Semi-flexible pavement is widely used in pavement engineering due to its excellent rutting resistance; however, it mainly fails due to cracking. Therefore, it is important to understand the properties of the aggregate–mortar–asphalt interfacial transition zone, to better understand the cracking mechanism of the semi-flexible pavement. In this work, we used pull-off tests and digital image analysis technology to compare and analyze the interfacial tensile strength and granite–bitumen–mortar interactions in three types of asphalt (70# matrix asphalt, PG76-22 modified asphalt and S-HV modified asphalt) at different curing ages. The analysis results showed that, for the three different bitumen materials, with settled mortar, the peak interfacial tensile strength values all occurred at approximately 14 d of curing. In addition, the order of the tensile strength followed the order of asphalt penetration degree; the order of the interfacial water damage resistance from weak to strong was 70# asphalt cementation specimen, PG76-22 modified asphalt cementation specimen, and S-HV modified asphalt cementation specimen. The results of this analysis highlight the original contributions of the optimum curing time for the composite interface of semi-flexible pavement materials prepared with different asphalts to reach optimum crack resistance.

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