MECHANICAL BEHAVIOUR OF CONCRETE MADE WITH INTEGRAL INCORPORATION OF CONCRETE SLUDGE WASTE

This study explores the potential of Concrete Sludge Waste (CSW) as a sustainable alternative to conventional fine aggregates in concrete production. CSW, a by-product of the concrete industry, offers an opportunity to reduce environmental impact by recycling waste materials into construction products. The objective of this research was to evaluate the effect of varying CSW content (10%, 30%, 40%, 50%, and 100%) on fresh properties, mechanical performance, and durability of concrete. Experimental results revealed that moderate CSW substitution (up to 50%) did not significantly affect the compressive strength, modulus of elasticity, or workability of the concrete. The 50CSW mix exhibited a compressive strength of 30.88 MPa, comparable to the control mix , indicating that CSW can be effectively incorporated into concrete at moderate substitution levels without compromising its structural integrity. However, 100% CSW replacement led to a significant reduction in strength due to the high porosity and water absorption of CSW particles, which weakened the bond between the aggregate and cement paste. Furthermore, the workability of the concrete decreased with increased CSW content, but this could be mitigated with adjustments in the water-to-cement ratio and the use of superplasticizers, particularly in high-CSW mixes. The fresh density of concrete also decreased with increasing CSW content, making CSW-based concrete a promising option for lightweight concrete applications. In conclusion, CSW proves to be a viable partial replacement for fine aggregates in concrete, particularly for non-structural applications or lightweight concrete when used in moderate proportions. However, high CSW content (100%) leads to performance deterioration, limiting its use in high-strength concrete. Future research should focus on optimizing mix designs, conducting long-term durability tests, and performing environmental impact assessments to further validate the potential of CSW in sustainable concrete production.