Reinforcement of Compressed Stabilized Earth Blocks With Biochar Resulting From Use of Agro-industrial Waste

Over the past few decades, the transformation and utilization of materials obtained from agricultural residues as a circular economy strategy have been extensively discussed. Rice husk has received special attention due to the presence of biogenic oxides or biosilica (Gomez-Vazquez et al., 2022; Shafigh et al., 2014; A. B. Souza et al., 2021). This study aimed to evaluate the technical feasibility of using rice husk biochar, a by-product of bioenergy utilization of this agroindustry waste, by developing a multi-factor statistical analysis during the formulation of compressed stabilized earth blocks (CSEB). A central composite experimental design was implemented to examine the contribution of factors such as the percentage of biochar (2.5–17%) and drying temperature (40–100°C) of the CSEB on its mechanical properties. The ANOVA analysis and response surface evaluation demonstrated that biochar up to 14.5% could be added while maintaining a minimum strength of 2MPa. Moreover, the drying temperature significantly affected the mechanical strength of the CSEB, and a complex interaction between clay and biochar was observed, allowing for high mechanical strength and adsorption capacities of the CSEB simultaneously.