Experimental evaluation of the shear performance of steel-asphalt interface considering temperature and humidity coupling

The direct shear tests were conducted to study the shear performance of steel-asphalt interface by taking epoxy asphalt (EA) as waterproofing adhesive layer (WAL) material when considering temperature and relative humidity (RH) coupling. The temperatures of 30 and 60 °C and RH of 30, 50, 70 and 95% for each temperature were chosen and the steel-WAL interface, WAL-pavement interface and composite structure specimens were cured under specified temperature and RH. The research results show that the influence of RH on the shear strength of the steel-asphalt composite structure without considering the effects of temperature and RH on interfaces is negligible and the traditional shear test method should be updated. However, the interface shear strength decreases with increased RH when it exceeds 70% by considering the effects of temperature and RH on interfaces.