Study of Dimensioning Aspects of FRC Based on the Beam Flexion Theory Iva E. Pereira Lima 1(&) and Aline S. Ramos Barboza 2 1 Civil Engineering/Structures from Federal University of Alagoas, Alagoas, Brazil ivaemanuellyl@gmail.com 2 Structural Engineering from the University of São Paulo and Professor Federal University of Alagoas, Alagoas, Brazil Abstract. The fiber reinforced concrete (FRC) have a higher load capacity in the post-cracking stage, however, this increase only occurs if the concrete is dosed and applied properly and, for this, there are standards that establish design aspects for use of the FRC. However, in these documents, the portion of the resulting resistant strength of the fibers is not fully described in their equations and is determined for specific situations. Therefore, and with the objective of obtaining the positioning and the resultant of the fibers of a model of fluid concrete reinforced with fibers, this work presents a study related to the deter- mination of the resultant of the fibers in the stretched part of the concrete. This determination was obtained based on the bending theory in beams, through the three-point bending test standardized by EN 14651 (2007) [8], where both beams with steel fibers and polymeric fibers were used. From this, the equation obtained analytically was compared with those determined by international codes and it was realized that, when comparing the three methods used, the intermediate value corresponded to the determined analytically, where the results showed variations due to the different forms of arrangement that each method uses. Keywords: Fiber reinforced concrete  Flexural test  Beam flexural theory  Determination of the resultant of the fibers 1 Introduction The use of fiber reinforced concrete (FRC) has been gradually increasing worldwide and has been undergoing several advances since the year 1970 [2, 12, 14]. From this advance, research with fiber-reinforced concrete began to show the application of fibers as a structural material and, together with this type of reinforcement, studies showed that the negative aspects of FRC could be reversed with the use of additives, where the fluidity of the composite allows the distribution of fibers to occur in a uniform way, being possible to use the flow of concrete launching to guide the fibers [7, 10, 17] The use of this type of concrete for structural purposes has been consolidated over the last 15 years with the development of concepts of fracture mechanics to describe its residual tensile strength [6, 10]. As regards the world scale, this growth trend is © RILEM 2021 P. Serna et al. (Eds.): BEFIB 2020, RILEM Bookseries 30, pp. 584–595, 2021. https://doi.org/10.1007/978-3-030-58482-5_53