Assessment of Metakaolin Blended Palm Kernel Shell Solid Concrete Blocks as a Sustainable Building Material

The effectiveness of Palm kernel shell (PKS) as a coarse aggregate substitute in metakaolin added solid concrete masonry blocks is examined in this paper. Control solid concrete blocks and Palm Kernel Shell (PKS) added concrete blocks with metakaolin were cast with sizes of 250mm × 200mm × 150mm and a mix ratio of 1:3:6 by varying the water-binder (w/b) ratio in 0.55, 0.60, and 0.65. The blocks were water cured for 28 days before batching, which was done per volume. There were 0%, 5%, 10%, 15%, 20%, 25% and 30% replacements of coarse aggregate with PKS, respectively. Slump tests were conducted on fresh concrete and the blocks were made using solid block making machine. At the end of 28 days curing period, compressive strength tests were conducted on hardened concrete blocks using a compression testing apparatus. The findings indicated that the slump height increased with the water-binder ratio but reduced with the proportion of PKS. For higher substitutions of coarse aggregate with PKS, favourable results are obtained with a w/b ratio of 0.60. According to IS: 2185 (Part 1) - 2005, solid concrete masonry blocks must possess a minimum compressive strength of 5N/mm². Although several samples meet this requirement, the optimized sample in terms of strength was a block with 25% PKS replacement at a w/b ratio of 0.60. The density, water absorption, and initial rate of absorption of the optimized sample were found to be lower than those of the control samples, however, both samples exhibit a similar pattern in alternate wetting and drying tests.