PSI - Issue 70

R. Mohanraj et al. / Procedia Structural Integrity 70 (2025) 82–88

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attained with a 3% SiO₂ concentration. The variability noted at higher SiO₂ levels (4 – 5%) emphasizes the vital need for achieving uniform dispersion of nanoparticles to prevent the formation of weak areas in the material. The results of these tests were carefully analyzed to compare the performance of the different mortar mixes. The UPV test allowed for an assessment of the density and internal integrity of the mortar, while the Rebound Hammer test indicated the material’s surface strength. The FTIR test, o n the other hand, helped to identify any chemical changes or enhancements in the cement paste due to the presence of nano-SiO 2 . By correlating the data from all three tests, it was possible to conclude the effects of nano-SiO 2 on the overall properties of cement mortar.

Table 3. Rebound Hammer Test SiO 2 Cube S. No. SiO 2 1%

SiO 2 2%

SiO 2 3%

SiO 2 4%

SiO 2 5%

1. 2. 3. 4. 5. 6. 7.

14 16 19 21 22 11 28

16 18 19 20 22 25 26

23 20 22 26 25 29 28

19 18 20 19 29 23 29

19 17 26 22 19 31 27

5. Conclusion In conclusion, the incorporation of nano-SiO 2 into cement mortar has a significant impact on its mechanical properties and durability. The results from the non-destructive testing demonstrated that the addition of SiO 2 improved the internal quality, surface strength, and chemical bonding of the mortar, with the optimal performance observed at lower concentrations of SiO 2 (1%-3%). Higher concentrations of SiO 2 (4% and 5%) showed diminishing returns in terms of performance, indicating a possible saturation point where the benefits of further addition are limited. The use of non-destructive testing techniques like UPV, Rebound Hammer, and FTIR spectroscopy proved to be effective in evaluating the properties of the cement mortar without causing damage to the samples, providing a valuable and cost effective approach for material assessment in construction. This study offers insightful information about how nano SiO 2 might be used to improve the functionality of cement-based materials. The results imply that adding nano-SiO 2 to cement mortars can enhance their strength, longevity, and general performance, making them more appropriate for use in demanding construction applications. Acknowledgements The authors gratefully acknowledge the financial support provided by the SRM Research and Development Centre through the SEED Grant (SRMUH/R&D/SM/001) for carrying out this research work. The corresponding author also extends sincere thanks to SRM University, Delhi-NCR, Sonipat campus, for their partial 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. References Balapour, M., Joshaghani, A., Althoey, F. 2018. Nano-SiO 2 contribution to mechanical, durability, fresh and microstructural characteristics of concrete: A review. Construction and Building Materials, 181, 27-41. Cheng, Y., Shi, Z. 2019. Experimental Study on Nano‐SiO 2 Improving Concrete Durability of Bridge Deck Pavement in Cold Regions. Advances in Civil Engineering, 2019(1), 5284913. Cui, Z., Zhao, H., Song, J., Liu, W., Zhang, S., Li, W. 2024. Preparation of ester-modified nano-SiO 2 /silicate coatings and its application in the impermeability of concrete. Construction and Building Materials, 455, 139217. Fan, C., Zheng, Y., Zhuo, J., Du, C., Hu, S. 2024. Study on mechanical and bonding properties of nano-SiO 2 reinforced recycled concrete: macro test and micro analysis. Journal of Building Engineering, 94, 109877.