Assessment of CO2 Emission Reduction in Road Construction Using Recycled Concrete Materials

Abstract

Climatic change is a grave threat for human life. After the industrial revolution, the rapid increase in atmospheric greenhouse gases, most notably carbon dioxide (CO2), is primarily responsible for global warming over the past 50 years. Particularly, the high emission of CO2 in civil works becomes a critical issue for urban development and construction due to its high energy demand and fuel consumption. Therefore, it is important to make the effort to reduce the CO2 emission from each quality construction project. Based on product-category rules (PCR), two major road construction materials, asphalt concrete and cement concrete, were studied in this paper. Carbon footprints of the studied materials were examined through the cradle-to-gate life cycle assessment (LCA) from raw material mining and transportation to factory manufacturing. Our results showed that the primary factor controlling the CO2 emission factor of recycled concrete is the proportion of recycled materials in the mixture of cement and fine-grained aggregates. The amount of CO2 emission of road construction using recycled asphalt concrete was 4.533 kg CO2 less than those using normal asphalt concrete.