预应力混凝土的广泛应用外文翻译.doc

西 南 交 通 大 学本科毕业设计外文资料翻译年 级:2006级学 号:20060058姓 名:郭 鹏专 业:土木工程指导老师:杨荣山 2010年 6 月西南交通大学本科毕业设计 第12页英文翻译原稿PrestressedConcretetheextensiveapplication Priestesses concrete is used in concrete structures under load before the production phase, the use of pre-stage of the tension zone imposed stress, the stress caused by an artificial state. When the components used to bear a load and stress, first of all to offset the pre-stress concrete, and then as the load increases, the Rajah area of concrete produced stress. Therefore, concrete cracks may delay the emergence and implementation, to meet the application requirements. In structural members to bear this load before the pre-tension zone imposed stress of the concrete structural members, called on priestesses concrete structures.Chinas use of priestesses concrete sleeper more than 30 years, the concrete sleeper in a lot of damage related to traffic safety, which is often considered failures sleeper operation should be replaced on the line. But to put the new sleeper, in addition to re-create, but also handling, transport and went to the line on the pillow-for-work, not only need to spend a lot of manpower and material resources, and sometimes impact on traffic, the cost is often a sleeper itself Cost Four to five times.Sleeper as a priestesss concrete structure, cracks are difficult to avoid, priestesses concrete sleeper on the causes and dangers of cracks on how the prevention and control of cracks, concrete sleeper to improve the durability of the structure, to extend the life of sleeper, Will be very important.1. causes cracks in concrete sleeperCracks in concrete sleeper can be generated from the structure, processes, materials and other aspects of, or from the design, manufacture, laying, use of research. Here, only physical, chemical, mechanical point of view for analysis.1.1 mechanical factorsConcrete sleeper suffered moment not only the size and Zhen hang dynamic pressure, but also with the sub occipital Ballast support of the state. The laying of the original design requirements and conservation should be the middle part of the sleeper emptied 400 ram, hollowed out part of Ballast top of the pillow at the end should be less than 30 mm, to avoid negative moment too large a pillow in the upper horizontal cleft. In recent years do not require the middle emptied, the middle should be floating pad for ballast. Assumption that the design of the middle part of the supporting force should be part of the track under 3 / 4 (hollowed out at 0). And the general priestesses concrete products different from the sleeper train with the state supported the operation and maintenance of conditions constantly changing, once supported state and Zhen hang vertical dynamic pressure arising from the combined effects of more than design limits at the moment, The corresponding part of sleeper will have a crack. In addition when the pre-stress increases Stripping too large and when concrete strength is inadequate, the end of the sleeper will have a vertical crack; rail trains running on the level and vertical force and spiral clip bolt caused by pulling on the edge and make sleeper Bolt clip bolt holes around a vertical and horizontal cracks.1.2 physical factorsPhysical factors means the sleeper manufacture and laying, in the course of operating the hot and cold, wet and dry, such as the role of freezing and thawing. When the conservation process of warming up steam soon, when the high temperature thermostat, the concrete gas, water, cement, gravel, and so different coefficient of thermal expansion of different materials, and concrete structure of the early intensity and low, so that high-temperature gas, water greatly expanded, resulting in Concrete internal structural deficiencies, easily lead to the surface in particular sleeper End of the concrete surface cracks, loose.For some time, many factories in the production of steam conservation sleeper no pre-custody time, warming up quickly, thermostat temperature is higher than 95 , Stripping at the end of the concrete sleeper swelling, loose situation often occurred.1.3 Chemical factorsChemical factors that steel corrosion, concrete corrosion, carbonated, alkali aggregate reaction, and so on. China on the concrete sleeper, which alkali aggregate reaction (AAR) caused the damage can not be ignored. Alkali aggregate reaction of the three conditions are: aggregate activity, high-alkali cement and water, the destruction of more than three is a chemical reaction, in the aggregate in the concrete and cement interface on the formation of silicate gel, Volume expansion caused concrete cracking. One of the most common base - silica reaction.As Chinas cement production for a long time not to limit alkali content. Using high-alkali cement increased cement production and reduce costs. China has some areas of concrete coarse aggregate (stone) has obvious base activity, a combination of both together, easy to form alkali aggregate reaction (AAR) damage. This issue is from the late 1960s, a factory production of priestesss concrete sleeper (and bridges) and the fracture occurred repeatedly cracking, and the structure, process, laying the conservation conditions to improve still further fracture, cracking there until the late 1980s, began to be recognized and confirmed by the pilot. Inspection process is: first concrete sleeper in the core-sample, the test items, including: the naked eye or using three-dimensional microscope, and then side-thin reflective microscope, the damage caused by the general AAR regular injury aggregate particles, the more cracks from the aggregate Extending to the slurry, and sometimes also obvious observation aggregate stars expected to split or torn edges. This feature is very important, because of salt corrosion, chemical corrosion, steel corrosion, carbonate, such as mechanical load will not make aggregate particles by injury, so this is AAR and other factors undermining the main features; coupled with the ability to rely on the electron microscope Spectrum analysis can be measured alkali silicate gels chemical composition, this is a direct proof of AAR. In addition, concrete aggregate for mechanical and chemical methods (generally deal with hydrochloric acid) separation, reuse and rapid method of identification its phase-alkali activity.To sum up, vertical cracks in the main by internal factors (materials, structure, technology factors) due to external factors (loading and freeze-thaw, wet and dry cycle) is only promote their development, horizontal cracks are internal (priestesses reinforced, section And concrete strength) and external factors (loading and sleeper boundary conditions) caused by a combination.来源：(/s/blog_4e5c779201009atn.html) - PrestressedConcretetheextensiveapplicationo_轩辕灵儿_新浪2. cracks in the concrete sleeper durability of the structure(1) sleeper in the open-air environment, because of dense concrete, water, gas will not infiltrate into the internal, but cracks in to a certain width and depth of cracks at the protection layer, water, gas will reach the penetration along the cracks gradually reinforced , Caused steel corrosion and rust, rust is a compound of iron (iron oxide), four times its volume expansion in the concrete caused internal stress, leading to further cracking concrete, reinforced and priestesses concrete and Bonding of lower Thus affecting the sleeper of the carrying capacity.(2) Study shows that only cracks in the concrete structure of a certain width, water, gas can be infiltrated, from steel corrosion. Domestic and international norms, reinforced concrete structure to allow the crack width of 0.1 0.3mm (depending on the media environment), priestesses concrete structure does not allow even a crack, its purpose is to ensure that no reinforcement corrosion. However, many times at home and abroad for the investigation and trial, and that crack width and not directly related to steel corrosion.(3) Research also shows that the vertical cracks on the durability of the general structure than the horizontal cracks serious. Reinforced concrete structures due to the longitudinal cracks will cause the steel corrosion protection layer peeling off; cracking concrete expansion will cause osteoporosis, swap block. The author had been taken from different routes 16, with a different state of the sleeper Split 11, the normal sleeper 5, case-by-track roots are cracking under section static strength and fatigue strength test. Table 3 from the test results can be seen: through cracks in the sleeper, most of the rail section under static load cracking strength obviously lower; end of the fracture or cracking of the sleeper, static cracking strength And fatigue, compared with the normal sleeper, in general there was no significant difference. This shows that the end of the rail fracture and multiple cracks from the surface, not to influence the development of concrete and steel of the Bonding.3. concrete sleeper cracks in the prevention and controlSleeper as a priestesss concrete structure, in order to completely eliminate cracks is very difficult to do. After all, but the crack is harmful. For this reason, every effort should be made to prevent the emergence of crack.Prevention and control of cracks, you can start with a three-pronged:First, from the mechanical point of view, in order to prevent horizontal cracks, except in accordance with the greatest possible load, the rational allocation of priestesses reinforced, we must also strengthen the end of the stirrups and the spiral reinforcement clip bolt whole configuration. In addition, to strengthen the conservation line maintenance so that the sleeper is in a good state support under the track and prevent the sleeper pillow horizontal cracks appeared in the major conditions.Stirrups and spiral reinforcement of the settings and prevent sleeper End and central fracture cracks and nail holes, but not the overall stirrups itself, and is reinforced and priestesses loose lap, in the prevention of fracture in a limited effect. Some factories will be strictly end of the stirrups layout from the end of the first 30 mm, and priestesses reinforced Bingham firmly together, thus found to prevent the end of the fracture have a good effect.Second, to strengthen production management and operationAfter the 1990s, Chinas concrete sleeper factorys management of the operation by strict requirements, such as strict concrete mix to ensure that the vibration and dense concrete strength (including a tensile strength), in particular steam conservation. Stripping the surface with the sleeper when the ambient temperature difference between the 20 40 , some factories are still sleeper Stripping deposited within three days of water conservation. These measures to reduce the sleeper cracks, especially cracking and fracture will be very beneficial.Third, strictly control the raw materials of concreteChinas natural river sand has not found a base activity, but many regions of coarse aggregate base has potential activity, it should vigorously promote the use of low-alkali cement (alkali of 0.6%) and low-alkali water reducer. In the current use of low-alkali cement and low-alkali super plasticizer still difficult circumstances, should control the largest amount of cement, concrete sleeper to make the alkali content does not exceed safety limits (3) o For example: When the cement alkali Volume up 1 percent, cement concrete sleeper amount of 500 , while the alkali in concrete for 500 1% = 5. Super plasticizer, if not doped, has greatly exceeded the safety limit 3 kg/m3 Value when alkali cement volume was 0.6%, the amount of water reducer alkali five percent, one percent for the amount of time, the amount of concrete alkali 5000.6% 10 5001% 5% = 3.25 3(safety limits), therefore, when the largest cement concrete on the amount reduced to 460 , because 460 0.6% 10460 1% 5% = 2.99 3(Safety limits), instead of the usual technical conditions stipulated in the 500 kg/m3.In short, the concrete in the early conservation, the main purpose is to maintain appropriate Temperature and Humidity conditions, so as to achieve the effect of both the one hand, the concrete from the adverse temperature and humidity deformation of the invasion, to prevent harmful Languor and shrinkage.In theory analysis, contained in the fresh concrete cement hydration water completely satisfy the requirements of a surplus. However, due to evaporation and other reasons often cause water loss, delay or prevent the hydration of cement, concrete surface and easily the most directly affected by such adverse effects. Therefore concrete pouring is the first days after the critical period of conservation, in construction should be earnestly pay attention to it.来源：(/s/blog_4e5c779201009atn.html) - PrestressedConcretetheextensiveapplicationo_轩辕灵儿_新浪博客译文：预应力混凝土的广泛应用预应力混凝土在使用荷载作用下作用于混凝土结构，在生产阶段，前阶段的施加压力的是由人工所造成的压力。当元件用来承受的负荷和压力，首先要抵消预应力混凝土，然后随着负载的增加，混凝土产生应力拉伸区。因此，混凝土裂缝可能会延迟出现，以满足应用的要求。在结构构件承受这个力会在之前加在预应力混凝土结构上，满足预应力混凝土结构的要求。中国的预应力混凝土轨枕使用已经超过30年，在对有关交通安全的损害上，通常被认为把损坏的轨枕更换就行了。但是，为了换新的轨枕，除了重新制造，而且还需要处理，运输和安装到线路上，不仅需要花费大量的人力和物力，有时对交通的影响，成本往往是轨枕本身的费用4至5倍。作为预应力的混凝土结构轨枕，裂缝很难避免，了解预应力的原因和裂缝的危险就如何预防和裂缝控制，对提高混凝土轨枕结构的耐久性，延长轨枕使用周期，是非常重要的。1混凝土轨枕轨枕裂缝的原因混凝土裂缝的生成的研究是从结构，工艺，材料和其他方面，或者是从设计，制造，铺设，研究使用。在这里，只有从物理，化学，力学的角度来分析。1.1机械因素混凝土轨枕不仅时刻遭受动态压力，而且轨枕的端部有关。铺设了原设计要求和保护应该是空400空间，出于对轨枕的保护，最后掏空中间部分的轨枕应小于30毫米，以避免负弯矩过大的枕头横向上裂。近年来，不需要中间掏空，中间应垫压载浮。假设，该轨枕的支持中部设计应在3 / 4（中间挖空了）轨道的一部分。和一般混凝土轨枕从具体产品与不同国家支持的轨枕车的运作和维修的条件不断变化，曾经支持国家和动压震垂直悬挂由合并后的影响而产生超过设计极限，目前，相应的部分轨枕将有一个裂缝。此外，当预加应力时，偏载过大，混凝土强度不足，对轨枕底将有一个垂直的裂缝，铁路列车的水平和垂直力的运行并造成螺旋夹螺栓围绕一个纵向和横向裂缝螺栓孔。1.2物理因素物理因素是指轨枕生产和铺设时冻融，冻结过程中的热与冷，干，湿，冻结和融化作用。当蒸汽升温快，养护过程中的高温恒温时，具体的煤气，水，水泥，砂石等各种不同材料的热膨胀系数不同，混凝土结构的早期强度低，使高温气体和水大大扩展，在混凝土内部的具有缺陷导致松散的结构，容易导致混凝土表面裂缝，特别是轨枕端面，很松散。一段时间以来，许多工厂轨枕在蒸汽养护期间没有预留停留时间，升温快，恒温器温度高于95，在混凝土轨枕底部剥离肿胀，松散的情况常常发生。1.3化学因素化学因素指钢筋锈蚀，混凝土腐蚀，碳化，碱骨料反应等。中国对混凝土轨枕研究中，碱骨料反应（AAR的）造成的损害是不能被忽略的。碱骨料反应的三个条件是：聚合活性，高碱水泥和水，这三个形成化学反应，在混凝土和水泥界面聚合，对硅酸盐凝胶形成更多的破坏，造成混凝土体积膨胀开裂。其中最常见的基地 - 硅酸反应。至于中国的很长一段时间没有限制碱水泥生产。使用高碱水泥增加水泥产量，减少成本。中国有一些地域的粗骨料（石）具有明显的基础活动，这两者结合在一起，容易形成碱骨料反应（AAR）破坏。这个问题从60年代末，一个预应力混凝土的混凝土轨枕（桥梁）发生多次打击骨裂，由于厂生产，加工，铺设保护条件不足，进一步提高断裂，开裂，直到，80年代后期有开始我们必须承认和肯定了试点。检查过程是：首先是核心混凝土轨枕样品，检测项目，其中包括：肉眼或使用立体显微镜，然后一边超薄反射镜，由一般AAR的定期骨料颗粒损伤所造成的损害，从扩展到浆聚合更多的裂缝，而且有时也明显观察分裂或破坏的边缘。此功能是非常重要的，因为盐腐蚀，化学腐蚀，耐腐蚀钢，碳酸盐，如机械载荷不会因受伤骨料颗粒，所以这是AAR和破坏的主要特点等因素，有能力依靠耦合在电子显微镜可以测量频谱分析碱硅酸盐凝胶的化学成分，这是AAR的直接证据。此外，混凝土骨料机械和化学方法（通常用盐酸处理）的分离，再利用和快速鉴别方法的逐步碱活性。总之，纵向裂缝是由于内