State DOT Life Cycle Benefits of Recycled Material in Road Construction

Abstract

The use of recycled materials in highway construction has the potential to achieve significant benefits affecting the triple-bottom line (environment, prosperity and society). Although state departments of transportation (DOTs) have been in the forefront of introducing recycled materials, they have not been able to clearly convey the benefits in a quantitative and transparent manner using easily understood metrics. What is lacking is direct information on sustainability assessment characteristics, i.e. greenhouse gas emissions, energy and water consumption, and waste generation. To determine the benefits of using recycled materials for DOTs, the Recycled Materials Resource Center (RMRC) is undertaking a project with the objective of providing a tool to quantitatively analyze and report the environmental and life cycle benefits of using recycled materials in highway construction. Subsequently, an analysis of the environmental benefits was conducted using PaLATE, a life cycle assessment (LCA) tool developed with RMRC sponsorship. The LCA analysis of four environmental parameters (energy use, water consumption, carbon dioxide emissions, and hazardous waste generation) showed significant environmental benefits when states used recycled industrial byproducts such as fly ash and recycled roadway materials such as recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP).