Formulation of soil-plant fiber composites for affordable and sustainable housing

Building with earth offers a promising solution for mitigating environmental impacts and promoting sustainable development in Cameroon. However, challenges like unclear soil selection criteria and inadequate strength and durability of unstabilized soils hinder their effective implementation. This thesis addresses these issues by proposing robust soil selection methods and enhancing the strength and durability of earthen constructions through reinforcement with locally sourced cassava stem fibers. Soils were sourced from five deposits, and analyzed by X-ray diffraction (XRD), methylene blue value (MBV), plasticity limits, and granulometric analysis. From these deposits, 50 soil samples with different granulometries were prepared. Compressed earth blocks (CEBs) were made from each sample and evaluated for compressive strength. Additionally, an optimized technique for extracting cassava stem fibers was developed. These fibers were later used to reinforce the CEBs. The research showed that the quantity and nature of fine particles were strong indicators of CEB’s compressive strength. Optimal extraction conditions produced fibers with a tensile strength of 49.89 MPa, and an optimal fiber-soil mix of 3% increased compressive strength by 18% to 138%. Future work will assess the durability, hygrothermal properties, industrialization, and life cycle of these CEBs.