Rheological and mechanical behaviour of self-compacting concrete with modified recycled concrete aggregate

Construction and demolition waste is increasingly used as a raw material in concrete manufacture which can assist in addressing environmental challenges associated with its disposal. In this study, recycled concrete aggregate (RCA) is used in Self-Compacting Concrete (SCC). As such, the work fills the gap in the literature by examining the influence of RCA impregnated with water glass solution on the physical and mechanical properties of fresh and hardened SCCs. Five different SCC mixtures are developed and tested. The replacement factor for RCA is 50 % (fractions II (4/8) and III (8/16)). Tests on hardened concrete reveal that the influence of water glass varies depending on the component it is coupled with, i.e., the combination with fly ash provides a maximal strength gain over 90 days, while the combination with silica fume gives low compressive strength during the entire testing period of 90 days.