Microscale investigation of mechanical characteristics: enhancing sustainable strength in concrete through the use of recycled aggregates

This paper explores the feasibility of using 100% recycled fine aggregate in concrete to meet strength requirements for various applications in sustainable construction. The physical and mechanical characteristics including: aggregate strength, gradation, absorption, specific gravity, shape and texture, play crucial roles in determining concrete strength. The quality of recycled aggregate is generally influenced by the loading and exposure conditions of demolished structures. The experimental program focused on assessing the mechanical properties of recycled aggregate over a 3-month period, incorporating cement of OPC 53 grade, Ground Granulated Blast Furnace Slag (GGBS), and Novel Additive (NA). The study evaluated concrete properties when utilizing both fine and coarse recycled aggregate. Various concrete mixes were formulated, featuring 100% recycled fine aggregate (RFA) with varying proportions of recycled coarse aggregate (RCA) from 0 to 100%. These results were compared to those of a control mix. Scanning Electron Microscopy (SEM) was employed to analyze the microstructure of selected mixes. The findings indicated that concrete with satisfactory strength could be achieved through the partial replacement of RCA with Natural Coarse Aggregate (NCA) using 10% NA in the 100% RFA concrete mix in Rheodynamic flowable concrete (Rd-FC). © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.