Study on Dynamic Behavior and Tensile Strength of Concrete Using 1D Wave Propagation Characteristics

Concrete structures are usually fractured under dynamic loadings, so it is important to have a clear knowledge of their dynamic behavior and tensile strength. First, the principle of one-dimensional (1D) stress wave reflection and superposition at free surface is briefed, and the spalling test method based on the Hopkinson bar is presented. Then, the attenuation law of stress wave is explored and the dynamic tensile/compressive moduli of concrete are evaluated according to the wave propagation experiment. Lastly, the influences of strain rate on the spalling tensile strength and failure patterns of concrete are further analyzed. The testing results demonstrate that the attenuation of stress wave accords with an exponential law when propagating in the concrete bar. The difference between the dynamic elastic moduli of concrete in tension and in compression is minor. Spalling tensile strength is sensitive to strain rate, and there is an obvious linear correlation between dynamic increase factor (DIF) and strain rate in a log-log plot for strain rate above 1.0/s; a single fracture occurs at low strain rate, while multiple fractures are detected with increasing strain rate.