STABLIZATION OF HIGH PLASTIC CLAY USING BIOMASS ASH AND GYPSUM WASTE COMPOSITE

Abstract

Industrial waste significantly harmed the environment and natural ecosystems at the same time that industrialization revolutionized production and living standards. Thus, in order to attain the Sustainable Development Goals (SDGs), the United Nations (UN) propose that waste be reduced, reused, or recycled worldwide. The current study focuses on the efficient reuse of biomass Ash waste and crushed gypsum waste. High plastic soils experience expansion and contraction depending on the level of water availability. Biomass ash and gypsum waste has cementations characteristics, hence these waste has the potential to be utilized for the stabilization of such soils. Understanding the impact of crushed gypsum and biomass ash on the mechanical properties of high plasticity clay is the main goal of this study. To investigate the mineralogical and morphological characteristics, microstructural investigation using XRD and XRF of materials was carried out. The binder ratio and curing time were the important variables which were examined in this study. First, Biomass Ash was used to stabilize expansive soil in order to determine the ideal Biomass Ash content based on UCS results. It was determined to be 12.5% and fixed as the study's total binder content. Crushed waste gypsum was used in place of biomass in the binder at ratios of 0:100, 25:75, 50:50, and 75:25 when adding it to the soil. The compaction, plasticity, and strength behavior of soil stabilized using composite binder (Gypsum: Biomass Ash) were investigated experimentally. In highly plastic clayey soil, it was observed that the plasticity index decreased with the addition of gypsum and biomass ash binder. After stabilization using a composite binder, shear strength and unconfined compressive strength (UCS) enhanced. Soil stabilized with biomass ash and gypsum increased by 3.38 times compared with the untreated soil. These experiments have demonstrated that the development of cementitious hydrates, which are created as a result of reaction between CaSO4 and CaO from gypsum and (CaCO3, SiO2 and Al2O3) from biomass ash and soil, and these are responsible for the increase in strength. It is proposed to use a 25:75 gypsum to biomass ash ratio to stabilize high plastic clayey soil. This study has demonstrated the efficacy and environmental friendliness of (Gypsum: Biomass Ash) composite binder in stabilizing high plasticity clayey soil