Recommendation for concrete mixture design and guidelines for ECP using marble and RCA

Engineers and designers have a significant concern regarding the sustainability of concrete. This research focuses on the manufacture of sustainable concrete by utilizing various types of construction and demolition wastes, as well as wastes generated during the preparation of traditional materials. The goal is to reduce the environmental impact of the concrete industry in both construction and demolition stages, minimize the need for landfills to dispose these wastes, and decrease reliance on non-renewable materials. The study explores the suitability and validation of materials like marble and recycled concrete for use in concrete production. To address these environmental and economic challenges, the research examines different types of construction and demolition wastes and their potential application in sustainable concrete production. The research divides the specimens into three main groups. In group 1 and group 2, natural aggregates are replaced with marble and recycled concrete aggregates, respectively. In group 3, cement is substituted with marble dust. The study investigates the properties of fresh and hardened concrete in group 1 and 2, along with durability tests and microstructure analysis. Mechanical properties for group 3 are tested at different replacement percentages. The findings indicate that marble and recycled concrete aggregates can be used as full replacements for natural coarse aggregates in concrete production, offering advantages over traditional concrete. However, using marble dust as a replacement for cement in mortars proves to be inefficient. Consequently, this research includes a comparative study that examines various codes and specifications related to the use of different types of construction and demolition wastes as substitutes for natural aggregates. Based on the experimental program of this research, recommendations are made for the Egyptian code of practice (ECP) regarding concrete production with different aggregate types, which is currently not addressed in the ECP but is covered by other codes and specifications of different countries.