Study on the workability and mechanical properties of recycled aggregate concrete containing ultra-fine fly ash

The subject of concrete recycling is regarded as very important in the general attempt for sustainable development in our times. Due to a wide range of variability of engineering properties for recycled concrete, a large number of experiments are usually required to decide a suitable mixture. Within the scope of this study, 13 different concrete mixtures were manufactured. The amount of recycled concrete aggregate (RCA) were 0%, 20%, 40%, 60%, 80%, and 100%, respectively. The replacement levels of ultra-fine fly ash are 0%, 15%, 25%, 35% and 50%, respectively. The physical and mechanical properties along with their workability of concrete produced with RCA and ultra-fine fly ash were investigated. The experiment results showed that ultra-fine fly ash replacement had an important effect on performance of concrete with different amount of RCA.