Microstructural investigation of mortars incorporating cockle shell and waste fishing net

Large amounts of cement and natural aggregates are used annually to produce concrete, and the high energy consumption required for the production of these materials is considered to be a major environmental concern globally. This study investigates the effect of marine wastes, such as cockle shells and waste fishing nets, on the microstructural characteristics of cement-based materials. Crushed cockle shells were used as a substitute for fine aggregates, and ground waste fishing nets were utilized as a fiber replacement to enhance the flexural performance of cementitious materials. Varying amounts of cockle shell and waste fishing net were washed and then used as substitutes for fine aggregates and fibers, respectively, in cement mortar specimens. 10, 20, and 30 wt.-% of cockle shells were substituted for fine aggregates, and the waste fishing net of 1.0% of the total volume was also considered in the mixtures. The compressive and flexural strength of the specimens were measured to examine the effect of marine waste replacement on the mechanical properties of cement-based composites. Scanning electron microscopy, X-ray diffraction, and micro-computed tomography were utilized to investigate the microstructural characteristics of the materials with different substitution ratios of cockle shells and waste fishing nets. The obtained results confirm that properly washed and processed cockle shell powder can be used as an alternative to fine aggregates for conventional cement-based composites, and waste fishing nets can be utilized as a reinforcement for improving the flexural performance of cement mortar.