PSI - Issue 70

Suresh Kumar Verma et al. / Procedia Structural Integrity 70 (2025) 327–334

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1. Introduction The growing demand for sustainable, high-performance construction materials has led researchers to explore advanced material technologies. Nanotechnology offers significant advantages in enhancing the physical, chemical, and mechanical characteristics of traditional cementitious composites. Nanomaterials have been studied extensively in cementitious systems for their ability to enhance mechanical and durability characteristics. Their performance varies depending on their chemical nature, particle size, and dosage. Ray et al. (2021) demonstrated that nanosilica accelerates hydration in tricalcium silicate using THz spectroscopy, confirming its role in enhancing early-age reaction kinetics. Additionally, Ray et al. (2021) showed that nanosilica improves the formation of C-S- H phases in C3S and β -C2S using nanoindentation analysis. Nano silica is one of the most researched nanomaterials in cement composites due to its high pozzolanic reactivity. It reacts with calcium hydroxide (CH) to form additional calcium silicate hydrate (C-S-H), leading to improved strength and reduced porosity (Said et al., 2012). Singh and Sharma (2014) observed that even at low dosages, nano silica enhances both early and late-age strength due to accelerated hydration and microstructure densification. Mohseni and Tsavdaridis (2016) reported that nano-alumina significantly enhances compressive strength and modifies the microstructure of cement pastes containing supplementary cementitious materials. These improvements are attributed to enhanced nucleation and densified matrix structure. Nano-alumina influences cement hydration by acting as a nucleating agent and enhancing the early-age strength. Its high surface area and reactivity can modify the morphology of hydration products. According to Nazari and Riahi (2011), the incorporation of nano-alumina leads to an increased rate of hydration and a denser C-S-H gel network. Recent findings by Su et al. (2024) indicate that nano-CaCO 3 , especially when combined with other nanomaterials like graphene oxide, contributes to better mechanical properties and durability by acting as a nucleation site and densifying the microstructure. Nano-CaCO 3 acts primarily as a filler and nucleation site for hydration products. It refines the microstructure by filling pores and accelerating the hydration of C₃S and C₂S phases (Chen et al., 2018). Recent studies suggest that hybrid combinations of nanoparticles (e.g., NS + NA, NS + NCC) can offer synergistic benefits. Zhang et al. (2017) showed that ternary systems optimize the packing density and improve both the mechanical properties and durability of composites. Hybrid systems provide better control over hydration kinetics and pore refinement. The efficiency of nanoparticles is highly dosage-dependent. Excessive content can cause agglomeration, reduced workability, and uneven dispersion, negatively impacting mechanical strength (Li et al., 2006). The optimal dosage is generally in the range of 2-3% by weight of cement. Traditional cement suffers from limitations such as high CO 2 emissions during production and microstructural imperfections that reduce long-term durability. Nanomaterials can address these drawbacks by improving cement particle packing, promoting nucleation, and modifying hydration kinetics. These properties can enhance early strength development, refine pore structure, and reduce permeability (Li et al., 2004). This study investigates the effect of nano-Al 2 O 3 , nano-SiO 2 , and nano-CaCO 3 at 1%, 3%, and 5% replacement levels by weight of OPC. The focus is on analysing, fresh properties, mechanical performance and durability properties of cementitious composites. 2. Materials and Methods 2.1. Materials The materials used in this study were selected based on their compatibility with cementitious systems and adherence to relevant Indian Standards to ensure reproducibility and practical applicability. • Ordinary Portland Cement (OPC) Ordinary Portland Cement (OPC), Grade 43 conforming to IS 8112:2013 was used as the primary binder. Grade 43 OPC is known for achieving a compressive strength of 43 MPa at 28 days. It is widely available and exhibits