FORTA® research and development has engineered several grades of fiber reinforcement for various applications and performance level values since our inception in early 1978. All fibers are not to be considered equal — each grade of fiber offers outstanding performance value when matched with the appropriate application. For instance, we would not recommend the use of our stucco fibers to take the place of welded wire fabric in a slab-on-grade application. FORTA'S 4-C's fiber characteristics formula assists the specifier, designer, or contractor to choose the correct fiber for a required performance level. Contact FORTA® for formula assistance and fiber selection.

Fiber chemistry is very important if the fiber is expected to hold up in the aggressive alkali environment of Portland Cement Concrete. For monofilament fibers, FORTA® offers two types of fibers to choose from: 1.) nylon, which possesses high strength and good resistance to alkali, and 2.) polypropylene, which combines strength with excellent (inert) resistance to alkali. Unlike nylon, polypropylene is hydrophobic (non-absorptive), which makes it an outstanding choice in freeze-thaw environments. For fibrillated or net-shaped fibers, polypropylene is the optimum choice, offering high strength, excellent resistance to alkali, and the ability to accept the fibrillating or slitting manufacturing process. The engineered fibrillation pattern introduced during manufacturing creates the net-like shapes that provide excellent bonding and anchoring capabilities in the concrete matrix. Second generation macro/structural fibers are produced from blends of polypropylene and co-polymers — all inert to alkali attack, chemically inert, non-absorptive and very high strength.

As the name suggests, monofilament fibers are single strand fibers, similar in shape to a standard finishing nail. Fibrillated fibers are deformed or irregular in shape, which offers better anchoring and bonding characteristics in concrete. Deformed rebar, anchors within concrete much better than smooth rebar. It is this same reasoning that has proven that fibrillated, net-like fibers (deformed) anchor much better than monofilament fibers (smooth and round) within the concrete.

FORTA® produces a complete family of synthetic fibers used at various dosages to meet the performance
requirements of a project or owner. In general, FORTA® typically recommends the following performance-based characteristics:

1. For plastic shrinkage crack-control during the early life of the concrete: 1.0 lb./cubic yard of a 3/4" long polypropylene or nylon monofilament fiber;
2. For shrinkage and temperature-related crack-control as an alternate to light non-structural wire mesh in most applications: a minimum of 1.5 Ibs./cubic yard of a 1-1/2" long polypropylene fibrillated fiber;
3. For shrinkage and temperature crack-control and enhanced post-crack properties to allow for a higher replacement level of conventional steel reinforcement: 4 + Ibs.1cubic yard of a 1-1/2" to 2-1/4'' long polypropylene/co-polymer blend of fibrillated and macro-monofilament fibers.

Contact FORTA® Engineering for fiber selection and dosage assistance.

The function of length is very similar to that of fiber shape with regards to anchorage ability. As with shape, if a short fiber pulls out of the concrete before it fails or breaks, the high tensile strength of the fiber has been wasted. Longer fibers are better equipped to bond and anchor in the concrete matrix, which results in better performance and improved long-term durability. Fiber purpose, shape, and chemistry may determine an optimum fiber length for a given concrete mix an application. Contact the FORTA® Technical Department for assistance to determine the proper fiber length for a specific application.