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Macrosynthetic Fibers Increase Project Profitability Over Conventional Temperature-Shrinkage Control

When using conventional WWF (welded wire fabric) or #3 & #4 rebar for temperature-shrinkage control Structural Engineers sometimes use a one-size-fits-all approach on projects to minimize the potential for the field crew to place the wrong reinforcement system in a cross-section. However, the Structural Engineer may determine what temperature-shrinkage reinforcement is needed for the most demanding concrete application and then specify that reinforcement throughout the construction.

If a project includes a maintenance garage and an office, then most often the office is specified the same temperature-shrinkage reinforcement as the maintenance garage — resulting in a costly dollars and cents penalty to the owner.

However, when macrosynthetic fibers are added to the concrete mix at the plant the dosage rate from truck to truck can be adjusted to meet the exact needs of the project. This means the office floor slab can be specified with the precise quantity of macrosynthetic fibers needed versus the overkill created when the maintenance garage floor slab reinforcement is used.

Save Macro Bucks

This over-specification of WWF is not the first hit in the owner’s pocket. The use of conventional temperature-shrinkage WWF creates additional costs related to labor, equipment, and material that are not present when using macrosynthetic fibers. For example, when placing a slab with WWF or #3 or #4 rebar for temperature-shrinkage control, the concrete trucks must stay off of the slab area, thus requiring the need for a concrete pump and a $2,500-plus-per-day added cost. Furthermore, the codes are now requiring that the steel is placed on permanent supports, producing yet more of a cost burden for the owner. All of this is eliminated when using macrosynthetic fibers.

Macro-Size Your Project Profitability and Quality

When macrosynthetic fibers are added to the concrete mix:

• You increase your profit on every load of concrete
• You have no extra labor expense
• There’s no extra material or labor required by the Contractor
• You increase the quality of every load of concrete
• You won’t have to rely on a contractor to properly place WWF to achieve a satisfactory product
• You’ll be confident your fiber products will outperform WWF & #3 or #4 rebar for secondary shrinkage reinforcement
• You’ll experience the additional advantages of macro fibers (see points 1-4 below)
• You’ll receive any assistance needed from your fiber sales representative.

Recommend a Value Engineering Solution for Structural Engineers

For the Structural Engineer macrosynthetic fibers provide a Value Engineering solution for replacing conventional temperature-shrinkage (non-structural) reinforcement used in Plain Structural Concrete. Plain Structural Concrete slabs utilize the thickness of the slab and the engineering properties of the concrete to determine the load-carrying capacity of the slab.

How to Specify Macrosynthetic Fibers

ABC Polymer’s Three-Part Master Specification: Macrosynthetic-Fiber Reinforced Concrete is a sample approach that Structural Engineers can use to specify macrosynthetic fibers as a Value Engineering alternative to WWF or #3 or #4 rebar for temperature-shrinkage control.
If you need additional information or have questions about the specification, simply contact Denzil Schmitz, SVP of Sales & Marketing, at Denzil@abcfibers.com.

Macrosynthetic Fibers Deliver Macro Benefits:

1. Increase post-first crack toughness/residual strength

The first generation of synthetic fibers (microsynthetic fibers) provided both plastic shrinkage crack reinforcement and temperature-shrinkage crack reinforcement.

The new generation of synthetic fibers (macrosynthetic fibers) affords the opportunity to expand on these contributions, thus enhancing further the durability of the concrete.

The difference in these two generations of synthetic fibers is considerable. For example, the macrosynthetic fibers are more robust with an increased cross-section and a minimum 1.5-inch fiber length versus the 0.75-inch standard length of microsynthetic fibers. The added length provides a better mechanical bond that contributes to increased post-first crack toughness/residual strength — the greatest enhancement and one that can be quantified.

2. Enhance Impact and Surface Abrasion Resistance

The minimum dosage rate of 3.0 pcy compared to 0.5 to 1.5 pcy for the microsynthetic fibers also contributes to enhanced engineering properties including impact and surface abrasion resistance. The three-dimensionally distributed fibers provide reinforcement to a concrete surface that resists a wide range of mechanical forces.

3. Reduce Water Migration/Bleeding

The three-dimensional reinforcement system provided by macrosynthetic fibers yields a number of benefits not remotely possible when using conventional WWF.

One of the principal benefits is a reduction in water migration/bleeding that produces a more homogeneous concrete with a much smaller water/cement ratio range. Thus the actual strength of the concrete in the slab surface will be increased.

4. Increase Fatigue Strength AND Service Life

A further benefit of extreme value in industrial and warehouse floor slabs is the measurable increase in fatigue strength, which translates into longer service life. Here we are talking about increasing the number of axle loads by some measurable number over the life of the concrete. Fatigue strength is key when designing an industrial or warehouse floor slab or pavement area where there is a high concentration of 18 kip loads.

Also, note that there will be less settlement of the plastic concrete due to the modification of the thixotropic properties of the concrete.

ABC Polymer’s Macrosynthetic Fibers: Engineered for Specific Applications

ABC Polymer Industries believes that a single macrosynthetic fiber does not provide the engineering response required for the broad range of applications available to this newest generation of synthetic fibers.

Looking at cast-in-place concrete, shotcrete and precast concrete as the principal application areas, ABC Polymer’s macrosynthetic fibers were developed to yield specific engineering properties for each application.

Our three macrosynthetic fibers are FiberForce 650™, Performance Plus DOT™ and Macro-Pro™.

In general, FiberForce 650 has been designed to maximize benefits in cast-in-place concrete. Performance Plus DOT works well in cast-in-place concrete as well as shotcrete, and Macro-Pro’s contributions to precast products like septic tanks and burial vaults are excellent.

Use ABC Polymer’s macrosynthetic fibers added to the concrete mix to meet the exact needs of each unit of the project while saving your client money.