EARLY STRENGTH CHARACTERISTICS OF CONCRETE MADE WITH RICE HUSK ASH AS PARTIAL REPLACEMENT OF CEMENT USING PERIWINKLE SHELL AS COARSE AGGREGATE

This research assessed the early strength characteristics of concrete made with Rice Husk Ash (RHA) as partial cement replacement and Periwinkle Shells (PWS) as coarse aggregate. The goal was to test the potential of these waste materials as sustainable alternatives in concrete. Concrete cubes of 50 × 50 mm were cast with RHA levels of 0%, 10%, 20%, and 30%, cured for 3 and 7 days, and tested. A correction factor of 0.80 was applied to adjust results to standard 150 mm cubes. The results showed that the control mix recorded the highest compressive strength at both curing ages. However, mixes with 10% and 20% RHA achieved strengths close to the control, confirming the effective pozzolanic action of RHA. At 30%, strength decreased sharply due to reduced cement content. PWS-based concrete was lighter than conventional mixes but showed a slight reduction in compressive strength compared with granite aggregate. The study concludes that RHA can replace cement up to 20% without major performance losses, while PWS serves as an eco-friendly lightweight aggregate. Such mixes are recommended for lightweight and non-load-bearing applications, with further study needed on durability and long-term strength. This research assessed the early strength characteristics of concrete made with Rice Husk Ash (RHA) as partial cement replacement and Periwinkle Shells (PWS) as coarse aggregate. The goal was to test the potential of these waste materials as sustainable alternatives in concrete. Concrete cubes of 50 × 50 mm were cast with RHA levels of 0%, 10%, 20%, and 30%, cured for 3 and 7 days, and tested. A correction factor of 0.80 was applied to adjust results to standard 150 mm cubes. The results showed that the control mix recorded the highest compressive strength at both curing ages. However, mixes with 10% and 20% RHA achieved strengths close to the control, confirming the effective pozzolanic action of RHA. At 30%, strength decreased sharply due to reduced cement content. PWS-based concrete was lighter than conventional mixes but showed a slight reduction in compressive strength compared with granite aggregate. The study concludes that RHA can replace cement up to 20% without major performance losses, while PWS serves as an eco-friendly lightweight aggregate. Such mixes are recommended for lightweight and non-load-bearing applications, with further study needed on durability and long-term strength.