Study On Performance Of Bridge Seamless Expansion Joint Filler

The quality and performance of the bridge expansion joint affects traffic safety,driving comfort and driving speed.It is placed on the relatively weak structure such as the beam end.Under the repeated impact of vehicle loads and various influences of external environment,the bridge deck pavement will be damaged,and even the main girder and pier and abutment will be affected seriously.Although some improvements have been made in the expansion joints,there are still many unsolved problems,such as garbage blockage,water seepage,car jumping,etc.Seamless expansion joint is an effective way to solve these problems.Seamless expansion joint is a kind of expansion joint filled with filler.The filler is mainly composed of modified asphalt and aggregate to form asphalt mixture with high elasticity,high viscosity and traffic load resistance.The basic method is to replace a certain range of pavement upper layer with asphalt mixture,so as to absorb the bridge deck displacement caused by temperature and traffic load,to ensure that the surface will not crack and damage.However,there are few studies on seamless expansion joint fillers.To this end,the main contents of this paper are as follows:(1)Based on theoretical analysis,this paper studied the calculation method of bridge expansion joint expansion,the width and thickness of seamless expansion joints were discussed,and dynamic shear rheological test was used to select the binder used in the next stage of filler test.(2)On the basis of traditional Marshall design method of asphalt mixture and SMA gradation,a mix proportion suitable for seamless expansion joint filling material was designed.According to this mix proportion,a large number of specimens were made,and the indoor test ratios such as trabecular bending test,direct tension test,splitting test,compression recovery test,rutting test and immersion Marshall test were carried out.The flexural properties,tensile properties,compressive properties,elastic recovery properties,high temperature stability and water stability of the filler were studied comprehensively.The test results show that the filler designed in this paper has excellent performance.It can meet the deformation requirement of general small and medium-sized girder bridges.(3)On the basis of the above performance test of seamless expansion joint filler,the full bridge models of seamless expansion joints and section steel expansion joints were established by using Abaqus finite element software.The stress and displacement changes of the two types of expansion joints under vehicle load and temperature load were analyzed.By comparing the numerical simulation results of the two kinds of expansion joints,it is found that the maximum principal stress and maximum longitudinal stress of the seamless expansion joints are smaller under the same temperature and load,which indicates that the seamless expansion joints are more inclined to flexible structures,and there is no obvious stress concentration in the joints.Compared with the section steel expansion joints,the problems of bending and tension failure and cracking are not easy to occur.(4)The construction technology and quality control measures of seamless expansion joints were proposed.The benefits of seamless expansion joints were analyzed from social and economic perspectives.The research results show that the filler designed in this paper has excellent performance and can meet the deformation requirements of general small and medium-sized girder bridges;seamless expansion joints tend to be flexible structures,which are less prone to bending failure and cracking than the expansion joints of profiled steel;and seamless expansion joints have significant social and economic benefits compared with the expansion joints of profiled steel and similar expansion joints.