Economic input-output life cycle assessment of concrete pavement containing recycled concrete aggregate

Abstract

Concrete pavement recycling has become a common practice for many states in the U.S. While material properties and structural performance of pavements with virgin concrete aggregates replaced by recycled concrete aggregate (RCA) have been extensively characterized, very little effort has been made to assess potential sustainability benefits of this application. A life cycle assessment to compare an RCA based portland cement concrete (RCA-PCC) pavement and a plain PCC pavement (i.e., without RCA) from all three aspects of sustainability (i.e., economic impact, social impact, and environmental impact) was carried out using an economic input-output life cycle assessment (EIO-LCA) approach. An inventory of stressors during materials production and construction, use, and end-of-life phases of pavement life cycle was obtained, followed by a life cycle impact analysis using the Tool for Reduction and Assessment of Chemicals and other Environmental Impacts (TRACI). Based on the results, the benefits of using RCA during the materials production and construction phase are invariably achieved for all the sustainability categories, but the RCA-PCC pavement would pose higher negative impacts during the use phase of pavement life. Still, the pavement made with RCA-PCC was found to be generally more environmentally and socially friendly compared to the pavement made with virgin aggregates, especially for the TRACI categories of ecotoxicity, human health cancer, and human health non-cancer. The sustainability benefits of using RCA for concrete pavement application will only be magnified with a growing level of environmental awareness, further diminishment of local virgin aggregate sources, and a rapid increase of landfill tipping costs for construction demolition debris in the future.