Investigation of sea salt erosion effect on the asphalt-aggregate interfacial system

Abstract

Under high-temperature and hygrothermal conditions, sea salt erosion can lead to asphalt-aggregate interfacial failure in porous asphalt concrete and cause aggregate raveling in coastal areas. Therefore, studying the damaging effect of sea salt erosion on an asphalt-aggregate interfacial system in a hygrothermal environment is necessary. First, the asphalt film thickness of a standard asphalt-aggregate specimen used in the simulation tests was determined according to the relationship between the tensile strength of the asphalt-aggregate specimen and the thickness of the asphalt film. The damaging effect of the salt solution was simulated by the 60°C high-temperature erosion test, and the solution type, solution concentration, and immersion duration were considered. The tensile strength and asphalt film-stripping ratio of the eroded specimens were analyzed, and the interfacial asphalt film dynamic equation σ2(t) and the stripping region interface dynamic equation σ2(t) were deduced. The results show that the 6 μm asphalt film thickness corresponds to the maximum tensile strength of the asphalt-aggregate specimen. With the increase of immersion duration, the tensile strength of asphalt-aggregate specimen decreased, and the asphalt film-stripping ratio of failure surface increased. In addition, the tensile strength of the interfacial asphalt film increased gradually due to the aging effect of the salt solution. The tensile strength of the stripping region’s interface did not descend to zero, but was obviously lower than the asphalt film. The 5% Na2SO4 solution has the highest damaging effect on the asphalt-aggregate interfacial system, followed by the 5% composite salt solution, 5% NaCl solution, water, and 10% NaCl solution..