Q:How do NyconXL macro fibers compare to other high-dosage, or so-called "structural" fibers?

A: NyconXL fibers fill a unique need in the concrete industry in that they are designed expressly for enhancing the post-first crack properties of the concrete composite. A fibrillated polyolefin-polypropylene fiber, NyconXL fibers generate a higher Average Residual Strength (ARS) at lower dosages than other high-dosage macro or so-called "structural" fibers. They are a cost-effective reinforcing system for ready-mix and precast applications involving seismic and catastrophic engineering.

Nycon conducted the extensive research on NyconXL at the South Dakota School of Mines and Technology using ASTM C1399. The purpose of the testing was to determine XL's benefits in concrete at dosages higher than other shorter-length, micro synthetic fibers, which are typically used as secondary reinforcement for temperature or shrinkage crack control. The testing included NyconXL 1-1/2" long fiber bundles (also available in 2" lengths), Nycon's own nylon fibers, NyconRC and MultiMesh, as well as Nycon's polypropylene fiber, ProConF.

There are two ASTM Test Methods used to evaluate the properties of macro fibers: C1609 and C1399, for testing toughness Index and average residual strength, respectively. Nycon chose C1399 for testing NyconXL because it is primarily used by government agencies to approve synthetic fibers: One of those agencies, the Florida Department of Health, developed a specification for fiber reinforced concrete septic tanks that based acceptance on attaining a specific ARS resulting from the use of C1399.

NyconXL fibers were introduced in the mix at a much higher dosage level (3-9 lbs/y³) than the standard or conventional fiber dosages of 1.0-1.5 lbs/y³. Results indicated that the higher the dosage of fibers, the greater the beneficial properties of the mix. For example, the properties of XL-reinforced concrete that demonstrated significant improvements were fatigue strength, which reflects the resistance of concrete to multiple, uniform loadings (testing calls for up to 2 million cycles of loading), as well as average residual strength, and impact resistance. (It is for these property enhancements that the Federal Highway Administration specifies for 3 lbs/y³ of synthetic fiber in ultra-thin whitetopping.)

When comparing NyconXL ARS data with the data of other fibers submitted to the Florida Department of Health, it was proven that NyconXL met the specification criteria at a dosage level lower than the other fibers tested. NyconXL met the specification at 3.5 pounds per cubic yards while the other materials typically required a dosage of 4 or more pounds per cubic yard.

In summary, when introduced at 3 lbs/y³ or more NyconXL macro fibers, with their higher count and longer length, reduce critical fiber spacing and increase fiber bonding within the matrix. They are a test-proven superior secondary reinforcement that performs well beyond all other macro fibers, as well as conventional micro fibers, not only for temperature and shrinkage crack control, but certainly for resistance to seismic and catastrophic elements in ready-mix and precast applications.

Technical Advantages of NyconXL-Modified Concrete:

• Increased average residual strength (C1399) and residual strength factor (C1609)
• Dramatically increased impact and penetration resistance
• Reduced risk of catastrophic failure of concrete
• Significantly increased fatigue strength
• Improved standard property enhancements over conventional synthetic fiber reinforcement used at normal dosage levels

Business Advantages of NyconXL Fibers

• Engineering improvements and reduced labor and material costs with the elimination of conventional welded-wire reinforcement.
• More efficient secondary reinforcement than other hybrid lower-dosage synthetic fibers.
• Lower dosage required (with less cost) than other high-dosage macro fibers to achieve the same benefits.

Please note that macro high-dosage synthetic fibers are used in plain structural concrete as secondary reinforcement. These fibers do not replace structural steel, as used in structural concrete per ACI 318. Macro fibers do not replace rebar where the cross-sectional area of rebar is used in calculating the loading properties of the concrete composite.

For a synopsis of NyconXL's test results, please go to the NyconXL "Additional Product Information" page.

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