Investigations on Strength and Durability Properties of Recycle Aggregate and Fly Ash in Concrete

In this investigative study the Natural Coarse Aggregate (NCA) were put back with Recycled Course Aggregate (RCA) at peculiar proportions, the mechanical performance and durability properties of concrete are examined. The inclusion of fly ash (FA) is also introduced as stand–in of Cement. The present investigation aims to determine the effect of RCA as an stand-in material to NCA and to analyze the fresh properties like workability, density and hardened properties like Compressive Strength, Flexure Strength, Split Tensile Strength and durability properties like Water permeability and Sorptivity. Mix is formulated for water cement ratio 0.40. The specimens were casted of replacing virgin aggregate with RCA by 10% and 20%, and cement with FA by 10%, 20% and 30%. All the specimens are cured for 7 and 28 days as per requirement later they are tested. The acquired data are then compared between the strength of NCA of concrete and the proportion of RCA and FA. The outcome view is in such a way that the workability of concrete will decline as the replacement of RCA increases, by which it should limited to a fixed percentage (10% or 20%). The density of concrete is not altered by the put back of FA, but raise in percentage of RCA replacement could alter the density of concrete. In case of Compressive, Flexure and Split tensile strength of concrete the optimum strength obtained for 10% FA and 10% RCA for 7 and 28 days was similar to that of 100% NCA and 0% FA and durability studies also gave the optimum results for the same replacement.