THE EFFECT OF UGWUEGU SANDSTONE ON THE MECHANICAL PROPERTIES OF CONCRETE

Abstract This research investigates the Effect of Ugwuegwu Sandstone as a Coarse Aggregate on the Mechanical Properties of Concrete in Afikpo North, Ebonyi State, Nigeria. Concrete cubes were cast using conventional aggregates (½ inch gravel, 1 inch gravel and ½ inch local, 1 inch local) and Ugwuegwu sandstone, and tested for compressive strength at curing ages of 7, 14, and 28 days. The average compressive strength results show that concrete with conventional gravel aggregates attained higher strengths, while Ugwuegwu sandstone concrete recorded comparatively lower values at all ages. At 28 days, gravel concretes achieved compressive strengths above 25 N/mm², while Ugwuegwu sandstone concrete achieved approximately 19.41 N/mm², which is below the minimum recommended for structural grade concrete. The lower strength performance of the sandstone is attributed to its porous structure and weaker interfacial bonding with cement paste. However, its availability, low cost, and ease of quarrying make it a potential material for non-structural applications such as paving blocks, mass concrete, and low-load bearing works. The study concludes that Ugwuegwu sandstone can be used as a partial or alternative aggregate in concrete where strength requirements are moderate, but further durability studies are recommended before large-scale adoption.