LOCUST BEAN POD SOLUTION (LBPS) AS A NATURAL ADDITIVE FOR IMPROVING THE STRENGTH CHARACTERISTICS OF NON-LATERITIC SOIL (NLS) SUBGRADE

This study investigates the effectiveness of locust bean pod solution (LBPS) as a natural additive for stabilising non-lateritic soil subgrades. The soils strength characteristics were evaluated through California bearing ratio (CBR) and unconfined compressive strength (UCS) tests: the results show that the addition of locust bean pod solution improves the soils strength, with optimal results achieved at 8% solution after 21 days curing. The California bearing ratio values for both soaked and un-soaked conditions ranges from 5,4- 96.35%, exceeding the minimum requirement of 5% for subgrade materials, the unconfined compressive strength value fell within the stipulated range of 750-1500kN/mm2 after 7 days of curing. The optimum moisture content and maximum dry density of the stabilised soil were also evaluated with results indicating improved soil density and stability. The study’s findings suggest that locust bean pod solution can be used as a sustainable and cost-effective alternative to traditional soil stabilisers. Thus, the use of the locust bean pod solution can potentially reduce the environmental impact and cost associated with soil stabilisation, while improving the strength and stability of non-lateritic soil subgrade. As such, the study recommends further exploration of locust bean pod solution as a viable additive for soil stabilisation in civil engineering applications.