ABSTRACT
Pavement is a critical part of the highway infrastructure, which deteriorates over time due to the combined effects of material aging, traffic loadings, and climatic factors. As pavement condition deteriorates, vehicle operating costs and adverse environmental impact would increase. As a typical pavement maintenance and rehabilitation (M&R) technique, asphalt overlay is commonly used to restore pavement performance. To make a cost-effective and eco-friendly decision in scheduling asphalt overlays, the effect of asphalt overlay strategy on life-cycle costs and environmental impact needs to be evaluated. In this study, an integrated life cycle assessment (LCA) - life cycle cost analysis (LCCA) approach is proposed to evaluate the life-cycle environmental and economic impacts of different asphalt overlay strategies. A post-overlay roughness progression model is incorporated in the integrated LCA-LCCA analysis. Based on the case study, for 2-in asphalt overlay projects, the application of 30% reclaimed asphalt pavement (RAP) materials would reduce the life-cycle energy consumption, greenhouse gas (GHG) emissions, criteria air pollutants, and economic costs by 1.6%, 1.8%, 13.7%, and 5.8%, respectively. Due to main impact of the use phase, the optimum overlay strategy for achieving the minimum life-cycle energy consumption and GHG emissions is 4-in milling and asphalt overlay with 30% RAP materials. While, due to main impact of production and construction phase, the optimum overlay strategy for achieving the minimum life-cycle criteria air pollutants and costs is 2-in asphalt overlay with 30% RAP materials.
