Development of a geopolymer binder based on local raw materials for sustainable construction in Douala, Cameroon: Experimental study and multiscale characterization

This study focuses on the development of a geopolymer binder formulated from abundant local raw materials, namely metakaolin sourced from Douala, recycled glass powder, and calcined oyster shells, within a waste valorization framework for sustainable construction in Douala, Cameroon. The investigation is based on a full factorial experimental design (2 3 ), involving three factors at two levels each, which enables the identification of complex third-order synergistic interactions among the constituent materials. A full factorial experimental design was employed to evaluate the influence of the relative proportions of these materials on the binder’s mechanical (compressive strength), physical (bulk density, water absorption, and porosity), and structural : Fourier Transform Infrared (FTIR) spectroscopy properties. Among the tested formulations, (50% metakaolin, 30% glass powder, 10% calcined oyster shell powder) achieved the highest compressive strength (∼14 MPa) and a water absorption rate of approximately 7.2%, outperforming several conventional cementitious binders reported in the literature. Due to this favorable balance between strength and water absorption, was selected as the optimal mix. These findings highlight the potential of locally sourced and recycled materials for producing eco-friendly and high-performance geopolymer binders, supporting the transition toward more sustainable construction practices in the region.