A finite element model of fracture toughness of ultra-high performance concrete

UHPC is the most promising building material. It is of great significance to establish a finite element model that is consistent with the actual situation for the study of the mechanical properties of UHPC. The paper presents a numerical method for modelling the fracture toughness of UHPC. The finite element model adopts separated modelling, considering UHPC as a two-phase material, and establishes a concrete matrix model and a steel-fibre model respectively. The concrete matrix adopts the concrete damaged plasticity (CDP) model. A large number of disjoint and randomly distributed cylinders are generated in Abaqus through Python to simulate steel fibres and are embedded in the concrete matrix. The bond-slip relationship between steel fibres and concrete is indirectly simulated through the tensile stress-strain relationship of steel fibres. The finite element model is used to simulate the uniaxial tensile experiment and the three-point bending experiment of UHPC. The established finite element model is of higher accuracy than the line-element steel-fibre model used in previous studies, and is more consistent with experimental data, which verifies the effectiveness of the numerical method.