Effect of recycled aggregates on fresh and hardened properties of self compacting concrete

Abstract

This article discusses the experimental investigation of fresh and hardened properties of Self Compacting Concrete (SCC) containing Recycled Aggregates (RA). In this study, Natural Coarse Aggregates (NCA) were replaced with Recycled Coarse Aggregates (RCA) at 0%, 50%, and 100% replacement levels. Similarly, Natural Fine Aggregates (NFA) were replaced with Recycled Fine Aggregates (RFA) at 0%, 25%, 50%, 75% and 100% replacement levels. In addition to Natural Aggregates (NA) replacement with RA, Fly Ash (FA) was partially substituted with Portland cement (PC), i.e., by 30% weight of cement for clean and sustainable development. The current study objective is to enumerate the significant usage of RCA and RFA for the SCC mixes and to evaluate their performance in their fresh and hardened state. The fresh properties of various SCC mixtures were examined using workability tests such as the Slump-flow test, T500 test, V: funnel test, and L: Box test. The Ultrasonic Pulse Velocity (UPV) test was performed for all SCC mixes in their hardened state. The compression strength of all SCC mixtures is also presented in contrast to the workability of concrete. It was concluded that with substitution of RCA and RFA with NCA and NFA respectively decline the workability properties due to high-water absorption and larger surface area of RCA and RFA than NCA and NFA respectively. The chemical admixtures were used in SCC mixtures with their varying dosage helps to maintain the workability and stability limits of all SCC mixes. It was observed that the UPV values of all SCC mixtures come in the excellent and good categories.