Method for Determining Compatibility Between Modifier and Asphalt Based on Phase Separation

This study presents a refined methodology for evaluating the compatibility between a modifier and base asphalt. Initially, six variations of styrene triblock copolymer (STC) modified asphalt, with and without a sulfur-based stabilizer, were examined using laser confocal microscopy (LSCM) to analyze their phase characteristics following high-temperature storage. Subsequently, Image Pro Plus was employed to extract key phase characteristic parameters and cigar tube tests were conducted to establish correlations between these parameters and the results of the cigar tube test. A novel compatibility assessment method was formulated based on the analysis of laser confocal microscopy images. The specific findings are as follows: observations indicate that STC-modified asphalt lacking an effective stabilizer exhibits an increase in the diameter of island-like structures and heightened fluorescent intensity with prolonged storage. Conversely, STC-modified asphalt with an effective stabilizer demonstrates minimal microstructural changes during high-temperature storage. This disparity introduces a novel approach for evaluating compatibility between the modifier and the asphalt. The fluctuation in the maximum average particle size, following a 120-min hold, exhibits the strongest correlation with the results of the cigar tube test. The recommended evaluation criterion suggests using the ratio between the maximum average particle size after 120 min of incubation and the maximum average particle size at 0 min of incubation, considering compatibility excellent if the ratio is less than 2.