Analysing the Structural Merits of Stabilised Earth of Hejaz Region for Construction

Earth as a building material saves energy, manufacturing, and transport costs and reduces environmental pollution if used on-site. Stabilised rammed earth construction (SREC) is ecologically friendly, and earth, as a building material, is cost-effective compared with conventional building materials such as baked clay bricks and concrete masonry units. Despite these benefits, earth building materials are not widely used in construction, suggesting factors limiting the universal adoption of SREC. The literature reveals few structured studies in Saudi Arabia on local soil typology and SREC structural suitability. This research aims to facilitate an easier understanding of Saudi Arabian Hijazi soil types and their structural merits for SREC. To achieve this, this study executed several geotechnical tests and identified and characterised the components of two soil specimens gathered from disparate areas of Hejaz. Three stabilisers, cement kiln dust (CKD), lime (slaked), and cement, were utilised to stabilise the Hejaz soil specimens at different dosages. To assess the structural achievement of the stabilised soil specimens, unconfined compressive strength was evaluated, while wetting/drying test was carried out for durability characteristics. The microstructural developments of stabilised soils were assessed using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis. Cement comparatively proved to be the best stabiliser in terms of strength gain and durability when used to stabilise the Hejaz soils. Lime became the second-best option to stabilise the soils. The SEM micrographs showed significant changes in the microstructure of the cement- and lime-stabilised soils, whereas microstructural changes were minimal in CKD-stabilised soils.