Environmental impact and comprehensive value assessment of epoxy-based binder for asphalt pavement recycling based on LCA and LCC

Epoxy-based materials are beginning to be used in asphalt pavement recycling technology to enhance the performance of recycled asphalt mixtures. However, in the context of low carbon and sustainable development, whether epoxy recycling technology has economic and environmental benefits has become a widespread concern. This study developed new recycling technologies with 100% recycled asphalt pavement (RAP) utilization using relatively inexpensive epoxy asphalt and waterborne epoxy resin as binders. The road performance of the different mixtures was investigated using AASHTO tests. The economic and environmental benefits were analyzed using the ‘cradle-to-gate’ LCA and LCC methods. The results indicated that epoxy asphalt-recycled warm-mix asphalt (RWMA) and waterborne epoxy-recycled cold-mix asphalt (RCMA) exhibited excellent pavement performance. Their moisture sensitivity and low-temperature performance were comparable to traditional reclaimed hot-mix asphalt (RHMA). The dynamic stability at the high temperature of RWMA and two RCMAs was improved by 1015.1%, 709.7%, and 765.9% over RHMA. LCA analysis shows that RWMA, and the two types of RCMAs contribute to approximately 44.8%, 55.4%, and 52.3% reduction in energy saving, and 39%, 39.7%, and 38.4% of greenhouse gas emissions, compared with regular RHMA. RCMAs are cost-effective, and the costs of RHMA and RWMA are 5.5% and 60.4% higher, respectively. Comprehensively considering performance, cost, and environmental impact, epoxy-based binders demonstrate potential for pavement recycling applications.