Ultrasonication Effect of Silica Fume on Compressive Strength of Cement Pastes

Portland cement production is responsible for about 6–8% of the world’s CO₂ emissions. To reduce this emission, several researchers have studied the replacement of clinker by highly reactive supplementary cementitious materials such as rice husk ash, metakaolin and silica fume in the production of high performance cementitious materials. In these studies, it was verified that the silica fume agglomerates due to the small size of its particles and with that its reactive potential is reduced. Thus, the objective of this research is to verify the ultrasonication effect of silica fume on the mechanical performance of cement pastes. Three cement pastes were studied, a reference with 100% Portland cement CP V-ARI and two with 10% substitution of the Portland cement by silica fume, one in its natural state and the other ultrasonicated. It was prepared 12 test specimens for each trait by setting the scattering at 140 ± 10 mm in the mini slump test. Three specimens were ruptured at 1, 3, 7 and 28 days of hydration. With the results, a statistical analysis ANOVA was performed through the Duncan’s test in Statistica v10 software. Through the results, it was verified that the ultrasonication of the silica fume increased its reactive potential and consequently its mechanical performance. Thus, by ultrasonication of silica fume it is possible to produce high-performance cementitious materials with lower consumption of Portland cement and consequently reduce the emission of CO₂ into the atmosphere.