Partially fly ash and nano-silica incorporated recycled coarse aggregate based concrete: Constitutive model and enhancement mechanism

• DOI: 10.1016/j.jmrt.2021.12.135
• Publication Date: 2022-01-04T07:18:40Z
• Authors: Wanhui Feng; Yunchao Tang; Yunqi Zhang; Changhui Qi; Liangyi Ma; Lijuan Li
• Keywords: Cementitious; Pozzolanic activity; Pozzolanic reaction; Properties of concrete

The single use of nano-silica (NS) or fly ash (FA) can improve the strength recycled aggregate concrete (RAC). However, studies on NS-FA-modified RAC (NFRAC) are limited, and further research is required to understand mechanical behaviors NFRAC over different curing ages. In this study, properties RAC, these two supplementary cementitious materials (SCMs) were utilized in together: NFRAC. workability as well compressive split tensile determined by an orthogonal test along with effects various factors, including age, coarse (RCA) replacement rate, SCM content performance was found have adequate properties, both early later Based 100% RCA rate main object, strain ductility, energy consumption, constitutive model explored. Scanning electron microscopy performed explore modified mechanism owing incorporation NS FA. Both SCMs successfully accelerate pozzolanic reaction, thereby improving properties. addition, also fill micropores RCAs react CH mortar form C–S–H gels, ITZ. weakens that be compensated incorporating spherical Finally, 10% FA 2% 3% recommended for RAC.