Q. Are steel fibers economically feasible when compared to conventional reinforcement?
With the wide range in the steel fiber dosage rate, 20 to 120 pounds per cubic yard, there is an equally large selection of applications. Therefore, one must chose the application and then determine the quantity of steel fiber that will perform the desired function before accessing the economic feasibility.

In comparing steel fibers to any conventional secondary/temperature-shrinkage reinforcement the major difference to note is the reduction in time, labor force and equipment required.

• First, no placement crew is required to position the wire mesh or rebar mat. This also means the time required for this exercise is totally eliminated.
• Second, the placing and finishing crew can be reduced by one laborer. The one laborer eliminated is the one that pulls up the mat, or should we say attempts to pull up the mat. There is always the question of needing chairs to support the wire mesh at the proper height in the cross-section of the concrete.
• No forklift and operator is required to move the steel from the truck to the storage location and then to point of use.
• No concrete pump is required to place the concrete, as there is no WWF or rebar to impede the direct placement of the concrete from the mixer chute to point of use. This eliminates a costly operation, which also is a potential bottleneck.
• Contractors have indicated they can place more steel fiber reinforced concrete per day than conventional steel reinforced concrete.
• Laser screed operators are proponents of steel fiber reinforced concrete.

These items are critical in calculating the true difference in cost between the conventional steel secondary reinforcement and steel fibers. Additionally, one must factor in a potential reduction in the concrete slab cross section when the steel fiber dosage level is sufficient to increase the flexural strength of the composite.

There was an engineering report prepared by the NRMCA relating their findings in a study, which looked at the structural value of wire mesh when used as secondary reinforcement. The specific application was a highway pavement. The study concludes that by adding just 1/8" of concrete to the pavement cross-section the structural values would be equal. Thus supporting the conclusion that conventional secondary reinforcement does not contribute to the structural design of the concrete cross-section.

Technically the three dimensionally distributed steel fibers contribute more to the cross-section than the single plain of conventional secondary reinforcement. This is important when looking at a specific application. As an example, through application testing the designers of automobile manufacturing plants have concluded that steel fibers and only steel fibers are used in all of the slab-on-grade concrete.

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