There are several methods to identify polypropylene fibers:

In comparison to visual measurement, superior fibers are characterized by uniform length, even thickness, and a light, lustrous, bright white color. The better quality fibers have minimal or no inclusion of spun fibers, slubbed fibers, thick fibers, twisted fibers, greasy fibers, clumped fibers, and impurities. The opposite is true for inferior quality fibers.

2. Bath Comparison Method: Pour 500ml of water into two cups, then add 0.4g of identical fibers to each. Stir for 10 seconds and observe; the superior quality fibers will disperse evenly and remain suspended in the water; while inferior quality fibers will not disperse evenly, or may float in the water as clumps or clusters.

3. Odor Identification Method: High-quality fibers: eco-friendly, mild without irritation; low-quality fibers: polluted, strong odor with potent irritation.

4. Moisture Removal Method: Some low-quality polypropylene fibers contain moisture (which is hard to detect by hand), and its moisture content can be measured through drying or sun-drying. Although the fiber is priced low, it essentially sells water. Assuming a moisture content of 5%, 1 kilogram of moisture-containing fiber is actually only 95% fiber, and the fiber price will be 1.05 times the original price.

5. The Sunlight Exposure Method: Low-quality polypropylene fibers, due to cost reduction, are not treated with UV resistance. Polypropylene fibers lose their strength within one to two years under sunlight exposure, making it difficult for low-quality polypropylene fibers to perform long-term in concrete. Simply by conducting on-site inspections (closely identifying the consistency between the long fibers submitted for testing and the short polypropylene fibers at the construction site), after prolonged exposure to sunlight and night dew, then testing their tensile strength, the difference can be distinguished.