LABORATORY AND FIELD EXPERIMENTATION ON THE USE OF CEMENT AND CALCIUM CARBIDE RESIDUE FOR STABILIZATION OF LATERITIC SOIL

Abstract

A fine lateritic soil collected at Lapai-Gwari along Talba farms, Niger State, Nigeria, was collected using the method of disturbed sampling. The soil was characterized and treated with cement and calcium carbide residue (CCR). The untreated lateritic soil and lateritic soil treated with 4 and 4% cement which was admixed with 0 and 2% CCR each. Compaction tests and California Bearing Ration (CBR) tests were carried out in the laboratory to evaluate the laboratory MDD and OMC as well as the laboratory CBR. The soil was divided into category A (soil treated with 4% cement and 2% CCR), category B (soil treated with 4% cement alone) and category C (soil treated with 0% cement and 0% CCR). These three categories of soil mixtures were constituted with their predetermined moisture contents and place on a road at three different sections (A, B and C). A light weight roller was used to compact the soil mixes of two lifts at 150mm thick each. The roller was allowed enough passes until the laboratory predetermined MDD was achieved. In-situ densities were evaluated using sand replacement method while in-situ CBR was evaluated using dynamic cone penetration (DCP) tests after 1 day, 7, 14, 28, 60 and 90 days. Result revealed that laboratory MDD and In-situ densities were observed to be in agreement. However, the laboratory CBR and field in-situ CBR showed wide differences. The in-situ CBR values were observed to increase with increase in curing days which confirms the action of the chemicals used in the stabilization. Based on the results obtained, the use of 4% cement plus 2% CCR is recommended for the treatment of Lapai-Gwari laterite for use as base material. The use of CCR as stabilizing agent will ensure economy in road construction, while providing an effective way of disposing CCR which has negative impact on the environment.