Efficacy of Class C Fly Ash as a Stabilizer for Marginal Residual Soil
Umar, M. and Alhassan, H. M.
Department of Civil Engineering, Faculty of Engineering, Bayero University Kano, Kano State, Nigeria.
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Two laterites samples known for their deficiency in road construction were used to assess the efficacy of Class C fly ash in improving their engineering properties. The two samples were taken from Danbare and Dausayi localities within Kano Metropolis and the fly ash was sourced from the Nigerian Coal Corporation, Enugu. Preliminary tests on the two samples confirmed their deficiency for use in road construction. The processed fly ash was blended with the laterite samples at 0, 3, 6, 9, 12, 15 and 18%. Hence, the treated soil samples were tested for plasticity, compaction and strength properties. Results obtained revealed reduction in plasticity properties as the fly ash contents increased. Similarly, Maximum Dry Density (MDD) decreased as the fly ash content increased while the Optimum Moisture Content (OMC) of the treated soils increased for the two samples. Peak CBR values of 16 and 35% were obtained at 9 and 15% fly ash contents for samples 1 and 2, respectively. The unconfined compression tests showed considerable improvement in strength properties higher than the values of the natural soils. The peak 7 days strength of 630 and 1410 kN/m2 were observed at 12% and 15% fly ash content for samples 1 and 2, respectively.
Keywords: Residual soil, Stabilization, Class C fly ash, California Bearing Ratio, Unconfined Compressive Strength.