Guayule Plant Extracts as Recycling Agents in Hot Mix Asphalt with High Reclaimed Binder Content

Abstract

Increased usage of reclaimed asphalt pavement (RAP) and reclaimed asphalt roofing shingles (RAS) in hot mix asphalt (HMA) has increased the need for recycling agents intended to return the age-hardened RAP/RAS binder (asphalt) to its original state. However, a decreasing supply of liquid asphalt and concerns over adverse health effects when using petroleum-based recycling agents have created the opportunity for bio-based solutions to these issues. The guayule plant is a woody perennial shrub that is native to areas of the southwestern U.S. and is a well-documented source of resin and high-quality rubber. The study objective was to determine the viability of using guayule-based materials as recycling agents in HMAs with high contents of RAP and/or RAS. Of the many guayule-based materials investigated, an acetone-extractable, residual resin in the rubber was shown to be effective in meeting the study objective.