A Uinited Evaluation Method For Adhesive And Cohesive Performance Of Crack Sealant Under Low Temperature

Up to now, crack sealing is the most widely used method in China. With regard to the early diseases, especially linear crack of asphalt pavement, practice has proved that crack sealing could effectively prolong the service life of pavement. However, early failure phenomena have commonly appeared in the process of using crack sealant, especially the adhesive failure and cohesive failure phenomena under the condition of low temperature and traffic load. Therefore, it is necessary to conduct researches about the failure extent identifying method of crack filling material, and the establishment of the unified evaluation system of cohesiveness and adhesion of crack filling material. The main contents of this paper are as follows:Firstly, based on the filling glue low temperature performance tester, test fixture and mould which are suitable for the unified evaluation system of cohesiveness and adhesion of crack filling material are developed in this paper. And on this basis, laboratory simulating tests are conducted to research the change rules of different kinds of cohesiveness and adhesion of crack filling material when changing the test temperature, loading rate, specimen dimension, and so on. Then we can determine the unified test parameters and methods of cohesiveness and adhesion.Secondly, according to the results of laboratory simulating tests, unified evaluation indexes(failure stress, strain, strain energy, and so on) of cohesiveness and adhesion of crack filling material are developed. The influences of these evaluation indexes are analyzed, respectively. The change rules of unified evaluation indexes of cohesiveness and adhesion are analyzed, when changing the aging characteristics, viscosity, glass transition temperature, and so on.Then, the influences of interfacial characteristics and different aggregated rocks on low temperature cohesiveness and adhesion of crack filling material are analyzed.Finally, a typical section of road in Heilongjiang province is chosen to conduct a tracking survey about the failure of crack filling material, and a method that applies for long-term survey is designed. Using statistical analysis, the survey finds that the early failure mainly concerns about cohesiveness and adhesion. In practice, crack width is used as an evaluation index of unified evaluation. According to practical situation, the method to evaluate the failure of crack filling material is proposed.