ASSESSMENT OF THE COMPRESSIVE STRENGTH OF RECYCLED CONCRETE USING THE REBOUND HAMMER

Concrete remains the most widely used construction material globally; however, its production is heavily reliant on natural aggregates, the continuous extraction of which causes considerable environmental impact. With increasing concerns over resource depletion and waste management, the utilisation of recycled coarse aggregates (RCA) derived from demolished concrete presents a sustainable alternative. This study, entitled “Assessment of the Compressive Strength of Recycled Concrete Using the Rebound Hammer,” investigates the feasibility of partially replacing natural coarse aggregates (NCA) with RCA while maintaining acceptable mechanical performance for structural applications.
The research involves the preparation of concrete mixes of grades M20, M25, and M30, with RCA replacement levels of 0%, 25%, 50%, 75%, and 100%, at a constant water–cement ratio of 0.5. Fresh concrete is assessed through the slump test to evaluate workability, while hardened concrete specimens undergo compressive strength testing at 7, 14, and 28 days, in addition to non-destructive testing using the rebound hammer. The study aims to establish the relationship between the rebound number and compressive strength to develop calibration equations specific to Recycled Concrete. It is anticipated that compressive strength will decrease with increasing RCA content; however, a 25% replacement level is expected to provide performance comparable to conventional concrete while enhancing material sustainability. The study further predicts a strong correlation between rebound hammer readings and compressive strength, supporting the use of the rebound hammer as a reliable tool for non-destructive evaluation of Recycled Concrete in both research and practical field applications.