Mechanical and fracture properties of concrete containing treated and untreated recycled concrete aggregates

This paper presents the results of an experimental research into concrete produced by replacing the natural aggregates with treated and untreated coarse Recycled Concrete Aggregates (RCA). The compressive and flexural strength as well as fracture energy tests were carried out. In order to determine the efficiency of treated and untreated RCA on fracture properties of concrete, single edge notched beam, semi-circular bend, and edge notched disc bend geometries were employed. The results indicated that although Treated Recycled Concrete Aggregates (TRCA) might push to more effort in production process, there are significant benefits in using TRCA in concrete mixtures. Denser microstructure and stronger interfacial transition zone in TRCA enhances crack resistance in fracture processing zone of concrete compared to RCA. In addition, the study showed that incorporating RCA and TRCA leads to a more intensive drop and brittle behavior in post-cracking extension. Furthermore, comparison of fracture toughness in different modes indicated that the RCA and TRCA are more prone to tensile opening mode compared to shear (in-plane and out-plane) modes. (C) 2019 Elsevier Ltd. All rights reserved.