Effective Economic Combination of Waste Seashell and River Sand as Fine Aggregate in Green Concrete

Abstract

This research elucidates the idea of eco-friendly concrete and highlights the benefits attainable from its effective practice towards sustainable construction materials. The design mix employed a water/cement ratio of 0.5, a concrete mix ratio of 1:2:4, varying percentages of 2.5 mm seashells, 4.75 mm river sand as fine aggregates, and granite 20 mm as coarse aggregates. Laboratory tests showed that the true slump was achieved for all mixes as a decrease in workability was observed with seashell additions. Compressive strength declined with increasing percentages of seashells at all curing ages (7, 14, and 28 days). No seashell-modified mix achieved the target strength for concrete grade 25. Nevertheless, the 10 and 20% seashell blends obtained strength requirements for concrete grade 20. The splitting tensile strength results indicated that 10–50% seashell-concrete blends yield acceptable splitting tensile strength after 28 days of curing. Correlation and regression analysis showed that compressive strength has a high negative correlation with seashell percentage and a significant correlation with splitting tensile strength. However, no significant correlation was seen between seashell percentage and splitting tensile strength. Models were further developed for predicting workability, splitting tensile strength, and compressive strength, with seashell percentage data. Green concrete production, which reutilizes waste seashells should be promoted, bearing in mind its environmental sustainability and economic prospects.