The influence from steel bar on concrete fracture behavior under different impact velocities

Abstract

Three‐point bending tests on notched plain concrete beams and lightly reinforced concrete beams were carried out with a drop‐hammer impact instrument. The shape of the specimen followed the RILEM recommendation, that is, 150 mm × 150 mm in cross section, 800 mm in length, and span was kept constant 600 mm. And only one conventional steel bar was placed in the lightly reinforced concrete beam. The high‐speed camera and digital image correlation (DIC) technology were applied to catch the fracture process under dynamic loads. And the reaction force, mid‐span deflection, crack velocity, the horizontal strain of concrete at the notch root, and the strain of steel bar midpoint were measured over three impact velocities (i.e., 9.89 × 102, 1.71 × 103, and 2.21 × 103 mm/s). The test results showed that the dynamic fracture energy for plain concrete and reinforced concrete increased with the increase of the impact velocity. When the impact velocity reached 2.21 × 103 mm/s, the steel bar reached yielding, which resulted in the influence from reinforcement on fracture energy weakened. Both of the dynamic fracture toughness for plain concrete and lightly reinforced concrete increased linearly as the growth of impact velocity. Furthermore, the crack extended with a decreasing speed for plain concrete and reinforced concrete. And the first‐stage crack velocity in concrete was inhibited effectively by steel bar, but the inhibitory effect declined as the increase of impact velocities.

A comprehensive experimental review of strain rate, size effect, creep and confinement in concrete: Part III

“…• Local damage that occur in first impact results in weakening of propagation of vibration under second impact. (Song et al, 2021) • Three-point bending beams of plain concrete and reinforced concrete are tested using a drop hammer test.…”

Comparison of Fracture Behavior in Single-Edge Notched Beams Reinforced with Steel Bars or CFRP Bars

“…This approach has been extensively applied in various fracture models to investigate the role of reinforcement in concrete beam fracture behavior. Alrayes et al [34] introduced a numerical modeling technique that employs the scaled boundary finite element model (SBFEM) for the simulation of crack propagation, which is applied to simulate the three-point bending tests of SEN concrete beams under various loading scenarios, confirming the efficacy of the proposed model. Additionally, alongside the three-point bending test, the four-point bending test is highly regarded for the study of beam bending failure behavior due to its ability to maintain a constant bending moment at specific locations on the beam, thereby achieving zero shear.…”

“…In previous studies, Song [34] conducted impact three-point bending tests on a plain concrete beam and a lightly reinforced concrete beam. This study assessed the influence of steel reinforcement on the crack velocity, fracture toughness, and fracture energy.…”

Mechanical Property Test and Damage Evaluation Analysis of Steel Fiber Stainless-Steel Reinforced Concrete Beams (SFSRCBs) under Impact Load

“…At present, the research on ship-bridge collision mainly focuses on the impact resistance mechanical properties of reinforced concrete(RC) structures. For example, the influence of impact mass, impact velocity, cumulative impact times and other factors on the impact force, structural deformation and failure mode of concrete structures (Song et al, 2021;Fu et al, 2020;Xu and Zeng, 2015). At the same time, some scholars have carried out research on the impact resistance mechanical properties of stainless steel reinforced concrete (SRC) structures, , and Zhang and Xu.…”