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The performance of cement-based materials depends critically on hydration kinetics, thermal stability, and microstructural characteristics. This study investigates the effect of gallium (Ga) as a novel additive on these properties of cement pastes. Experimental studies were conducted with varying water-to-cement ratios (w/c), types of Portland cement, and pozzolanic and inert materials to evaluate to evaluate the impact of Ga incorporation on these properties. Comprehensive characterization techniques, including isothermal calorimetry, thermogravimetric analysis (TGA), optical microscopy (OM), and field emission scanning electron microscopy (FE-SEM), were employed to assess the effects of Ga incorporation. Observations indicate that Ga-modified pastes significantly slowed hydration kinetics, reducing both initial and cumulative heat evolution by approximately 20 %–30 % compared to non-Ga pastes, particularly in reactive mixes with low w/c ratios (0.25 and 0.38) and in mixes containing pozzolans such as silica fume and rice husk ash. TGA reveals that Ga enhances the thermal stability of hydration products, as evidenced by reduced dehydration loss ( Ldh ), improved residue retention, and increased decomposition peak temperatures (e.g., from 145.28 °C to 163.58 °C for the w/c-0.45 Ga mix). Microstructural analyses using OM and FE-SEM confirmed that Ga significantly reduces porosity, densifies the hydration matrix, and improves connectivity among hydration phases. These findings demonstrate the capacity of Ga to enhance the microstructure and thermal properties of cementitious systems, particularly in highly reactive and low w/c mixtures. The study highlights the potential of Ga as a novel additive for high-performance, durable, and sustainable concrete mixtures while underscoring the need for further optimization for specific mix designs.
Makul et al. (Sat,) studied this question.