TITLE:
Performances of Clay Soils Stabilised Using Recycled Glass Powder and Cement for Sustainable Construction
AUTHORS:
Sylvain Ndinga Okina, Sedel Okassa Mouele, Alain S. Ndongo, Louis Ahouet, Alexis Nkombo
KEYWORDS:
Eco-Materials, Recycled Glass, CEB, Soils Building, Earth Construction
JOURNAL NAME:
Geomaterials,
Vol.16 No.4,
October
10,
2026
ABSTRACT: Clay soils are abundant and readily available in the Congo; their main limitation for housing construction lies in their high sensitivity to water and to cycles of wet and dry conditions. Stabilising these soils using recyclable waste is now an ideal alternative for producing environmentally friendly materials for the construction of sustainable housing. The methodology of this experimental study involves, on the one hand, incorporating recycled glass waste powder into clay soils sourced from the Samba Alphonse (SA) and Mouyondzi (MY) deposits. Secondly, it involves combining this recycled glass powder with 2% cement in order to improve the properties of these soils and assess their potential for use. Two types of soil had to be identified and 14 samples (SA soil) and 15 samples (MY soil) characterised, mixed with different percentages of glass powder (10, 15, 20, 30, 40, 50%). The results show a significant improvement: a reduction in the plasticity index from 17.5% to 8% (SA) and from 14.4% to 10.8% (MY), an increase in dry density from 1.98 t/m3 to 2.03 t/m3 (SA) and from 1.94 t/m3 to 2.01 t/m3 (MY). These physical and mechanical properties are enhanced by chemical reactions between the amorphous silica present in the glass or cement and the clay minerals, which can help to improve the material’s durability. Both stabilised soils are suitable for the production of compressed earth bricks (CEB) and adobe bricks, which are needed for the construction of sustainable housing in developing countries.