Compressive Strength and Workability of Concrete Incorporating Laterite as Partial Replacement of Fine Aggregate

Abstract

The study examined laterite, an abundant and eco-friendly material, as a partial replacement for fine aggregate in concrete. It considered how laterite affected workability, compressive strength, and split tensile strength by using a mix of 1:1.5:3 (cement:fine aggregate:coarse aggregate). The laterite replaced 0%, 5%, 10%, and 15% of fine aggregate, both with and without 1% superplasticizer (based on the weight of cement). A total of 144 cubes (150mm) and 144 cylinders (150mm × 300mm) were cast and tested at various intervals: 3, 7, 10, 14, 28, and 42 days. The workability tests revealed that 5% laterite without superplasticizer achieved the highest slump at 55mm. Meanwhile, 10% and 15% dropped to 40mm, while the control was at 35mm. The presence of superplasticizer increased the slump by 109 to 271%, making all mixes practical for construction. At 28 days, the mix with 10% laterite and no superplasticizer showed the highest compressive strength at 31.19 MPa, which was better than the control at 29.26 MPa. When superplasticizer was added, 5% laterite reached 42.27 MPa, a 5% improvement over the control at 40.26 MPa. The split tensile strength also peaked at 3.01 MPa with 5% laterite plus superplasticizer, exceeding the control by 1.69%.. The mix at 5% laterite with superplasticizer gave maximum compressive strength of about 40 N/mm2, making it suitable for structural applications. Laterite shows itself to be a viable alternative to sand. It is effective up to 10% without superplasticizer and 15% with it, supporting eco-friendly construction in areas rich in laterite.