A life cycle based environmental impacts assessment of construction materials used in road construction

Industrial byproducts such as coal fly ash, coal bottom ash, and recycled concrete pavement (RCP) are being used in considerable amounts as a full or partial replacement of natural aggregates. Studies comparing road construction byproduct materials with natural aggregates are limited. In the present study, a comparison of these byproducts with natural aggregates was carried out with respect to cost, environmental pollutants generated, and energy consumption. Pollutant emission data were aggregated to express results in terms of global warming potential (GWP), acidification potential and various toxicity potentials. For assessment of toxicity potentials, all the toxicities were represented with respect to 1,4 dichlorobenzene. Mixed results were found from the Life Cycle Assessment (LCA) and no single material performed superiorly in all categories. Fly ash and bottom ash were found attractive in cost, GWP, and acidification potential categories. RCP had higher GWP and acidification potential compared to natural aggregates. In toxicity categories, in some cases fly ash and bottom ash had higher; and RCP, in all cases, had much lower toxicity compared to natural aggregates.