Investigating the Use of Basalt Rock Powder in the Partial Replacement of Cement in Plain Concrete

Abstract

This research study aimed to determine the optimal replacement ratio of asalt Rock Powder (BRP) that can be used as a supplementary material to partially replace cement in concrete, while achieving maximum compressive strength. asalt rocks sourced from the Mugarama site in Kibaale District were crushed to form powder for use in the study. The physical and mechanical properties of concrete ingredients such as sand and coarse aggregates were evaluated through various tests, including sieve analysis, x-ray fluorescence, and water absorption. The control mix comprised 430kg of cement, 675kg of fine aggregate, 206kg of water, and 1007kg of coarse aggregate. Cement replacement with BRP ranged from 0% to 30%, with concrete cubes of size 50mmx150mmx150mm casted and tested at 7 and 28 days. The results indicated that an increase in the percentage replacement of cement with BRP led to an initial increase in compressive strength, peaking at 43.9MPa at 15% replacement, before gradually declining. Setting time decreased while workability increased with higher BRP replacement percentages. The compressive strength, setting time, and workability remained within acceptable ranges according to literature standards, with the 15% replacement ratio deemed optimal as it exceeded both the control concrete strength of 40.5MPa and the target strength of 35.1MPa.