Optimization design of fiber rubber asphalt gravel sealing layer based on fatigue crack resistance test

Crack is one of the main diseases of pavement structure. In order to improve the anti-reflective crack ability of pavement, fiber rubber gravel sealing layer is proposed as the stress absorbing layer. In view of the shortcoming that Mcleod design method can not be associated with road performance, a sealing layer optimization design method based on fatigue crack test is proposed. Firstly, the reinforcement effect of fiber on rubber asphalt was studied through force ductility testing. Secondly, the optimum dosage of fiber, asphalt and gravel was optimized through fatigue cracking resistance test. Finally, the cracking resistance of fiber rubber gravel seal was verified through fracture energy test. The results show that fibers can significantly increase the maximum tensile force and strain yield energy of rubber asphalt, and basalt fiber has the best reinforcement effect. The most obvious effect on cracking resistance performance in the sealing layer is the amount of fiber, followed by the amount of asphalt, and finally the amount of gravel. The optimized material combination with the best crack resistance is 120g/m2 fiber, 14kg/m2 gravel and 2.4kg/m2 rubber asphalt, and the fatigue resistance times can reach 19532 times. The fracture energy of the composite pavement treated by the optimized sealing layer is nearly double that of the non-treated pavement structure, and it has a good anti-crack effect.