Comprehensive evaluation of energy consumption and carbon emissions of asphalt pavement recycling technology

To assess the energy saving and emission reduction effects of recycling technology, the quantitative analysis of energy consumption and carbon emission of recycled asphalt pavement is conducted of asphalt mixture production, transportation, paving and compaction. Firstly, the calculation model for energy consumption and carbon emissions of recycled asphalt pavement is established during the construction stage. In addition, the energy consumption and carbon emission of four recycling technologies, including the HCPR, HIR, CCPR and CIR, were compared. Finally, the FCE method is used to evaluate the actual effect of energy saving and emission reduction from the perspectives of the ecological benefit and the economic benefit. The research results indicate the most serious stage of energy consumption is the new material production stage, and the most serious stage of carbon emission is the asphalt mixture production stage of recycled asphalt pavement. Taking the HCPR technology as an example are calculated in detail. The energy consumption of the HCPR technology in the four stages of the construction stage was 17.59 MJ, 344.45 MJ, 228.51 MJ and 25.85 MJ, respectively, and the emissions in the four stages of the construction stage were 1307.89 g, 5971.28 g, 19251.24 g and 1949.82 g, respectively. For different recycling technologies in the construction stage, the energy-saving ratios of HCPR, HIR and CCPR are 13.62%, 9.61% and 19.24% respectively when compared with the typical scheme, which have a certain energy-saving effect. However, the energy consumption of CIR reduced by 43.63%, which the energy saving effect is most significant. Moreover, the emission reduction ratios of HCPR, HIR and CCPR are 2.3%, 9.23% and 1.01% respectively when compared with the typical scheme, the emission of CIR reduced by 30.76%, so the emission reduction effect of CIR is most significant. Furthermore, the comprehensive evaluation score of the CIR technology with the most significant energy saving and emission reduction effect is 0.8021 in terms of ' ecological benefits ' and 0.8074 in terms of ' economic benefits '. In summary, it is recommended to adopt CIR technology in the engineering project, which can achieve the most significant energy-saving and emission reduction effects.