Análise comparativa das propriedades reológicas no estado fresco e mecânicas de concretos autoadensáveis com substituição parcial do cimento por sílica de casca de arroz

Abstract

The need for new technologies in the building industry has led more and more specialists to develop new materials, in order to optimize constructions. The self-compacting concrete emerges as a proposal where there is a reduction in costs and failures resultants from manual vibration’s process due to having the ability to thicken with only the gravity’s force. Its use in conjunction with waste by products from industrial areas such as the rice husk ash,can provide not only ecological gains, but also performance gains for the material concrete, particularly as regards the resistance at the hardened state and marked reduction of the phenomena of segregation and oozing fresh. For this research was dosed a dash for SCC with 3,57%of partial replacement of the cement forrice husk ash and other reference dash, without replacement. For finding their rheological properties, were used the assays of Slump Flow Test and Slump Flow Test T50 to check the fluidity, the assay of L -Box to test the concrete’s ability of pass by obstacles and the V Funnel 5Minutes to the knowledge of the ability to resist the phenomenon of the material’s segregation. As for the hardened state, were brokenup bodies of evidence at ages 7 days and 28 days to verify the axial compressive and traction by diametrical compression.. The results indicate that the use of rice husk ash in self-compacting concretes provides decrease in fluidity, since it generates higher viscosity in the paste, making it more difficult to handle compared to the reference concrete. On the other hand, there was a reduction of the exudationand segregation in the concrete with RHA. In terms of strength, the use of RHA provided increment of resistance in axial compression and in traction by diametrical compression.