Solid Waste Generation in Asphalt and Reinforced Concrete Roadway Life Cycles

Conserving natural resources for future generations is a common objective of sustainable design and construction. Making use of materials in an efficient manner to improve sustainability is especially applicable on roadway construction projects which can consume significant quantities of materials. An understanding of how best to eliminate material waste on roadway projects requires knowledge of the amount of material waste generated during the various phases of the roadway life cycle. This paper presents a research study undertaken to quantify the amount of materials wasted during the roadway life cycle. The study included life-cycle inventory assessments (LCI) of a continuously reinforced concrete (CRC) roadway and an asphalt concrete (AC) roadway with respect to the waste generated from extraction of raw materials through the end-of-life (EOL) of the roadways. For the CRC roadway, waste was primarily generated at the roadway EOL, accounting for approximately 53% of the total amount of waste generated over the roadway's entire life cycle. A similar trend was observed for the AC roadway in which 59% of the total waste occurred at EOL. For both CRC and AC roadways, waste created during placement of materials is almost negligible compared to that generated during the manufacturing phase and at EOL. The results suggest that application of sustainable concepts (reduce, recover, reuse, and recycle waste) and use of recycled instead of natural materials would help create sustainable roadways.