Testing Innovation on America’s Oldest Highway: BATT’s Ultra Flexible Interlayer Debuts on the PA Turnpike
In September 2024, a high-performance asphalt test section was placed on Milepost 146 of the westbound lanes of I-76, better known as the Pennsylvania Turnpike—the nation’s oldest turnpike. Designed to address chronic cracking issues on aging concrete pavement, the project introduced a reflective crack relief asphalt interlayer (RCRAI) reinforced with aramid fiber designed by Blankenship Asphalt Tech & Training (BATT).
A Smarter Solution for a Tough Problem
Faced with cracking and reflective distress, the PTC was evaluating two options: A full reconstruction involving the removal and replacement of existing pavement or a performance overlay that would extend the existing pavement’s life. Opting for a less disruptive and more cost-effective path, the PTC chose to test the innovative RCRAI mix developed by Phil Blankenship, P.E., using a high-asphalt binder content, low-air-void design and Surface Tech’s ACE XP™ aramid fiber reinforcement system, known commercially as ARMI.
“We wanted as little delay to the traveling public as possible, while achieving a smooth, durable roadway,” said Chris Forry, Materials Management Supervisor for the Commission. “Phil Blankenship and his lab staff and Surface Tech were excellent to work with.”
Field Testing in Two Phases
Before moving onto live traffic lanes, the Commission wisely tested the mix on a 1,000-foot abandoned section of the highway on September 19, 2024. The trial confirmed the mix could be reproduced reliably and met expectations of quality control, including volumetrics and field compaction.
Two weeks later, crews from New Enterprise placed the test section on I-76 at MP 146 westbound, working overnight in two 9-hour shifts—left lane one on night, right lane on the next. The paving was efficient, with minimal disruption to traffic, and the condition of the pavement remains excellent as of today.
What Makes the Interlayer Mix Different?
The 0.475 NMAS mix design—developed by BATT in July 2024—was created to meet the PTC's interlayer performance specs where the objective was to maximize flexibility and crack resistance. After placement of the one-inch asphalt interlayer, a two-inch 12.5mm, 64E-22, surface mixture was paved over it. The combination of the RCRAI crack resistant mix and the new, durable riding surface will provide PTC customers with a smooth, longer life pavement.
Key interlayer performance features include:
High binder content: 8.5%
50-gyration, low air voids mix at 18.9% VMA (significantly above the norm)
IDEAL-CT cracking resistance >1,000 with 4,900+ passes in the HWT
2x dose (4.2 oz/ton) of Surface Tech's ACE XP 38mm aramid fiber
Mix designed for maximum flexibility and high strain absorption
“The combination of a slightly modified binder in a unique aramid-reinforced mix created a high-performance, flexible Big Beautiful Interlayer,” joked Phil Blankenship, President of BATT.
Looking Ahead
The Pennsylvania Turnpike Commission hopes to achieve five or more years of service life from this innovative overlay. Based on BATT’s track record with this solution, five years should be the minimum expected performance. The ultra-flexible interlayer technology has proven effective on other projects throughout the U.S. since 2000. The PTC will conduct ongoing monitoring to assess long-term performance.
Why It Matters
This project demonstrates how forward-thinking agencies can use innovative materials and partnerships to stretch budgets, extend pavement life, and deliver smoother, safer roads with less disruption to the traveling public.
For more on the performance and benefits of asphalt interlayers reinforced with aramid fiber, visit:
Ultra-Flexibility: The Latest Advancement in Asphalt Interlayers. You may also access this technical paper for more in-depth reporting on BATT’s interlayer asphalt solutions and results: https://www.tac-atc.ca/wp-content/uploads/simons1.pdf
