Experimental And Evaluation Study On Pavement Performance Of Straw Fiber Composite Materials

Aiming at the early failure of asphalt pavement, the paper from the material aspects, attempted to extract road straw composite fiber from waste straw and blended straw fiber into the asphalt mixture to improve the performance of asphalt pavement. The straw composite fiber materials on the road performance of SMA pavement were evaluated through the marshall test, Marshall Immersion test, high temperature wheel rutting test and low temperature cracking test. The main work includes: extraction of straw composite fiber through soda cooking, optimization of raw materials and aggregate grading design. The optimal asphalt-stone ratio of asphalt was determined through marshall test. The water stability, high temperature stability and low temperature crack resistance of SMA pavement under different fiber types and different levels of straw fiber were researched. Considering the stability of SMA mixture, marshall modulus, residual stability, bending stiffness modulus and dynamic stability of five performance indicators, the influence of different amount of fiber to road performance of asphalt pavement were analyzed using multiple linear regression statistical methods, and the best straw fiber content in SMA mixture were determined.Marshall test results show that, the optimum asphalt ratio of SMA asphalt mixture is 6.0%, dosage range of Straw fiber is about 0.3%. Wheel tracking test shows that, when straw fiber content is about 0.3%, dynamic stability is the Maximum. Fiber content of 0.2%~0.3% can meet the requirements of high temperature stability. Low temperature cracking test results showed that the low temperature crack resistance of polyester fiber and polypropylene fiber is highest, straw fiber is secondly, and the wood fiber is the lowest. Fiber content of 0.2%~0.6% can meet the requirements of low-temperature cracking resistance. Immersion marshall test, freezing and thawing split test results show that the order of residual stability is straw fiber, wood fiber, polyester fiber and polypropylene fiber. After freeze-thaw cycles the TRS of straw fiber is the highest, followed by lignin fiber, polyester fiber and polypropylene fiber is the minimum. Integrated water stability test results, straw fiber content are 0.2% to 0.4%. Considering the variety of indicators, evaluate the optimum proportion of the straw fiber through multiple correlation and regression analysis. The best content of straw fiber is 0.282%. The research results have significance and value in achieving utilization of straw, improving the quality of road and reducing the cost of road construction.