Análise da influência do empacotamento dos agregados na porosidade do concreto

Abstract

The resistance to external actions which the concrete element is subject is related to the porosity of concrete. One of the factors that interfere in resistance is the water / cement ratio, where the higher the water / cement is less resistance. This water consumption is related the voids of concrete in the hardened state; The more concrete water consumption, the greater the influence on the voids. In the curing process of incorporated air bubbles are trapped inside the mass of concrete generally interconnected to each other, creating small capillaries which facilitate the penetration of aggressive agents and consequently as the mass of concrete becomes non-uniform, creating points fragility. Models of packagings of particles aim to reduce this voids, filling these voids with smaller and smaller particles, making the interconnection of air bubbles incorporated in the kneading of the concrete. There are some mathematical models which are divided into continuous distribution and discrete distribution models, for determining the packaging of the particles. The presented work aims to apply two models, one model group representative discrete distribution model and the other group representative continuous distribution. Traces of concrete had the chipping size modified by mathematical models, thus creating new features with new particle size distribution. These two models were compared to the mark set by tracing used in some concrete in the state of Paraná. The same materials that concrete producers to make their practical use were used. The analysis of particle packaging was performed by testing aiming to examine the durability of mass concrete. To compare the samples, they were prepared and tested in a standardized manner. The best results were obtained for traits that had their grain size defined by mathematical models of particle packaging. The concrete produced by dashes with particle size controlled by a mathematical model showed better results in relation to the concrete produced at the mark, getting a concrete more resistant to aggressive agents, in other words, with greater durability.