Stabilization of tropical soil using calcium carbide residue and rice husk ash

Abstract

Many alternative stabilizers have been used in improving soil properties for road applications. However, they were mostly used to complement/partially replace cement or lime. This study seeks to use zero - cement/lime binders in the evaluation of engineering characteristics of soil stabilized with the best binary Calcium Carbide Residue (CCR) and Rice Husk Ash (RHA) treatment possible. The oxide compositions of the soil, CCR, and RHA were determined. The natural soil was subjected to index property tests), compaction, Soaked California Bearing Ratio (SCBR), Unconfined Compressive Strength(UCS), and erodibility. To achieve optimal CCR: RHA ratio, compaction and CBR were used. Atterberg limits, compaction, SCBR, Unconfined Compressive Strength, and erodibility were used to evaluate the engineering performance of the soil stabilized at 2, 4, 6, 8, 10% of the optimum CCR: RHA mix. The RHA is a class N pozzolan while the CCR's CaO of 61% indicates how cementitious the residue is. The soil sample is non-lateritic. CCR: RHA combined ratio of 40:60% offered the best strength and compaction performances. Further, the addition of the optimum CCR: RHA at 2, 4, 6, 8, 10% improved the soil's Plasticity Index (PI). Only 8% addition had a Maximum Dry Density (MDD) of 1770 kg/m3 meeting the AASHTO standard. The addition of CCR: RHA improved the soil's strength properties in terms of UCS and CBR. However, the CBR values generally do not meet the FMWH and AASHTO recommendations for subgrade. Erodibility behaviour showed that increasing CCR and RHA content improves soil durability. CCR and RHA have undoubtedly increased soil strength, but not to the desired level. Therefore, further research should be conducted to determine their compatibility with other stabilizers.