Assessment of bamboo leaf ash/lime-stabilized lateritic soils as construction materials

Abstract

This paper evaluates the suitability of stabilized lateritic soils as highway and building (bricks) construction materials and the influence of locally available, cheap and environmental friendly stabilizer on the mechanical strength. The laboratory study employed four lateritic soil samples stabilized with varying amount of bamboo leaf ash (BLA) ranging from 2–8%. BLA was later kept constant at 5% and further added with lime (LSL) ranging between 2.5–10%. This resulted in four different LATERITE–BLA–LSL mix which are mix-1 (20:1:0.5), mix-2 (20:1:1), mix-3 (20:1:1.5) and mix-4 (20:1:2), respectively. The engineering properties of the specimens were evaluated through unconfined compression strength (UCS), California Bearing Ratio (CBR), compressive strength and water absorption. The UCS for the stabilized soils increased as BLA increased from 2 to 6% and the mix increased from mix-1 to mix-4, with maximum UCS observed between 5–6% BLA and mix-3 (7.5% LSL). The soaked and unsoaked CBR values, which ranged between 10–44 and 27–76%, respectively, satisfied the minimum requirement for most building standards for subgrade and sub-base of 10 and 30%, respectively. Results of BLA + LSL bricks indicated that compressive strength increased, while water absorption decreased with increase in the firing temperature and percentage of stabilization, which met the American Standard for Testing Materials (ASTM) standard specification for concrete building bricks. This study has shown the combined optimum improvement of soils and its suitability as subgrade, sub-base and building bricks construction materials.