Resistance evaluation of SFRC beams using accelerated drop-weight impact testing equipment

This study investigates the flexural and impact resistance of steel fiber-reinforced concrete (SFRC) beams using both drop-weight and spring-accelerated impact testing machines. Simply supported concrete beams with 0.0 %, 0.5 %, and 1.0 % steel fiber by volume were tested under quasi-static and dynamic conditions. Three impact scenarios were employed: free-fall of a 300 kg mass (F300), and spring-accelerated drops with 300 kg (A300) and 100 kg (A100) masses, enabling separate evaluation of mass-dominant and velocity-dominant impacts. Increasing fiber content notably improved performance across all loading types. Under quasi-static loading, the 1.0 % SFRC beam exhibited 83 % higher peak flexural strength and over three times greater energy absorption compared to plain concrete. In impact tests, fiber-reinforced beams demonstrated higher peak reaction forces and smaller, more distributed cracks, indicating effective crack control. Energy dissipation also significantly increased, affirming the crack-bridging action of steel fibers. Beams with 1.0 % fiber content absorbed up to three times more impact energy and retained structural integrity under repeated impacts, whereas plain beams failed rapidly. These results confirm that moderate steel fiber inclusion greatly enhances toughness, energy dissipation, and damage tolerance. Therefore, SFRC is highly suitable for applications in protective structures and impact-critical infrastructure, supporting performance-based design strategies.