EVALUATION OF STRENGTH CHARACTERISTICS OF LOW PLASTIC CLAY SOIL TREATED WITH CERAMIC DUST

Abstract

The effect of ceramic dust addition on the geotechnical characteristics of tropical clay was investigated. In the study, moisture content, particle size distribution, Atterberg limits, specific gravity, compaction tests, Califonia Bearing Ratio (CBR) and Unconfined Compressive Strenght (UCS) were carried out on samples of tropical clay with ceramic dust concentrations of 0 - 40% by dry weight of soil. Result obtained shows the average moisture content of the tropical clay in its natural state was 14.27 %, the tropical clay contain high proportions of clay-silt fractions ( 71.76%) and classified as A-6, having Liquid Limit of 37.8%, Plastic Limit of 22.64% and Plasticity Index of 15.16%. The plastic limit of the tropical clay decreases from 22.64 to 16.8%, the liquid limit decreases from 37.8 to 20.8% and the plasticity index decreases from 15.6 to 3.0% when ceramic dust is increased from 0 to 40% respectively. The liquid limit with 28.4 – 20.8% value range when stabilized with ceramic dust content variation of 20 - 40% respectively is in line as specified by the Nigeria general specification interms of Pavement Design (30%) but the Plasticity Index values (10.3 -3.0%) is below those specified by the Nigeria general specification interms of Pavement Design (13%). The tropical Clay sample had improved the MDD from its natural value using 0 - 20% ceramic dust, but beyound 20% ceramic dust, with further increase of OMC, the amount of voids in soil gots increased and dry density decreased under loading condition. The CBR increased from 14.23, 20.49 at 0% Ceramic Dust content to 20.49, 35.95 at 40% ceramic dust content respectively for 3 and 28 days unsoaked bearing test, but the bearing strength of the soaked tropical clay soil decreased significantly, with the addition of ceramic dust up to 40% content, the CBR decreased from 5.31, 1.52 at 0% to 11.38, 2.56 at 40% Ceramic Dust content respectively for 3 and 28 days soaked bearing test. however, both results indicate that a better CBR was achieved without soaking. therefore, the mechanical strength was improved. The UCS value of the soil sample increased from 18.11, 20.92, 19.62, 28.75 and 24.65 kN/m2 to 18.54, 23.65, 29.64, 50.4 and 41.80 kN/m2 for 0 - 28 days curing when ceramic dust is increased from 0 to 40%.