Effect of guinea-corn husk and saw-dust ash on the mechanical and microstructural properties of interlocking concrete block

Interlocking concrete blocks have gained significant attention in sustainable construction due to their inherent advantages, including reduced mortar requirements and ease of assembly. This study investigates the influence of incorporating Guinea-Corn Husk Ash (GCHA) and saw-dust ash (SDA), on the mechanical and microstructural properties of interlocking concrete blocks. Concrete mix proportions were established with a mix ratio of 1:2:4 (cement-GCH and SDA), and a water-to-cement (w/c) ratio of 0.6. The aggregates, GCHA, SDA, and granite, underwent sieve analysis to determine particle size distribution in accordance with BS 812-103.1standards. Manual concrete mixing was carried out following the procedures outlined, and the resulting concrete mixes were poured into plastic molds and subsequently placed in a curing room at a temperature of 27 ± 5 oC. The concrete samples treated with cement and subjected to Scanning Electron Microscope (SEM) analysis at different magnification rates (x8000, x9000) and resolutions (10 µm, 50 µm, 100 µm) for a curing period of 56 days, were then analyzed. For the elemental composition of the cement samples, the control sample indicates that calcium is the major element in ordinary Portland cement, constituting 69.10 wt%. However, for samples with blended cement of guinea-corn stalk and sawdust ash, calcium remains the major element but with varying percentages of 60.30, 40.00, 50.00, 56.15, 50.00 wt%, respectively. The results suggest that the addition of GCHA and SDA with cement leads to a decrease in calcium composition, potentially impacting construction.