Preparation And Properties Of Cross-linked Polyethylene Modified Asphalt

With the increased traffic,overloaded vehicles and extreme weather,a higher demand for asphalt pavement performance is presented.One of the most important methods for improving the performance of asphalt pavement is to modify asphalt,so exploring new modifier and studying the performance of modified asphalt are very important.As a modified polyethylene cross-linked into three-dimensional network structure,cross-linked polyethylene?XLPE?has better mechanical properties,heat resistance and chemical stability.In this article,the performances of cross-linked polyethylene modified asphalt prepared with XLPE modifier were studied by conventional performance test,dynamic shear rheometer test?DSR?and repeated creep and recovery test.The results of conventional performance test show that XLPE modifier reduces the penetration,improving the softening point and high temperature performance of asphalt.The method of evaluating modified asphalt by low-temperature ductility has some limitations.It can be seen that XLPE has little effect on the low-temperature performance of asphalt by the equivalent brittle point_2.1T.The storage stability of modified asphalt reduces with increasing of XLPE modifier content.In the temperature sweep test of DSR,the complex shear modulus G^*and rutting factor G^*/sin?of asphalt are increased,and the phase angle?of asphalt is reduced.So the rutting resistance of asphalt is improved,and the elastic component of asphalt is increased.The cross-linked polyethylene modified asphalt has minimal variation of viscoelastic parameters after ageing,so the XLPE modifier can improve the aging resistance of asphalt.In the frequency sweep test,the deformation resistance of asphalt is improved,especially in low frequency region.The shift factor of complex shear modulus G*curve is calculated based on time-temperature superposition principle.The low temperature performance of asphalt is improved by XLPE modifier from the results of glass transition temperatureT_g and the crossover frequencyf_c.In the creep recovery test,it can be seen that the resiliency of asphalt is improved significantly by XLPE modifier,and the high temperature perpformance of asphalt are improved by the result of Gv fitted.The analyses of applicability and limitations of different evaluation indices of high temperature propertie of asphalt show that Gv could present high temperature propertie of modified asphalt better.