纳入碳化吸收的多配合比再生混凝土碳足迹核算

Carbon footprint accounting for recycled aggregate concrete with multi-mix designs considering carbonation absorption effect

  • 摘要: 摘要碳足迹的精确核算是推动建筑业能耗“双控”向碳排放总量和强度“双控”的重要依据。针对当前再生混凝土生命周期评价体系存在的局限,研究依据生命周期评价理论,综合考量再生混凝土生命周期内的碳源与碳汇,建立了包含碳化吸收效应的再生混凝土碳足迹通用计算模型。结合太原市实际生产条件,对不同配合比设计的500种再生混凝土与150种普通混凝土进行碳足迹核算,并运用灰色模型方法,明确再生混凝土减排优势与环境效益。结果表明,平均生产1 m3再生混凝土综合碳足迹为326.79 kg(以CO2当量计),较普通混凝土降低13.56%。在减排贡献中,运输距离缩短、碳化吸收增强以及避免垃圾填埋的环境效益分别占2.83%、23.55%与73.62%。基于灰色模型预测,2030年太原市废弃混凝土产量将达到2 675.18万t,按照60%资源化利用率计算可实现碳减排301.8万t。因此,推广再生混凝土应用,对建筑业落实“碳达峰、碳中和”目标具有重要实践意义。

     

    Abstract: The accurate accounting of carbon footprint is crucial for promoting the "dual control " of energy consumption to the "dual control " of total carbon emissions and intensity in the construction industry. To address the limitations of the current life cycle assessment (LCA) framework of recycled aggregate concrete, this study established a general calculation model of carbon footprint that incorporated carbonation absorption effect. The model integrated both carbon sources and sinks throughout the life cycle of recycled concrete, based on the theory of LCA. Combined with the actual production conditions in Taiyuan City, the carbon footprint of 500 recycled aggregate concrete and 150 natural aggregate concrete designs with different mix ratios was calculated. The grey model was employed to clarify the emission reduction advantages and environmental benefits of recycled aggregate concrete. The results showed that the average comprehensive carbon footprint of 1 m3 recycled concrete was 326.79 kg CO2e, which was 13.56 % lower than that of natural aggregate concrete. In terms of emission reduction contribution, the environmental benefits of shortened transportation distance, enhanced carbonation absorption, and the avoidance of landfill accounted for 2.83 %, 23.55 %, and 73.62 %, respectively. Predictions using the grey model indicate that the output of waste concrete in Taiyuan City will reach 26.75 million tons in 2030, achieving a carbon emission reduction of 3.02 million tons at a 60 % resource utilization rate. Therefore, promoting the application of recycled concrete is of great practical significance for the construction industry to implement the “Carbon Peak and Carbon Neutrality” goals.

     

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