EVALUATION OF STRENGTH PROPERTIES OF LATERITIC SOIL STABILIZED WITH CEMENT KILN DUST

Abstract

The production of sub-standard building materials and increase in cost of construction in Nigeria and other developing countries created the need for findings into locally and readily available materials. This study presents the strength properties of Lapai-Gwarri lateritic soil stabilized with cement kiln dust. The scope includes determination of the physical composition, index properties, compaction and strength characteristics of lateritic soil-cement kiln dust mix. All the test procedures were carried out in accordance with British Standard Institution guide. The soil used was obtained at Lapai-Gwarri area of Minna, using the disturbed sampling technique at a depth of 1.5m and was classified according to AASTHO soil classification. From the results obtained, soil sample encountered is classified as A-7-6 corresponding to CL, it is organic silts and organic silty-clays of very low to medium plasticity, gravelly clays, silty clays and lean clays according to AASHTO and USCS system of soil classification respectively. There was a sharp reduction of plasticity index from 22.20% to 11.09%, with increase in quantity of cement kiln dust, the Compaction characteristics of cement kiln dust soil mixed from 0 and 16% gives the Optimum Moisture Content (OMC) values which decreased from 19.69 - 13.02%. The Maximum Dry Density (MDD) increase in value from 1.50 - 1.79 g/cm³. The Unconfined Compressive Strength test at 7, 14 and 28 days of curing for Cement kiln dust of 0, 4, 8, 12 and 16% obtained average values of 170, 369,511, 461 and 347 (kN/m2) respectively. The replacement of 8% cement kiln dust to samples of laterite soil significantly improves its compressive strength characteristics and is considered as the Optimum percentage of cement kiln dust present and reduces construction costs.