The occurrence of cohesive/adhesive hybrid failure at the bitumen-aggregate interface is widely acknowledged, however, the quantitative evaluation of the cohesion/adhesion proportion is relatively weak. This study explored cohesive/adhesive hybrid failure and provided a quantitative analysis of the proportion between cohesion and adhesion. For this reason, this study considered a variety of experimental factors that included temperature (5 °C, 15 °C, and 25 °C), mineral morphology (three mineral types and three surface textures), and measured film thickness (varying from 10 μm to 900 μm). By performing the bonding strength test, the strength was recorded and interface failure was accordingly captured. The results indicated that the cohesion/adhesion proportion varied significantly with the temperature, mineral morphology, and measured film thickness. In addition, it was found that bonding strength decreased with the increase in the film thickness and temperature, which can be well explained by variation in adhesion/cohesion proportion. Complete cohesive failure was observed when the film thickness increased beyond a critical value at a relatively high temperature. An additional noteworthy finding was the resemblance of a lunar crater for the failure interface at high temperatures, signifying the heterogeneous composition of the bituminous binder around the interface.
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- Adhesion/cohesion proportion
- Bitumen-aggregate interface
- Failure mode
- Film thickness
- Mineral surface morphology