Effect of Biorejuvenator on Postconsumer Recycled Plastic Modified Asphalt Mixes: Laboratory Investigation and Environmental Impact Analysis

Incorporation of postconsumer recycled (PCR) plastics in asphalt mixes is reported to improve the mechanical performance of asphalt mixes when used at a lower dosage. However, overstiffening of asphalt mixes due to the addition of higher amounts of plastic has been a serious concern. To this end, this study aims at increasing the percentage of plastic in asphalt mixes by incorporating a biorejuvenator. For this purpose, a control mix was designed using the balanced mix design (BMD) approach and then modified with two different types of PCR plastics, namely low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). The asphalt mixes were then further modified by adding a biorejuvenator. The volumetric properties were determined, and the mechanical performances (rutting, cracking, and moisture-induced damage resistance) of the asphalt mixes were evaluated using the Hamburg Wheel Tracking (HWT) and Indirect Asphalt Tensile Cracking Test (IDEAL-CT). The optimum dosage of plastics was determined using the BMD criteria. The optimum dose of LDPE was found to be 1.5% with 2% waste cooking oil (WCO)-modified binder. In addition, environmental impact analyses were performed on the plastic-modified mixes. A significant reduction in greenhouse gas emission was observed from the use of plastic in asphalt mixes. A minimum of 7.5% reduction in greenhouse gas generation was found by using optimum LDPE and WCO-modified asphalt mixes.