Geological and geotechnical assessment of natural sands in Ilorin, Nigeria

Abstract

The quality of aggregates used in plastering mortar contributes to its quality. This work evaluates the suitability of two grades of sand, sharp sand collected along active/old river courses and plastering sand collected from burrow pits, as plastering materials. X-ray diffraction and X-ray fluorescence analysis were used to access their mineralogy, major, minor, and trace element components. Grain size distribution analysis, natural moisture content, specific gravity, Atterberg limits, matric suction and permeability tests were also carried out on the sand samples. In both sands, silica (SiO2) content was more than 80%. The plastering sand exists at a higher natural moisture content than the sharp sand. The fines modulus ranges from 1.79 to 2.06 and 0.76 to 1.44, respectively, in sharp sand and plastering sand. The permeability coefficients and matric suction of sharp sand are larger than those of plastering sand. This implies that sharp sand will allow easier water passage through its pore spaces, therefore tending to exist in a dryer state than plastering sand. Sharp sand may be suitable for plastering because the test results are within the acceptable limits for good plastering materials according to national and international standards for good plastering sand.