Geological and geotechnical assessment of natural sands in Ilorin, Nigeria

Abstract

The quality of the aggregates used inplastering mortar contributes to the properties of the mortar. This study evaluated the suitability of two grades of sand – sharp sand collected along active/old river courses and plastering sand collected from borrow pits – as plastering materials. X-ray diffraction and X-ray fluorescence analysis were used to study their mineralogy and 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, the silica content was more than 80%. The plastering sand had a higher natural moisture content than the sharp sand. The fineness modulus ranged from 1.31 to 1.83 and 0.53 to 1.01, respectively, for the sharp sand and the plastering sand. The permeability coefficients and matric suction of the sharp sand were larger than those of the 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. The tested sharp sand may be suitable for plastering because the test results were within the acceptable limits for good plastering materials according to national and international standards.