預應力混凝土的廣泛應用外文翻譯.doc

西 南 交 通 大 學本科畢業(yè)設計外文資料翻譯年 級:2006級學 號:20060058姓 名:郭 鵬專 業(yè):土木工程指導老師:楊榮山 2010年 6 月西南交通大學本科畢業(yè)設計 第12頁英文翻譯原稿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.來源：(/s/blog_4e5c779201009atn.html) - PrestressedConcretetheextensiveapplicationo_軒轅靈兒_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.來源：(/s/blog_4e5c779201009atn.html) - PrestressedConcretetheextensiveapplicationo_軒轅靈兒_新浪博客譯文：預應力混凝土的廣泛應用預應力混凝土在使用荷載作用下作用于混凝土結構，在生產階段，前階段的施加壓力的是由人工所造成的壓力。當元件用來承受的負荷和壓力，首先要抵消預應力混凝土，然后隨著負載的增加，混凝土產生應力拉伸區(qū)。因此，混凝土裂縫可能會延遲出現(xiàn)，以滿足應用的要求。在結構構件承受這個力會在之前加在預應力混凝土結構上，滿足預應力混凝土結構的要求。中國的預應力混凝土軌枕使用已經超過30年，在對有關交通安全的損害上，通常被認為把損壞的軌枕更換就行了。但是，為了換新的軌枕，除了重新制造，而且還需要處理，運輸和安裝到線路上，不僅需要花費大量的人力和物力，有時對交通的影響，成本往往是軌枕本身的費用4至5倍。作為預應力的混凝土結構軌枕，裂縫很難避免，了解預應力的原因和裂縫的危險就如何預防和裂縫控制，對提高混凝土軌枕結構的耐久性，延長軌枕使用周期，是非常重要的。1混凝土軌枕軌枕裂縫的原因混凝土裂縫的生成的研究是從結構，工藝，材料和其他方面，或者是從設計，制造，鋪設，研究使用。在這里，只有從物理，化學，力學的角度來分析。1.1機械因素混凝土軌枕不僅時刻遭受動態(tài)壓力，而且軌枕的端部有關。鋪設了原設計要求和保護應該是空400空間，出于對軌枕的保護，最后掏空中間部分的軌枕應小于30毫米，以避免負彎矩過大的枕頭橫向上裂。近年來，不需要中間掏空，中間應墊壓載浮。假設，該軌枕的支持中部設計應在3 / 4（中間挖空了）軌道的一部分。和一般混凝土軌枕從具體產品與不同國家支持的軌枕車的運作和維修的條件不斷變化，曾經支持國家和動壓震垂直懸掛由合并后的影響而產生超過設計極限，目前，相應的部分軌枕將有一個裂縫。此外，當預加應力時，偏載過大，混凝土強度不足，對軌枕底將有一個垂直的裂縫，鐵路列車的水平和垂直力的運行并造成螺旋夾螺栓圍繞一個縱向和橫向裂縫螺栓孔。1.2物理因素物理因素是指軌枕生產和鋪設時凍融，凍結過程中的熱與冷，干，濕，凍結和融化作用。當蒸汽升溫快，養(yǎng)護過程中的高溫恒溫時，具體的煤氣，水，水泥，砂石等各種不同材料的熱膨脹系數(shù)不同，混凝土結構的早期強度低，使高溫氣體和水大大擴展，在混凝土內部的具有缺陷導致松散的結構，容易導致混凝土表面裂縫，特別是軌枕端面，很松散。一段時間以來，許多工廠軌枕在蒸汽養(yǎng)護期間沒有預留停留時間，升溫快，恒溫器溫度高于95，在混凝土軌枕底部剝離腫脹，松散的情況常常發(fā)生。1.3化學因素化學因素指鋼筋銹蝕，混凝土腐蝕，碳化，堿骨料反應等。中國對混凝土軌枕研究中，堿骨料反應（AAR的）造成的損害是不能被忽略的。堿骨料反應的三個條件是：聚合活性，高堿水泥和水，這三個形成化學反應，在混凝土和水泥界面聚合，對硅酸鹽凝膠形成更多的破壞，造成混凝土體積膨脹開裂。其中最常見的基地 - 硅酸反應。至于中國的很長一段時間沒有限制堿水泥生產。使用高堿水泥增加水泥產量，減少成本。中國有一些地域的粗骨料（石）具有明顯的基礎活動，這兩者結合在一起，容易形成堿骨料反應（AAR）破壞。這個問題從60年代末，一個預應力混凝土的混凝土軌枕（橋梁）發(fā)生多次打擊骨裂，由于廠生產，加工，鋪設保護條件不足，進一步提高斷裂，開裂，直到，80年代后期有開始我們必須承認和肯定了試點。檢查過程是：首先是核心混凝土軌枕樣品，檢測項目，其中包括：肉眼或使用立體顯微鏡，然后一邊超薄反射鏡，由一般AAR的定期骨料顆粒損傷所造成的損害，從擴展到漿聚合更多的裂縫，而且有時也明顯觀察分裂或破壞的邊緣。此功能是非常重要的，因為鹽腐蝕，化學腐蝕，耐腐蝕鋼，碳酸鹽，如機械載荷不會因受傷骨料顆粒，所以這是AAR和破壞的主要特點等因素，有能力依靠耦合在電子顯微鏡可以測量頻譜分析堿硅酸鹽凝膠的化學成分，這是AAR的直接證據(jù)。此外，混凝土骨料機械和化學方法（通常用鹽酸處理）的分離，再利用和快速鑒別方法的逐步堿活性。總之，縱向裂縫是由于內