Multiscale optimization analysis of high strength alkali-activated concrete containing waste medical glass under exposure to carbonation and elevated temperatures

This study focused on optimizing the effect of recycled medical glass (RMG) on the performance of high-strength alkali-activated concrete (AAC) at different scales. RMG was incorporated into the AACs to substitute a portion of the precursor, followed by the addition of fine and coarse RMG to replace a portion of the fine and coarse river sand, respectively. Thus, the effects of these variables on compressive strength, splitting strength, and water absorption using the simplex centroid design method were examined. Additionally, freezing-thawing, carbonation resistance, and residual strength at elevated temperatures of AACs were investigated. The experimental results showed that AACs had compressive strengths between 46.8 and 102.0 MPa, tensile strengths between 6.20 and 13.60 MPa, and water absorption between 2.93 and 4.82%. The optimized AACs showed a significant increment in residual strength at high temperatures as compared to the control mixture. The AAC with RMG may provide a compact microstructure with low porosity to enhance carbonation and freeze-thaw resistance. Finally, the outcomes of the ecological evaluation support the usage of RMG in high strength AAC as a sustainable building and construction material.