Abstract:In order to provide an asphalt mixture with excellent road performance as an ultra-thin wear layer for preventive maintenance engineering, the SAC-5 asphalt mixture was designed using the gravel asphalt mixture (SAC) grading design method. The road performance of the mixture under three porosities of 4%, 6%, and 8% was compared and analyzed. The results show that the coarse aggregate content in the SAC-5 asphalt mixture accounts for more than 70%. When the target porosity increases from 4% to 8%, the mineral aggregate gradation in the mixture does not change much, and the optimal oil-stone ratio decreases. With the increase of void ratio, the dynamic stability, residual stability, residual strength ratio, structural depth and swing value of SAC-5 asphalt mixture increase, and the low-temperature bending strain decreases, but still meets the specification requirements; For sections with steep slopes and other roads that require high anti-skid performance, it is recommended to use asphalt mixture with a target porosity of 8% as the ultra-thin wear layer.