Experimental study of aggregate skeleton shear properties for asphalt mixture under different compaction stages

Abstract

The permanent deformation diseases of asphalt pavement, such as rutting and slippage, are mainly influenced by its shear resistance. The shear properties of asphalt mixtures are the macroscopic result of mutual friction and contact between particles. Compared with the compaction degree, the shear properties can more directly reflect the compaction quality of mixtures. Based on the self-developed “asphalt mixture aggregate skeleton shear tester”, this research addressed the challenges in obtaining the compaction performance of asphalt pavement, and the aggregate skeleton shear tests were carried out under different test conditions with AC-13C and asphalt mortar. The test evaluation index was optimized by statistical analysis and ANOVA method, and the test means and coefficients of variation were obtained to evaluate plate-claw combinations and torsional loading speeds. Besides, the shear properties of asphalt mixtures under different test temperatures and compaction numbers were investigated. The results show that the shear failure strength (FP) exhibits the best regular statistics and displays good differentiation for various gradations, moreover, it is recommended to use the combination of 190&10 plate-claw and a loading speed of not more than 3°/min. As the test temperature decreases, the average value of FP increases in a power relationship. In addition, the average value of FP shows a good linear positive correlation to the compaction number. However, the shear strength of asphalt mixtures under the same compaction number still varies greatly, and the coefficient of variation reaches 22.1%. In summary, the effect of compaction test conditions on the shear performance of asphalt mixtures can be better evaluated by the proposed aggregate skeleton shear properties test.