Preparation and investigation on terminal blend asphalt binders with high content of activated crumb rubber

Abstract

ABSTRACT Crumb rubber (CR), as a recycled rubber product manufactured from scrape tires, has been diffusely applied in asphalt binder for modification due to the environment benefit and performance improvement. To improve the content of CR and maintain the road performance of asphalts, CR was first treated with waste oil and then activated using microwave, named as waste oil pre-expanded and microwave activated CR (PMACR). Subsequently, the high-content (50–70%) PMACR-modified asphalts were prepared using terminal blend (TB) process. The components and microtopography of three CRs were investigated by Fourier Transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) tests. The rheological properties, high- and low-temperature performances, fatigue resistance, cohesion characteristic, storage stability of asphalts with various PMACR contents were examined. The results demonstrate that the high-content PMACR-modified asphalts are successfully manufactured in the laboratory, in which the PMACR content is approximately 70% by weight of matrix asphalt. With the increase of PMACR, the high- and low-temperature performance, fatigue resistance of TB PMACR-modified asphalts are greatly improved. When the content is up to 60%, the softening point difference of top and bottom of asphalt is less than 2.5 °C and the viscosity value of less than 2.5 Pa·s at 180 °C, which indicates high-content PMACR-modified asphalts pose sound compatibility and workability.