Optimizing sustainability in cement production: a combined LCA and TOPSIS approach for evaluating GGBS substitution and alternative energy strategies

Cement production is a major source of global anthropogenic CO₂ emissions. Although many studies evaluate decarbonization options, they often treat environmental impacts, mechanical performance, and economics separately. This approach makes it difficult to make decisions in the real world when there are trade-offs. This study proposes an integrated decision-support framework combining life cycle assessment (LCA), probabilistic cost modeling, 28-day compressive strength evaluation, and multi-criteria decision analysis (MCDA) using the technique for order preference by similarity to ideal solution (TOPSIS) to assess hybrid decarbonization pathways based on biomass wood chips, solar energy, and ground granulated blast furnace slag (GGBS) substitution. Six scenarios were modelled via SimaPro software using Ecoinvent datasets and the CML-IA baseline (v3.10) method. Relative to the baseline (906 kg CO₂ eq./ton), the optimal hybrid scenario (S6), which comprises 50% GGBS substitution integrated with solar and biomass energy, reduced the global warming potential (GWP) by 62.9% to 336 kg CO₂ eq./ton and achieved the lowest human toxicity impact (7.60 × 10² kg 1,4-DB eq.), representing a 97% reduction. Furthermore, the abiotic depletion potential of fossil fuels (ADPf) decreased by 33% (from 4.54 × 10³ MJ to 3.04 × 10³ MJ), quantifying the strategy's reduced reliance on finite resources.