Influence of the type of fiber on the structural response and design of FRC slabs

Most codes for the design of fiber-reinforced concrete (FRC) structures are based on experience gained over the years with steel fibers. Recent codes include the possibility of applying the same considerations for FRC structures with plastic fiber. However, the consequences of assuming identical design considerations regardless of the type of fiber is scarcely known in terms of the structural behavior of full-scale elements. The main goal of this paper is to assess the influence of the type of fiber on the performance of full-scale concrete slabs, emphasizing the consequences of using a common design approach. For that, a comparative experimental study was conducted to expose differences regarding crack patterns and load-deflection behavior. Then, finite-element simulations were performed using the constitutive equations from a commonly used model code. The results indicate distinct levels of overestimation of the structural behavior measured experimentally, confirming that specific design considerations are required depending on the type of fiber used. Based on the findings, correction factors are proposed for the design of FRC slabs with each fiber.