外文翻译--再生改性混凝土的性能

中文 3074 字 毕业设计 (论文 )外文资料翻译 系 别： 建筑工程系 专 业： 土木工程 班 级： 姓 名： 学 号： 外文出处： 汉斯国际期刊土木栏 附 件： 1. 原文 ； 2. 译文 2013 年 12 月 29 日 原 文 ： The Regeneration Performance of Modified Concrete Abstract: the removal of the original building, to make use of the abandoned concrete, can Protect environment and related to the sustainable development of building. The waste concrete crushing recycled aggregate, need to establish a process. Currently relatively mature methods are: the use of swelling shrinkage compensating admixture can be made from recycled concrete C50. Keywords: ecological environment; recycled aggregate; basic properties; shrinkage compensation 1 Introduction In todays world, environmental problems have become increasingly prominent, the sustainable development has been put on the agenda. Efficient, rational use of limited resources is the most important way to achieve sustainable development. Concrete production requires a large amount of coarse and fine aggregate and sand, with the continuous mining of sand, natural building aggregate tends to dry up, the high cost of mining, the damage to the ecological environment is also very serious. On the other hand, the rapid development of city construction and all kinds of natural disasters have abandoned concrete waste a lot of. Recycling with the strategy of sustainable development requirements of the waste concrete, can bring significant social, economic and environmental benefits, the rise of the recycled concrete has become an important research topic in many developed countries. 2 International renewable development status of concrete The waste concrete block by crushing, grading and mixing according to certain proportion to form aggregates known as recycled aggregate and recycled concrete aggregate. As a part or the whole of the recycled aggregate concrete as recycled aggregate concrete, recycled concrete, the traditional building materials production and use caused by excessive consumption of resources, energy shortages and environmental pollution and other serious problems, cement and concrete is an important cause of these problems. Cement concrete structure is usually only a few decades of life cycle, completed in the structure of its use, the old concrete will be abandoned. According to statistics, industrial solid wastes produced 40% is the construction industry, construction industry to produce waste concrete is the biggest waste. In twentieth Century 90 in the early 1990s, the national annual output of waste concrete is 50000000 tons, USA is 60000000 tons, about 12000000 tons of Japan. Facing the increasing shortage of sand and other natural resources, the grim situation of construction waste is increasing, governments and research institutions have established policies, the development of new technology, in order to promote the construction waste especially recycling old concrete utilization. According to statistics, since the 90s, the annual consumption of the world total has more than 80 tones of concrete. In concrete aggregate accounted for over 70% of the total mass. 3 Compensating shrinkage of modified concrete Normal concrete is to use a wide range of building materials, but because of its limit extension rate is low, easy to crack in the dry shrinkage, creep, temperature effect, resulting in leakage caused by corrosion of reinforcement and concrete engineering, use function and the life of structures. The research indicated that, the swelling agent or expansion of shrinkage compensating concrete cement, concrete cracking is to solve the effective technical way infiltration problem because of shrinkage compensating concrete hardening process in water can produce 0.20.7 Map pre compressive stress (or stress), the stress can be offset or partially offset by concrete shrinkage, creep, temperature induced tensile stress, so as to improve crack resistance of concrete engineering; in addition, due to the hydration expansion hole filling effect of products, the large hole in cement paste is smaller, the total porosity, which can improve the pore structure of concrete, greatly improve the impermeability of concrete, therefore make shrinkage compensating concrete expansive cement in foreign countries is also known as the waterproof cement. The shrinkage compensating concrete is an important branch of modern concrete science, its unique properties, is to solve the volume stability, high performance concrete is an important technical basis to improve the durability of concrete, the research on it has yet to be further and perfect, this paper expounds some basic properties of shrinkage compensating concrete. 3.1 Expansion agent Physical and chemical properties: refers to the concrete expansion agent in concrete mixing process and the cement, water mixing after hydration reaction of stringier 3CaO Al2O3 3CaSO4 32H2O or calcium hydroxide Ca (OH) 2, make concrete produce volume expansion admixture. Concrete expansion agent is used to prepare the expansive concrete (including shrinkage compensating concrete and self stressing concrete), shrinkage compensating concrete shrinkage and compacting concrete with, improve concrete anti permeability role compensation concrete, in civil engineering in two aspects mainly used for waterproofing and anti cracking, now use more occasions is preparation of high grade waterproof concrete and appropriate to extend the expansion joint or post cast band spacing. 4 Basic properties of shrinkage compensating concrete 4.1 Material 4.1.1 Concrete before hardening Agent content and fresh initial concrete slump expansion: expansion agent effect on the initial slump of fresh concrete degree, largely depends on the expansion agent fineness, when the expansion and cement fineness difference, mixing water demand is basically the same, almost has no effect on the initial slump. 4.1.2 Setting time Effect of expansive agent on setting time of concrete expansion admixture added: no matter what, will make the concrete setting time, expansion admixture amount bigger, the setting time is fast, doping agent will have the same results with and without the addition. 4.1.3 Curing conditions Compared with ordinary concrete, shrinkage compensating concrete need more water conservation fully, because the water is the essential factors of expansion, long in the water curing of concrete can obtain the biggest expansion. Expansive concrete to dry air (RH = 60 5%) curing shrinkage, too, but then return maintenance, and can restore the previous expansion. 4.1.4 Drying shrinkage As with ordinary concrete, shrinkage compensating concrete will also occur in air drying shrinkage, factors affecting the drying shrinkage of concrete with ordinary roughly the same, but the relative humidity of the external factors, internal factors of water binder ratio is more important. Under the same conditions, drying shrinkage fall of shrinkage compensating concrete and common concrete in roughly the same. 4.2 Recycled concrete Strength with the matrix concrete of recycled concrete strength, regeneration substitution rate and recycled concrete mixture ratio is closely related to aggregate crushing technology, recycled aggregate. Due to the strength of concrete, the matrix using environment and carbonization degree each are not identical, differences of disintegration, crushing process and quality control measures, resulting in regular changes of concrete strength regeneration is poor, different researchers have different conclusions. Test results show that: 1) the compressive strength of recycled concrete is lower than the compressive strength of natural aggregate concrete ratio, reduce the range of 0%30%. Improve and strength of recycled aggregate concrete with strength of recycled aggregate concrete matrix increased; and with the increase of recycled aggregate replacement rate decreased, when the recycled aggregate replacement rate is less than 30%, the recycled concrete strength decreases little; recycled concrete replaced natural coarse aggregate with recycled coarse aggregate strength decreased less, and regeneration concrete recycled fine aggregate instead of natural fine aggregate strength decreased obviously, the age showed the same trend; the water cement ratio of recycled concrete strength with great effect, reducing the water cement ratio, with the natural aggregate concrete strength contrast, more and more small to reduce the strength of recycled concrete. For the recycled concrete with different strength grade, the origin and nature of the influence of recycled aggregate on the strength degree is different: preparation of high strength recycled aggregate concrete, influence on strength of recycled aggregate concrete sources and properties of recycled aggregate; recycled aggregate medium strength concrete, the strength of recycled aggregate concrete and influence; preparation of recycled aggregate concrete with low intensity, the regeneration effect of mixed coagulation on the strength is very small. 2) because of recycled aggregate adsorption with lots of old mortar, resulting in elastic modulus of recycled aggregate concrete is usually low, generally for natural aggregate concrete 70%80%, reduce the average 25%. The elastic modulus of recycled aggregate concrete is lower, resulting in lower brittleness, toughness increased, the seismic performance of recycled concrete structure is favorable, and enhance the ability to resist dynamic loads. Poisson recycled concrete is usually in the range of 0.180.23. 3) compared to recycled concrete and natural aggregate concrete, the dry shrinkage and creep increased by an average of about 60%. Dry shrinkage increases depends on the matrix properties of concrete, recycled aggregate and recycled concrete than with the quality. Have a certain influence the popularization and application of shrinkage and CSU Biennia Conference on recycled concrete, this will make the recycled concrete structure produce more non loading cracks, if cracks through the inside and outside environment, water and other harmful substances can easily penetrate into concrete, is disadvantageous to the durability of structures. But such as the use of recycled aggregate is low water cement ratio and high strength, test results show, can reduce the recycled concrete shrinkage and creep. Therefore, for the promotion of recycled concrete, it can be used in structural concrete, need further study to improve the strength of recycled concrete way, reducing shrinkage and creep method of recycled concrete, micro structure and failure mechanism of recycled concrete. 5 Conclusion Expansive cement invention has been 70 years of history, the history of the application of shrinkage compensating concrete is also 50 years, from the day of its birth, its location is a kind of special concrete anti seepage, and formed a set of more perfect theory system. Engineering practice that, the shrinkage compensating concrete anti cracking performance is excellent, and is an ideal concrete structure from waterproof materials, shrinkage compensating concrete underground buildings, can be completely canceled waterproof, not only shorten the construction period, but also save the engineering cost, waterproof life and buildings. In recent years, the rapid development of concrete technology, especially the application of high performance concrete is becoming more and more widely, put forward higher requirements on the shrinkage compensating concrete shrinkage compensation theory, the urgent need to have the new breakthrough, instructional materials, design, construction and inspection method innovation. Can be expected in a fairly long period of time, the technical field of concrete may not be new technology to replace the shrinkage compensating concrete, so in order to improve the performance of shrinkage compensating concrete cracks, relief has broad prospects for development, but the need to keep pace with the times, innovation. 译文 ： 再生改性混凝土的性能 摘 要 ：拆除原有的建筑物，对废弃的混凝土加以利用，既可以保护环境又关系到建筑的可持续发展。将废弃的混凝土破碎再生骨料，需要建立一套工艺方法。现就目前比较成熟的方法是：使用膨胀剂能够制成 C50的补偿收缩再生混凝土。 关键词 ：生态环境；再生骨料；基本性能；补偿收缩 1 引言 当今世界，环境问题日益凸显，可持续发展被提上日程。有效、合理地利用有限的资源是实现可持续发展的首要途径。混凝土生产需要大量的粗细骨料 砂石，随着对砂石的不断开采，天然建筑骨料趋于枯竭，开采成本高，对生态环境的 破坏也十分严重。另一方面，城市建筑业的迅速发展以及各种自然灾害产生了大量的废弃混凝土垃圾。对这些废旧混凝土进行回收利用符合可持续发展战略的要求，能带来显著的社会、经济和环境效益，由此兴起的再生混凝土技术已成为许多发达国家的重要研究课题。 2 国际上 再生混凝土发展状况 将废弃混凝土块经破碎、分级并按一定的比例混合后形成的骨料称为再生骨料或再生混凝土骨料 。 利用再生骨料作为部分或全部骨料配制的混凝土称为再生骨料混凝土 ， 简称再生混凝土 ， 传统的建筑材料生产和使用造成资源的过度消耗、能源短缺和环境污染等严重的问题，水泥 和混凝土是导致这些问题的重要原因。水泥混凝土结构通常只有几十年的生命周期，在这些结构完成其使用功能后，旧混凝土就会被废弃。据统计，工业固体废弃物中 40%是建筑业产生的，废弃混凝土是建筑业制造出的最大的废弃物。 20世纪 90年代初，欧共体国家每年产出废弃混凝土为 5000万吨，美国为 6000万吨，日本约 1200万吨。面对砂石等自然资源日益短缺，而建筑废弃物日渐增加的严峻形势，各国政府和研究机构纷纷制定政策，发展新技术，以促进建筑废弃物尤其是旧混凝土的再生利用。据统计，90 年代以来，每年全世界总体混凝土的消费量己 超过 80亿吨。而混凝土中砂石骨料占总质量的 70%以上。 3 补偿收缩改性混凝土的组成 普通混凝土是用途极广的建筑材料，但是由于它的极限延伸率较低，在干缩、徐变、温度等作用下容 易开裂， 导致混凝土工程渗漏并引发钢筋锈蚀，影响构筑物的使用功能和寿命。国内外的研究表明，采用膨胀剂或膨胀水泥配制的补偿收缩混凝土，是解决混凝土材料裂渗问题的有效技术途径这是因为补偿收缩混凝土在水化硬化过程中能够产生 0.20.7 MPa预压应力 (即自应力 )，该应力能抵消或部分抵消由混凝土干缩、徐变、温度等引起的拉应力，从而提高混凝土工程 的抗裂性能；另外，由于水化膨胀产物的填孔作用，使水泥石中的大孔变小，总孔隙率减小，从而改善了混凝土的孔结构，大幅度提高了混凝土的抗渗性能，因此配制补偿收缩混凝土的膨胀水泥在国外又称为“不透水水泥”。补偿收缩混凝土是现代混凝土科学的一个重要分支，其性能独特，是解决高性能混凝土体积稳定性、提高混凝土耐久性的一个重要技术基础，对它的研究还有待进一步深入和完善，本文综合阐述了补偿收缩改性混凝土的一些基本性能。 3.1 膨胀剂 物理化学性能：混凝土膨胀剂是指其在混凝土拌制过程中与水泥、水拌和后经水化反应生成钙矾石 3CaO Al2O3 3CaSO4 32H2O或氢氧化钙 Ca(OH)2，使混凝土产生体积膨胀的外加剂。混凝土膨胀剂主要用来配制膨胀混凝土 (包括补偿收缩混凝土和自应力混凝土 )，补偿收缩混凝土具有补偿混凝土干缩和密实混凝土、提高混凝土抗渗性作用，在土木工程中主要用于防水和抗裂两个方面，现在使用较多的场合是配制高等级防水混凝土和适当延长伸缩缝或后浇带间距。 4 补偿收缩改性混凝土的基本性能 4.1 材料性能 4.1.1 混凝土硬化前的性质 膨胀剂掺量与新拌混凝土初始坍落度的关系：膨胀剂对新拌混凝土初始坍落度的影响，很大程度上决定于膨胀剂的细度，当膨胀剂的细度与水泥相差不大 时，拌合需水量也基本相同，对初始坍落度基本没有影响。 4.1.2 凝结时间 膨胀剂对混凝土凝结时间的影响：无论掺加何种膨胀剂，都会使混凝土凝结时间提前，膨胀剂掺量越大，凝结时间越快，掺与不掺减水剂都有相同的结果。 4.1.3 养护条件的影响 与普通混凝土相比，补偿收缩混凝土更需要充分的水养护，因为水分是其产生膨胀的必要因素，长期在水中养