Aramid Fibers Enhance Pavement Performance and Sustainability

Twelve years ago, FORTA-FI® fibers arrived on my desk, and I was tasked with determining their efficacy. Having been in the asphalt industry since the mid-90s, I was initially skeptical. Fibers had been tried before, and if they had been successful, they would already be in widespread use. However, after conducting tests, the results were impressive. Unlike traditional fibers, FORTA-FI utilizes high-tech aramid fibers with remarkable properties: a tensile strength of 400,000 psi, a diameter one-tenth that of a human hair, a melting point of 853°F, and a dosage of just one pound per ton of asphalt, equating to approximately 19 million 3/4-inch fibers per ton. While there were initially no direct side-by-side comparisons [of aramid fibers to others], the last decade has provided ample case studies. Below is an analysis of three significant projects that demonstrate the long-term benefits of aramid fiber reinforcement in asphalt pavements.

Surface Tech Announces Adoption of ASTM Standard D8395-23 for Aramid Fibers in Asphalt Mixtures

Three Cases for Reinforcing Infrastructure

Enhancing pavement durability and longevity is a priority for agencies, and aramid fiber reinforcement is proving it can assist. Evaluations in Pennsylvania and Maryland, which Kindler and Associates Engineering conducted using advanced methodologies such as ASTM D 6433 guidelines and the PAVER Pavement Management System, underscore the ability of aramid fibers to improve asphalt performance, reduce maintenance costs, and extend service life. The following case studies illustrate its impact.

Case Study 1

In 2013, the Pennsylvania Department of Transportation (PennDOT) District 2-0 overlaid a 1-mile section of SR 4014 Rockton Road in Clearfield County with an aramid fiber-reinforced mix as a test section. The mix, a PG64-22 warm-mix asphalt (WMA) with aramid fibers in a 9.5-mm wearing course overlay was placed 1.5 inches thick and was compared to an adjacent control section without fibers.

In 2024, the SR 4014 sections were evaluated. The fiber-reinforced section had a pavement condition index (PCI) score of 92.3 and showed minor weathering and longitudinal-transverse cracking but no rutting, indicating excellent structural integrity.

The control section, which had been chip sealed, had a PCI score of 87.6. Joe Kindler, Sr., P.E., with over 30 years of pavement evaluation experience, projects that the fiber-reinforced overlay will maintain its “good condition” rating for several more years, to outperform the control section.

Case Study 2

Between 2012 and 2013, SR 2020 Tyburn Road in Bucks County, Pennsylvania, was constructed using aramid fibers in all asphalt layers, from the base to the wearing course. This industrial road, designed for 30+ million ESALs, endures 47% heavy truck traffic, including trash trucks, cement mixers and intermodal freight vehicles.

In 2024, the Tyburn Road sections were evaluated. The fiber-reinforced pavement, Westbound section, had a PCI score of 85.7. The eastbound section had a PCI score of 86.1, averaging a PCI of 86. The deterioration rate was only 1.5 points per year, with no structural distresses. The primary distress was minor centerline joint cracking, manageable with routine maintenance. The absence of significant structural issues demonstrates the resilience of fiber-reinforced pavement under heavy traffic.

The comparison, adjacent, non-reinforced sections, built 15-20 years ago, had an average PCI of 49, with deterioration rates of 2.6-3.4 points per year.

Case Study 3

In 2015, US Route 40 in Washington County, Maryland, was paved with eight test sections comparing an aramid fiber-reinforced mix to an MSHA premium gap-graded mix. The fiber-reinforced mix utilized a standard PG64-22 binder with a dense-graded aggregate, while the premium mix incorporated a PG64E-22 binder in a gap-graded structure.

In 2024, the US Route 40 sections were evaluated. The aramid fiber mix sections had a PCI score of 86.3. The gap-graded mix sections had a PCI score of 85.4.

The fiber-reinforced mix delivered comparable performance to the premium mix at a lower cost. Slightly wider cracks and early signs of raveling were noted in the gap-graded sections near cracking zones, whereas fiber-reinforced sections maintained superior surface integrity.

Sustainability

These case studies highlight the sustainability and economic advantages of aramid fiber reinforcement. Reduced deterioration rates and the absence of structural distress translate to lower life-cycle costs, fewer necessary maintenance interventions and extended pavement longevity. By minimizing material usage and reducing greenhouse gas emissions associated with frequent repairs, aramid fiber-reinforced pavements align with sustainability goals.

The findings from SR 4014, Tyburn Road and US Route 40 validate the potential of aramid fiber reinforcement in asphalt pavements. Lower deterioration rates, higher PCI scores, and enhanced resistance to structural distress make the addition of aramid fibers to the mix design a compelling solution for agencies looking to maximize their asphalt investments.

Scott Nazar is the technical manager for the Asphalt Division at Forta Corporation, where he leads the asphalt team in the development and testing of fiber reinforcement solutions for pavement durability. He collaborates with agencies, municipalities, and Departments of Transportation (DOTs) to integrate fiber reinforcement into asphalt pavements, enhancing their performance and longevity.