Impact of chemical pre-treatment on crumb rubber for coating property of rubberized asphalt

The aggravation of scrap tires in landfills has negative impacts on human life and the surrounding environment. Therefore, many studies have been conducted to recycle and reuse scrap tires in other areas. One such area is the asphalt pavement, where the crumb rubber (CR) from scrap tires are recycled for asphalt modification. This study focuses on improving the coating properties, and moisture resistance of the rubberized asphalt materials, with the proposed chemical soaking pre-treatment methods. The Fourier transform infrared (FTIR) spectroscopy results revealed significant changes in the CR surface chemistry after pre-treatments, involving the reduction and oxidation of chemical bonds. There was a decrease in the C-H functional group when treated by heating in distilled water and soaking in a potassium permanganate solution. In addition, the intensity of the peaks related to the ether functional group increased when soaking in a potassium permanganate solution. It was further found that the pre-treatment methods enhanced the coating properties of rubberized asphalt mixtures. Meanwhile, the pre-treatment efficacy was notably affected by the binder type. This study demonstrated substantial improvements in the moisture resistance of rubberized asphalt materials following the proposed chemical CR pre-treatment.