Umudike Journal of Engineering and Technology

In this study, the durability of fat clay stabilised with blends of additives and cement (PC) as subgrade materials was determined. The blends and compositions used were as follow: Drill Cuttings Ash (DCA)-PC (1:1), sand-PC (4:1), and lateralite-PC (2:1). The durability test using CBR procedure yielded values in the range of 24 – 41% after 5 cycles of wetting and drying. This procedure caused instability and radial cracks on the compacted surface of soil-DCA-PC and soil-sand-PC blends respectively after 3 cycles while the compacted surface of soil-lateralite-PC was relatively stable after 5 cycles. The soil-blends were subjected to different curing procedures namely: wrapped and dry; wrapped and moist; not wrapped and moist for 28 days before the Unconfined Compressive Strength (UCS) test. Soil-sand-PC and soil-lateralite-PC developed optimal UCS values of 0.38 MPa and 0.36 MPa respectively after wrapped and dry curing, while soil-DCA-PC had an optimal UCS value of 0.39 MPa after wrapped and moist curing. All the soil-blends responded poorly when exposed to water directly. The durability test using UCS procedure yielded values in the range of 0.11 – 0.18 MPa after 1 cycle. The results showed that stabilised fat clay could be adopted as subgrade material.