Research On Applied Technology And Performance Of Modified Asphalt Bridge Expansion Joints

The modified bitumen bridge expansion joint is a new kind of bridge expansion devices which has been applied and developed in bridge construction in china. After surveying the disease form of bridge expansion devices, and analyzing the cause of diseases, the main factors of bridge expansion devices damage are concluded which are based on the research of the technology of the new long seamless bridge deck which is widely used in Chengdu to Renshou expressway. The pavement performance and expansion performance of modified asphalt concrete are obtained through test. This paper studies the law of mechanical response on the interface by building the model of expansion joint structure under the environment of finite element software of ABAQUS. Construction technology, application effect and advancement of the bridge expansion joint are analyzed also.(1) For the performance test of raw material, a modified asphalt cement material is selected with high viscosity, high temperature performance and strong elastic-plastic performance,and the range of basalt size is from9.5mm to16mm.(2) According to the relevant documents, they propose that the asphalt-aggregate ratio is1:3. The performance index of it is tested that of strength characteristics, high temperature stability, water stability, water permeability, low temperature crack resistance and fatigue resistance of the modified asphalt mixture. The results indicate that this modified asphalt mixture has a good performance to adapt the stretching deformation, recovery performance, tensile properties, and bonding properties with cement concrete.(3) Making the bond interface roughly could improve the bond strength between the asphalt mixture and the end of the beam concrete. The results show that if the temperature is below0℃, the enhancement rate is more than20%, and if between10℃to40℃, that is between10%to20%,while above50℃, that is lower than10%. The effect is significant at low temperature.(4) Based on the internal stress and displacement distribution of the structure, a conclusion is obtained that the interface of the structure is likely to cause tension and compression damage and shear failure. Making the interface more roughly and embedding some steel may reduce the interface damage to a certain extent.(5) The test of deflection by baker-man beam shows that the pavement with modified bitumen bridge expansion joint can meet the requirement of the carrying capacity. At the same time, it has a good social benefit and considerable economic benefit.