Multi-scale investigation on water stability and anti-aging performance of granite asphalt mixture modified with composite anti-stripping agents

Abstract

This study aims to improve the water damage resistance of granite asphalt mixtures. Five types of composite modified asphalt were developed using organic anti-stripping agents AMRIII, LQ-2020, ultrafine hydrated lime (HL), and SBS modified asphalt, and the effects of aging on the mechanical properties of these modified asphalt mixtures were evaluated. Fourier Transform Infrared Spectroscopy (FTIR), pull-off tests, and indirect tensile strength tests were the primary analytical methods used. The results indicated that the anti-stripping agents physically mixed with the SBS modified asphalt without any chemical reaction. The SBS modified asphalt containing anti-stripping agents exhibited better mechanical strength compared to unmodified SBS asphalt, with the combined use of multiple anti-stripping agents proving more effective than individual applications. At five freeze-thaw conditions without aging, the enhancement ratios of indirect tensile strength test results of single addition of AMRIII, LQ-2020, HL and combined addition of AMRIII/HL and LQ-2020/HL were 27.27%, 36.36%, 14.29%, 50.91% and 46.41%, respectively. The addition of the anti-stripping agent enhanced the cohesive and adhesive energy. Aging reduced the water stability of the mixtures. Different modified asphalts have various sensitivity to aging, with the combination of AMRIII and HL showing the best aging resistance performance. Additionally, it was found that surface free energy had a strong correlation with water damage indicators, suggesting its potential for verifying the water stability of asphalt mixtures.