Modeling PPFRC beams: assessment of constitutive and bond models

Numerical modeling of reinforced concrete (RC) elements is well established, but hybrid rebar–fiber-reinforced concrete (RFRC) systems introduce additional challenges due to high nonlinearity from complex material behavior and fiber-rebar interaction. With Eurocode 2 (2027) incorporating fiber-reinforced concrete provisions, reliable constitutive models are essential. This study evaluates modeling strategies for RFRC beams in Abaqus using the Concrete Damaged Plasticity model. Two post-cracking tensile laws are examined: the Eurocode 2 Annex L formulation and an inverse-analysis model derived from notched beam tests. Rebar–concrete interaction is modeled using both embedded constraints and cohesive zone approaches. Moel validation is performed against four-point bending tests from an ongoing program on minimally reinforced beams with three polypropylene fiber volume fractions. Results show that the Annex L model provides reasonable predictions for polypropylene fibers. Both interaction approaches capture global structural behavior with respective advantages in computational efficiency and deformation accuracy, although the final failure response remains mesh-sensitive when strain-based material criteria are used.