To address SDG12 (ensure sustainable consumption and production patterns), and to provide technical evidence for alternative concrete constituents to traditional natural river sand, stone fine aggregate (SFA), brick fine aggregate (BFA), ladle-refined furnace slag aggregate (LFS), recycled brick fine aggregate (RBFA), and washed waste fine aggregate (WWF), ready-mix concrete plants were investigated. Concrete and mortar specimens were made with different variables, such as replacement volume of natural sand with different alternative fine aggregates, water-to-cement ratio (W/C), and sand-to-aggregate volume ratio (s/a). The concrete and mortar specimens were tested for workability, compressive strength, tensile strength, and Young’s modulus (for concrete) at 7, 28, and 90 days. The experimental results show that the compressive strength of concrete increases when natural sand is replaced with BFA, SFA, and LFS. The optimum replacement amounts are 30%, 30%, and 20% for BFA, SFA, and LFS, respectively. For RBFA, the compressive strength of concrete is increased even at 100% replacement of natural sand by RBFA. For WWF, the compressive strength of concrete increases up to a replacement of 20%. Utilizing these alternative fine aggregates can be utilized to ensure a circular economy in construction industries and reduce the consumption of around 30% of natural river sand.

The aim of this study was to characterize the chemical, molecular, and rheological properties of different asphalt emulsions including a newly introduced tire-rubber modified asphalt emulsion (CRS-2TR). Three emulsions (CRS-2TR, CRS-2P, and CRS-2) and one asphalt rubber binder (AC20-5TR) were evaluated in this study. The superpave performance grade (PG), surface performance grade (SPG), and the multiple stress creep recovery (MSCR) test were conducted to evaluate the rheological properties of the binder residues. Evaluation of the differences in the functional groups, molecular weight distribution, and chemical composition of the asphalt binder residues was conducted using Fourier transform infrared spectroscopy (FTIR), high-pressure gel permeation chromatography (HP-GPC), and saturates, aromatics, resins and asphaltenes (SARA) fractionation, respectively. The chemical and molecular characterization test results indicated that the tire-rubber modified emulsion had lower carbonyl indices and colloidal instability indices as compared to the other conventional emulsions, indicating a higher resistance to aging. On the other hand, the rheological test results showed that the performance of CRS-2TR was comparable to CRS-2P and was expected to perform better than CRS-2. In addition, the moisture susceptibility of the binder residues from the bitumen bond strength (BBS) test showed that CRS-2TR had a greater pull-off tensile strength in both dry and wet conditions as compared to CRS-2 and had statistically equal performance results as compared to CRS-2P.