Experimental Study and Mechanism Analysis of the Shear Dynamic Performance of Basalt Fiber-Reinforced Concrete

Basalt fiber (BF) has been proven to play a positive role in strengthening the toughness of concrete. At present, there are many studies that investigate its compressive and tensile behavior. However, concrete is often subjected to shear action in practical engineering. In order to explore the shear dynamic performance of BF reinforced concrete (BFRC), a systematic direct shear dynamic performance experiment was carried out using BFRC specimens with four different fiber lengths and four different fiber contents while considering the influence of earthquake magnitude strain rate. The experimental results showed that BFRC had an obvious strain rate effect, and the increase in strain rate significantly increased the shear stress of BFRC. As either the BF content or length increased, the concrete shear dynamic increase factor first exhibited an increasing trend followed by a decreasing trend. Based on the comprehensive analysis of static and dynamic data, the shear stress and dynamic increase factor of BFRC reached the maximum values at the fiber content of 0.2% and BF length of 6 mm, and the corresponding shear stress and dynamic increase factor were 10.48 MPa and 1.29, respectively. According to the general trend analysis, the plastic deformation capacity of BFRC was gradually improved with the increase of BF content and length. Meanwhile, scanning electron microscopy (SEM) and computerized tomography (CT) technology were used to systematically analyze the stress mechanism of BFRC from the microscopic point of view. Overall, this study provided a theoretical basis for the application and development of BF in concrete.