Sustainable Stabilization of Lateritic Soils Using Industrial Residue Grits: Mechanical and Microstructural Insights

Abstract

This study investigates the potential use of industrial grits waste, both alone and in combination with Portland cement, as a sustainable stabilizing agent for lateritic soils. Grits, a by-product of the pulp and paper industry with a high calcium oxide content, was characterized using laser granulometry and thermogravimetric analysis. The soil and mixtures were subjected to physical characterization and mechanical performance tests, including compaction, unconfined compressive strength, and consolidated undrained triaxial tests. Additionally, pH measurements, X-ray diffraction, and scanning electron microscopy analyses were conducted to assess the physicochemical mechanisms of stabilization. The incorporation of grits, either alone or combined with cement, significantly improved the mechanical properties of the soil, promoting increases in compressive and shear strength, porosity reduction, aggregate formation, and microstructural densification. Mixtures with 5% and 10% grits showed the best performance, while higher content resulted in reduced reactive efficiency due to the excess of inert particles. Stress–strain behavior generally exhibited a brittle failure pattern, characteristic of stabilized soils. The effective cohesive intercept increased by approximately 250% in mixtures containing 5% and 10% grits and by 46% in the mixture with 15% grits, compared to the soil alone, indicating the formation of a cohesive matrix. The use of grits proved to be a viable and environmentally advantageous technique, representing a sustainable alternative for the stabilization of lateritic soils, contributing to the valorization of industrial residues and to the reduction of CO 2 emission potential in geotechnical stabilization works.

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