PSI - Issue 70

R. Mohanraj et al. / Procedia Structural Integrity 70 (2025) 409–416

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4. Conclusions Microstructural analysis by scanning electron microscopy and X-ray diffraction further supported these findings by highlighting the improved bonding and distribution of calcium‒silicate‒hydrate (CSH) gels in the optimized mixture. The even distribution of CSH gels and reduced microlevel cleavages indicated better structural stability and resistance to fracture propagation. The experimental investigation of the durability of an improved concrete mixture incorporating rubber fine aggregate and steel slag demonstrated promising results in terms of resistance to chemical attacks and structural integrity. The findings revealed that the improved concrete mixture exhibited a lower weight loss when exposed to HCl and H 2 SO 4 , indicating enhanced resistance to acid attack compared with the conventional control mixture. Specifically, the weight loss percentages for the improved mixture were 3.18% and 2.11% for HCl and H 2 SO 4 , respectively, which are significantly lower than those of the control mixture. Additionally, the improved concrete mixture showed superior performance against salt encrustation, with lower weight gains when exposed to MgSO 4 and NaCl. The percentage weight gains for the improved mixture were 1.22% and 0.95% for MgSO 4 and NaCl, respectively, whereas higher values were observed for the control mixture. These results suggest that the use of RFA and SS not only contributes to improved durability against chemical attacks but also minimizes detrimental salt deposition. Acknowledgements The corresponding author thanked SRM University, Delhi-NCR, Sonipat campus for their full financial support (Letter, dated 24.12.2024) in terms of registration fee to attend the International Conference on Structural Integrity and Interactions of Materials in Civil Engineering Structures. 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