Sustainable Roadway Construction: Energy Consumption and Material Waste Generation of Roadways

Sustainable roadway construction can be defined as the optimal use of natural and man-made resources during the roadway lifecycle causing negligible damage to the environment. Two means of improving the sustainability of roadways are to minimize the amount of energy consumed for their construction and to efficiently use roadway materials to reduce waste. This paper describes two separate studies conducted to estimate the amount of energy consumed and the amount of waste generated in continuously reinforced concrete pavement (CRCP) and asphalt pavement (AC) roadways from extraction of raw materials through the end of construction. For CRCP, energy is primarily consumed during the manufacture of cement and reinforcing steel, while for AC the majority of energy is consumed during asphalt mixing, drying of aggregates, and the production of bitumen. With regard to material waste, most of the waste generated from CRCP roadways occurs during extraction and production of cement and aggregates. For AC, the extraction and production of aggregates produce the majority of waste. The results indicate that the amount of waste generated is greater for CRCP than for AC. The results of the two studies highlight where sustainable design efforts to reduce energy consumption and waste generation can best be directed in the initial phases of a pavement's life cycle.