Performance Characteristics of Asphalt Binders Modified with Microwave-Activated Crumb Rubber

Abstract

This study investigates the use of microwave activation as a pretreatment method to enhance the compatibility between crumb rubber and asphalt, and systematically evaluates the road performance of microwave-activated crumb rubber modified asphalt (M-CRMA). Scanning electron microscopy (SEM) observations revealed that, after microwave activation, the crumb rubber surface became rougher with an increased specific surface area and higher reactivity, thereby facilitating stronger interactions with asphalt. Rheological properties were comprehensively analyzed through dynamic shear rheometer (DSR) tests, multiple stress creep recovery (MSCR) tests, and bending beam rheometer (BBR) tests, under varying crumb rubber contents (20%–60%). Results showed that M-CRMA exhibited optimal performance at a 50% crumb rubber content, significantly improving high-temperature stability, durability, and moisture resistance, although the enhancement in low-temperature cracking resistance was limited. This research provides an effective approach for preparing high-content CRMA and demonstrates considerable potential for engineering applications.