Hooked End Steel Fiber Concrete Has Good Crack Resistance and Integrity

1. About the hooked end steel fiber

Hooked end steel fibers can replace stirrups to meet the requirements of joints in terms of strength, ductility, and energy consumption. Hooked end steel fibers are used in seismic frame nodes. Hooked end steel fibers can also provide a function similar to that of stirrups to confine concrete and solve the construction problem that the extrusion of steel bars in the node area makes it difficult to pour concrete. Steel fiber also has good crack resistance, which can make the component in the elastic stage without cracking under the standard load, and there will be no stress redistribution. The self-waterproof prestressed roof panel made of hooked end steel fiber not only improves the crack resistance of the self-waterproof prestressed roof panel but also reduces the reinforcement ratio of longitudinal prestressed bars and improves the durability of the structure.

2. The performance of hooked end steel fiber reinforced concrete

Steel fibers do not spring back when 40mm fibers are used. It can control the rebound. The quality of concrete steel fibers is uniform, which usually reaches 55MPA strength. In special operations, it can reach 100MPA. The environmental conditions are good, the dust is less, and the fiber operation is safe. It does not require anti-corrosion treatment, which prevents electrolysis and accelerated corrosion.

When using steel fiber reinforced concrete, it will be found that there are some randomly scattered short fibers in the steel fiber reinforced concrete. This is mainly to hinder the expansion of micro-cracks inside the concrete and prevent the generation of micro-cracks. In the early stage of loading (pulling and bending), the cement base and the fibers receive external forces together. When concrete cracks, the fibers spanning the cracks become the primary recipients of external forces. Therefore, freeze-thaw resistance, heat resistance, wear resistance, cavitation resistance, and corrosion resistance are significantly improved.

When the steel fiber reinforced concrete is damaged, most of the fibers are pulled out rather than broken due to the good crack resistance and integrity of the hooked end steel fiber reinforced concrete. According to various theories of the reinforcement mechanism of steel fibers, such as the theory of steel fiber spacing, composite material theory, and microscopic fracture theory, as well as the analysis of a large number of experimental data, it can be determined that the reinforcement effect of the fiber mainly depends on the strength of the matrix, the aspect ratio of the fiber, the effect of fiber volume fraction, fiber-matrix bond strength, and fiber distribution and orientation in the matrix.