Comportamento estrutural de elementos de concreto reforçado com fibras moldados em camadas

Abstract

The addition of steel fibers to concrete, mainly in Brazil, presents as main limitation its high cost, making it unavailable for application of steel fiber reinforced concrete (SFRC) in the practical field, for example on industrial floors and tunnel lining. In view of the difficulty of ensuring competitiveness of SFRC in the civil construction market, this work presents an analysis on double layer concrete elements, combining a layer of SFRC and another conventional concrete layer, using steel fibers in the regions of greater structural demand, thereby reducing its production cost. In this context, it is necessary to validate the double layer pieces, so this work aims to perform the three-point bending test recommended by EN 14651 (2007), which allows to obtain flexural tensile strength as well as residual strength. Beyond validation performance obtained for the double layer elements, it is necessary to evaluate the fiber orientations, since this parameter is of great importance for the control quality of SFRC parts. Thus, this work applies the method proposed by Torrents et al. (2012) to determine the orientation of the fibers of the elements analyzed in this work. From the analysis of the results of the tests, it was observed that pieces of double layer met the performance criteria established by FIB Model Code (2013), besides the change on preferential orientation of the fibers due to molding process, that interfered on the post cracking resistance of double layer materials.