PSI - Issue 70

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

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and additives have been explored, and one such promising additive is nano-SiO 2 (Najigivi et al. (2013); Khaloo et al. (2016)). Nano-SiO 2 particles possess unique properties, such as a very high surface area and enhanced reactivity, which can contribute to improved microstructure and enhanced properties of cementitious materials (Cheng and Shi (2019)). The incorporation of nano-SiO 2 into cement mortar has been shown to influence various parameters such as compressive strength, workability, and durability (Nazari and Riahi (2010)). This study aims to explore the effects of incorporating different percentages of nano-SiO 2 particles into cement mortar (Zhao et al. (2012)). The objective is to evaluate whether the addition of nano-SiO2 at different concentrations improves the overall performance of cement mortar and to investigate its effects on the material’s microstructure and physical properties (KM et al. 2025). This will be accomplished by performing non-destructive testing on the concrete samples to assess changes in properties like strength and structural integrity (Li et al. (2023); Li (2004); Regalla (2024)). The significance of this research lies in its potential to improve the performance of cement-based materials through the use of Nano-technology (Gopalakrishnan et al. 2024). The addition of nano-SiO 2 particles could address some of the inherent issues with conventional cementitious materials, such as reduced durability, low resistance to environmental attacks, and inadequate long-term performance (Xu et al. (2024); Yang et al. (2024); Fan et al. (2024)). Additionally, as infrastructure development continues to grow globally, the demand for more durable and efficient materials is increasing (Cui et al. (2024); Majeed et al. (2024); Zhou et al. (2024)). Therefore, improving the mechanical properties of cement mortar using relatively low-cost and readily available materials like nano-SiO 2 can have substantial benefits in terms of construction quality, sustainability, and longevity (Qu et al. (2025); Jing et al. (2024)). The results from this study could also provide valuable insights for future research, potentially influencing the development of new materials and techniques for improving cement-based construction materials. Furthermore, the use of non-destructive testing methods in this study provides an efficient and non-invasive way to evaluate the properties of cement mortar without causing any damage to the samples, ensuring that the testing is both reliable and cost-effective. 2. Materials and their properties The materials used in this experiment play a crucial role in determining the mechanical and durability characteristics of the cement mortar (Khan et al. (2024). Flyash-based Portland Pozzolana Cement (PPC) of 53 Grade was used due to its high strength and reliability in structural applications. It has a specific gravity of 3.15, ensuring optimal density, with a fineness retention of 8% on a 90-micron sieve (Zhou et al. (2024)). The setting times of OPC are also critical; an initial setting time of 30 minutes allows sufficient workability, while the final setting time of 600 minutes ensures stable hydration and strength development (Mohanraj et al. 2024; Mohanraj et al. 2023). Fine aggregates, primarily sand, were used to enhance the mortar’s compactness and bonding. The sand had a specific gravity of 2.65, ensuring compatibility with cement, and a fineness modulus of 2.3, which indicates a well-graded distribution of particles. The water absorption rate was 1.5%, affecting the water-cement ratio, and the sand was classified under Grading Zone II as per IS 383:2016, confirming its suitability for mortar preparation (Feng et al. (2025)). Water used in the mix had a neutral pH of 7 and was free from organic impurities and harmful salts, ensuring that there was no adverse reaction with cement hydration. Nano-SiO 2 , the primary additive in this study, had a particle size ranging from 10-50 nm, providing a substantial increase in the surface area available for reaction (Ravikumar et al. 2024; Ravikumar et al. 2023). With a specific surface area of 200 m²/g and purity exceeding 99%, the amorphous nature of nano-SiO 2 contributed significantly to enhancing the microstructural properties of the mortar. To investigate the effects of nano-SiO 2 on the properties of cement mortar, a series of experimental procedures were carried out (Sun et al. (2025)). The first step was to prepare a standard cement mortar mix, Fig. 1(a). The materials used in the experiment were ordinary Portland cement (OPC), fine aggregates (sand), water, and nano-SiO 2 . The nano-SiO 2 used was of a high-purity grade and had a particle size range suitable for incorporation into the cement (Shanmugasundaram et al. 2022; Velumani et al. 2023). The cement mortar was mixed with varying percentages of nano-SiO 2 particles: 1%, 2%, 3%, 4%, and 5% by weight of the cement. A control mix was also prepared without any addition of SiO 2 , which served as a baseline for comparison. The mixing process followed standard procedures, ensuring that the ingredients were uniformly distributed throughout the mixture. The water-to-cement ratio was kept constant across all the mixes to ensure uniformity in workability and consistency. Once the mortar mixtures were prepared, cube samples were cast in standard molds with dimensions of 150mm x 150mm x 150mm, Fig. 1(b). These cubes were left to cure