Experimental and analytical study of the high-strain rate flexural behavior of SFRC

Abstract

Steel fiber-reinforced concrete (SFRC) with hooked-end steel fibers was created for use in urban furniture to protect against blast and impact loads. Due to the variety of impact loads that these structures may experience, it is necessary to assess the impact of high strain rates on the flexural behavior of SFRC. This study involved testing SFRC beams with 1% volume content of hooked-end fibers, which were 30 mm long and had an aspect ratio of 80. The beams were tested at different strain rates and in a three-point loading configuration. Four strain rates were tested, ranging from 10−6 to 10−2 s−1, and impact tests were conducted using a drop weight impact test machine and varying drop heights, corresponding to strain rates ranging from 1 to 20 s−1. Two load cells were used to measure the total impact force and one reaction force, which were then used to assess the inertial force. Two accelerometers measured the maximum acceleration at the midspan of the beams. The results included quasi-static and dynamic load-deflection relationships, dynamic flexural tensile strength, and failure mode of SFRC specimens, as well as the relationship between the inertial force and strain rate. The study revealed that deflection capacity and flexural tensile strength increased with loading rate. The study also provides dynamic to static property ratios, such as flexural tensile strength and fracture energy, which are compared with those recommended by the CEB-FIP Model Code and other researchers.