INVESTIGATION OF THE PROPERTIES OF CONCRETE WITH BAMA GRAVEL AND CRUSHED SANDSTONE AS COARSE AGGREGATE

ABSTRACT This study investigates the suitability of Bama gravel and crushed sandstone as alternative coarse aggregates in concrete production. The research was motivated by the high cost and scarcity of conventional aggregates in Northeastern Nigeria, and the need to explore locally available materials that can enhance sustainability and reduce construction costs. Preliminary tests were conducted on the materials in accordance with relevant British Standards to determine their physical and mechanical properties, including specific gravity, water absorption, aggregate crushing value (ACV), and aggregate impact value (AIV). Concrete mixes were prepared using varying proportions of Bama gravel and crushed sandstone, and their workability was assessed through slump and compaction factor tests. Mechanical properties of the hardened concrete were evaluated through compressive strength tests conducted at 7, 14, and 28 days, as well as flexural and split tensile strength tests at 28 days. Durability performance was examined using acid effect test. Results showed that Bama gravel improved workability due to its rounded texture, while crushed sandstone enhanced strength and durability because of its angular and rough surface characteristics. The study concludes that crushed sandstone is suitable for structural applications requiring higher strength, while Bama gravel is appropriate for non- structural works. A blended mix of both aggregates is recommended for cost-effective, high-performance concrete in the region. Key words: Bama gravel, Crushed sandstone, Coarse aggregate, Northeastern Nigeria, Specific gravity, Durability