Guidelines for Selection and Use of Coarse Recycled-Concrete Aggregates in Structural Concrete

This paper presents guidelines for using recycled-concrete aggregate (RCA) as a full or partial replacement for natural coarse aggregate in new concrete (RCA concrete). Several international standards and guidelines for the use of RCA in concrete are reviewed and contrasted to identify areas in which further development is required. The main results of an extensive experimental research program by the authors are summarized here to provide a basis for the development of a framework for using RCA in structural concrete. Several RCA performance classes are proposed, each with a specific set of requirements and suitable applications. The proposed performance classes define further requirements and guidance for the use of RCA beyond the requirements of Canadian Standards Association A23.1 and ASTM C33. The authors propose a detailed decision tree to allow engineers, concrete producers, aggregate suppliers, and contractors to assess whether a particular RCA source is suitable for use in reinforced concrete or plain concrete or as fill material.