Comparative Life-Cycle Assessment of Fast-Curing Methods for Dry-Mix and Wet-Mix Cement Pastes

Abstract

In the precast concrete industry, steam curing is commonly used to accelerate early-stage strength development. Recently, CO2 curing also claims to offer advantages, including mitigating the CO2 burden and anticipating fast curing for cementitious materials. However, to the best of our knowledge, the environmental impacts of these fast-curing methods, compared with standard curing methods, have not been critically justified yet. In this study, a comparative evaluation for both dry-mix and wet-mix cement pastes adopting different curing methods was performed by life-cycle assessment (LCA), which is a commonly used evaluation method for the sustainability of concrete. The environmental impacts of each group, including global warming potential (GWP), ecosystem quality potential (EQP), and human health potential (HHP), were quantified. According to the results, adopting both CO2 or steam curing could reduce greenhouse gas (GHG) emissions by 20%–50% concerning the standard curing for both dry-mix and wet-mix cement pastes. Instead of purified CO2 gas, adopting flue gas for CO2 curing could further reduce GHG emissions by up to 80%. Comparing the GWP/strength ratio over the investigated times, the CO2 curing method exhibited the highest environmental benefits in the first 3 days of curing. Moreover, the use of renewable energy sources and flue gas carbonation will significantly reduce the environmental impact of CO2 and other GHG and add to the sustainability aspect by utilizing renewable resources and waste.