PERFORMANCE EVALUATION OF LATERITIC SOIL AS FILLS IN ROAD PAVEMENT STABILIZED WITH COAL ASH IN SOUTHWESTERN, NIGERIA.

Abstract

This study evaluated the feasibility of using coal ash to enhance the engineering qualities of problematic lateritic soil samples collected from five different locations along the Akure-Ikere Ekiti road in Southwest Nigeria. In the laboratory, soil samples were allowed to air dry for 14 days before analysis. Tests such as liquid limits, plastic limits, plasticity index, shrinkage limits, specific gravity, compaction, and California bearing ratio were conducted on each soil sample. Lateritic soil samples received progressive additions of coal ash at 2% by soil weight, with a range of 2% to 10%. The impacts of Coal ash on the above stated tests were determined based on relevant standard procedures. “Her soil was stabilized by adding different percentages of cement in the range of 3%, 6%, 9%, and 12% by weight.” With the gradual addition of coal ash up to 6% by the weight of the soil, the findings indicate that the stabilized linear shrinkage dropped from 7.9% to 4.1%, the liquid limit from 33.3% to 18.7%, the plastic limit from 19.5% to 16.1%, and the plasticity index from 13.8% to 1.9%. The addition of coal ash also enhances the engineering qualities of the soil, as evidenced by the rise in MDD from 1960 Kg/m3 to 2091 Kg/m3, OMC from 15% to 16.9%, soaked CBR from 13% to 32%, and unsoaked CBR from 28% to 48%. The degree of lateralization in the research area was indicated by the increase in specific gravity, which varied from 2.41 to 2.66. Consequently, coal ash is discovered to be an effective stabilizing agent for lateritic soils.