Petrographic and geotechnical evaluation of Ogwashi-Asaba ferruginised sandstone, Niger Delta, as aggregates for construction

Abstract

The need to reduce the high cost of long-distance haulage of aggregates has necessitated the search for suitable aggregates close to the construction site(s). The petrographic and geotechnical properties of Ogwashi-Asaba ferruginised sandstone were investigated to ascertain their utility potential. The petrographic, physical, and mechanical properties investigated include; the modal composition, texture, packing density, degree of interlocking of grains, specific gravity (SG), water absorption capacity (WAC), aggregate crushing, aggregate impact, and Los Angeles abrasion values. Which were determined according to BS and ASTM standards. The percentage of iron (Fe2O3) was determined by fusion inductively coupled plasma (FUS-ICP). The results show the mean value of quartz as 59.4%, sub-angular to angular shape, medium, medium-coarse, and coarse-grained with sutured, concavo-convex, and long contacts. The mean values for the S.G., WAC, ACU, AIV, and LAAV are 2.68, 4.80%, 53.76%, 41.99%, and 50.12% respectively, and 17.8% for Fe2O3. The medium-grained sandstone is preferred because of its relatively higher quartz percentage, more sutured contacts, and a greater degree of grains interlocking. Fe2O3 in sandstone has a strong negative correlation with AIV and ACV. This implies that Fe2O3 in sandstone will influence strength in sandstone thereby enhancing its utility potential. Though the ferruginised sandstone may be suitable as base course material in high-density traffic roads, it can be utilized as sub-grade and sub-base materials in low-density traffic roads.