Study On The Durability Of Post-Tensioned System In The Environment With Simulated Acid Rain

Prestressed concrete structure with its superior performance was widely used in civil engineering, construction, water conservancy , traffic engineering and other fields. Just as other structures, prestressed concrete structure also appeared failure of the durability under the long-term erosive environment. However, at home and abroad there was little relevant research on the durability of prestressed concrete structure, much work should be done to the basic research.This paper was mainly about the study on the durability of prestressing system in the environment with acid rain, combining with climatic characteristic of Chongqing, analyzed the causes of corrosion of PC track beam. A 20m full-scale prestressed concrete beam was build, and according to the acid rain characteristic, acid rain was deployed to make a accelerate corrosion test on the beam. Then the PC stranded steels, anchor systems, grouting-materials and grouting technologies were contrasted in the test. On this basis, the factors of affecting the durability of prestressed concrete structure were determined and measures that would improve the prestressing system durability were brought forward.Through research, some results were obtained and listed as followed: the relevant performance of strand, duct, anchorage and concrete block after 3000h accelerate corrosion test; the shrinking value of different grout materials; the gap proportion in the duct after grouting.With the analysis of the result, a combination was put forward to guarantee the durability of prestressed system, the corrosion model of prestressed concrete structure was established, the mechanism of aperture formation after grouting was explained and a lot of control measures were advanced in the construction and maintenance.