Performance Evaluation of Concrete Using Recycled Coarse Aggregate and Sea Sand as Sustainable Alternatives

With growing environmental concerns over the depletion of natural resources and the adverse impact of excessive sand mining, there is an increasing demand for sustainable alternatives in concrete production. This study investigates the performance of concrete incorporating recycled coarse aggregate (RCA) and sea sand as replacements for natural aggregates, aiming to reduce environmental impact while maintaining strength and durability. Recycled coarse aggregate addresses the waste management issue in construction, while sea sand offers a plentiful alternative to natural river sand, though it requires treatment to mitigate chloride contamination. The experimental program included a comprehensive evaluation of concrete properties, such as workability, compressive strength, water absorption, porosity, and resistance to aggressive environments. The results showed that the use of RCA slightly reduced workability but had minimal impact on compressive strength, especially in mixes with treated sea sand (R40-T). The treated sea sand improved workability and enhanced durability by reducing water absorption, porosity, and resistance to acid and sulphate attacks. The mix R40-T-30 demonstrated the best overall performance in terms of both strength and durability. This study demonstrates that the combination of recycled coarse aggregate and treated sea sand provides a sustainable solution for concrete production, balancing environmental benefits with structural performance.