Concrete pipes reinforced with a combination of steel and polypropylene fibers: Numerical Simulation of the Three-Edge Bearing Test

Concrete reinforced with two or more different types of fibers, rationally combined, is known as Hybrid Fiber-Reinforced Concrete (HFRC). This composite material offers enhanced properties, particularly in terms of ductility and crack control. Its application in drainage pipes, as a partial or total replacement for conventional reinforcement, may have a positive impact on the precast industry from both technical and economic perspectives. HFRC can be produced and cast in molds, similarly to traditional concrete. The reinforcing fibers are added to the mix like any other aggregate, allowing for the elimination of traditional steel mesh reinforcement and simplifying the production process. This study presents the numerical simulation of the Three-Edge Bearing Test (ASTM C497) to evaluate the mechanical behavior of Class II reinforced concrete pipes (RCPs) according to ASTM C76, and hybrid fiber-reinforced concrete pipes (HFRCP). HFRC, composed of steel and polypropylene fibers, is modeled as an equivalent homogeneous material with average properties (macroscopic model). The problem is solved using a nonlinear finite element code that incorporates a constitutive model with coupled damage and plasticity. Finally, numerical results are compared with experimental data obtained from a testing campaign involving six HFRCPs produced and tested with two different hybrid fiber dosages. The numerical model reasonably reproduces the bearing capacity and deformation of both HFRCPs and RCPs, considering the large number of variables involved.