Effects of kapok fiber and bamboo leaves ash as soil stabilizer for expansive soil in road application

Abstract

Clayey soils pose a risk and damage to life and property and are unsuitable for direct engineering application due to their shrink-swell behavior. Pavement cracks and swells are some effects due to soil excessive distress under volumetric changes of its underlying soil. With this, researchers explore different methods to stabilize expansive soils using fibers and cementitious materials. This paper used Kapok Fiber (KF) and Bamboo Leaves Ash (BLA) as soil stabilizers. It seeks to determine the soil classification, test its effects on compaction, investigate the swelling of the soil and change of consistency. Varying concentrations are 0.5% KF and 6%BLA, 0.8% KF and 6%BLA, and 1% KF and 6%BLA by weight of the soil. Test samples undergo sieve analysis, Atterberg limit, compaction, and swell index test. Results revealed that adding fibers to the soil matrix increases maximum dry density (MDD) while optimum moisture content (OMC) varies indirectly. In addition, soil swelling decreases after adding KF and BLA with an optimum design mix of 0.5% KF and 6%BLA. T-test showed that swell index under 10, 30, and 65 blows significantly differ between the control and the optimum ratio. Furthermore, the consistency of the soil changes from highly plastic to low plasticity. Therefore, KF and BLA are good sources of soil stabilizers for pavement subgrade purposes.