Influence of Rice Husk Ash Fines on Geotechnical Properties of Lime Stabilized Lateritic Soil

Abstract

Different fines of rice husk ash (RHA) are typically used as a binder for soil stabilization. This study aims to assess the performance of RHA fines as a binder with lime in the improvement of plasticity and compaction characteristics of stabilized soil. Consistency limits, particle sieve analysis, and compaction tests were conducted on the natural lateritic soil, while consistency limits and compaction tests were conducted on the stabilized lateritic soil. The tests conformed to BS 1377 (1990). The chemical compositions of the RHA were assessed. Lateritic soil samples were mixed with lime in the proportions of 2, 4, 6, 8, and 10% by weight of dry soil. Plasticity Index (PI) was used as the determinant of optimum performance of lime-stabilized lateritic soil and this was obtained at 8% of lime addition. Thereafter, binder ratios (Lime: RHA) of 0:8, 2:6, 4:4, 6:2, and 8:0 were employed in the blending of the lateritic soil. The Plasticity Index (PI) of the stabilized soil were generally lowered to 7.82%, 21.36%, 18.97%, 19.71%, 15.03% when stabilized with BR2:675μm, BR4:475μm, BR6:275μm, BR2:6300μm and BR6:2300μm respectively. All binder ratios containing both lime and RHA size of 75 μm reduced the PI. Also, the effect of all binder ratios containing both lime and all RHA sizes showed increment in the Maximum Dry Density (MDD). Similarly, soil stabilized with BR2:6150μm, BR4:475μm, BR4:4150μm, BR4:4300μm, BR6:2150μm and BR6:2300μm offered a lowered OMC. 75μm RHA and BR4:475μm had the potential to improve Lime-RHA stabilized lateritic soil mixture especially for road application.