Effect of Recycled Aggregate on Concrete Strength

The fast depletion of natural resources in the globe particularly those aiding global warming calls for general review of materials being used in the construction industry and the civil engineering realm. This work examined the effects of recycled coarse aggregate on concrete strength targeting a grade M30 concrete and using 0.55% w/c ratio natural coarse aggregate was replaced with recycled coarse aggregate at 25% 50% 75% and 100% respectively. The aggregate particle grading was even as determined by sieve analysis the water absorption rate and specific gravity of fine aggregate NCA and RCA were 2.02% 3.26% 7.07% and 1.25 2.16 1.97 respectively. The final setting time of cement used was 4hours 18 minutes. The compressive strength of Natural aggregate concrete NAC cured for 28 days was 33.78KN/m2 while NCA replaced with RCA in concrete at 25% attained a compressive strength of 30.37N/mm2 other percentage replacements such as 50% 75% and 100% showed compressive strength lower than 30.00N/mm2.