Feasibility study on replacing ordinary portland cement with coal gangue-based geopolymer based on LCA and LCIA

Document Type

Article

Publication Date

12-1-2025

Abstract

To investigate the feasibility of replacing traditional ordinary Portland cement mortar (OPCM) with coal gangue-based geopolymer mortar (CGM), a multi-dimensional evaluation approach covering mechanical performance, environmental impact, uncertainty analysis, and life cycle sustainability cost (LCSC) was established. Using 1 m³ of structurally equivalent mortar as the functional unit and a cradle-to-gate life cycle model based on ISO 14040/14044 standards, the differences between CGM and OPCM were quantified in terms of environmental indicators including Global Warming Potential (GWP100), Acidification Potential (AP), and Abiotic Depletion Potential (ADP). Sobol sensitivity analysis and Monte Carlo uncertainty simulation were introduced to explore the influence mechanisms and variability characteristics of key parameters. The results showed that, compared to the ordinary Portland cement system, the coal gangue geopolymer reduces GWP100 by about 43 %, significantly lowering the life-cycle carbon footprint, but it entails higher burdens in the AP and ADP indicators (greater resource consumption and acid gas emissions). Sensitivity analysis indicates that the activators (water glass and NaOH) and coal gangue calcination are the primary driving factors of CGM’s environmental impacts. Uncertainty simulation suggests that the CGM system is relatively stable for GWP100 but shows pronounced variability in the AP and ADP dimensions. Although CGM outperforms OPCM in environmental externality costs, its total LCSC reaches ¥1219 nearly three times that of OPCM primarily due to the high cost of activator materials. In summary, coal gangue geopolymer, as a green building material, has broad application potential in carbon emission reduction and engineering performance, but its sustainable adoption will depend on coordinated efforts such as developing greener activators, optimizing energy pathways, and exploring high value-added applications.

Publication Title

Materials Today Communications

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