Study On Road Performance Of Polyester Fiber Asphalt Concrete

Asphalt pavement is widely used in Expressway because of its short construction period,easy maintenance and low noise.In recent years,with the rapid development of China’s economy,asphalt pavement has been widely used in low-grade rural roads throughout the country.With the development of rural economy,the increasing traffic volume and the accelerating growth of overloaded and overloaded vehicles,the early diseases of asphalt pavement such as rutting,pits and cracks appear during the service period.Therefore,the improvement of asphalt concrete pavement performance is extremely urgent.Polyester fiber is a kind of high polymer fiber,which has stabilization,toughening and reinforcing effects.It has a wide application prospect to mix polyester fiber into asphalt concrete.In order to study the influence of polyester fibers on the pavement performance of asphalt concrete,the pavement performance of fiber asphalt concrete was studied experimentally by using AC-13 gradation to select polyester fibers of different lengths and dosages.The main research contents are as follows:1.Through dynamic shear test,viscosity test and determination of three major indicators of fiber asphalt mortar,the influence of fiber content on high temperature fluidity,viscosity and ductility of asphalt mortar was analyzed.The results show that polyester fiber can effectively improve the penetration,softening point,ductility,high temperature fluidity and viscosity of asphalt mortar.2.Choose the length of polyester fiber as 6mm and the content of polyester fiber as 0,0.2%,0.3% and 0.4% respectively.Through Marshall test,the optimum asphalt content of fiber asphalt concrete is determined.The optimum asphalt content of each fiber is 4.5%,4.8%,4.9%,5.0% respectively.Under the optimum asphalt content,the length of fiber is 6mm,9mm and 12 mm respectively.Marshall test was carried out on concrete,and the effects of polyester fiber length and content on Marshall technical index were analyzed.3.The effects of different fiber length and content on the high temperature performance,low temperature performance and water stability of asphalt concrete were studied.The rutting test,trabecular bending test,immersed Marshall test and freeze-thaw splitting test were carried out on asphalt concrete with 0,0.2%,0.3%,0.4% and 6mm,9mm and 12 mm polyester fibers respectively.The experimental results show that polyester fiber can effectively improve the rutting resistance,crack resistance and water stability of asphalt concrete at high temperature.There are optimum matching parameters for the length and content of polyester fibers.Fiber parameters of 0.2%-9mm and 0.3%-6mm are the best for improving high temperature stability and water stability,while fiber parameters of 0.2%-12 mm and 0.3%-9mm are the best for improving low temperature crack resistance.4.Combining the results of asphalt mortar performance test and fiber asphalt concrete pavement performance test,the strength mechanism of fiber reinforced asphalt concrete is analyzed by scanning electron microscope test on the microstructure of fiber asphalt mortar and fiber asphalt concrete.