FORTA FI^® Reinforcement Fiber for Asphalt Pavement

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Mahac improved technical solutions, turned recent knowledge into opportunities for the customer through timely and effective communication.

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Mahac shows a collection of tests carried out in different countries of the world, using FORTA FI® Polymeric Macrofibers in bituminous conglomerates.

These fibers increase:

• resistance to flexural strength,
• increase rutting resistance,
• resistance to fatigue,
• increasing stability
• increase stiffness
• increased durability, with a reduction in asphalt maintenance costs, extending their useful service life.

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FORTA Corporation, founded in 1978, was the first producer to introduce synthetic fiber reinforcements to the U.S. construction market. Today, FORTA Corporation holds more patents than any other company in the fiber industry. FORTA is recognized as a leader in synthetic fiber research and development, with successful applications around the world.

FORTA Corporation prides itself as the most recognized and respected name in the synthetic reinforcement fiber industry. The FORTA team is seasoned, knowledgeable, innovative and determined to find solutions for the demanding construction industry. FORTA is a strong believer in research and development to not only create a product, but to create the best product available.

FORTA has engineered a fiber blend specially formulated to reinforce all working temperatures of asphalt mixes. This innovative fiber, FORTA-FI®, has been tested by today’s tough standards. It offers cost savings or life extension by reducing asphalt thickness or by extending the serviceable lifetime of your pavement.

FORTA FI® is part of FORTA’s legacy of innovation that began with their first patent for an asphalt- reinforcing product. Building on its history of developing, testing, and producing fiber reinforcement blends for a variety of applications, FORTA products have played an important role in improving the performance and durability of asphalt for many years. Millions of pounds of FORTA FI® have been produced and can be found in roadways all over the world.

FORTA is not only known for superior products, but also for top-notch service. FORTA will always be attentive, responsive and pay close attention to our customers. From the lab to the job site, FORTA will be there every step of the way. Our mission to build a Stronger Lasting™ future continues with our determination to exceed the needs of our partners, and our passion for what we do & who we are.

Dispersion Testing

FORTA FI® has consistently proven that it has the ability to strengthen asphalt pavement and keep those pavements in a good and serviceable condition longer.

TEST: ADSR is used to quantify aramid dispersion in an asphalt concrete mixture. For the fiber to perform to the best of its ability, it must disperse well as individual fibers into the mix. High ADSR values are indicative of high individual fiber dispersion. The ADSR value is calculated after a liquid extraction is performed on the asphalt mixture. After collecting the fibers from the extraction process, they are assessed by the amount of fiber in each physical state (Table 1).

FORTA FI® Results: Test results show FORTA FI® is dispersed more uniformily with more single fibers spread throughout the mix. With less bundles and clusters, FORTA FI® provides a higher percent of reinforcement throughout the entire pavement mat.

For this test, two different brands of fibers were tested during a fiber vs fiber project in Arizona using a Marshall mix designed for a 3in overlay. The asphalt was plant produced and then transported to the Advanced Pavement Lab at Arizona State University for testing. Table 2 shows the ADSR values for both mixes.

Rut Resistance Testing

TEST: The repeated load deformation test, or flow number, is a cyclic loading test used to evaluate the permanent deformation characteristics of asphalt mixtures. The total cumulative plastic strain and the number of load cycles is defined by three separate regions in the graph: primary, secondary and tertiary. The flow number is the number of cycles to reach the tertiary region.

FORTA FI® Results: FORTA FI® increases the flow number, resulting in an increase in resistance to permanent deformation (rutting).

 

Rut Resistance Testing

TEST: The Hamburg Wheel Tracking Device measures the combined effects of rutting and moisture damage on an asphalt pavement. A rolling steel wheel is run across the surface of an immersed asphalt concrete test specimen for a specified number of cycles under a constant load. The deformation sustained on the specimen is recorded.

FORTA FI® Results: FORTA FI® can increase the number of cycles to reach failure during the test, indicating that it helps to distribute loads evenly throughout the pavement surface and make the asphalt mix significantly more resistant to rutting when comparing it to a control mixture without fiber.

Crack Resistance Testing

TEST: The indirect tensile strength test is used to determine the tensile properties of an asphalt mixture.
FORTA FI® Results: FORTA FI® provides an asphalt mixture increased tensile strength, giving the pavement stronger cracking resistance (fatigue and thermal) and higher resistance to permanent deformation.

 

TEST: The Texas overlay test is used to characterize both crack initiation and crack propagation properties of asphalt mixes. Testing is conducted with an applied cyclic load for a set amount of cycles or when failure occurs.

TEST: The C* test was developed by Arizona State University at their Advanced Pavement Labratory. This test assesses the fracture resistance and crack propagation properties of an asphalt mix.

FORTA FI® Results: The use of FORTA FI® shows a greater resistance to fracture, crack propagation and reflective cracking when compared to mixes without fiber reinforcement.

CRACK RESISTANCE TESTING (SCB-Semi Circular Bending)

TEST: The Semi-Circular Bending test measures the asphalt mixtures ability to resist cracking, delay crack propagation and crack growth. Fracture energy characterizes the mixtures ability to resist cracking while the Flexibility Index denotes an improved resistance to cracking and crack propagation. A lower Flexibility Index implies a brittle and crack prone asphalt pavement.

Crack Resistance Testing

TEST: The uniaxial fatigue test applies a repeating sinusoidal load to develop constitutive models to describe the fatigue behavior of asphalt. The fatigue analysis is performed using the simplified viscoelastic continuum damage (S-VECD) approach where the damage characteristic curves were established and used to obtain the fatigue relationship.

Material Modulus Testing

TEST: Dynamic Modulus is a material response measured under sinusoidal, non-static, loading conditions. Dynamic modulus of a viscoelastic material is calculated by dividing the maximum peak to peak stress by the recoverable peak to peak strain. The time lag between the applied stress and resulting strain defines the phase angle.

FORTA FI Results: FORTA FI® decreases the material strain which helps mitigate and resist low temperature cracking, high temperature permanent deformation, and improve overall rideability.

 

Material Modulus Testing

TEST: The resilient modulus represents the relationship between tensile stress and recovered strain. The repeated load indirect tension test for resilient modulus is conducted by applying a haversine wave and loading and unloading the test specimen.

The strain pulse response is analyzed to determine the amount of strain that recovers during the rest period. Although seldom used in the United States, resilient modulus testing is still used in various regions of the world.

Resilient Modulous Test Setup

 

 

FORTA FI® Results:

Pavement Condition Testing

TEST: The PCI was originally developed by the US Army Corps of Engineers to quantify the in-place quality of pavements. Using a visual survey of the road, deduct values are used with their respective associated distress values and severities, and a rating is assigned to the section. The ratings score from 0 to 100 to represent the overall condition of the pavement. PCI data is useful in determining required pavement maintenance applications and scheduling.

FORTA FI RESULTS: FORTA FI® gives asphalt pavements the ability to resist cracking and rutting, leading to an increase in durability and longevity and a better PCI score.

PERFORMED BY:
Arizona State University
GMU Geotechnical, Inc. (GMU) Joe Kindler & Associates

“After reviewing the PCI numbers of the FORTA-FI and regular HMA resurfacing, walking the pavements and studying the PAVER output, it is my Professional Opinion that it is reasonable to expect an increased life in the range of 40 to 50% by adding the FORTA FI® fibers to a standard HMA all factors being equal.” – Joe Kindler

Description
FORTA FI® is a high tensile strength synthetic f1ber blend formulateci to reinforce asphalt mixes. FORTA FI® helps to control and reduce fatigue cracking, thermal cracking, reflective cracking, rutting, and raveling.

In new construction or rehab projects, FORTA FI® provides initial cost savings through reduced pavement layer thickness which gives the same durability as conventional mixes, or a Iife cycle cost reduction when placed at conventional asphalt pavement thickness which extends the pavement Iife.

Reinforcement Objective
To three-dimensionally reinforce pavements by controlling thermal, reflective, and fatigue cracking as well as reduce rutting and raveling.

APPLICATION
FORTA FI® fiber blend is added directly to the asphalt mix during production creating a three-dimensional materiai reinforcement throughout the entire pavement layer. This reinforcement helps control thermal, reflective, and fatigue cracking, as well as reduce rutting and raveling.

FORTA FI® is a cost effective way to improve the durability and longevity of a variety of transportation applications such as airports, streets, highways, interstates, and industriai parking lots, etc. FORTA FI® is an innovative way to help transportation agencies achieve sustainability objectives by lowering Life Cycle Costs.

PERFORMANCE BENEFITS

• Extreme durability
• Life cycle cost reduction
• No change to construction process or JMF
• Extend pavement life
• Provide 3-dimensional reinforcement against pavement distresses

Addition & Mixing

FORTA FI® mixes well in batch and drum plants without compromising production. The fibers are added at a rate of one (1) pound of fibers perone (7) ton of asphalt mix. Add fiber during the production process after the flame but before introduction of the liquid AC. For batch plants, the fibers are added either manually using pre-measured bags or with a FORTA ® Delivery System.

For drum plants, bags can be placed on the RAP conveyor manually or directly into the drum with a FORTA Delivery System. Ensure minimum mix production temperatures as follows: 220°F minimum far bulk fiber use; or 275°F minimum for pre-measured bags (bags may not fully dissolve below 275°F).
FORTA offers severaI types of f1ber delivery systems such as the Voyager, The Big Shot and The Little Shot. Some feeders automatically track and record the amount of fiber fed into the plant for quality assurance.

Packaging

Fiber Vs. Control

This county road suffered sever alligator cracking from years of heavy truck traffic. To repair the road, engineers wanted to explore FORTA FI® as an alternate reinforcement method. They applied a 2 inch overlay directly onto the existing pavement without milling.
They used the same base mix for the entire road; however, for one-half of the road, the mix included FORTA FI®, and for the other half, the mix dici not.

After 7 months, the side without f1ber reinforcement had begun to reflect cracking from the old asphalt layers below.

As you can see, the FORTA FI® section outperformed the control section when it carne to reducing reflective and alligator cracking, which will directly lead to an extension of Iife.

Additional lnformation

Additional information such as the Safety Data Sheet, Certifications, videos and other literature can be found on the forta-fi.com website. The website also features Project Profiles that show the many applications and benefits of FORTA FI® and other fibers for asphalt firsthand.

Limited WarrantY

FORTA® Products are warranted to be free of defects in materiai and will meet all published physical properties as set forth herein.

EXCEPT FOR THE EXPRESS LIMITED WARRANTY SET FORTH HEREIN, NEITHER FORTA NOR ANY PERSON ON FORTA’S BEHALF HAS MADE OR MAKES ANY EXPRESS OR IMPLIED REPRESENTATION OR WARRANTY WHATSOEVER, EITHER ORAL OR WRITTEN, INCLUDING ANY WARRANTIES OF MERCHANTABILITY, FITNESS FORA PARTICULAR PURPOSE, TITLE, OR NON-INFRINGEMENT, WHETHER ARISING BY LAW, COURSE OF DEALING, COURSE OF PERFORMANCE, USAGE OF TRADE OR OTHERWISE, ALL OF WHICH ARE EXPRESSLY DISCLAIMED.

The exclusive remedy for defective product is outlined in FORTA’s Standard Terms and Conditions of Sale, available upon request.
CONSEQUENTIAL DAMAGES ARE SPECIFICALLY EXCLUDED.
FORTA reserves the right to change the features and specifications of its products without prior notice.

The data summarized in the following pages has been performed and collected by:
Advanced Infrastructure Design, Inc. Arizona State University
Department of Road Structures, Czech Republic
Faculty of Civil Engineering, Czech Technical University in Prague FDOT
Federal Highway Administration (FHWA) GMU Geotechnical, Inc.
Kindler & Associates MnROAD
National Center for Asphalt Testing (NCAT) NC State University
NCE NJDOT
Northern Arizona University
Ohio Department of Transportation Ohio University
Penn State University PennDOT
Rowan University Rutgers
South Dakota School of Mines
University of Illinois with the Illinois Center for Transportation University of Texas at Austin
University of Texas at Tyler Virginia DOT