Evaluación de la segregación estática en concreto autoconsolidable utilizando un dispositivo basado en la ley de Stokes

Abstract

Abstract. In the present study the displacement of a spherical particle, to simulate the segregation of coarse aggregate in self-compacting concrete, was evaluated. For this purpose, a Stokes' Law Based Device (SLBD), which allowed to monitor the movement of a particle in opaque fluids, was designed and built. This device contains an arrangement of pulleys, a system to suspend spheres, an optical sensor to monitor the spheres displacement, and a data acquisition system. Tests were performed on pastes and mortars containing different dosages of superplasticizer and viscosity modifying agent, in order to obtain the terminal velocity of the falling sphere. The results indicate that using the SLBD was possible to simulate the movement of an aggregate in cement pastes and mortars, and determine the dosage of additives necessary to ensure a minimum displacement of the sphere in the fluids. The obtained information was used to design concrete mixtures which were characterized by using the extensibility and V-funnel tests; as a result, concrete mixtures had adequate flow and segregation resistance characteristics required for this type of concrete.