Paper Title
Effectiveness of Using Recycled Coarse Aggregates (RCA) in Making High Strength Concrete

Abstract
Construction & Demolition waste has greater potentiality in replacing fully or partially in main line construction activities. In this paper an experimental program is undertaken in which three different mixes (i) Replacing 10mm, (ii) 20mm and (iii) 20mm, 10mm Recycled Coarse Aggregates (RCA) to the normal aggregates in the mix with a proportion of 20%, 25%, 30%, 35%, 40%. For each mix admixture, Glenium ACE 30 � 0.55% of cementitious material is added for attaining early strength and three cubes are casted, then compressive strength of concrete at age of 12 hours, 3 days, 7 days and 28 days are determined and the results are compared with compressive strength of conventional concrete. From the Compressive strength test results, it is observed that 40% replacement of 10 mm aggregates and also 40% replacement of 20 mm aggregates in RCA mixing attains more strength when compared to conventional mix at 28 days curing. It is also observed that, on 20% Replacement of 10 mm, 20 mm and combination of 10 mm and 20 mm in RCA mix cubes, compressive strength results are closer to the compressive strength results of conventional concrete at 12 hours, 3 days, 7 days, 28 days curing. However, Compressive strength is decreased, while replacing recycled coarse aggregates of 30% in mix at 28 days. But the earlier strength is same as conventional concrete mix. Keywords - Recycled Coarse Aggregate (RCA), Compressive Strength, C&D Construction and Demolition Waste