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 infrastructure projects, it has been challenging 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, energyand water consumption and waste generation.
To determine the benefits of using recycled materials for DOTs, the Recycled Materials Resource Center (RMRC) conducted life cycle assessments (LCA) and cost analyses using recycled material quantities provided by six member state DOTs; Georgia (GDOT), Illinois(IDOT), Minnesota (MnDOT), Pennsylvania (PennDOT), Virginia (VDOT) and Wisconsin(WisDOT). PaLATE was used as the LCA analysis tool, after researching other publicly available tools to find an optimal analysis. Four environmental parameters (energy use, water consumption, carbon dioxide emissions and hazardous waste generation) showed percent reductions ranging between 70 and 99 percent 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). The cost analysis indicated potential savings of up to 17 million dollars.
The full thesis may be found in the following file: