Design And Performance Research Of Non-roller Compacted Asphalt Mixture For Transition Zone Of Bridge Expansion Joints

The bridge expansion joint is an indispensable part of the bridge structure which is usually located between the two beam ends or between the abutment and the beam end or on the connection part of the bridge.It plays an important role in adjusting the displacement and connection between the bridge superstructure caused by factors such as vehicle load.However,heavy traffic accompanied by environmental impacts have led to the destruction of bridge expansion devices.The main forms of damage are concrete damage in the transition zone and debonding between concrete and steel plates or new and old concrete.At present,cement-based repair materials are generally used for such diseases,but they not only have a long curing time,but also have insufficient durability.In response to this,this paper proposed non-roller compacted asphalt concrete which was a flexible expansion joint material based on asphalt concrete to fill the anchorage zone.Subsequently,this paper carried out the design and performance research of non-roller compacted asphalt mixture materials suitable for bridge expansion joints,which has important practical significance and engineering value.Firstly,a structural model of bridge expansion joints was established using finite element software.The mechanical responses of key parts of bridge expansion joints under different vehicle speeds,loads,and temperatures were studied using static and dynamic loads.It was found that heavy loads and low temperatures can cause greater stress in the bridge expansion joint structure,and the longitudinal tensile stress at the transition zone and steel plate joints was greater.After that,technical property tests were conducted on selected raw materials.Through Marshall test and fluidity test,it was determined that the void ratio,gross bulk density,Marshall stability,flow value,and fluidity were used as the design indicators for roller free asphalt mixture,and the optimal oil stone ratio was obtained this paper referred to Marshall test and fluidity test and used void ratio,gross bulk density,voids filled with asphalt,Marshall stability,flow value and fluidity as indicators to comprehensively determine the optimal mix ratio.Next,three additives were selected to evaluate the high temperature stability,low temperature crack resistance,moisture stability,and fatigue properties of non-roller compacted asphalt mixture through experiments.After that,it was determined that the 0.3%Sasobit content had the most significant improvement in the comprehensive performance of non-roller compacted asphalt mixture combined with analytic hierarchy process.In addition,it was found that the interfacial adhesion performance of SBS modified emulsified asphalt was the best when the spraying amount was 0.8 L/m~2 through the interfacial adhesion test.The deformation properties of roller free asphalt mixture were evaluated using direct tensile test and compressive elastic recovery test.Finally,the relaxation performance of non-roller compacted asphalt mixture was evaluated through stress relaxation tests and mathematical models.