The Suitability of Granite and Granite-Gneiss of part of Minna Sheet 164 SW North-Central Nigeria as Construction Aggregates

Abstract

Geotechnical tests were performed on granite and granite-gneiss rock samples of parts of Minna to know their suitability as construction aggregates. Eight rock samples were selected for porosity test, impact value, specific gravity and absorption capacity. The average porosity of the samples is 0.21, 0.12, 0.30, 0.10, 0.25, 0.25, 0.24 and 0.11 respectively for L1, L14, L15, L19, L21, L23, L25 and L29 which shows they are normal except L15 with a high porosity. Average impact value of the samples show they are suitable for wearing surface course in road and bridge construction, except samples L14 and L19 with average impact value of 32.8 and 34.9 respectively making them suitable only as bituminous macadam (maximum value = 35%). Sample L1 is not suitable as construction aggregates because it exceeds the maximum value specified for that purpose. The average specific gravity of the rocks are L1=2.68, L14=2.65, L15=2.65, L19=2.67, L21= 2.63, L23= 2.71, L25=2.65, and L29=2.69 respectively and which make them suitable as normal weight materials for construction. The average absorption capacity values of the rock samples are 0.20%, 0.20%, 0.50%, 0.10%, 0.25%, 0.10%, 0.50% and 0.20% respectively for samples L1, L14, L15, L19, L21, L23, L25, and L29. All testing followed the respective ASTM standards.