Effect of mineral admixture on CO2 emissions and absorption in relation to service life and varying CO2 concentrations

AbstractCarbonation is a critical deterioration phenomenon, particularly for underground reinforced concrete (RC) structures due to the surrounding environment having a high CO2 concentration. This paper presents an evaluation of CO2 emissions and absorption with varying intended service life periods based on actual geometry and mix ratios of concrete for RC underground structures. Four mix ratios of concrete and CO2 diffusion coefficient based micro modelling are considered, and the CO2 emission and storage are evaluated for each step with material production and conveyance. Simulations for the CO2 amount are also performed for varying intended service life periods and CO2 concentrations. As the intended service life increases, the CO2 emission rapidly increases due to the repeated repairs. In order to reduce CO2 emissions, reducing ordinary Portland cement (OPC) by replacing it with a mineral admixture like fly ash (FA) is a crucial point in the initial construction stage, since CO2 storage in use is li...