Análise estatística das propriedades do concreto autoadensável misturado com resíduo de borracha de pneus

Abstract

The present work aims to analyze the influence of the incorporation of rubber waste from scrap tires (RWT) in different contents and granulometries, in partial replacement for sand, in the physical and mechanical properties of self-compacting concrete. The civil construction market and the numerous technological innovations in the area have increasingly demanded materials that have special characteristics, thus seeking, among other benefits, the improvement in the durability and performance of the structures. Thus, concrete, the main construction material used today and the second most used in the world, has been the target of many researches and experiments. It is notable that the use of self-compacting concrete (SCC) has been described by many researchers as a major revolution in concrete technology due to its fluidity and viscosity characteristics, besides providing energy savings during its construction. The different ways of using waste rubber from scrap tires in the composition of the SCC has been a subject that has been extensively explored in several researches in the area, always looking for the sustainable use of waste and the benefits that it can provide to the final product. To obtain the SCC trace, this research was based on the Gomes Method, and for the best packaging of concrete aggregates, the EMMA software (Elkem Materials Mixture Analyzer) was used. Several mixtures were prepared with 10%, 30% and 50% of RWT and with particle sizes smaller than 0.6 mm and particle sizes between 0.6 mm and 4.8 mm. In the fresh state, all mixtures were subjected to tests that met the parameters required for an SCC. In order to evaluate the mechanical behavior of concretes, the tests in the hardened state (resistance to axial compression, sclerometry, static elasticity module, immersion absorption, frequency and damping factor) were also performed at 7 and 28 days, as well as, voids index and specific mass of concretes. Finally, using the DOE methodology (Design of Experiments), an analysis was carried out and the various effects that the content and granulometry of the RWT and the curing time caused on the results of the experiments were statistically observed. Curing time was the main statistically significant factor for the results of natural frequency and damping factor. Regarding the resistance to axial compression and the static elasticity module, the factor with the greatest statistical influence was the rubber content used in the mixtures.