Carbon Emission Calculation Method and Low-Carbon Technology for Use in Expressway Construction

There is a need for a quantitative calculation method for carbon emissions during asphalt pavement construction. In this study, the carbon sources were detected and carbon emission during pavement construction was divided into two parts—the emission resulting from energy consumption and that arising from the volatilization of asphalt mixtures itself. The carbon emission calculation model of energy consumption is presented based on the energy consumption list and calorific value method proposed by the Intergovernmental Panel on Climate Change. The model of the carbon emission from volatilization of asphalt mixtures was introduced based on a combination of on-site inspection data and the greenhouse gas diffusion rate and calculated volume. Finally, high-carbon emission processes and total carbon emissions were obtained, and the corresponding low-carbon technologies were proposed for different types of carbon emissions. The results show that the ratio of carbon emission generated by energy consumption and the volatilization of asphalt mixtures is 3:2; aggregate and asphalt heating are high-carbon emission processes of energy consumption, while asphalt mixture rolling and mixing are the high-carbon emission processes of asphalt mixture. Furthermore, the use of natural gas can control carbon emission in energy consumption; low-carbon asphalt mixtures and warm mixing technology can effectively reduce carbon emission from the volatilization of asphalt mixtures. This study lays a theoretical foundation for green pavement construction.