Abstract:Hot mix ultra-thin friction course is one of the effective technologies of highway preventive maintenance. The pavement performances of ultra-thin friction courses of different gradations are tested and studied based on a preventive maintenance of expressway. Results show that the porosity of mixtures at different grades decreases with the increase of 2.36-mm sieve pore passing rate. Both fine aggregates and mineral powder will fill the mixture pore and the filling effect of mineral powder is 3 times of fine aggregates. With the gradation of ultra-thin friction course from coarse to fine, the Marshall stability of mixture increases, the Cantabro flying loss decreases and the fatigue life reduces. The used mineral powder as the mixture performance of a filler is significantly better than that of fine aggregates. The correlation analysis results show that the Marshall stability, flying loss and fatigue performance of ultra-thin friction course mixture are well correlated with the porosity. TSR result is well correlated with asphalt film thickness. The indicators of porosity and asphalt film thickness should be highly considered during the design of ultra-thin friction course.