Experimental Investigation on the Rheological Properties and Erosion Mechanisms of Chloride Salt–Modified Asphalt Mortar

Abstract

The direct action of salt on asphalt materials has received limited research despite the abundance of studies on salt erosion and its effects on the moisture stability of asphalt concrete. This study aimed to investigate the effects of chloride salt on the rheology of asphalt and erosion mechanisms. Microscopic properties of asphalt mortar were analyzed through scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR), and the erosion degree of salt in asphalt mortar was evaluated based on three major indexes. Rheological properties of asphalt mortar were determined through temperature sweep and multiple stress creep and recovery (MSCR) tests, while the modified water-boiling test was conducted to evaluate the adhesion of asphalt mortar. Results showed that as salinity increases, the agglomerate phenomenon tends to occur in asphalt mortar, leading to physical aging effects on its basic properties. Meanwhile, chloride salt modified asphalt concrete is prone to cracking at low temperatures and has reduced durability at high temperatures, making it unsuitable for standard load or heavy traffic pavement requirements of PG64 modified asphalt. Furthermore, the presence of chloride in asphalt mortar was not conducive to its adhesion.