INVESTIGATION OF THE PROPERTIES OF COARSE AGGREGATE IN CONCRETE PRODUCED FROM UNHEATED QUARRY AGGREGATE AND HEATED LOCALLY SOURCED AGGREGATE

Coarse aggregate is an essential constituent of concrete, influencing its strength, durability, and workability. In some quarrying operations, heating is applied to rock masses to facilitate easier extraction and breaking. This study investigates the properties of coarse aggregates sourced from two different production methods: Unheated crushed quarry aggregates and heated locally soursed crushed aggregates. The heated aggregates were obtained from Gusau Bungudu Road (Kwanar Gero), where traditional heating is used to fracture rock before extraction. The unheated aggregates were collected from Kwatarkwashi, where crushing is performed without heating. Both sources lie within the same local government area to minimize geological variation. Laboratory tests conducted in accordance with British Standards (BS) included: water absorption (BS 812-2:1995), aggregate impact value (BS 812-112:1990), slump test (BS EN 12350-2:2019), and compressive strength of concrete cubes (BS EN 12390-3:2019) at curing ages of 7, 14, and 28 days. Results showed that unheated aggregates had lower water absorption, higher resistance to impact, and greater compressive strength than heated aggregates, though workability was slightly reduced. These findings suggest that unheated quarry aggregates are more suitable for structural applications where strength and durability are the primary concerns. However, adjustments in mix design may be needed to improve workability when using heated aggregates.