Variation of Compressive strength and water absorption of concrete made by Two-Stage Mixing Approach using Fly ash with the variation of percentage of Recycled Coarse Aggregates.

Nowadays construction materials are increasingly evaluated by their ecological characteristics. Concrete recycling gains importance because it protects natural resources and eliminates the need for disposal by using the readily available concrete as an aggregate source for new concrete or other applications. The concrete in this paper is produced by utilizing alternative and recycled waste materials such as fly ash and recycled concrete aggregates to reduce energy consumption, environmental impact, and usage of natural resources. The inferior quality of recycled aggregate (RA) has restricted its use to low-grade applications such as roadwork sub-base and pavements, while its adoption for higher-grade concrete is rare because of the lower compressive strength and higher variability in mechanical performance of RA. A new concrete mixing method, two-stage mixing approach (TSMA), was advocated to improve the quality of RA concrete (RAC) by splitting the mixing process into two parts. In the current paper we will discuss two parameters on which the concrete made by TSMA has been tested for strength characteristics viz. compressive strength and flexural strength. These parametric properties are compared with the conventional concrete with the variation of percentage of recycled coarse aggregates(RCA) and fly ash.