The quality of steel fiber can be identified from the following aspects:
Appearance inspection: The shape of the steel fiber should meet the design requirements. Common shapes include straight, wavy, hooked, etc. The appearance should be free of defects such as rust, bending, and breakage.
Dimension inspection: Use a caliper or outside micrometer to measure the length and diameter of the steel fiber to ensure the uniformity of the size and meet the design standards. For steel fibers with irregular cross-sections, it is necessary to measure their stretch length to calculate the equivalent diameter.
Mechanical property inspection:
Tensile strength: Test the tensile strength of steel fiber by a tensile testing machine to ensure that it has sufficient tensile properties and improve the tensile strength of concrete.
Bending performance: Test the bending performance of steel fiber to ensure that it is evenly distributed in concrete and not easy to break, thereby improving the crack resistance of the overall structure.
Corrosion resistance: Test the corrosion resistance of steel fiber in a humid or corrosive environment by methods such as salt spray test.
Surface quality inspection: Visual inspection is used to ensure that the surface of the steel fiber should be kept dry and clean, and should not be sticky with residues, including surface oxides, oil stains, dirt and other substances that affect the workability of steel fiber in concrete.
Processing debris test: Check whether there are adhesion pieces, rust, impurities, etc. in the steel fiber caused by poor processing and severe corrosion. The total weight of these impurities should not exceed 1% of the weight of the steel fiber.
The above testing methods can comprehensively evaluate the quality of the steel fiber to ensure that it meets the requirements for use.