Experimental and numerical studies of size effects of Ultra High Performance Steel Fibre Reinforced Concrete (UHPFRC) beams

Ultra High Performance Steel Fibre Reinforced Concrete (UHPFRC) is a relatively new construction material with high strength, fracture toughness and ductility. Although many aspects of UHPFRC have been investigated extensively, the size effects on structural strength of UHPFRC members remain largely unknown. This is mainly due to the lack of sufficient and reliable experimental data. This study investigates the size effects on flexural strength of similar notched UHPFRC beams under three-point bending tests. Nonlinear finite element simulations using the concrete damage plasticity (CDP) model in ABAQUS were also conducted, using material properties extracted from uniaxial tensile and compressive laboratory tests. It was found that the size effect on the beam nominal strength is little due to high ductility of UHPFRC. The numerical simulations using the CDP model can predict load–displacement curves and crack propagation process with good agreement with experimental data.