Experimental study on dynamic mechanical properties and constitutive model of basalt fiber reinforced concrete

Basalt fiber reinforced concrete, a new high performance cement-based composite material, is a focus of attention and has developed rapidly in recent years. In this paper, the impact behavior of BFRC with six kinds of volume content (0%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%) subjected to various high strain rates was investigated using a 74 mm-diameter split Hopkinson pressure bar (SHPB) apparatus. And the effects of volume fractions and strain rate on dynamic compressive strength and toughness were studied according to the stress-strain curves obtained by the experiment. From the microscopic point of view, by analyzing the scanning electron microscope (SEM) photographs, this paper made a research on the micro-properties and pore structure of BFRC. The fiber distribution situation and the interface between fibers and cement were observed. By studying the micro-properties and pore structure of BFRC, the interface properties and the strengthening mechanism of BFRC were analyzed. In the end, the dynamic constitutive law of BFRC was derived based on an improved Zhu-Wang-Tang (ZWT) dynamic constitutive model which took into account the material damage. The new equation was used to fit the experimental stress-strain curves.