Hooked End Steel Fiber Can Enhance the Bond Strength of Concrete

Steel fiber concrete has the same mixing, operation and construction performance as ordinary concrete. The fiber will not be spheroidized in the concrete and is evenly distributed. It can be produced in a commercial concrete mixing station and can be used for pumping construction.

The rough and clean surface of steel fiber can be firmly combined with cement slurry in concrete, which is the fundamental reason for the hooked end steel fiber to improve the various properties of the concrete. So what functions of concrete can be enhanced by hooked end steel fiber produced by concrete fiber suppliers?

1. The length of hooked end steel fiber

The length of hooked end steel fiber refers to the straight line distance between the two ends of the fiber, expressed in Lf, and its scale can be 15 to 60mm. The diameter or equivalent diameter of the fiber cross-section (when the steel fiber is a non-circular cross-section, its cross-sectional area is equivalent to the diameter of the circular cross-sectional area), expressed by df is generally 0.3 to 1.2mm. The length-to-diameter ratio of hooked end steel fiber refers to the ratio of the length of the steel fiber to the diameter or equivalent diameter, that is, Lf/df, which is generally 30 to 100. The volume ratio of hooked end steel fiber refers to the percentage of fiber in the volume of fiber concrete. Expressed by PF, it indicates the amount of steel fiber in the mixture.

2. Hooked end steel fiber can reinforce the bond strength of concrete

The failure of concrete is mainly caused by the pulling out of fiber rather than the breaking of fiber, the strengthening of fiber mainly depends on the bond strength of steel fiber concrete matrix interface. In addition to the function of the matrix, the bond strength of the steel fibre should be improved from the appearance and shape of the fiber. In order to improve the bonding strength of the fiber, it is often used to roughen the surface of hooked end steel fiber and increase the contact area and friction with the matrix with an irregular cross section; indent or press the fiber surface into a waveform to add mechanical bonding force; The two ends of the fiber are shaped into hooks or big heads, etc., to increase its anchoring force and pull-out resistance.

The reinforcing effect of steel fiber is related to the length, diameter (equivalent diameter) and aspect ratio of steel fiber. The reinforcing effect of hooked end steel fiber increases with the increase of aspect ratio. The length of hooked end steel fiber of the steel wire is too short to enhance the effect. Too long length is difficult to construct and affects the quality of the mixture. If the diameter is too small, it will be easily bent during the mixing process. If the diameter is too long, the enhancement effect will be poor at the same volume rate.