Effect of silane coupling agent on improving the adhesive properties between asphalt binder and aggregates

Moisture damage negatively affects the pavement service life. A typical way to delay the moisture damage is to improve the adhesion between asphalt binder and aggregates. The purpose of this paper is to investigate the effects of silane coupling agent (SCA) on improving the adhesion between asphalt binder and aggregates. In this paper, the contact angles of the aggregates modified by different SCA hydrolysates were measured. The adhesion energy and stripping energy between asphalt binder and aggregates modified by different SCA hydrolysates were calculated. Secondly, the tensile strengths between asphalt binder and aggregates before and after immersion in water were measured. Lastly, the interfacial interactions between SCA and the aggregates were studied by Fourier transform infrared (FTIR) and scanning electronic microscopy (SEM). The surface energy results prove that the SCA can significantly improve the adhesion energy and stripping energy between the aggregates and the asphalt binder. The tensile test results show that the tensile strength of the aggregates modified with a type of SCA (KH550) hydrolysate before immersion in water was increased by 58%, and the tensile strength after the immersion in water was increased by 155%. Based upon these results, it can be concluded that using SCA has a superior effect on improving adhesive properties between asphalt binder and aggregates.