Abstract
The increasing accumulation of mangrove clam (Polymesoda erosa) shell waste in coastal communities presents environmental challenges and highlights the need for sustainable waste utilization strategies. This study aimed to develop and evaluate low- cost coastal bricks incorporating crushed mangrove clam shells as a partial replacement for coarse aggregate and to determine their physical, mechanical, and durability properties at varying particle sizes. An experimental research design using a Completely Randomized Design (CRD) was employed. Five treatments were tested: crushed mangrove clam shells sieved through No. 10 (2.0 mm), No. 18 (1.0 mm), No. 30 (0.6 mm), and No. 80 (0.18 mm) mesh sizes, and a positive control consisting of pure concrete bricks. The developed bricks were subjected to physical property evaluation (color, texture, weight, and density), mechanical testing (compressive and flexural strength), and durability assessment through water absorption testing. Morphological analysis showed that large-sized mangrove clams comprised 66.67% of the collected specimens and exhibited the largest shell dimensions and shell weight. The incorporation of crushed mangrove clam shells did not significantly affect the color, texture, weight, and density of the developed coastal bricks (P > 0.05). However, significant differences were observed in compressive strength, with bricks containing the finest shell particles (0.18 mm) producing the highest mean compressive strength of 12.650 MPa, significantly higher than the pure concrete control (6.923 MPa) at the 5% level of significance. Flexural strength did not significantly differ among treatments (P
> 0.05), although shell-containing bricks generally exhibited higher mean values than the control. Water absorption differed significantly among treatments (P < 0.01), with bricks containing 0.6 mm shell particles exhibiting the lowest water absorption value (5.93%). The findings demonstrate that waste mangrove clam shells can be effectively utilized in coastal brick production while promoting sustainable waste management. Shell particle size significantly influenced compressive strength and water absorption, with smaller particle sizes producing higher compressive strength and lower water absorption values. These results highlight the potential of mangrove clam shell waste as an environmentally sustainable alternative material for coastal brick manufacturing.
