Effect of the addition of nanoparticles of CaCO 3 and different water-to-powder ratios on the physicochemical properties of white Portland cement

The addition of calcium carbonate nanoparticles (nano-CaCO ) accelerates the hydration of Portland cement improving its mechanical properties. Conversely, nano-CaCO addition leads to reduction in the water required during initial PC hydration. Therefore, the use of a correct water-to-powder ratio is fundamental for manipulating this hydraulic cement. This study evaluated the effect of nano-CaCO addition and different water-to-powder ratios on the physicochemical properties of white Portland cement (WPC). WPC was associated to different concentrations of nano-CaCO , and the following experimental groups were created: G1a (no nano-CaCO ); G2a (0.5% nano-CaCO ), G3a (1% nano-CaCO ), G4a (2% nano-CaCO ), and G5a (5% nano-CaCO ). The setting-time (ST), compressive strength (CS), dimensional change (DC), solubility (S), and pH were assessed (24 hr and 30 days). Next, WPC + 5% nano-CaCO was manipulated varying the water-to-powder ratio: G1b (WPC/0.33 ml); G2b (WPC/nano-CaCO /0.33 ml); G3b (WPC/0.29 ml); G4b (WPC/nano-CaCO /0.29 ml); G5b (WPC/0.26 ml); and G6b (WPC/nano-CaCO /0.26 ml). The tests were repeated. The data analysis (2-way ANOVA and Tukey test, α = 5%) demonstrated that ST was shorter for samples containing nano-CaCO (p