将会越来越好。
一种对新的和需要修理的混凝土之间的电化学差别的更广泛理解认为对修理的结构使用有效的钢筋保护是必要的。
关键词：碱度腐蚀保护耐久性抑制剂强化1 序言这是一个不幸的事实。
全世界范围内,大量混凝土结构都处在恶化/ 危险状态的阶段。
同时，必须承认的是，很多被修理的混凝土结构在几年后，一修再修。
被修理混凝土结构的保持性能的长久表现则最大限度的取决于它们的设计，建设，维护和使用。
与建筑在修理的几年之后出现裂缝相比，几乎没有问题能加剧公众与政府之间的冲突，并且导致他们对我们提供的建筑物用途的功能感到不满意。
然而与预期相反，不管是恶劣的环境状况还是适合的环境状态,在混凝土修理过程中,腐蚀的问题已经变得非常普遍.因而，混凝土修理业正面临一项主要的挑战：怎样制止全世界物质基础设施的腐坏。
它是如此重要，对当今的混凝土修复，我们要迫切检查腐蚀和腐蚀保护措施的发行，且探索在不久的将来它有可能改进的地方，即：如何使现在的修理能耐用到将来。
毕业设计外文资料翻译——翻译译文
毕业设计外文资料翻译（二）外文出处：Jules Houde 《Sustainable development slowed down by bad construction practices and natural and technological disasters》2、外文资料翻译译文混凝土结构的耐久性即使是工程师认为的最耐久和最合理的混凝土材料，在一定的条件下，混凝土也会由于开裂、钢筋锈蚀、化学侵蚀等一系列不利因素的影响而易受伤害。
近年来报道了各种关于混凝土结构耐久性不合格的例子。
尤其令人震惊的是混凝土的结构过早恶化的迹象越来越多。
每年为了维护混凝土的耐久性，其成本不断增加。
根据最近在国内和国际中的调查揭示，这些成本在八十年代间翻了一番，并将会在九十年代变成三倍。
越来越多的混凝土结构耐久性不合格的案例使从事混凝土行业的商家措手不及。
混凝土结构不仅代表了社会的巨大投资，也代表了如果耐久性问题不及时解决可能遇到的成本，更代表着，混凝土作为主要建筑材料，其耐久性问题可能导致的全球不公平竞争以及行业信誉等等问题。
因此，国际混凝土行业受到了强烈要求制定和实施合理的措施以解决当前耐久性问题的双重的挑战，即：找到有效措施来解决现有结构剩余寿命过早恶化的威胁。
纳入新的结构知识、经验和新的研究结果，以便监测结构耐久性，从而确保未来混凝土结构所需的服务性能。
所有参与规划、设计和施工过程的人，应该具有获得对可能恶化的过程和决定性影响参数的最低理解的可能性。
这种基本知识能力是要在正确的时间做出正确的决定，以确保混凝土结构耐久性要求的前提。
加固保护混凝土中的钢筋受到碱性的钝化层(pH值大于12.5)保护而阻止了锈蚀。
这种钝化层阻碍钢溶解。
因此，即使所有其它条件都满足(主要是氧气和水分)，钢筋受到锈蚀也都是不可能的。
混凝土的碳化作用或是氯离子的活动可以降低局部面积或更大面积的pH值。
当加固层的pH值低于9或是氯化物含量超过一个临界值时，钝化层和防腐保护层就会失效，钢筋受腐蚀是可能的。
外文翻译(word版)再生骨料参量在生产过程中对混凝土性能的影响
Mechanical behaviour of concrete made withfine recycled concrete aggregatesL. Evangelista a, J. de Brito b,*Abstract：This paper concerns the use of fine recycled concrete aggregates to partially or globally replace natural fine aggregates (sand) in the production of structural concrete. To evaluate the viability of this process, an experimental campaign was implemented in order to monitor the mechanical behaviour of such concrete. The results of the following tests are reported: compressive strength, split tensile strength,modulus of elasticity and abrasion resistance. From these results, it is reasonable to assume that the use of fine recycled concrete aggregatesdoes not jeopardize the mechanical properties of concrete, for replacement ratios up to 30%.2007 Elsevier Ltd. All rights reserved.Keywords: Sustainable construction; Concrete waste; Fine recycled aggregates; Structural concrete1. IntroductionConcrete demolition waste has been proved to be anexcellent source of aggregates for new concrete production.There are many studies that prove that concrete made withthis type of coarse aggregates can have mechanical propertiessimilar to those of conventional concretes and evenhigh-strength concrete is nowadays a possible goal for thisenvironmentally sound practice [1–3].However, the fine fraction of these recycled aggregateshas not been the subject of thorough similar studies sinceit is believed that their greater water absorption can jeopardizethe final results. The results of several studies presentedin the past have caused the existing codes concerning recycledaggregates for concrete production to strongly limit theuse of these products [4–6].The investigation conducted, in which the recycled fineaggregates were obtained from laboratory grade concrete2. Experimental research program2.1. Recycled concrete aggregate productionThe fine recycled concrete aggregates that were usedduring the entire research program were obtained froman original concrete (OC), of standard composition and properties, which was made in laboratorial conditions,solely for the purpose of being crushed afterwards. Byusing this procedure, it was possible to fully controlthe concrete’s composition and to determine its main properties, which, if not known, could become an additional variable, when analysing and concluding about theachieved experimental results. The OC composition canbe observed in Table 1. The average compressive strengthof the OC, after a 28 day period of wet curing, was29.6 MPa.The concrete was crushed on the 35th day, using a smalljaw crusher, which produced aggregates with a maximumnominal size of 38.1 mm. The aggregates were then separated according to their dimension, by mechanical sieving,and only the fractions between 0.074 mm and 1.19 mmwere used, so the particle size range for both fine natural aggregates (FNA) and fine recycled aggregates (FRA)would be the same. In spite of this, the grading curves ofthe natural and recycled were different (Fig. 1), and therefore, it was necessary to adjust the latter to match the formerto achieve a similar fineness modulus. To accomplishthis, it was necessary to separate the recycled aggregates according to their different particle sizes. After separation, the aggregates were stored in tight containers to avoidmoisture exchanges with the environment. Although thistype of procedure is too difficult for practical application,it enables comparisons between mix compositions withthe same particle size distribution, even though the replacement ratios differ.The main properties of the fine natural and recycledaggregates (after correction of its grading curve) were studied and are displayed in Table 2. FRA present a lower densitythan FNA, due to its greater porosity, that leads tomuch higher water absorption.Table 1Original concrete composition2.2. Mix compositionsThe different mixes’ compositions were designed using Faury’s method [8], with a common target slump of80 ± 10 mm. The mix design was primarily conceived forthe reference concrete (RC), made only of natural aggregates. It was then adapted for the remaining mixes, takinginto account the different water/cement ratios, expected to increase along with the recycled aggregates replacement ratio. The increase of water has to do with FRA’s greater absorption and to the greater need of mixing water, onaccount of the greater particle friction that recycled aggregates generate [7].To estimate the water that the FNA would absorb duringthe mixing, the relationship proposed by Leite [3] was considered, which established the FRA water absorptionthrough time. The author concluded that during the periodof 10–30 min of mixing, the FNA water absorption stabilizes, reaching around 50% of its maximum capacity. Leitealso proposed, based on Neville’s observations [9], thatafter introducing the binder in the mixture, the recycled aggregates absorption was significantly reduced, becauseit seals the aggregates pores, limiting water exchanges.The experimental research was divided in three distinctstages: in the first stage, different concrete compositionswere studied and tested in order to fine-tune the mix proportions to comply with the stipulated workability; the goal ofthe second stage was to perform a preliminary evaluation ofthe concrete mixes, based on parameters both mechanical (compressive strength and shrinkage) and durability-related (water absorption); the third stage’s main purpose was to evaluate, as thoroughly as possible, the mixes that presentedthe most promising results at the second stage.To check the suitability of Leite’s proposal, two different techniques for mixing the fine aggregates (both natural and recycled) with water were used. In the first technique,applied at the first stage of the campaign, the fine aggregates were inserted into water (2/3 of the required mixingwater, plus the water that was estimated to be absorbed),and were mixed during a period of 10 min, after whichthe remaining constituents were placed. In the second technique, used at both second and third stages, the same mixingprocedure was used, except that the duration of mixingwas extended to 20 min.It was expected that the replacement of FNA with the correspondent FRA would cause a large increase in thew/c ratio [10,11]. In order to keep it at an acceptable level (below 0.45 since, for a 100% replacement ratio, existing2.3. TestingCompressive strength tests were carried out on 150 mmcubes, according to NP EN 12390-5 [12]. Tested specimenswere subjected to 28-day wet curing, for first and second stages, while for third one, 7, 28, and 56 days wet-cured specimens were evaluated. For split tensile strength and modulus of elasticity tests, 150 mm diameter cylinders300 mm tall 31 days wet-cured were used, according to NPEN 12390-6 [13] and LNEC E397 [14], respectively. As for abrasion resistance, 71 · 71 · 40 mm prisms were tested, using a grinding wheel, according to DIN 521081 [15].3. Results and discussion3.1. Compressive strengthThe compressive strength results obtained for the three different stages (the second and third stages’ joint results were presented, since there were no differences in their mixing process), at 28 days of age, are shown in Table 4.Strength variations of the various concrete mixes in relation to the reference concrete (designated by D) and thestrength variations between first and second/third stages (presented in the d (between stages) column) are alsoshown. It is possible to realize that, within each stage, the strength resistance had insignificant variations and no visible trend due to the FNA replacement with FRA. Whencomparing the results of the different stages, the differences between them are also small, although the second/thirdstages generally present slightly lower compressive strength resistances than the first stage.A reasonable explanation for the maintenance of thecompressive strength with increasing fine aggregatesreplacement has been proposed by Katz [16], which concludedthat recycled aggregates have high levels of cement(both hydrated and non-hydrated), that can reach as muchas 25% of its weight, increasing the total amount of cementin the mix.Although the differences between the first and second/third stages were small, a possible cause for the slight resistance loss has been proposed by Poon et al. [17] and Barrade Oliveira and vasquez [18], that concluded that the saturation level of the recycled aggregates may affect thestrength of the concretes, since at higher saturation levelsthe mechanical bonding between the cement paste andthe recycled aggregates becomes weaker. Therefore, asin the second/third stages the mixing period was longerthan in the first one, that may have led to a weaker performanceof those concretes.The variation of compressive strength with time (Fig. 2)indicates that the reference concrete’s resistance, made exclusively with natural aggregates, almost stabilized after28 days of age. In opposition, the compressive strength ofthe concrete mixes made with fine recycled aggregates continuesto increase after that age. This result somehow corroboratesthe assumption that there is non-hydratedcement mixed with the fine recycled aggregates that contributesto the overall resistance. The reference concretewas made of high hydration speed cement (CEM type I),which would justify the rapid stabilization of its compressive strength. On the contrary, the original concrete, usedto produce the recycled aggregates, was made with normalhydration speed cement (CEMtype II), that takes longer to。
混凝土裂缝论文中英文资料对照外文翻译文献综述
混凝土裂缝论文中英文资料对照外文翻译文献综述Causes and control measures of concrete cracks study the problemKeywords: Causes prevention of concrete cracksAbstract: At present, paid close attention to the problem of concrete cracks, this crack in the concrete on the basis of classification, analysis of the causes of different cracks, and proposed measures to crack prevention and treatment.1.IntroductionIs the maximum amount of concrete as a building material, widely used in industrial and civil construction, agriculture and forestry with urban construction, water conservancy works in the harbor. However, many concrete structures occurs during the construction and use of different degrees and different forms of fracture. This not only affects the appearance of the building, but also endanger the normal use of buildings and structures durability.Therefore, the cracks become people concerns. In recent years, with the ready-mixed concrete and vigorously promote the use and structure become increasingly large, complex, making the problem even more prominent.However, cracks in concrete structures is a fairly common phenomenon, large number of engineering practice and modern science on the concrete strength of micro studies show that the structures of the crack is inevitable, which is a property of the material. Therefore, the scientific treatment of cracks in the crack problem is to classify on the basis, adopt effective measures to harmful levels of crack control to the extent permitted. This concrete structure will cause cracks in common, control measures and the repair method to analyze some light.2.Classification of concrete cracks2.1 Divided by Crack According to the causes of concrete cracks, structural cracks and can be divided into two major categories of non-structural cracks.(1) Structural cracks Caused by a variety of external loads cracks, also called load cracks. It includes the external loads caused by the direct stress cracks and the structure under external loads caused by secondary stress cracks.(2) Non-structural cracks Deformation caused by the change from a variety of cracks. It includes temperature, shrinkage and swelling caused by factors such as differential settlement cracks. Such cracks in the structure when the deformation is restricted due to the stress caused. Research data from abroad and a large number of engineering practice, non-structural cracks in the works in the majority, about 80%, which led to shrinkage cracks.2.2Divided by the time the cracks(1)Cracks during construction Including plastic shrinkage cracks, settlement shrinkage cracking, drying shrinkage cracks, shrinkage cracks itself, the temperature cracks, the cracks were improper construction operations, the role of early frost, and some irregular cracks caused by cracks.(2)Use of crack during Including the expansion of steel corrosion cracks generated, salt and acid erosion type liquid medium caused by cracks, the cracks caused by freezing and thawing, alkali aggregate reaction, and cracks caused by cyclic loading cumulative damage caused by cracks.2.3Classification of fractured by cracks in the shape of the shape can be divided by:(1)Longitudinal cracks parallel to the bottom component, the distribution along tendons, mainly caused by the role of steel corrosion(2)Transverse cracks perpendicular to the bottom component mainly by the loading, temperature effects caused(3)Shear cracks due to displacement caused by vertical load or vibration(4)Diagonal cracks eight shaped or herringbone cracks, common in the wall of concrete beams, mainly due to the uneven foundation settlement, and thermal effects caused by(5)X-shaped cracks common in the framework of beams, columns and walls on the ends, due to the impact effect, or moment loads caused by earthquake(6)All kinds of irregular cracks such as repeated freezing and thawing, or fires caused by cracksIn addition, concrete mixing and transport time for long cracks due to mesh, squareappears floor slab or plate surface radial cracks appear in the cross cracks and so on.2.4 The development of the state divided by cracksAccording to fracture the movement in which the state and development trends, can be divided into the following categories:(1)Stable crack This crack does not affect the persistence of applications, including two types.One is in motion the process of self-healing of fractures could be common in a number of new water projects, this is because the crack of cement particles in the leakage of water further compounds the process, precipitate Ca (OH) 2 crystal and part of the Ca ( OH) 2 has dissolved in the water with CO2 carbonation reaction to form CaCO3 crystallization occurs, both the formation of cracks in the gel material will be glued closed, and thus stop the leakage, cracks to heal. The other is in a stable movement of the cracks, such as the periodic load generated by the cyclical expansion and closure of cracks.(2)Unstable crack This will result in instability of crack extension, affecting the sustainable use of structures, should be considered part of its expansion, to take corresponding measures.3.Causes of cracks in concrete and control measures3.1 Shrinkage cracks Shrinkage cracks are caused by the humidity, it accounts for non-structural cracks in concrete in the main part. We know that concrete is a cement as the main cementing material to natural sand, stone aggregate mixing water, after casting molding, hardens and the formation of artificial stone.In the construction, in order to ensure its workability, often adding cement hydration than water needed for 4 to 5 times more water. More of these water to free state exists, and the gradual evaporation of the hardening process, resulting in the formation of large pores inside the concrete, voids or holes, resulting in volume shrinkage of concrete. In addition, the hardening process of concrete hydration and carbonation of concrete volume will lead to shrinkage. According to the experimental determination of the ultimate shrinkage of concrete is about 0104% ~ 0106%.Shows that shrinkage is the inherent physical properties of concrete, in general, the larger water-cement ratio, the higher the concrete strength, aggregate less, the higher the temperature, surface water loss is larger, the larger the value of its contract, the more easily shrinkage cracks. According to the formation of shrinkage cracks and formation mechanism of the time, works in the common shrinkage cracksare mainly plastic shrinkage cracks, settlement shrinkage cracking and drying shrinkage cracks in three categories, in addition to their contract (chemical shrinkage) cracks and carbonation shrinkage cracks.3.1.1Plastic shrinkage cracks Plastic shrinkage cracks in concrete plastic stage, before the final set. The cause of this is concrete paste and quickly evaporating water flow to the surface, with the increase in water loss, capillary negative pressure generated by contraction of the concrete surface of the drastic volume shrinkage. Strength of concrete at a time has not yet formed, which resulted in cracking of the concrete surface.This multi-cracks in dry weather, hot and windy, the fracture shallow, intermediate width, both ends of the fine, of different lengths, and disconnected.3.1.2 Settlement shrinkage cracking Settlement shrinkage cracks in concrete pouring about half an hour after the occurrence and hardening stops. The cause of this is occurring after the slurry in the Pouring uneven sink, sinking of coarse aggregate, cement grout float, when the settlement was inhibited (such as steel or embedded parts of the block) is due to shearing and cracking of the concrete. In addition, floating in the plasma layer formed on the surface will be a result of bleeding and cracking.This multi-cracks in the concrete surface, and pass along the long direction of the reinforcement, or the stirrups the distribution width of both ends of the narrow middle, is a common early cracks, especially in the pump construction is more common.3.1.3 Drying shrinkage cracks Drying shrinkage cracks in the concrete curing only appeared after completion. Its formation was mainly due to the concrete to harden, the water evaporation caused by shrinkage of the concrete surface, when the shrinkage deformation of concrete by internal constraint, have a greater tensile stress to crack the concrete surface is pulled.Shrinkage cracks on the surface generally produces very shallow location, multi-component along the short direction of distribution, were parallel, linear, or mesh, can be severe throughout the member section.3.1.4 Self-shrinkage cracks Shrinkage cracks itself has nothing to do with the outside humidity, but because of the hydration reaction of cement clinker in the process, the reaction resultant of the average density of smaller volume shrinkage caused by system (called chemical shrinkage) due. Mainly due to hydration products of free water into a part of it39;s specific volume reduced by 1 / 4 (ie 0125cm3Pg).Therefore, the chemical shrinkage of the sizeof the reduction depends on the chemical combination of cement hydration products in the amount of water.3.1.5 Carbonation shrinkage cracking Carbonation carbonation shrinkage cracks are free ions generated by water evaporation, causing shrinkage in the slurry. Carbonation is atmospheric CO2 conditions in the water reacts with the hydration product of CaCO3, alumina, silica and water free state, this part of the volume shrinkage of concrete caused by water evaporation (known as carbonation shrinkage), and its essence is the carbonate of the cement corrosion.General alkalinity of cement hydration products and the higher the concentration of CO2 in air and moderate humidity (50%), the more prone to carbonation. Therefore, this crack propagation in alternating wet and dry environment, and dry or water saturated environment, there is not easy; and because the crack of carbide precipitation will form a gel product, stop the CO2 into, it usually only occurs on the surface.Prevention of shrinkage cracks on the above can take the following measures:(a) mixed with superplasticizer, pumping agent to minimize water consumption; construction, cutting should not be too fast, and the vibration compacting.(b) For the prevention of early shrinkage cracking, in addition to strengthening the early conservation, the final setting of concrete should be conducted before the second wiping pressure, the material can be mixed with coagulant, and the appropriate use of high early strength and good water holding capacity of ordinary Portland cement; for the prevention of shrinkage cracks, can be appropriately extended curing time, the material should use fly ash in cement and other cement or shrinkage rate of small species.(c) minimize the amount of cement, coarse aggregate content increases, and limestone as the coarse aggregate should be chosen because of its superior shrinkage cracking resistance andesite and sandstone; should strictly control the sand content of aggregate, sand ratio should not be too big, should have good aggregate grading.(d) reduce their shrinkage cracking effective way is to use a low C3A content of cement, as C3A Portland cement clinker in the greatest chemical shrinkage reduction is a C2 S 3 times, C4AF of 5 times.(e) to prevent the carbonation shrinkage cracks key is to reduce the resultant alkalinity, good for fresh concrete wet water conservation, and the use of which the concrete structure to stay as dry as other corrosive gases in the high CO2 environment to good anti-corrosionmeasures.(f) pouring concrete trowel promptly after the straw with the wet or plastic film cover, the wind should be set up wind facility construction season.3.2 Crack Crack is the concrete difference in temperature, or seasonal temperature changes and the formation of excessiveIn the concrete pouring process, the cement hydration reaction will release a lot of heat (generally 502J per gram of cement can release heat), so that the internal temperature of concrete at a certain age there temperature peak, then declined.Since the slow cooling inside the concrete surface, fast heat, will form in the temperature difference between inside and outside, for the coordination of the temperature deformation, the concrete surface will have a tensile stress (ie thermal stress), when after more than make the cracking of concrete tensile strength. Such cracks are mostly cross-cutting and deep, severely reducing the overall stiffness of the structure; usually a few months after the end of the construction. In addition, concrete curing period, if the invasion by the cold will cause cracks in the concrete surface, but the lighter, smaller and harmful. Control of temperature cracks start mainly from the lower temperature, can take the following preventive measures:(a) the materials are advised to use fly ash or cement C3A and C3 S low-low-heat cement, to minimize the amount of cement can be mixed with superplasticizer; on the concrete, can be properly mixed with stones ; in the mixing water and aggregate were mixed and ice water cooling.(b) During the construction, the construction process should be reasonable arrangements to improve the construction process, such as pouring a large volume of concrete, pipes laid in concrete or block cyclic thermal stratification placement; improve the structure of constraints, such as a long structure to be set temperature, joints or back strip, when poured on bedrock, to shop 50 ~ 100 mm sand to remove the embedded solid role.(c) in the design, calculation of thermal stress is mainly good, according to temperature stress may have taken the appropriate structural measures, such as proper temperature reinforced configuration, shared concrete temperature stress.(d) In addition, still need to strengthen the concrete curing, good surface insulation measures (such as water conservation or covering wet straw, etc.), an appropriate extension of time for form removal to the slow cooling of the concrete surface; for the concrete, control ofentry mold temperature, and for temperature tracking, control the temperature difference between inside and outside of concrete in less than 25 ℃.3.3 Subsidence cracks Subsidence cracks is all part of the building after completion caused by differential settlement occurs, mostly cross-cutting, its location and settlement in the same direction. Eight-shaped wall buildings or herringbone cracks is a typical settlement pacted backfill without treatment, formation of soft layer containing the building was in use during the ground water (rain, water, etc.) long-term immersion and other factors will cause uneven settlement of the building to crack. The foundation also works in the new construction, if not make the necessary measures (such as the set of retaining walls, diaphragm walls) to prevent soil or groundwater intrusion instability will undermine the foundations of the adjacent old building capacity, resulting in building subsidence cracking. In concrete construction, due to insufficient template rigidity, support spacing is too large, too early form removal and other factors, there will be settlement cracks.Subsidence cracks are often severely affected structures, and endanger the durability of the structure, control measures to prevent its formation are:(a) in the basic design to ensure the bearing capacity of the bearing layer of uniform strength and foundation, in the story and the different parts of the junction of old and new buildings set the settlement joint.(b) In construction, the template should have sufficient strength and rigidity, and support reliable; Also, pay attention to the construction sequence, such as after the first high-rise low-rise, after the first of the main podium.(c) Geological Survey of pre-construction work to do, as far as possible a good choice of the bearing layer, after the completion of the foundation to avoid being soaked in rainwater.3.4 Other crack In addition to these cracks, the construction process in the structure will be various forms of construction cracks; in the structure will appear during use of different types of corrosion cracks.(1) Construction of crack Construction is due to cracks in the construction of improper operation or component itself, not the stiffness of such factors.If PC project, improper tension will form a component due to strength or strength not been made insufficient cracking; template project, if the concrete form removal or bonding with the template template upgrade easily to concrete crack; hoisting project, because of lateral reinforcement component lessstiffness of poor or incorrect lifting point on factors such as cracks. The key is to prevent such cracks in strict accordance with construction specifications, such as prestressed tension must be over 75% component intensity when, brushing between the template and concrete release agent, form removal, or sliding, the first uniform loose, and then slow detachment or upgrade.(2) corrosion cracks Corrosion cracking is due to structure a long period caused by corrosive liquid environment, which includes the corrosion of concrete and its reinforcement corrosion. Such cracks are often caused by the concrete is not dense, they are usually associated with shrinkage cracks, joint action of temperature cracks, leading to crack expanding and eventually weaken the structure of durability.Control measures are mainly doing the concrete surface and reinforcing steel corrosion protection, cracks should be repaired in time. In addition, if the existing concrete aggregate base active ingredient, cement high MgO content (> 5%) or UEA expansive agent such as too much content, alkali aggregate reaction will occur, or because of the hydration reaction of MgO to produce expansion of the gel, resulting in concrete expansion cracks, formed mostly mesh or irregular cracks.Such cracks tend to occur several years after completion of the structure, because the chemical reaction is extremely slow. The key to prevention is to eliminate or reduce the concrete in the presence of such substances.4. Treatment of crack Once the cracking of concrete structures should be identified on the basis of immediately take appropriate measures. At present, the commonly used methods of surface sealing repair, pressure grouting and filling blocking method.4.1 Surface sealing Less than 012mm for the width of the micro-cracks can be polymers of cement paste, permeability of flexible sealant or waterproofing agent brushing on the crack surface, to restore its water resistance and durability. The construction method is simple, but only superficial cracks.(1) process: the surface of the bristles and wash →embedding surface defect (available epoxy cement mortar or latex) →selection of coating compound.(2) construction elements;(a) As the coating is thin and should use strong adhesive material and not aging;(b) Cracks on the activities, should be greater flexibility in material elongation;(c) Tufu uniform, not a bubble.4.2 Pressure Grouting Width and depth greater than 013mm for the larger cracks can be chemical grouting material (such as polyurethane, epoxy or cement slurry) injected by pressure grouting equipment to deep cracks in order to restore structural integrity, water resistance and durability.(1) process:cutting grooves →laid slurry seal mouth →sealing →Check →→filling →preparation of slurry sealing →grouting quality control.(2) Construction of main points:(a) grouting materials should use strong adhesive resin can be irrigated with good material, usually used epoxy resin;(b) For large crack width is greater than 2mm, cement-like material can be used for active cracks should adopt the diluted epoxy resin or polyurethane;(c) chemical grouting pressure control in the 012 ~ 014MPa, pressure control of cement grouting in the 014 ~ 018MPa, increasing the pressure does not improve the filling rate, is not conducive to filling effect;(d) after grouting, when grout without leakage when the initial setting before grouting remove mouth (boxes, tubes).4.3 Complete blocking law Width greater than 015mm for the large cracks or cracks in steel corrosion can crack the concrete digged along the "U" type or "V" groove, and then filling them with repair materials to restore the water resistance, durability or part of the restoration of structural integrity .(1) process:cutting grooves →primary treatment (decontamination of concrete, steel rust) →brushing binder (epoxy grout) →→workmanship surface repair material handling.(2) Construction of main points:(a) Filling them with materials to choose depending on the particular epoxy resin, epoxy mortar, polymer cement mortar, PVC, clay or asphalt ointment;(b) For the corrosion cracks, the first completely rust on steel, and then cover rust paint. 5．SummaryConcrete Crack is a technical problem, long plagued engineering. In recent years, with high early strength cement is widely used as commercial concrete pumping vigorously promote the construction of the concrete strength grade increase, the emergence of mass concrete, to achieve results in the crack problem, while also more prominent, and even become Concretequality focus.The present concrete shrinkage cracks are mainly caused by deformation and deformation temperature, control of these cracks in addition to the general construction in the design and construction take appropriate measures, also need researchers have developed as quickly as possible to reduce shrinkage and hydration heat of cement efficient materials, which will crack the problem reduced to minimum.混凝土裂缝成因和防治措施问题的研究探讨摘要：目前混凝土裂缝问题倍受关注,本文在对混凝土裂缝进行分类的基础上,分析了不同裂缝的形成原因,并提出了裂缝防治的措施及处理方法。
混凝土工程中英文(个人整理)
混凝土工程concrete works一、材料袋装水泥bagged cement散装水泥bulk cement砂sand骨料aggregate商品混凝土commercial concrete现浇混凝土concrete-in-situ预制混凝土precast concrete预埋件embedment（fit 安装）外加剂admixtures抗渗混凝土waterproofing concrete石场aggregate quarry垫块spacer二、施工机械及工具搅拌机mixer振动器vibrator电动振动器electrical vibrator振动棒vibrator bar抹子（steel wood）trowel磨光机glasser混凝土泵送机concrete pump橡胶圈rubber ring夹子clip混凝土运输车mixer truck自动搅拌站auto-batching plant输送机conveyor塔吊tower crane汽车式吊车motor crane铲子shovel水枪jetting water橡胶轮胎rubber tires布袋cloth-bags塑料水管plastic tubes喷水雾spray water fog三、构件及其他专业名称截面尺寸section size（section dimension）混凝土梁concrete girder简支梁simple supported beam挑梁cantilever beam悬挑板cantilevered slab檐板eaves board封口梁joint girder翻梁upstand beam楼板floor slab空调板AC board飘窗bay window（suspending window）振捣vibration串筒a chain of funnels混凝土施工缝concrete joint水灰比ratio of water and cement砂率sand ratio大体积混凝土large quantity of pouring混凝土配合比concrete mixture rate混凝土硬化hardening of concrete(in a hardening process 硬化中)规定时间regulated period质保文件quality assurance program设计强度design strength永久工程permanent works临时工程temporary works四、质量控制及检测不符合规格的non-standard有机物organic matters粘土clay含水率moisture content（water content）中心线central line安定性soundness （good soundness 优良的安定性）坍落度slump (the concrete with 18m m±20mm slump)混凝土养护concrete curing标养混凝土试件standard curing concrete test sample同条件混凝土试件field-cure specimen收缩shrinkage初凝时间initial setting time终凝时间final setting time成品保护finished product protection混凝土试件concrete cube偏心受压eccentric pressing保护层concrete cover孔洞hole裂缝crack蜂窝honeycomb五、句子1，Usually we control the cement within 2% 我们将水泥的误差控制在2%2，Are there any pipe clogging happened during the concreting?浇筑混凝土中有堵管现象吗？3，Will the pipe be worn out very fast？管道磨损很快吗？4，This embedment is fixed at 1500mm from the floor and 350mm from the left edge of the column. Would you measure the dimension by this meter?预埋件的位置在地面上1500mm，离柱边350mm。
土木工程文献外文翻译(中英互译版)
使用加固纤维聚合物增强混凝土梁的延性作者：Nabil F. Grace, George Abel-Sayed, Wael F. Ragheb摘要：一种为加强结构延性的新型单轴柔软加强质地的聚合物(FRP)已在被研究，开发和生产(在结构测试的中心在劳伦斯技术大学)。
这种织物是两种碳纤维和一种玻璃纤维的混合物，而且经过设计它们在受拉屈服时应变值较低，从而体现出伪延性的性能。
通过对八根混凝土梁在弯曲荷载作用下的加固和检测对研制中的织物的效果和延性进行了研究。
用现在常用的单向碳纤维薄片、织物和板进行加固的相似梁也进行了检测，以便同用研制中的织物加固梁进行性能上的比较。
这种织物经过设计具有和加固梁中的钢筋同时屈服的潜力，从而和未加固梁一样，它也能得到屈服台阶。
相对于那些用现在常用的碳纤维加固体系进行加固的梁，这种研制中的织物加固的梁承受更高的屈服荷载，并且有更高的延性指标。
这种研制中的织物对加固机制体现出更大的贡献。
关键词：混凝土，延性，纤维加固，变形介绍外贴粘合纤维增强聚合物（FRP）片和条带近来已经被确定是一种对钢筋混凝土结构进行修复和加固的有效手段。
关于应用外贴粘合FRP板、薄片和织物对混凝土梁进行变形加固的钢筋混凝土梁的性能，一些试验研究调查已经进行过报告。
Saadatmanesh和Ehsani（1991）检测了应用玻璃纤维增强聚合物(GFRP)板进行变形加固的钢筋混凝土梁的性能。
Ritchie等人（1991）检测了应用GFRP，碳纤维增强聚合物（CFRP）和G/CFRP板进行变形加固的钢筋混凝土梁的性能。
Grace等人（1999）和Triantafillou（1992）研究了应用CFRP薄片进行变形加固的钢筋混凝土梁的性能。
Norris，Saadatmanesh和Ehsani（1997）研究了应用单向CFRP薄片和CFRP织物进行加固的混凝土梁的性能。
在所有的这些研究中，加固的梁比未加固的梁承受更高的极限荷载。
钢筋混凝土中英文资料外文翻译文献
钢筋混凝土中英文资料翻译1 外文翻译1.1 Reinforced ConcretePlain concrete is formed from a hardened mixture of cement ,water ,fine aggregate, coarse aggregate (crushed stone or gravel),air, and often other admixtures. The plastic mix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical hydration reaction lf the cement/water mix, resulting in hardened concrete. The finished product has high compressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth lf its compressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete element.It is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design. The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved. This is possible because concrete can easily be given any desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned, the finished product becomes strong, durable, and, in combination with the reinforcing bars, adaptable for use as main members of anystructural system.The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it is a column, a bean, a wall, a slab, a foundation. a mass columns, or an extension of previously placed and hardened concrete. For beams, columns, and walls, the forms should be well oiled after cleaning them, and the reinforcement should be cleared of rust and other harmful materials. In foundations, the earth should be compacted and thoroughly moistened to about 6 in. in depth to avoid absorption of the moisture present in the wet concrete. Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type, as the case requires, unless it is placed by pumping. It must be kept in mind, however, that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concrete.Hydration of the cement takes place in the presence of moisture at temperatures above 50°F. It is necessary to maintain such a condition in order that the chemical hydration reaction can take place. If drying is too rapid, surface cracking takes place. This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydration.It is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element, such as geometrical width, depth, area of reinforcement, steel strain, concrete strain, steel stress, and so on. Consequently, trial and adjustment is necessary in the choice of concrete sections, with assumptions based on conditions at site, availability of the constituent materials, particular demands of the owners, architectural and headroom requirements, the applicable codes, and environmental reinforced concrete is often a site-constructed composite, in contrast to the standard mill-fabricated beam and column sections in steel structures.A trial section has to be chosen for each critical location in a structural system. The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load. Since more than one trial is often necessary to arrive at the required section, the first design input step generates into a series of trial-and-adjustment analyses.The trial-and –adjustment procedures for the choice of a concrete section lead to the convergence of analysis and design. Hence every design is an analysis once a trial section is chosen. The availability of handbooks, charts, and personal computers and programs supports this approach as a more efficient, compact, and speedy instructionalmethod compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design.1.2 EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering, this is a field where there are real opportunities for the enthusiast. In 1935 most of the methods now in use for carrying and excavating earth with rubber-tyred equipment did not exist. Most earth was moved by narrow rail track, now relatively rare, and the main methods of excavation, with face shovel, backacter, or dragline or grab, though they are still widely used are only a few of the many current methods. To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines. Generally the only reliable up-to-date information on excavators, loaders and transport is obtainable from the makers.Earthworks or earthmoving means cutting into ground where its surface is too high ( cuts ), and dumping the earth in other places where the surface is too low ( fills). Toreduce earthwork costs, the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill. This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness. From the available maps ahd levels, the engineering must try to reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork. On the site when further information becomes available he can make changes in jis sections and layout,but the drawing lffice work will not have been lost. It will have helped him to reach the best solution in the shortest time.The cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine. This is not always possible, but when it canbe done it is ideal, being both quick and cheap. Draglines, bulldozers and face shovels an do this. The largest radius is obtained with the dragline,and the largest tonnage of earth is moved by the bulldozer, though only over short distances.The disadvantages of the dragline are that it must dig below itself, it cannot dig with force into compacted material, it cannot dig on steep slopws, and its dumping and digging are not accurate.Face shovels are between bulldozers and draglines, having a larger radius of action than bulldozers but less than draglines. They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a dragline.Each piece of equipment should be level of their tracks and for deep digs in compact material a backacter is most useful, but its dumping radius is considerably less than that of the same escavator fitted with a face shovel.Rubber-tyred bowl scrapers are indispensable for fairly level digging where the distance of transport is too much tor a dragline or face shovel. They can dig the material deeply ( but only below themselves ) to a fairly flat surface, carry it hundreds of meters if need be, then drop it and level it roughly during the dumping. For hard digging it is often found economical to keep a pusher tractor ( wheeled or tracked ) on the digging site, to push each scraper as it returns to dig. As soon as the scraper is full,the pusher tractor returns to the beginning of the dig to heop to help the nest scraper.Bowl scrapers are often extremely powerful machines;many makers build scrapers of 8 cubic meters struck capacity, which carry 10 m ³ heaped. The largest self-propelled scrapers are of 19 m ³ struck capacity ( 25 m ³ heaped )and they are driven by a tractor engine of 430 horse-powers.Dumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials. Dumpers have the earth container over the front axle on large rubber-tyred wheels, and the container tips forwards on most types, though in articulated dumpers the direction of tip can be widely varied. The smallest dumpers have a capacity of about 0.5 m ³, and the largest standard types are of about 4.5 m ³. Special types include the self-loading dumper of up to 4 m ³and the articulated type of about 0.5 m ³. The distinction between dumpers and dump trucks must be remembered .dumpers tip forwards and the driver sits behind the load. Dump trucks are heavy, strengthened tipping lorries, the driver travels in front lf the load and the load is dumped behind him, so they are sometimes called rear-dump trucks.1.3 Safety of StructuresThe principal scope of specifications is to provide general principles and computational methods in order to verify safety of structures. The “ safety factor ”, which according to modern trends is independent of the nature and combination of the materials used, can usually be defined as the ratio between the conditions. This ratio is also proportional to the inverse of the probability ( risk ) of failure of the structure.Failure has to be considered not only as overall collapse of the structure but also as unserviceability or, according to a more precise. Common definition. As the reaching of a “limit state ” which causes the construction not to accomplish the task it was designedfor. There are two categories of limit state :(1)Ultimate limit sate, which corresponds to the highest value of the load-bearing capacity. Examples include local buckling or global instability of the structure; failure of some sections and subsequent transformation of the structure into a mechanism; failure by fatigue; elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure; and sensitivity of the structure to alternating loads, to fire and to explosions.(2)Service limit states, which are functions of the use and durability of the structure. Examples include excessive deformations and displacements without instability; early or excessive cracks; large vibrations; and corrosion.Computational methods used to verify structures with respect to the different safety conditions can be separated into:(1)Deterministic methods, in which the main parameters are considered as nonrandom parameters.(2)Probabilistic methods, in which the main parameters are considered as random parameters.Alternatively, with respect to the different use of factors of safety, computational methods can be separated into:(1)Allowable stress method, in which the stresses computed under maximum loads are compared with the strength of the material reduced by given safety factors.(2)Limit states method, in which the structure may be proportioned on the basis of its maximum strength. This strength, as determined by rational analysis, shall not be less than that required to support a factored load equal to the sum of the factored live load and dead load ( ultimate state ).The stresses corresponding to working ( service ) conditions with unfactored live and dead loads are compared with prescribed values ( service limit state ) . From the four possible combinations of the first two and second two methods, we can obtain some useful computational methods. Generally, two combinations prevail:(1)deterministic methods, which make use of allowable stresses.(2)Probabilistic methods, which make use of limit states.The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which are then combined to define the safety factor. probabilistic approaches depend upon :(1) Random distribution of strength of materials with respect to the conditions offabrication and erection ( scatter of the values of mechanical properties through out the structure );(2) Uncertainty of the geometry of the cross-section sand of the structure ( faults and imperfections due to fabrication and erection of the structure );(3) Uncertainty of the predicted live loads and dead loads acting on the structure;(4)Uncertainty related to the approximation of the computational method used ( deviation of the actual stresses from computed stresses ).Furthermore, probabilistic theories mean that the allowable risk can be based on several factors, such as :(1) Importance of the construction and gravity of the damage by its failure;(2)Number of human lives which can be threatened by this failure;(3)Possibility and/or likelihood of repairing the structure;(4) Predicted life of the structure.All these factors are related to economic and social considerations such as：(1) Initial cost of the construction;(2) Amortization funds for the duration of the construction;(3) Cost of physical and material damage due to the failure of the construction;(4) Adverse impact on society;(5) Moral and psychological views.The definition of all these parameters, for a given safety factor, allows construction at the optimum cost. However, the difficulty of carrying out a complete probabilistic analysis has to be taken into account. For such an analysis the laws of the distribution of the live load and its induced stresses, of the scatter of mechanical properties of materials, and of the geometry of the cross-sections and the structure have to be known. Furthermore, it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material, on the cross-sections and upon the load acting on the structure. These practical difficulties can be overcome in two ways. The first is to apply different safety factors to the material and to the loads, without necessarily adopting the probabilistic criterion. The second is an approximate probabilistic method which introduces some simplifying assumptions ( semi-probabilistic methods ) 。
土木工程专业中英文翻译文摘
Finite element method analysis of a concrete bridge repaired with fiber reinforced plastic laminatesJoseph W.Tedesco, J.Michael Stallings.Mahmoud El-Mihilmy, Department of Civil Engineering,Auburn University,Auburn,AL 36849,USAMartin Peltyn and Early,Reno,NV 89502,USAAbstractMany reinforced concrete bridges throughout the United States on county and state highway systems are deteriorated and/or distressed to such a degree that structural strengthening of the bridge or reducing the allowable truck loading on the bridge by load posting is necessary to extend the service life of the bridge .The structural performance of many of these bridges can be improved through external bonding of fiber reinforced plastic(FRP) laminates or plates.This paper summarizes the results of a comprehensive finite element method(FEM)analysis of a deteriorated reinforced concrete bridge repaired with externally bonded FRP laminates.Static and dynamic analyses of the bridge were conducted for conditions both before and after the FRP repairs,with loading by two identical test trucks of known weight and configuration.The results of the FEM analyses were corroborated with field test data.The results of a parametric study to assess the effects of altering the cross sectional dimensions and material properties of the FRP laminates upon bridge girder deflections and reinforcing steel stresses is also presented.在美国，许多通过各地县，洲际的公路系统的钢筋混凝土桥梁被恶化和/或困扰到这种程度，桥梁结构加固或通过荷载记录减少卡车容许载荷对延长大桥服务年限是必需的。
混凝土外文翻译---天然粗骨料对再生粗骨料物理和力学性能的影响（有word版..
ORIGINAL ARTICLEEffect of natural coarse aggregate type on the physical and mechanical properties of recycled coarse aggregatesC.J.Zega ÆY.A.Villagra´n-Zaccardi ÆA.A.Di MaioReceived:4June 2008/Accepted:29January 2009/Published online:18February 2009ÓRILEM 2009Abstract Many environmental problems caused by the large volumes of construction and demolition waste (C&DW),the lack of adequate deposition sites and the shortage of natural resources have led to the use of C&DW as replacement of natural aggregates in the production of new concrete.As in the case of natural aggregates,when recycled aggregates are used to manufacture structural concrete,the assessment of their physical,mechanical and durable characteristics is a key issue.The different physical and mechanical properties of the recycled coarse aggregate (RCA)are evaluated.RCA was obtained by crushing conven-tional concretes with different strength levels (different w/c ratios)containing four different types of natural coarse aggregates (three crushed stones and a siliceous gravel),which differ in shape,composition and surface texture.There is a significant influence of the natural coarse aggregate (NCA)on the properties of RCA,which in many cases is greater than that of the w/c ratio of the source concrete.Keywords Natural aggregate ÁRecycledaggregate ÁAbsorption ÁLos Angeles abrasion ÁFlakiness index ÁMortar content1IntroductionAll sectors of society are responsible for environ-mental pollution problems,but the incidence of the construction industry is particularly high,owing to both waste generation and the exploitation of natural resources.However,there are many possibilities and alternatives to contribute to environmental protection.Although in Argentina there still are vast areas where suitable aggregates for concrete manufacture can be obtained,it is certainly true that in many cases large distances have to be travelled to obtain good-quality natural aggregates.Besides,because of their composition,certain types of natural rocks may cause different durability-related problems such as the alkali-aggregate reaction in rocks containing reactive minerals or the occurrence of expansive clays in the microstructure of some basalts,which would further add to the damage caused by the use of natural aggregates.Large urban centres are also facing the problem of not having adequate deposition sites,which leads to large accumulations of construction waste material.One of the ways of mitigating such problems is related to the use of recycled aggregates,obtained by crushing waste concrete,as replacement of natural aggregates in the production of new concrete.This would obviously reduce the amount of deposited waste.Owing to their composition,where the mortar and the rock form mixed particles with varying proportionsC.J.Zega (&)ÁY.A.Villagra´n-Zaccardi ÁA.A.Di MaioLaboratorio de Entrenamiento Multidisciplinario para laInvestigacio´n Tecnolo ´gica (LEMIT),La Plata,Argentina e-mail:**********************Materials and Structures (2010)43:195–202DOI 10.1617/s11527-009-9480-4of each of them,recycled aggregates have different characteristics than natural aggregates,such as lower specific gravity and higher water absorption and Los Angeles abrasion[1–3].However,to our knowledge there are no studies about the influence of the type of natural coarse aggregate(NCA)on the properties of recycled aggregates obtained from crushed concrete. Some studies on this subject have analysed how the quality of the crushed original concrete influences the properties of the recycled coarse aggregate(RCA), arriving at various conclusions[3–5].It is well known that the shape and surface roughness of NCA have some influence during concrete production since they can change concrete proportions(w/c ratio,cement content,fine aggre-gate/coarse aggregate ratio,etc.)as well as some of its fresh state characteristics.Moreover,the above-mentioned characteristics of NCA exert a great influence on hardened concrete properties because of the change in the aggregate-matrix interface[6–9].Thefirst part of an extensive study regarding the behaviour of recycled concretes is presented in this paper.The purpose is to evaluate the effect of the type of NCA used in the manufacture of conventional concretes with different strength levels on the physical and mechanical properties of the recycled aggregates obtained by crushing them.Four natural coarse aggre-gates that are usually employed in the central region of Argentina were selected.They have different charac-teristics related to their origin,composition,shape and surface texture that change both their properties and those of the concretes made with them[10].For each type of NCA used,concretes with w/c ratios of0.45and0.65were made,which were then crushed to obtain eight different types of RCA. Different physical and mechanical properties of the NCA and of the resulting RCA are presented,such as specific gravity,water absorption in24h,Los Angeles abrasion,unit weight,void content,material finer than75l m,flakiness index and mortar content. 2ExperimentalThe NCA consisted of three crushed stones and a rounded aggregate,all of them with a nominal size of 6–20mm.The NCA has differences in composition, particle shape and surface texture,which makes its physical,mechanical and durable characteristics also different.The crushed stones consisted of one of igneous plutonic origin(granitic—G),one of igneous volcanic origin(basaltic—B)and the other of sedi-mentary origin(quartzitic—Q),whereas the fourth NCA was a siliceous gravel from the Uruguay River (siliceous gravel—S).Concretes with w/c ratios of0.45and0.65were made with each one of the four NCAs,keeping the volume content of the concrete coarse aggregate constant.Each of these concretes was cured for 28days,crushed in a jaw crusher and subsequently sieved to obtain eight RCAs6–20mm in nominal size. The recycled aggregates are designated by the letter R followed by a second letter that indicates the type of NCA they contain,and by a number that refers to the w/c ratio of the source concrete.Thus,aggregates RG45 and RG65denote the RCA obtained by crushing conventional concretes,made with granitic aggregate (G),with a w/c ratio of0.45and0.65,respectively.On each coarse aggregate sample(four natural and eight recycled coarse aggregates)different physical and mechanical properties were determined,such as specific gravity at saturated and surface-dry state, water absorption in24h,weight loss by the Los Angeles abrasion test,percentage of materialfiner than75l m,unit weight measured by the shovelling procedure,void content,flakiness index,weight loss after immersion in ethylene glycol for30days(only in the case of aggregate B)and loss on acid digestion in order to estimate the RCA mortar content.The standards used for each test performed are included in Table1.The basaltic aggregates(B)may be contaminated with secondary minerals such as clays of the mont-morillonite group,which exhibit a laminar structure and may undergo significant increases in volume and cause aggregate fracture when they are subjected to Table1Test standards usedProperties Test standardSpecific gravity and absorption ASTM C127-01 Los Angeles abrasion ASTM C131-03 Materialfiner than75l m ASTM C117-03 Unit weight ASTM C29-03 Voids ASTM C29-03 Flakiness index BS812-105.1:1985 Durability in ethylene glycol IRAM1519:1982drying and wetting cycles.The durability test in ethylene glycol is carried out to evaluate whether these aggregates have these characteristics,and they will be considered as acceptable whenever their weight loss is not over10%.In order to determine the RCA mortar content, samples of a10–20mm fraction of each of them were taken and covered with a known volume of water to which the same volume of hydrochloric acid was added,obtaining a1:1dilution.Heating to incipient boiling was then performed and the samples were stored for24h.Finally,the remaining aggregates were washed,dried to constant weight and then sieved through a sieve#4to obtain the rock particles of the original NCA.The weight losses of NCAs were also determined by the same procedure.The reported values correspond to the net percent of mortar loss for each RCA since each NCA loss has been deducted.2.1Characteristics of NCAThe aggregate G consists of a medium-grained,very compact and unweathered granitic migmatite,con-taining30–40%quartz with cataclastic structure and undulatory extinction.The aggregate B is composed of alkaline basaltic rocks originated from fracture outflow that are petrographically classified asfine-grained,massive and slightly altered nepheline basanites.The aggregate Q consists of orthoquartzite of sedimentary origin,containing97–99%quartz forming subrounded,subangular and even angular grains bonded by siliceous cement.They have afine-grained structure with grains ranging between0.5and 0.8mm,which are yellow to dark brown because of iron hydrolysis.The fourth NCA is a siliceous gravel (S)from deposits of the Uruguay River,which iscomposed of rounded clasts containing quartz (*30%),chalcedony(*50%)and sandstones-silt-stones(*20%).The physical characteristics of shape,surface texture and grain size of each of the four NCAs selected are summarised in Table2.2.2Results and analysisFigure1shows the grading of the four NCAs together with the limits set by the Argentine CIRSOC regulations[11],and Table3reports the different properties determined on each of them.It can be observed that aggregate Q has the highest absorption and Los Angeles abrasion values,as well as lower specific gravity,which is directly related to its origin.Aggregate S has the highest unit weight value, although its specific gravity is not the highest,and the lowestflakiness index,which is directly associated with its shape that gives it a lower void content.The grading determined on each of the eight RCAs is shown in Fig.2,together with the above-mentioned limits set by the CIRSOC regulations for natural aggregates of the same maximum nominal size.It can be noted that the eight RCAs have similar particle-size distribution,regardless of the type of Table2Characteristics of natural coarse aggregates Characteristics G Q B S Shape Angular Rounded Surface texture Rough SmoothGrain size MediumFineFig.1Grading of natural coarse aggregatesTable3Properties of natural coarse aggregatesProperties G Q B S Specific gravity(kg/dm3) 2.72 2.48 3.03 2.60 Absorption(%)0.3 2.00.80.5 Los Angeles abrasion(%)25.059.89.118.8 Materialfiner than75l m(%)0.60.90.30.2 Unit weight(kg/m3)1410131015301580 Voids(%)48.046.249.338.4 Flakiness index(%)19.225.326.79.9 Weight loss in ethylene glycol(%)–– 2.5–NCA and the w/c ratio of the source concrete.The results obtained agree with some other results reported in the literature,where the grading of RCAs is independent of the w/c ratio of the original concrete [3,5]and meets the limits prescribed for NCAs.It is also clear that the grading of RCA is not influenced by the different characteristics of shape and texture of the NCAs in the source concrete.The physical and mechanical properties deter-mined on each of the eight RCAs under study are given in Table 4,as in the case of natural aggregates,but including their mortar content.The relative specific gravities at saturated and surface-dry state of each RCA with respect to the specific gravity of the corresponding NCA are indicated in Fig.3.It is worth noting that for each type of NCA,the specific gravity of the corresponding RCA is lower and that there is no significant difference depending on the source concrete quality,which is in agreement with literature reports on this subject [5,12].The specific gravity values of RCAs decreased byapproximately 7,4,12and 6%in relation to those of the natural aggregates G,Q,B and S,respectively.Besides,as expected,the higher the specific gravity of the NCA used in concrete production,the greater the influence of the mortar present in RCA particles.This implies a larger decrease in specific gravity,which is more clearly shown in the case of aggregate B.Although the specific gravity of RCAs decreases in relation to that of NCAs,the specific gravity of an RCA from a concrete made with a certain type of NCA may be greater than that of another type of natural aggregate.This is the case of recycled aggregates RB45and RB65as compared to the natural aggregates S and Q.So,recycled concrete would not always present a lower unit weight than conventional concrete.As expected,24h water absorption of RCAs shows a significant increase with respect to that of NCAs for each type of natural aggregate used (see Table 4),which is directly related to the presence of mortar as a constituent part of these aggregates.RCAabsorptionFig.2Grading of recycled coarse aggregatesTable 4Properties of recycled coarse aggregates PropertiesRG45RG65RQ45RQ65RB45RB65RS45RS65Specific gravity (kg/dm 3) 2.52 2.51 2.37 2.35 2.66 2.65 2.45 2.44Absorption (%)4.0 4.15.96.0 3.9 4.5 3.9 4.4Los Angeles abrasion (%)34.837.452.255.425.330.331.637.0Material finer than 75l m (%)0.60.10.20.20.20.40.10.1Unit weight (kg/m 3)12201190110011401260129011901210Voids (%)49.450.950.948.550.949.249.548.1Flakiness index (%)12.910.114.912.711.39.911.210.4Mortar content (%)45.641.864.457.648.442.049.344.2Fig.3Relative specific gravities of recycled coarseaggregatesvalues were approximately14,3,5and8times higher than those of aggregates G,Q,B and S,respectively.In contrast to what happens with the specific gravity,the RCAs from concretes of lower quality(0.65w/c ratio) have absorption values higher than those of the RCAs from concretes with a w/c ratio of0.45.These results agree with thefindings of some studies[13,14]but completely disagree with others[3,4,12].Figure4shows the weight loss values from the Los Angeles abrasion test for each RCA in relation to those of natural aggregates,using gradation‘‘B’’as defined in the standard(see Table1).From the tests conducted so far,it follows that the porosity of RCAs,estimated by the absorption andspecific gravity tests,increases in relation to that of each of the four NCAs.This behaviour is different in the Los Angeles abrasion test,where increases in abrasion values are observed for recycled aggregates RG,RB and RS in relation to those of the corresponding NCAs,with average values of45, 200and82%,respectively.The greatest abrasion in RCAs occurs in concretes with a weaker matrix(w/c of0.65),which is expected and agrees with what has been reported in the literature[5,13].A particular case is that of the quartzitic aggregate where RQ showed less abrasion than Q(of the order of5%).This is a clear indication of the lower quality of the natural aggregate,since even the RCA from a concrete with a w/c ratio of0.65showed less abrasion than the NCA.Figure5shows the unit weights of RCAs in relation to those of the corresponding NCAs,deter-mined by the shovelling procedure.Unit weight values are lower for RCAs because of their lower specific gravity;there are no significant differences among those from concretes with a w/c ratio of0.45and0.65.The average decreases were15, 15,17and25%for the aggregates RG,RQ,RB and RS,respectively.The larger decrease in the case of aggregates RS must be attributed to the additional effect of the change in shape of the recycled aggregate particles.This is evidenced by the higher void content of both aggregates RS in relation to that of S.Theflakiness indexes of RCAs in relation to those of the corresponding NCAs are presented in Fig.6.The RCAs from concretes containing aggregates of angular shape(G,Q and B)have a lowerflakiness index than the corresponding NCAs.Because of the presence of oriented weak planes in the natural rocks, the crushing process will lead to a larger fracture on these planes forming a larger number offlaky particles in the NCAs[15].In the case of crushed concretes,weakness planes(interfaces)are distrib-uted without a defined orientation,which makes the RCA particles have similar sizes in thethree Fig.5Relative unit weight of recycled coarseaggregates Fig.4Relative weight losses by the Los Angeles abrasiontest Fig.6Relativeflakiness index of recycled coarse aggregatesdirections.However,the type of crusher used will have a strong influence on the shape of the particles formed[15,16].Another peculiarity shown in Fig.6,for the four types of NCA used,is that the recycled aggregates produced from concretes with a higher w/c ratio are lessflaky.The lower matrix strength of concretes with a w/c ratio of0.65would lead to a larger mortar loss during their crushing,making these RCA parti-cles lessflaky than those from concretes with a w/c ratio of0.45.This can be confirmed with the results from other tests,as shown below.In Table4,it can be seen that the RCAs from concretes with a w/c ratio of0.65show lower mortar content values than those from concretes with a w/c ratio of0.45,which occurs for the four types of NCA selected.As mentioned above,this can be attributed to a greater mortar loss during the crushing of concretes with a high w/c ratio,because their matrix is weaker than that of concretes with a w/c ratio of0.45.The grading of recycled samples after the hydrochloric acid attack confirms these results.As an example,the particle-size distribution of the original natural basalt (B)and those of the natural aggregate extracted by means of the diluted hydrochloric acid attack to aggregates RB45and RB65(named B in RB45and B in RB65,respectively)are shown in Fig.7.The grading of B in RB45is the one that differs more from that of the natural aggregate B.This clearly shows that in the case of RB45,the fracture process occurs mainly through the natural aggregate because of the higher matrix strength.Whereas in RB65,because of the lower matrix strength the fracture preferably occurs through the mortar,leading to a coarser particle size than in the former case althoughfiner than that of B.The relationships between Los Angeles abrasion loss and the mortar content of the RCAs under study, for both RCAs from concrete with w/c ratios of0.45 and0.65(R45and R65,respectively),are shown in Fig.8.For both w/c ratios the abrasion loss tends to increase with the mortar content of the aggregates. For a given mortar content,aggregates R65attain higher Los Angeles abrasion values than R45,which is in agreement with the lower quality of the mortar.Owing to the characteristics of aggregate Q,the abrasion loss values are high in the corresponding RCA(the upper points in Fig.8),indicating the strong influence that the properties of the original natural aggregates may have on those of the resulting recycled aggregates.So a recycled aggregate obtained from a concrete with a w/c ratio of0.45 may exhibit a higher abrasion value than another one from a concrete with a w/c ratio of0.65,which is the case of the aggregate RQ45with respect to RB65. This allows confirming that the w/c ratio of the original concrete is relatively less important than the abrasion loss value of the NCAs it contains.Figure9shows the relative differences between aggregates R65and R45in the absorption,Los Angeles abrasion and mortar content tests,for the four types of natural aggregates used.It must be remembered that the mortar contents of aggregates R65were lower than those of R45,so in thefigure the axis corresponding to this determination is on a negativescale.Fig.7Grading of aggregates B,B in RB45and B inRB65Fig.8Relationships between Los Angeles abrasion and themortar contentThere is a marked difference in absorption and abrasion between the recycled aggregates that contain the natural aggregates G and Q and those that contain the aggregates S and B;the differences in mortar content are lower but still show the same tendency.The behaviour observed must be analysed taking into account the matrix strength together with the surface texture of the NCA,which are known to change the characteristics of the aggregate-matrix interface [10,17].If the matrix is weak (w/c ratio of 0.65),the smooth surface texture of natural aggre-gates B and S negatively affects adherence.This facilitates mortar separation from NCAs during crushing and the formation of particles made up of only mortar in aggregates RB65and RS65.In the case of natural aggregates G and Q,owing to their rough surface textures,the improved aggregate-matrix interface led to higher fracture of NCAs and the formation of a larger number of mixed particles (rock-mortar).3ConclusionsBased on the physical and mechanical characteristics determined on different RCAs (6–20mm in nominal size)from crushed conventional concretes with different w/c ratios and made with NCAs of the same nominal size,having different surface rough-ness,shape,and physical and mechanical behaviour,the following conclusions can be drawn:–The grading and the unit weight of RCAs are not influenced by any of the two variables studied(type of NCA and w/c ratio).The specific gravity,water absorption and Los Angeles abrasion clearly indicate that RCAs are of lower quality than NCAs because of the mortar they contain.–The natural quartzitic aggregate is a particular case because in the Los Angeles abrasion test the recycled aggregates have lower weight loss than NCA,which is directly related to its low quality.–The mortar content is lower in RCAs from concrete with a higher w/c ratio,which must be attributed to a higher mortar loss during the concrete crushing process owing to the weaker matrix.–For the NCAs used and the w/c ratios studied,the properties evaluated for RCAs are more affected by the type of NCAs than by the w/c ratio of the source concrete from which the recycled aggre-gates were obtained.References1.Zega CJ,Di Maio AA (2007)Efecto del Agregado GruesoReciclado sobre las Propiedades del Hormigo´n.Boletı´n Te´cnico del Instituto de Materiales y Modelos Estructu-rales.IMME Venezuela 45(2):1–112.Zega CJ,Taus VL,Villagra´n ZYA,Di Maio AA (2005)Comportamiento Fı´sico-Meca ´nico de Hormigones someti-dos a Reciclados Sucesivos.Memorias Symposium fib ‘‘Structural Concrete and Time’’,La Plata,Argentina,28–30September 2005,pp 761–7683.Hansen TC (1986)Recycled aggregates and recycled aggregate concrete.Second State-of-the-art.Report developments 1945–1985.RILEM Technical Committee–37-DRC,demolition and recycling of concrete.Mater Struct 19(111):201–246.doi:10.1007/BF024720364.Sri Ravindrarajah R,Tam CT (1985)Properties of concrete made with crushed concrete as coarse aggregate.Mag Concr Res 37(130):29–385.Hansen TC,Narud H (1983)Strength of recycled concrete made from crushed concrete coarse aggregate.Concr Int ACI 5(1):79–836.Van Mier JGM (1997)Fracture processes of concrete,CRC Press,USA,448p,Chap 2,pp 17–537.Mehta PK,Monteiro PJM (1998)Concreto:estructura,propiedades y materiales.Instituto Mexicano del Cemento y del Concreto,A.C.,Mexico8.Tasong WA,Lynsdale CJ,Cripps JC (1999)Aggregate-cement paste interface:part I.Influence of aggregate geochemistry.Cement Concr Res 29(7):1019–1025.doi:10.1016/S0008-8846(99)00086-19.Tasong WA,Lynsdale CJ,Cripps JC (1998)Aggregate-cement paste interface:part II.Influence of aggregate physical properties.Cement Concr Res 28(10):1453–1465.doi:10.1016/S0008-8846(98)00126-4Fig.9Relative differences between aggregates R65and R45for the absorption10.Giaccio G,Zerbino R(1998)Failure mechanism of con-crete:combined effects of coarse aggregates and strength level.Adv Cement Based Mater,USA,vol7(1),pp41–48 11.Reglamento CIRSOC-201.Proyecto,Ca´lculo y Ejecucio´nde Estructuras de Hormigo´n Armado y Pretensado.Tomo I.Instituto Nacional de Tecnologı´a Industrial,Argentina 12.Di Maio A,Gutierrez F,Traversa LP(2001)Compor-tamiento Fı´sico-Meca´nico de Hormigones Elaborados con Agregados Reciclados.Memorias148Reunio´n Te´cnica de la Asociacio´n Argentina de Tecnologı´a del Hormigo´n, October2001,Olavarrı´a,Argentina,pp37–4413.Tavakoli M,Soroushian P(1996)Strengths of recycledaggregate concrete made usingfield-demolished concrete as aggregate.Mater J,ACI,March–April1996,pp182–19014.Hasaba S,Kawamura M,Torik K,Takemoto K(1986)Drying shrinkage and durability of the concrete made of recycled concrete aggregate.Trans Japan Concr Inst,vol3, 1981,pp55–60(Cited in[3])15.Czarnecka ET,Gillott JE(1982)Effect of different typesof crushers on shape and roughness of aggregates.Cement Concr Aggreg4(1):33–3816.Bouquety MN,Descantes Y,Barcelo L,de Larrard F,Clavaud B(2007)Experimental study of crushed aggregate shape.Construct Build Mater21(4):865–872.doi:10.1016/ j.conbuildmat.2005.12.01317.Neville AM(1977)Tecnologı´a del Concreto.Tomo I.Instituto Mexicano del Cemento y del Concreto, A.C., Mexico天然粗骨料对再生粗骨料物理和力学性能的影响2008年6月收到:4 /接受:1月29日,2009年/在线发表:2009年2月18日RILEM 2009年摘要大量的拆建废弃物(C&DW)导致许多环境问题,缺乏足够的埋藏地点和自然资源的匮乏致使在新混凝土生产中作为天然骨料的取代物。
再生混凝土的概念英译
再生混凝土的概念英译嘿，朋友！你可曾听说过再生混凝土？要是没听过，那咱可得好好唠唠。
再生混凝土，用英文来说，那叫 Recycled Concrete 。
这可不是啥生僻的词儿，它在建筑领域那可是相当重要的角色呢！你想想啊，咱们平时盖房子、修马路，得用多少混凝土啊？那要是用完的混凝土就这么扔了，多浪费，多可惜呀！就好比你买了一堆好吃的，吃不完就全扔了，不可惜吗？所以啊，这再生混凝土就出现了，它就像是个“环保卫士”，把那些原本要被抛弃的混凝土材料重新利用起来，变废为宝。
再生混凝土可不是随随便便弄弄就行的。
它得经过一系列严格的处理和加工，就像一个优秀的厨师，得精心挑选食材，认真烹饪，才能做出美味佳肴。
那些废弃的混凝土得先被打碎、筛选，把里面的杂质啥的都清理掉，然后再加上一些新的材料，重新搅拌、成型。
这过程可不简单，得有专业的技术和设备支持。
这再生混凝土的好处可多了去了！它能减少对自然资源的开采，你想想，要是一直不停地挖石头、采沙子来做新的混凝土，那咱们的山啊、河啊，不得遭罪？而且，用再生混凝土还能降低垃圾的产生，让咱们的环境更干净、更美好。
这就好比给地球做了一次“美容”，让它变得更漂亮、更健康。
你说，要是大家都不用再生混凝土，那得造成多大的浪费和污染啊？那咱们的子孙后代可怎么生活？所以啊，咱们得重视再生混凝土，让它发挥更大的作用。
在未来，再生混凝土的应用肯定会越来越广泛。
说不定有一天，咱们住的房子、走的路，大部分都是用再生混凝土建的呢！这多好啊，既环保又实用。
总之，再生混凝土是个好东西，咱们得好好利用它，为咱们的地球、为咱们的未来出一份力！。
土木工程外文翻译--关于再生混凝土空心砌块的研究
1850单词，9500英文字符，2900汉字出处：Ding X, Liu W, Ye J, et al. Research of Recycled Bearing Concrete Hollow Block[C]// International Conference on Civil Engineering and Urban Planning. 2012:498-503.毕业设计（论文）外文翻译设计（论文）题目：学院名称：建筑工程学院专业：土木工程学生姓名：学号：指导教师：2014年10月23日外文一：Research of Recycled Bearing Concrete HollowBlockXiaoyanDing*,WenkunLiu*,JihongYe*,ZhongfanChen*,andMingXu**(SoutheastUniversity,KeyLaboratoryofConcreteandPrestressedConcreteStructuresoftheMinistryofEducatio n;No.2,SipailouRoad,Nanjing210096;Tel:150********)ABSTRACTOn the premise of using stone chips, the paper studies the effect of the replacement level ofrecycledaggregatesandw/conthecompressiblepropertiesofrecycledconcretehollowblocks,thenfindoutthe lin ear relationship between the ratio of R k / R l ( R k : the compressive strength of recycled concretehollow block;R l:thecompressivestrengthofrecycledconcretecube)andX(thereplacementlevelofrecycl ed aggregate), provide the theoretical basis to popularization and application of recycled concretehollowblock.KEYWORDSRecycled Concrete; Block; Compressive Strength; ReplacementLevelINTRODUCTION Usingwasteconcretetoprocessofrecycledaggregateforrecycledconcreteandrecycledconcreteblockhasimportan tpracticalsignificanceandbroadprospectthatisavaluablemeasuretoachievetheefficientrecycling of the waste concrete. The domestic research of recycled concrete strength has reached acertaindegreeatpresent.Buttheconclusionthatthestrengthofconcreteblockaftermixingrecycledaggregatecan rise are usually inconsistent for difference in these aggregate category. This paper discussesthecompressive strength of recycled concrete hollow blocks (RCB) through the recycled concrete injectedintostone chips of natural aggregates, and seeking for relation between the recycled level andcompressivestrength,thustoprovideausefulreferenceoftryingtoimplementtherecycledblocks. EXPERIMENTAL MATERIALSRecycledconcreteaggregate(RCA)wasobtainedfromanoldbuildinglocatedinNanjing.Therecycledaggregate with high water absorption is indisputable (Zhao & Deng 2007 and Xiao 2008).We tookmeasures of RCA to pre-absorb. The crushed concrete was processed to pass through a mechanicalsievingsystemtoproduceandthefinishedaggregateswithparticlesizesof0.16-8mm.Thephysicalpropertiesisin table 1.Cement were sourced from Zhonglian factory in Nanjing, P.O42.5. Table 1. Properties of Recycled and NaturalAggregatesProperties Natural RecycledDensity-SSD2/(kg/m3) 2650 2630Density-Bulk/(kg/m3) 1500 1370Porosity/% 43 48Waterabsorption/% 2.43 5.8Alkali-aggregate reaction/% 0.006 0.066Particlesize/mm 2~8 0.16~8Finenessmodulus 2.7 3.2Stone powdercontent 1.00 0.25MIX PROPORTIONDESIGNDesignbasis.Nowadays,wedesigncompressivestrengthofconcreteblockswith150mmcubictestforfoundationin China.Blocksandconcretespecimensarecomposedofthesamematerials,butthereareanumerousofdifference:①Thesizeofblockswithpluralityofholesandatthelevelof25%to50%ofhollow is larger than concrete cube which is in a small size. ②The strength calculation of blocks withgrosssection differ from concrete cube with net section. ③The diversity of them are in moldingcondition,systemandtimeofvibration,formingnumberandequipmentmaterial,etc.However,thefailure modeisdistinctfromeachotherforblockswithholeandthin-wallwhilecubewithshortcolumns.Usually, the mix design of concrete blocks were summarized as follows (Zhang 2007):①Determinetheconversion relationship of compressive strength between block and concrete cube;②CalculateW/Caccording to the requirements of strength and durability;③Determine water requirement and cementquantity on the basis of type and specification of aggregate;④The experiment of concrete cubeinaccordancewiththestandardmethodfinishuntilmeetingthedesignrequirements,thencarryonconcretehole blockstrengthexperiment;⑤Issuewiththemixproportiondesign.Mix proportion determination.The blocks were designed with internal dimensions of 360 mm inlength,240mminwidth,and115mmindepth.Therewerefiverowsofholescrossarrangedtheblocks,whichwith dent in short side and plane in long side. The eight mixtures included two control mixture usingonlynatural aggregates, six mixtures with recycled aggregates and the replacement of natural aggregates wasatlevels from 25 to 100% by weight. All these mixtures were expected to achieve a targetcompressivestrength of not less than 5 MPa at the age of 28 days. According to section 2.1 of the paperandconstruction criterion, concrete experimental strength should be increased than the design by 10% to15%.Both two W/C (0.48 and 0.64) in this paper were based on the forming quality of hole block by field testinseveral times. Meanwhile wefoundRCBweredifficulttoshapeattheaggregatelevelat100%.Wesuggestthewaterdoseofconcreteperm3shouldbeconsideredandadditionallevelofwaterabsorptionofre cycledaggregatesisinrangefrom3%to10%.EightgroupsRCBmixproportionusedforblocksweredesigned in this experiment, see Table2.Table 2. Mix Proportions Used forBlocksType TypeW/CRESULTS ANDDISCUSSIONExperimentaldetails.TheblockscamefromNanjingSHIHAOBuildingEnergyLimitedCompanyforthe hydraulic vibration molding equipment. The formed blocks were first in a standard curing room for72hours,andthenconditionaltransportedoutoftheconservation.Thetemperatureandrelativehumiditywereco ntrolledat20°Candnotlessthan90%accordingtothestandardrequirement.Therearefivespecimens in each group foratotalof40specimens.Thecompressivestrengthoftheblockspecimenswasdeterminedusingacompressiontestingmachinewithamaximumcapacityof2000kN,accordingtost andard methods(GB/T 4111 ——1997, 1997). Table 3 shows the results of the compressive strengthofblock specimens, which is given as the averages of fivemeasurements.Experimentalphenomenondescription.TheexperimentfoundthatdestructivepatternofRCBwerebasicallythe sameineverykindofsubstitutionlevel,whichisalmostasthesameasnaturalblocks.Thefailuresurfacestartedfromb ondfailureofnatural,recycledaggregateandcement.However,noobviousprecursor to failure is observed prior to the occurrence of instability. At the preliminary stage of load,withload increasing, thesurfaceRL W NA RA C W RL/ NA RA C W/% /C/kg/kg/kg /kg %/kg/kg/kg /kg RCA1 0 0.48 1845 0 375 180 RCB1 0 0.64 1938 0 375 170 RCA2 25 0.48 1384 461 375 194 RCB2 25 0.64 1453 485 282 195 RCA3 50 0.48 922 923375208 BCB3 50 0.64 969 969282209 RCA4750.48 4611284 375 222BCB4 750.644851453 282224Table 3. Compressive Strength ofBlocksCompressivestrength(MPa) NotationNotationCompressivestrength(MPa)of block specimens were without any change while the readings of pressure gage wereuniformincreased.When pressure reaches the limit loads of 60% ~ 70%, most block specimens occurred fine visible cracksatthe corner or dent while the readings of pressure gage were increased slowly. As pressureincreasedfurther,thecrackdevelopedveryfast,andemergedsomenewcracksinthefaceoftheblockspecimens,thes ecracksnearthesidewall.Whentheloadcontinuedtoincrease,pressurereachedlimitload,theverticalcracks rapidly expand together untilblock specimenscompletelydestroyed(Figure1).Besides, if formed blocks with waney orsubtlevertical cracks, they would damage in thesepartsat first. Therefore, the forming quality ofhollowblocks must be controlled. Especially thewaneyand vertical cracks must bereduced. Figure 1.Destructive patternofblocksReplacement level effect on compressivestrength of block. Compressive strengthtestresultsforfourdifferentmixesat7daysan d28days from two w/c ratio are presented in Figure2and Figure3.It shows that RCA produced stronger strength than natural aggregates and with recycled replacementlevelincreased, the compressive strength of blocks improve margin increased more. The compressive strengthofeach block were more than 5.0MPa and that in the replacement level of 25%, 50%, 75% increased by3.9%,7.1% and 23.4% as compared with the control sample (RCA-1), respectively. Similarfindingswerealsoinseries2,theincreasewere6%,11.6%and25%.Whenreplacementlevelincreasedto75%inbothseries,thebloc kspecimensattainedthehighestcompressivestrength(7.5MPa).Therefore,itcanbeconcludedthatforasuitablew/c,morerecycledaggregates,morecompressivestrengthRCBwillreach,RCBcanbeused asthe seismic requirements of masonry structure. From to ensure the 28 days compressive strength ofRCB,Wecan believethatreplacementlevelofrecycledaggregatescanbereachedto75%.Ofcourse,Suchasimprovingconservationconditions,appropriatetoprolongthecuringtime,compressivestrengthofR CB can reach higher, which will be 10MPa.W/C effect on compressive strength of block.Due to the characteristics of forming process forconcreteblockscomposedofstiffconsistencyconcreteinvibratoryandpressuredcompaction,theactualw/cratio onstrengthoftheblockisfarfromtheimpactofthewetconcretestrength. Afterdeterminedw/c,thetoppriority was forming performance, rather than the strength of blocks. That is the best w/c ratio shouldmaketheconcretecanbemoldingandthedensitytomaximize,requireforforminginashorttimeandnoteasyfo rmat,butitdoesnotmeanw/chasnoeffectonthestrengthofblocks.Tomeetprocessandotherperformance7-days 28-days7days 28days RCA-1 4.28 6.89 RCB-1 3.84 6.12 RCA-2 4.35 7.16 RCB-2 3.98 6.49 RCA-3 4.67 7.38 RCB-3 4.06 6.83 RCA-45.088.5RCB-44.47.65requirements of blocks, w/c is still as small aspossible.Relationsbetween R k /R l andX.Astheshape,sizeandcalculatemethodsaredifferent,evenwiththe samematerials,t hecompressivestrengthbetweenRCBandRCCalsocangetthedifferentresults,buta certain relation is between them. By comprehensive analyses of the results obtained, it is found that R k /R l were interrelated with X . The formula for R k / R l =a+bX was put forward throughstatisticalregression analysis,aandbwereregressioncoefficient.TherelationbetweenthemwereshowninFigure4andFigure5Figure 4.R k / R l and X(W/C=0.48) Figure 5. R k / R l andX(W/C=0.64)Correlation coefficient R is a quantitative index which indicates the intimate level of linearcorrelationbetween measured data and regression equation, the value is closer 1, it means the more theyrelateclosely,thebetterthecorrelationreaches.Thus,aboveresultsR≥0.9demonstratethatitiscanbeusedinsimilarp ractical work for bothformulas. SUMMARYInstudyingtheeffectsofRCAonthemechanicalpropertiesofRCB,mixdesignswithtwow/cratioandstone chips as the natural aggregates composition were referenced. The conclusions drawn fromthisinvestigation are as follows:∙ The compressive strength of RCB increased with the increase in replacement level of recycledaggregates. The highest compressive strength was attained when the replacement level ofrecycledaggregatereachedthelevelof75%,RCBcanbeusedastheseismicrequirementsofmasonrystructure.Ho wever,withoutanyadmixture,RCBishardlytomoldatthereplacementlevelof100%.Nevertheless,howmanythere placementleveltobemadeismostappropriate?Theproblemremainstobefurtherelucidated.∙ Onthepremiseofprocessandotherperformancerequirementsofblocks,w/cisstillassmallaspossible.∙ The relationship between R k / R l and X is linear respectively, this provide theoretical basis for preparationof RCB with stonechips.∙ ItisfoundthatformingqualityofRCBmustbecontrolled,especiallytoreducewaneyandthenumberof vertical cracks by failure mode ofRCB. ACKNOWLEDGEMENTThefinancialsupportsfromtheTechnologyPillarProgramduringtheEleventhFive-YearPlanPeriod(project 2008BAJ08B11) areacknowledged.REFERENCESGB/T411-1997,1997:ExperimentalMethodofConcreteHoleBlock[S],Beijing.ChinaArchitecture&BuildingPress. Lu,K.A.(1999).“BerequiredbyComprehensiveUseofConstructionWaste.”J.RecycledResourcesresearch,p.33 -34.X,J.Z.(2008).“RecycledConcrete.”[M],ChinaArchitecture&IndustryPress.Z,J.&D,Z.H.(2007).“ExperimentalStudyonRecycledConcreteCoarseAggregate.”J.CementandConcrete,p.17-20.Z,W.C. (2007). “Practicality Manual of Concrete Hole Block and Concrete Brick.”[M], ChinaMaterials&IndustryPress.译文一:关于再生混凝土空心砌块的研究丁晓燕1，刘文坤2，叶继宏3，陈钟帆4，徐明5（东南大学教育部混凝土和预应力混凝土结构重点实验室;南京路四牌楼2号,邮编210096;电话:150********）摘要对使用石屑的前提下，研究了再生骨料和再生的W /C更替水平对再生混凝土空心砌块的抗压性能的影响，找出R k/R l（R k：抗压强度的再生混凝土空心砌块；R k：再生混凝土的抗压强度立方体）和X（再生骨料的替代水平）比值之间的线性关系，为推广再生混凝土空心砌块的应用提供了理论依据。
大学英语作文之废物的回收利用 Recycling Waste
大学英语作文之废物的回收利用 Recycling Waste European countries are now making an active effort to reuse materials more than they used to. This is called recycling. Materials such as paper, glass or metal are collected, sorted, treated and used again. Old papers are recycled. The ink is taken out by a special technique, and new paper is made. Oil from fatories and motor oil can be treated and resued. In many cities in Europe rubbish is collected separately. Empty glass bottles are collected, and the glass is broken and reused for making new bottles. Developing countries all over the world already recycle materials. In India, waste paper is collected, sorted and recycled. Paper bags are made from unsold newspapers. In Egypt, waste is collected by rubbish cars and sorted. Leftover food is given to pigs and vegetable matter is put back onto the fields. In some Asian countries, shoes are made from the rubber of old car tyres.The Chinese government is also working hard against poilution. More than 60,000 small factories which seriously polluted the enrivonment were shut down in 1996. Many materials like used rubber gloves, glass bottles, cans and other containers are treated or recycled. However, no single country can save the environment alone.欧洲国家现在正在积极努力比过去更多地重复使用旧材料。
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废弃混凝土再生新技术探索【摘要】本文对目前废弃混凝土再生技术的研究做了论述,并指出了其中存在的一些问题。
结合混凝土各组成部分的结构特点,提出了通过低温煅烧对废弃混凝土综合利用的新方法。
在750℃温度条件下煅烧1h,可以实现水泥浆与骨料的分离。
脱水后的水泥浆可以重新获得水化活性。
得到的混凝土骨料可以满足使用要求。
【关键词】废弃混凝土;再生技术;煅烧;水化活性;压碎指标【中图分类号】TU352·8【文献标识码】A【文章编号】1001-6864(2009)09-0004-02国家“十五计划”纲要指出:“坚持资源开发与节约并举,把节约放在首位,法保护和合理使用资源,提高资源利用率,实现永续利用。
推进资源综合利用技术研究开发,加强废旧物资回收利用,加快废弃物处理的产业化,促进废弃物转化为可用资源。
”保护环境、节约能源、减少废料、以持续的方式使用可再生资源是可持续发展战略的重要内容。
建材工业是典型的基础原料工业,在国民经济发展中具有重要作用。
建材工业又是典型的资源、能源消耗型工业,在其快速发展的同时,面临着资源、能源的过度消耗和环境的严重污染。
建筑和建材行业的根本出路就是走可持续发展的道路[1]。
起初,我国对混凝土的利用仅是简单的破碎充当再生粗骨料,这种生产的再生骨料性能与天然粗骨料的性能存在一定差异,主要表现在密度低、吸水率高、压碎指标大,表明再生骨料的空隙率高,强度低,这主要是由于其表面附着有大量水泥砂浆及在破碎过程中引入一定量的微裂纹的缘故[2],生成的混凝土性能低,耐久性、抗冻融、抗腐蚀能力差。
研究者根据再生骨料再利用过程中存在的问题,对再生骨料进行了物理、化学改性以及整形改性。
如朱崇绩等通过整形除去再生骨料表面的砂浆,使颗粒变得光滑,需水量降低,使所配制的混凝土收缩降低,但仍高于天然骨料混凝土[3]。
没有解决再生骨料中微裂纹带来的弊端。
目前有研究者对废弃混凝土进行了综合利用研究,通过筛分获得砌筑砂浆或进步筛分生产具有水化活性的再生水泥。
如孙荣光等[4]对旧水泥浆高温处理后的再水化胶凝特性研究,得出再生水泥具有再水化的能力,同时生成C-S-H凝胶、Aft和CH等物质,说明水化产物结构相同,但由于大量脱水相的存在使水化速度快。
余睿等[5]通过对水泥浆的研究得出石膏和粉煤灰组成改性剂能延长活化水泥浆的初凝时间,增强其抗压强度,但不能减少活化水泥浆的标准稠度需水量。
由于易水化的水泥石脱水需要时间,所以煅烧时间和脱水温度对再生水泥性能不容忽视。
1．废弃混凝土裂解温度确定混凝土是由水泥、粗细集料、矿物掺合料等加水拌合,经水化硬化而形成的一种微观不均匀,宏观均匀的人造石。
废弃混凝土在低温煅烧时的温度由水泥脱水温度与石灰石分解温度共同决定。
1·1水泥水化产物脱水温度文献认为,含水矿物中普通吸附水的脱水温度一般为100~110℃,存在于层状硅酸盐结构中的层间水或胶体矿物中的胶体水多数要在200~300℃以内脱水,个别要在400℃以内脱水;架状结构的硅酸盐结构水则要在400℃左右才大量脱出。
结晶水在不同结构中的矿物中结合程度不同,其脱水温度也不同。
结构水是矿物中结合最牢的水,脱水温度较高,一般要在450℃以上才脱水[5]。
为了确定废弃混凝土的低温煅烧温度,保证在该温度条件下骨料和水泥浆能够充分分离,水泥石完全脱水,本课题对水泥浆进行了热重分析(TGA),热失重曲线及(TG)及差热曲线(DTG)如图1所示。
从图1可以看出,水泥浆在100℃前后分别有一个明显的失重过程,理论上应当是失去自由水和弱吸附水所形成的过程。
在500℃以前又有一个明显的失重过程,该失重过程温度范围较窄,但失重速度较快,从水泥石的组成看应当是Ca(OH)2失水形成的。
另一个水泥石脱水过程发生在682~775℃之间,脱水的峰值速率发生在740℃。
这一过程脱水过程剧烈,持续时间较长,这一失水过程使C-S-H凝胶分解,重新生成为具有潜在水化活性的胶凝材料。
温度继续升高,直至1000℃再无明显的吸热峰出现。
另外,温度再渡升高可能影响混凝土骨料的结构。
因此,混凝土分解温度确定为750℃。
经过高温处理的水泥浆因脱水而重新获得水化活性,这一性能已在实验中得到证实。
1·2碎石分解温度粗骨料(碎石)的成分主要由CaCO3和在少量的MgCO3组成,其中MgCO3的分解温度较低,600℃就开始剧烈反应,CaCO3剧烈分解温度则更高达到900℃左右,但其开始分解温度较低,在650℃就开始分解。
所以在550~900℃范围内煅烧混凝土时,随着温度的升高,骨料发生分解的量增大,使骨料的强度降低。
过渡区是混凝土的薄弱环节,一方面搅拌时在骨料表面被水膜覆盖,妨碍了水泥粒子与骨料表面接触,骨料周边水灰比变大,另一方面,水化反应溶出的迁移性大的Ca2+、Al3+、SO4-3离子为使浓度平衡向骨料表面扩散。
在骨料表面附近,六角板状结晶的氢氧化钙和针状结晶的钙钒石的析出比较显著,形成大且连续的空隙构造[8]。
使过渡区的水分也几乎以层间水及自由水的形式存在,所以在较低的煅烧温度就可实现骨料与水泥砂浆的分离,理论上在300℃以上即可实现分离。
为了探究煅烧温度对骨料强度的影响,本试验分别对600、700、800℃煅烧温度时所得到的粗骨料压碎值进行了研究,并与天然碎石和直接破碎的混凝土进行了比较,实验结果如图所示。
从图2可知在燃烧温度600℃时,碎石的压碎指标略高于天然碎石,而随燃烧温度的提高,压碎指标明显增大,标志着骨料强度降低。
但在800℃所得到的骨料强度仍高于混凝土直接破碎得到的骨料强度,所以在混凝土煅烧温度不超过800℃时是可行的。
2结语根据混凝土各组分的结构特点,采取煅烧的方法把骨料和水泥浆分离是可行的。
经分解后的粗骨料可以在新拌混凝土中应用,其强度高于混凝土直接破碎得到的再生骨料。
经分离得到的水泥浆重新获得了再次水化的活性。
为废弃混凝土的回收以及骨料和水泥浆的再生和利用开辟了一条新的途径。
参考文献[1]水中和,曹蓓蓓,万惠文.废弃混凝土再生利用技术及其发展前景[J]·资源节约与综合利用,2006,(3):8-11·[2]王耀新.混合应用天然与再生骨料混凝土的基本性能[J]·混凝土,2005,(8):49-53·[3]朱崇绩,李秋义,李云霞.颗粒整形对再生骨料混凝土耐久性的影响[J]·水泥与混凝土,2007,(3):6-10·[4]孙荣光,余睿,玄东兴,水中和.旧水泥浆高温处理后的再水化胶凝特性研究[J].武汉理工大学学报,2007,(9):115-118·[5]余睿,水中和,玄东兴.再生水泥浆的改性研究[J]·2009,(4):104-107·[6]SidneyMindess·混凝土(原著第二版)[M].吴科如,等译·北京:化学工业出版社,2005·1·[7]王培铭,许乾慰.材料研究方法[M].北京:科学出版社,2005,236-249·[8]徐新生,徐卫生.混凝土过渡区对混凝土物质渗透性影响[J]·山东建材,1999,(3):10-13·EXPLORATION ON RECYCLING TECHNOLOGY OF WASTE CONCRETEMA Xin-wei1,ZHANG Dong-qing2,YINWei-feng2,LI Ning2 (1·Department of Civil Engineering, Harbin Institute ofTechnology at Weihai, Shandong Weihai 264209, China;2·School ofMaterials Science and Engineering, Harbin Institute ofTechnology, Harbin 150001, China)Abstract:The current research situation on the recycling technology ofwaste concrete and existing problems in applicationwas summarized·Consideringthe structural characteristics of cement paste and aggregate, a new recycling technology through calcination is presented·The cement paste and aggregates could be separated at 750℃for one hour·The dehydrated cement paste can have reactivity again, and the aggregates can meet the requirement of application·Key words:waste concrete;recyclyingte;chnology;calcination;reactivity;crushing indexNational "tenth five-year plan" outline pointed out: "insists resource development and save the save itself, in the first place, protect and rationally use method of resources, and improve the resource utilization rate, to achieve sustainable use. Push technology research and development resources comprehensive utilization of waste materials, strengthen recycling, accelerate the industrialization, promote waste disposal of waste into usable resources." Protect the environment and save energy, reducing waste, with continuous way, using renewable resource is the important content of strategy of sustainable development. The building materials industry is typical of basic raw materials industry in the national economy development, plays an important role. The building materials industry is typical resources, energy consumption industries in its rapid development, at the same time, facing the excessive consumption of resources, energy and environmental pollution. Construction and building materials industry is the fundamental way to walk the path of sustainable development [1].At first, the use of concrete in the crushing only a simple as recycled coarse aggregate, the production of natural regeneration aggregate performance and the performance of coarse aggregate, main show there is some difference in density low, bibulous rate is high, crush index is big, show the gap regeneration aggregate rate high, low intensity, and it is mainly because the surface adhesion has large cement mortar and crushing process in certain micro cracks of introducing the sake [2] and generated concrete performance low, durability, freezing-thawing resisting, corrosion resistance is poor. The researchers based on renewable aggregate reuse the problems existing in the process of recycled aggregate, carried on the physical and chemical modification and plastic modification. As such ZhuChong performance by plastic toremove the mortar, renewable aggregate surface water that particles, smooth, prepared by reducing shrinkage of concrete lower, but still higher than the natural aggregate concrete [3]. Not solve the regeneration aggregate micro cracks in the malpractices. Currently have researchers of the waste comprehensive utilization of concrete research, through the screening get bonding mortar or progress screening production of renewable cement hydration activity with. If SunRongGuang etc [4] to the old cement. after high temperature treatment of slurry rehydration characteristics study gel, it is concluded that renewable cement with a rehydration ability, while generating C - S - H gel, Aft and CH that hydration products such material, but same structure dehydrated phases because of the existence of hydration speed to. YuRui etc [5] for water mud through the research that fly ash and composition modifier gypsum slurry can extend the initial setting activation time and strengthen the compressive strength, however does not reduce activation of standard slurry water viscosity. Due to easy hydration of cement stone dehydration need time, so calcining time and dehydration temperature of recycled cement performance cannot be ignored.1. Determine the decomposition temperature of waste concreteConcrete is made of cement, thick aggregate, such as mineral admixture, the water hydration sclerosis regarding mix-proportion formed a microscopic uneven, macro uniform man-made stone. Abandoned the concrete in low temperature calcination temperature by cement dehydration temperature decomposition temperatures decided together with limestone.1 · 1 cement hydration products dehydration temperatureLiterature in minerals that water cut the dehydration temperature ordinary adsorption water for 100 ~ 110 ℃commonly, exists in layer silicate structure between layers of the colloid water or colloid mineral water in 200 ~ 300 much ℃in within dehydration, individual ℃400 within dehydration; Frame shape structure of silicate structure in 400 ℃water is only around large emerge. The minerals in different structure gesso combination of different degree, the dehydration temperature is different. Structure combination of water is mineral water, the most jail dehydration temperature is higher, typically in 450 ℃above just dehydration [5]. In order to determine the low temperature calcining temperature waste concrete, guarantee the temperature conditions in slurry aggregates, and can be fully separation, cement stone completely dehydration, this topic to the slurry thermogravimetric analysis (TGA), thermo-gravimetric curve and (TG) and differential thermal curve (DTG) as shown in figure 1 below.Temperature（℃）Slurry thermogravimetric analysis curvesFrom figure 1 in 100 ℃, water slurry before an obvious weightlessness, respectively, in theory should be losing process of free water and weak adsorption water by the formation of the process. In 500 ℃ago and have an obvious of weightlessness process, this weightlessness process temperature range is narrower, but weightlessness faster, the composition of the cement paste.the watch from shall be the Ca (OH) 2 water loss formation. Another cement stone anhydration process occurs in 682 ~ 775 ℃between, dehydration rate occurred in 740 ℃peak. This process a severe dehydration process, continues for a long time, the water loss process makes C - S - H gel decomposition, born again into a potential hydration activity of cementitious material. Temperature continues to rise again until 1000 ℃, has no obvious heat-sink peak appearing. In addition, temperature rise again crossing may influence the structure of concrete aggregate. Therefore, concrete decomposition temperature determined for 750 ℃. The slurry high-temperature processing for dehydration and regain hydration activity, this performance has been confirmed in the experiment.1 ·2 gravel decomposition temperatureThe coarse aggregate (gravel) mainly by the ingredients in a small amount of CaCO3 and MgCO3 composition, which MgCO3 decomposition temperature is lower, 600 ℃began to react vigorously CaCO3 decomposition temperatures, severe ℃is high reached 900 around, but its start decomposing temperature is lower, at 650 ℃began to decompose. So in 550 ~ 900 ℃ scope when calcined concrete, with the rise of temperature, aggregate ratio increases occurred decomposition, aggregate strength decreased. Transitional zone is the concrete and the weak link in aggregate, on one hand, mixing the surface is water film covering, hampered cement particles and aggregate surface contact, aggregate peripheral water-cement ratio change, on the other hand, the transference of hydration reaction dissloution Ca2 +, big Al3 +, SO4-3 ion to make to the aggregate balance of surface concentration of diffuse. In aggregate, hexagonal near the surface plate crystallization of calcium hydroxide and needle crystal stone precipitation of calcium vanadium, forming a notable large andcontinuous space structure [8]. Make the moisture in the transition between layers also almost free water and water exists in the form of lower, so in the calcining temperature can achieve aggregate and cement mortar in the separation of more than 300 ℃, the theory can be realized separation. In order to explore calcining temperature effect on the strength of aggregate respectively, and the test of 600, 700, 800 ℃ calcining temperature get the coarse aggregate crush values are studied, and directly with natural gravel and broken concrete were compared, and the experiment results as shown.600 700 800Natural aggregate broken concreteFrom graph 2 600 ℃in combustion temperature that when the crush index, gravel, and slightly higher than the natural macadam with combustion temperature rise, crush index increased, marked the aggregate strength decreased. But in 800 ℃obtained aggregate strength is still higher than the aggregate concrete crushing get directly in the concrete intensity, so no more than 800 ℃calcination temperature is feasible.2 .EpilogueAccording to the structure characteristics of various components of the concrete methods of, take the aggregate and pellets slurry separation is feasible. After the decomposition of coarse aggregate in concrete in new mix, its strength of concrete application of crushing get directly than renewable aggregate. The slurry isolated from getting the hydration activity again. For the collection and aggregate concrete waste water and mud regeneration and use open a new way.References[1] water and CaoBeiBei, WanHuiWen. Abandoned, recycled technology and its development of concrete [J] prospect, conservation of resources and comprehensive utilization, 2006, (3) : 8-11 ·[2] WangYaoXin. Mix with application of natural regeneration aggregate concrete, basic properties of concrete [J], 2005, (8) : 49-53 ·[3] ZhuChong performance LiQiuYi, LiYunXia. Particles, of recycled aggregate concrete durability plastic [J], the influence of cement and concrete, 2007, (3) : 6-10 ·[4] SunRongGuang, YuRui, XuanDongXing, the water and the mud. Old water high temperature treatment rehydration gelling properties research [J]. Journal of wuhan university of technology, 2007, (9) : 115-118 ·[5] YuRui, the water and the mud. XuanDongXing renewable water, modified study [J] DE 2009, (4) : 104-107 ·[6] SidneyMindess ·concrete (original second edition) [M]. WuKeRu, etc, Beijing: chemical industry translation press, 2005 · 1 ·[7] WangPeiMing, research methods XuQian comfort. Materials [M]. Beijing: science press, 2005,236-249 ·[8] XuXinSheng, XuWeiSheng transition region. Concrete of concrete material [J], osmotic influence of shandong building materials, 1999, (3) : 10-13 ·。