Abstract: Higher strength and toughness concrete infrastructures are essential for resilient city construction. There are still some challenges in the existing mesoscopic model and fracture performance simulation research of steel fiber reinforced concrete (SFRC). Here, with the secondary development of Abaqus pre-processing method aiding with Python software, a three-dimensional mesoscopic model of SFRC was established, and cohesive units were inserted globally to simulate the interface between the aggregate and concrete matrix to study the effects of volume content of steel fiber V_SF, concrete matrix strength, and particle size of aggregate on the uniaxial compressive fracture performance of SFRC. Results show that, in the range of 0% to 2.0%, the larger the V_SF is, the superior the rupture resistance of SFRC is, and the greater the residual stress is. When V_SF is 2.0%, the stress of SFRC is 60.64% higher than that of concrete without steel fiber. When the strength of concrete matrix increases, the maximum stress corresponding to C60 and C80 grade concrete increases by 66.48% and 91.39%, respectively, compared with that for C40 grade concrete, the toughness of SFRC also increases and the stress-step curve of SFRC becomes steeper in the elastic phase. In the 5~7 mm range of aggregate particle size, the rupture resistance of SFRC increases significantly with the increase of aggregate particle size. Therefore, it can be concluded that the incorporation of dispersed, non-directional ductile steel fiber into a brittle concrete matrix can effectively enhance the seismic toughness and rupture resistance of the corresponding concrete infrastructure.

Key words: concrete, mesoscopic model, steel fiber reinforced concrete, cohesive unit, rupture resistance, interfacial toughness