Comparative environmental assessment of wet and dry carbonation for construction materials using an LCA approach integrating CO2 sequestration kinetics

[Geoengineering News]

https://www.sciencedirect.com/science/article/abs/pii/S0950061826019525

Authors: Zhenghao Wang, Zoe Li, Pengxiao Zhou 

https://doi.org/10.1016/j.conbuildmat.2026.147044

13 June 2026

Highlights

●Environmental impacts of wet and dry carbonation of BOF slag are systematically compared.

●Wet carbonation shows a greater net GWP reduction potential than dry carbonation.

●The influence of regional electricity mixes on carbonation-related GWP is quantified.

●Carbonated slag utilization in cement paste and other construction materials is evaluated.

●The relationship between GWP and reaction time was evaluated by integrating LCA with carbonation kinetics.

Abstract

Carbonation is an effective approach for treating and utilizing steel slag, enhancing slag’s stability while contributing to CO2 emission reduction. This study evaluated the environmental impacts of wet and dry slag carbonation and the subsequent utilization of the carbonated products through life cycle assessment. The assessment examined multiple scenarios, including a baseline scenario in Ontario, Canada, where carbonated slag was produced and incorporated into cement paste, as well as additional scenarios reflecting regional variations in electricity mixes and construction material applications. Furthermore, the study integrated carbonation kinetics with Global Warming Potential (GWP) calculations. Results show that producing and transporting one tonne of carbonated slag via wet carbonation achieved a negative GWP of −94.4 kg CO2-eq. Incorporating the carbonated slag into cement paste reduced the GWP from 940.3 to 733.6 kg CO2-eq per tonne. Scenario analysis revealed that, under identical conditions, the electricity mix in Maharashtra, India would lead to 234.5 kg CO2-eq higher emissions per tonne of carbonated slag compared to that of Ontario. Among the evaluated construction materials, slag-blended bricks achieved the highest GWP reduction (55.56%). Coupling carbonation kinetics with GWP calculations demonstrated that GWP decreased with reaction time, reaching its minimum at 105 min. These findings provide guidance for optimizing steel slag carbonation processes by refining reaction conditions, identifying cost-effective reaction time, and improving slag allocation strategies for sustainable construction.

Source: ScienceDirect