Aggregate Packing Density Approach for Sustainable SCC using Un-Processed Coarse Recycled Concrete Aggregates

Abstract

The production of Self Compacting Concrete (SCC) needs a large amount of binder (cement) to fulfill its flow requirements. The production of cement is associated with high energy consumption and CO2 emissions, which result in serious environmental pollution. Making SCC with Coarse Recycled Concrete Aggregate (CRCA) throws further challenges. Mix proportions of a 40 MPa SCC-CRCA were estimated using the aggregate proportions obtained by aggregate packing density method (APD), Indian Standard (IS 10262), and those based on Compressible Packing Method (CPM). It was observed that the APD method yielded an SCC-CRCA with reduced binder content by 5.40% and 26%, as compared to the other two methods. Also, in the SCC-CRCA mixes proportioned by using APD method, resulted in a reduction in total energy consumption by 5.10%, total emission of CO2 by 9.23 % and material cost by 14.44 % at the prevailing rates in comparison to the IS 10262 design method. No significant variation in the flow and mechanical properties of SCC-CRCA was observed up to a replacement of 45 %, in the total coarse aggregate which is higher than that recommended in Indian (20 %) and International specifications (35 %) for traditionally vibrated (conventional) concrete.

Keywords

• self compacting concrete, coarse recycled concrete aggregate, aggregate packing density, flow properties, and mechanical properties