Abstract This research aimed to assess the efficacy of synthetic zirconia nanomaterials (NZr) in improving the physico-mechanical, textural, fire resistance, and photocatalytic properties of Ordinary Portland Cement composite pastes. Zirconia nanoparticles (NZr-NPs) were synthesized via a precipitation method, with an average crystallite size between 7 to 15 nm and a surface area of 88.01 m 2 /g. Six composite formulations were prepared, denoted as NZr0, NZr1, NZr2, NZr3, NZr4, and NZr5, with varying NZr doses. The physicochemical characteristics were investigated over hydration periods up to 3 months. After 28 days of hydration, specimens were dried and fired at temperatures ranging from 200 to 1000°C to assess their thermal resistance. The addition of 0.25% NZr was identified as the optimal dosage, enhancing the fire resistance of the composites. However, increasing the NZr content to 0.50–1.00% led to a reduction in compressive strength (CS), although it remained higher than that of the unmodified paste. The composite incorporating 1.5% NZr demonstrated superior photocatalytic degradation performance, exhibiting the highest dye degradation percentages after 300 min of UV irradiation at 3, 7, 28, and 90 days, measuring 83%, 86%, 89%, and 97%, respectively. These results highlight the enhanced photocatalytic degradation capabilities of the composite containing Zr-NPs. These findings identify several promising avenues for future research, particularly the optimization of zirconia dosage and its integration into cementitious systems to improve durability, environmental performance, and cost-effectiveness in sustainable construction applications.
Heikal et al. (2026) studied this question.