Study on the Effect of Using Seashells to Partially Replace Large Aggregates in Concrete

Growing concern about resource depletion and global pollution has spurred the development of novel materials derived from renewable resources. Numerous byproducts are used as concrete aggregates. Because seashells acomposed primarily of calcium and have a coarse texture, they can partially replace coarse aggregates, providing a cost-effective alternative to conventional materials such as gravel. Experiments were conducted on both standard concrete and a mixture of concrete and seashells. The percentage of replacements ranges between 3 and 11 percent. Evaluation of the mechanical properties of concrete, including compressive strength, tensile strength, flexural strength, and workability. This research assists in understanding the behavior of concrete blended with seashells and determining the optimal mix ratio. The results indicate that when the rate of gravel replacement by seashells reaches 3%, the compressive strength of concrete reaches its maximum value exceedings the strength of standard concrete samples, and then gradually decreases when the amount of shell replacement reaches 11%. Therefore, seashells can be recommended as a replacement for gravel in concrete mixes, particularly in coastal and near-freshwater regions where shells have been discovered as abundant.