Impact of partially replacing natural stone coarse aggregates with crushed burnt clay brick aggregates on the slump and compressive strength of concrete

Abstract

ABSTRACT This study project was aimed at assessing the impact of partially replacing natural stone coarse aggregates with crushed burnt clay brick aggregates on the slump and compressive strength of concrete. Burnt clay products from PAN brick and tiles manufacturers limited were obtained and crushed to make the crushed brick aggregates. The replacements were in percentages of 25, 50, 75 and 100% with 0% as the control mix. The first objective of the study was to assess the suitability of crushed burnt clay bricks aggregates in the production of concrete of compressive strength 25N/mm2 . Other objectives of the study included determining water absorption, specific gravity of crushed burnt clay brick aggregates, unit weight of concrete with different replacements of brick aggregates and the effect of varying percentages of crushed burnt clay brick aggregate on the slump and compressive strength of concrete at 7, 14 and 28 days. M25 grade concretes were prepared for the control mix of 0% replacement of crushed burnt clay brick aggregates and for other mixes with varying percentages of crushed burnt clay brick aggregates and tested to compare the slump, unit weight and compressive strength. The compressive strength and workability of the concrete made from partially replacing stone coarse aggregates with crushed burnt clay brick aggregates was enhanced by coating the brick aggregates with fly ash and using a water reducing admixture. A total number of 45 concrete cubes were tested for unit weight and compressive strength at 7, 14 and 28 days The test results obtained for conventional concrete were compared with those for the concrete obtained from replacing natural stone aggregates with crushed burnt clay brick aggregates, the results show that the compressive strength reduced by 5, 9, 19 and 37% for 25, 50, 75 and 100% respectively and the slump reduced by19, 33, 49, and 59% for 25, 50, 75 and 100% respectively giving an optimum value for compressive strength and slump at 50% replacement.