Investigating crack propagation speed in ultra-high performance concrete using digital image correlation method

Abstract

This paper presents the research results on a method for determining the crack propagation rate in ultra-high-performance concrete (UHPC) specimens, both reinforced and non-reinforced with steel fibers, under different loading rates. Three-point bending tests were conducted on pre-cracked specimens under static loading using a universal testing machine (UTM) and under high-speed dynamic loading using an energy frame system (I-SEFIM). The crack propagation rate was recorded using a high-speed camera system and analyzed through the digital image correlation (DIC) method. The results indicate that the crack propagation rate is significantly influenced by the loading rate, and the presence of fibers in the concrete notably reduces the crack propagation rate in the specimens under both static and dynamic loading conditions.