Internal Damage Mechanism of Permeable Asphalt Mixture by the Freeze-thaw Splitting

Abstract

The splitting strength of the permeable asphalt mixture before and after freeze-thaw cycles was obtained by freeze-thaw splitting test. And the CT scanning images of the specimen in different layers before and after freeze-thaw splitting was obtained. The micro-structures damage characteristics of the permeable asphalt mixture after freeze-thaw splitting was analyzed, and the evolution law of the inner micro-structures of the permeable asphalt mixture was analyzed by the damage variable. The results of this paper show that with the increasing number of freeze-thaw cycles, the splitting strength of the asphalt mixture decreases gradually. Most of the cracks of the permeable asphalt mixture after freeze-thaw cycled occurred at the initial void density distribution of the specimen, and the spreading direction of the void is basically consistent with the direction of the initial void. The mechanical properties of asphalt mixtures are poor with larger voids, and the increasing of the damage variable with larger voids is more than that with less voids.