Roadway carbon emissions and intensities with pavement thickness incorporated

Studies calculating the carbon emissions or the emission intensity per functional unit (FU) of road projects have focused on one or only a few cases without considering the influence of pavement thickness on carbon emissions and intensity. This study investigated the carbon emissions of roadways and explored the effect of pavement thickness on area-based carbon emission intensity. It classified the attributes of 23 road cases; calculated the carbon emissions of roadway; identified the factors affecting carbon emissions; and finally evaluated emission intensities by area. The average carbon emissions for the 23 cases were 16,368 tCO2e, and the carbon emission intensity by area was 276 kgCO2e/m2. Emissions differed by road type, structure, and materials. The correlation coefficient between road area and carbon emissions was 0.412, whereas that between pavement volume and carbon emissions was 0.885. Thus, pavement volume is a more suitable FU for representing carbon emissions for road projects compared with pavement area. The carbon emissions per square meter were found to be up to 128.6% greater or 67.3% smaller when pavement thickness was incorporated into the calculation. Thus, estimated emission intensity varies widely depending on whether pavement thickness is incorporated.