Alkali-activation of agro-industrial waste for stabilization of lateritic soils

This paper focuses on enhancing the geotechnical properties of lateritic gravelly soil (LGS) through chemical stabilization using an alkali-activated binder produced with sugarcane bagasse ash (SBA) and a sodium hydroxide (NaOH) solution. For this, mechanical strength tests, specifically unconfined compressive strength (qu), and durability tests, including accumulated loss mass (ALM) and volumetric variation (Delta V), were conducted on compacted specimens of the LGS-SBA blends. These specimens were molded with varying concentrations of NaOH solution (ranging from 3 to 10 Molarity) and different SBA content (ranging from 3 to 10 %). The physical-chemical characteristics of the optimal blend were further analyzed through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The results demonstrate that the stabilization of LGS with an alkali-activated binder modifies compaction properties and enhances the mechanical strength and durability of LGS. Hence, a good correlation between qu and ALM was established, enabling the formulation of practical engineering equations to predict the behavior of the blends. Based on the results, it can be concluded that the stabilized LGS exhibits promising potential as an alternative geomaterial for use in subbase/base layers for pavements exposed to harsh climatic conditions in the low-lying Amazon region.