Avaliação da sinergia de nanopartícula de dióxido de titânio (TiO2) e pó de resíduo de construção civil na substituição parcial do cimento em pastas de cimento Portland

Abstract

The process of manufacturing building materials involves intense energy consumption, which significantly contributes to carbon dioxide (CO2) emissions. The reuse of waste reduces the need for the production of new materials, and for this, it is necessary to conduct research that ensures technical parameters for the use and safety of recycled products. In this study, an analysis was performed on the effect of adding titanium dioxide nanoparticles and construction waste powder to Portland cement pastes to verify if there is a synergy between the nanoparticles and the Portland cement. For this purpose, two series of Portland cement pastes with a water/cement ratio of 0.4 were prepared. In one of the series, 1% nanoparticles by mass of binder were added, while in the other series, there were no nanoparticles. In both series, construction waste powder was added in proportions of 5%, 10%, and 15% relative to the cement. Fresh state tests were conducted: spread, specific mass, and calorimetry, in the reference mix and those with the addition of 1% titanium dioxide nanoparticles, and tests in the hardened state at 28 days, including flexural tensile strength and compressive strength, as well as the test to determine the dynamic modulus of elasticity. Based on the observed results, it is concluded that there is an effective interference in the addition of titanium dioxide (TiO2) nanoparticles in Portland cement pastes that had partial replacement by construction waste. According to the conducted tests, it is possible to recommend the adoption of a 15% cement replacement with RCC in cement pastes with a water/cement ratio of 0.4, with a proportion of 1% TiO2, which tends to mitigate the potential negative effects this replacement might have on the performance of these pastes.