1、 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 1 页 英文翻译原稿 Prestressed Concrete the extensive application Priestesses concrete is used in concrete structures under load before the production phase, the use of pre-stage of the tension zone
2、 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 implementa
3、tion, 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 o
4、f 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 materi
5、al 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
6、 sleeper to improve the durability of the structure, to extend the life of sleeper, Will be very important. 1. causes cracks in concrete sleeper Cracks in concrete sleeper can be generated from the structure, processes, materials and other aspects of, or from the design, manufacture, laying, use of
7、research. Here, only physical, chemical, mechanical point of view for analysis. 1.1 mechanical factors Concrete 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 c
8、onservation 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 西南交通 大学本科 毕业设计 第 2 页 avoid negative moment too large a pillow in the upper horizontal cleft. In recent years do not require the middle emptied
9、, 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 an
10、d 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
11、 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 factors Phy
12、sical 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 di
13、fferent 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 s
14、urface 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 factors Chemical
15、 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
