Estudo da sinergia entre nanossílica e nanotitânia em pasta de cimento Portland

Abstract

This study evaluated the effect of adding nanosilica and nanotitania to Portland cement paste to investigate the potential synergy between nanoparticles and Portland cement. Portland cement pastes with a water-to-cement ratio of 0,5 and 1% nanoparticle content by mass of cement were prepared, with different combinations of nanosilica and nanotitania. The addition of nanoparticles was found to reduce the workability of the cement pastes. The semi-adiabatic calorimetry test revealed that nanoparticle addition affects the hydration kinetics, with the formulation containing 0,25% nanosilica and 0,75% nanotitania showing a significant acceleration. The apparent specific mass test showed a decrease in both age groups for formulations with nanoparticle combinations. In the three-point bending test, variations of up to 11% were obtained, with the formulation containing 0,25% nanosilica and 0,75% nanotitania being the only one that showed a 2% increase at 28 days. In terms of compressive strength, an increase of up to 39% was observed in the formulations with both nanoparticle additions at 7 days, and at 28 days, the formulation with 0,25% nanosilica and 0,75% nanotitania stood out with a 17% increase. Regarding water absorption and void index, the simultaneous incorporation of nanoparticles did not result in statistically significant improvements with a 95% confidence level. The study revealed the potential for synergy between nanoparticles, but additional microstructural analyses are required to investigate nanoparticle dispersion.