Flow behavior, microstructure, strength and shrinkage properties of self-compacting concrete incorporating recycled fine aggregate

• Published in: Construction & building materials 2019-12, Vol.228, p.116819, Article 116819
• Main Authors: Behera, Monalisa, Minocha, A.K., Bhattacharyya, S.K.
• Format: Article
• Language: English
• Subjects: Drying shrinkage; Flow behavior; Flow retainability; ITZ; Mechanical strength; Microstructure; Recycled fine aggregate; Self-compacting concrete
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.116819

•The influence of RFA on the flow properties of SCC has been studied.•The surface structure of RFA plays a key role in controlling the flow parameters.•RFA has potential to be used as raw material in developing Eco-friendly SCC.•SCC with RFA achieved considering: water absorption kinetics, SP dosage and VMA.•Higher percent replacement of RFA is sensitive to flow retainability. The present research investigates the behavior of flowable concrete by reusing the construction and demolition (C&D) waste to replace natural resources. It gives an insight into the feasibility and effectiveness of developing an eco-friendly self-compacting concrete (SCC) using recycled fine aggregate (RFA) with maximum cement replacement. This study aims at evaluating the flow behavior, mechanical strength, shrinkage characteristics and the microstructure of SCC ascertaining the synergistic effect of RFA with the binary or ternary blend binder as a partial substitution of cement. From performance point of view, it is observed that the presence of RFA enhances the flowability, but certainly affects the other flow attributes to a certain extent with time at a higher replacement level. The interaction between RFA particles and the fluid media to maintain the flowability and to achieve the functional requirements of SCC have also been explored. It is found that the desired flow could be achieved for all the SCC mixes based on three independent variables (water absorption kinetics, SP and VMA dosage) by maintaining the powder content constant. The target strength is achieved for all the mixes except the mix with 40% fly ash and 100% RFA. This study reveals that the stability of the resulting SCC made with RFA can be acquired by properly designing the fluid media, considering the material properties. However, the complete replacement of natural fine aggregate with RFA has significantly influenced the performances of SCC and so with binary blend binder.