Correlation of strength development of RCA in quaternary blended cementitious system

Recycled concrete aggregate (RCA) obtained from demolished structures can be used for concrete making, and is established as a promising material in the field of construction. In the present study, the effect of RCA on the mechanical properties of different strength concretes admixed with Micro silica, fly ash and nano-silica as a part replacement to cement was considered. The quantity of cement varied from 350-690 kg/m3 with the additions of Fly ash at 0, 20 and 30%, micro silica at 0, 5, 10 and 15%, and Nano silica at 0, 1, 2, 3 and 4%. The samples were cured for 7, 28, 56 and 90 days and tested for Compressive strength. Split tensile and flexural strength evaluation was carried out on samples which have been cured for 28 days. The workability of fresh concrete was determined. With the help of the tested database, equations for prediction of compressive strength using modified Bolomey's equation were generated. Equations for the flexural strength and split tensile strengths based on compressive strength were developed and compared with equations available in the literature.