Strength, shrinkage and creep of concrete including CO2 treated recycled coarse aggregate

Abstract

Strength development and long-term behaviour of recycled aggregate concrete (RAC) were investigated. Recycled coarse aggregate (RA) replaced natural coarse aggregate (NA) by 30%, 50%, and 100% by vol. in this study while natural fine aggregate was always used. For the investigation of strength development, 3, 7, 28, 56, 90, and 180 day compressive strengths and 28 day split tensile strength and flexural strength havebeen determined. Shrinkage and creep behaviours of RAC with 0%, 50%, and 100% RA replacing NA have
been studied up to 6 months. The compressive strength of RAC was not affected by 30% replacement, but it was reduced by 50% and 100% replacement. Split tensile strength was not affected significantly while flexural strength was reduced with increasing amount of replacement. Shrinkage strain of RAC with 50% RA was similar to that of natural aggregate concrete, but shrinkage increased with 100% replacement. Specific creep of RAC with 100% RA increased by 38% over that of natural aggregate concrete. The strength of concrete with CO2 treated RA was lower than that of concrete with RA without CO2 treatment. Shrinkage of RAC with and without CO2 treatment was similar, while the creep of RAC with CO2 treated RA was smaller than that of RAC including RA without CO2 treatment.