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The Pavement Innovation Report
City of Hillsboro Achieves 63% Less Pavement Cracking
"Why is one lane cracking a whole lot less?"
When City Engineer, Aaron Janicke, P.E. asked this question in 2022, it took the staff on a 9-year journey back through the City of Hillsboro, Oregon’s history to uncover this unexpected success.
Aaron was driving down NE Grant Street, a two-lane residential roadway which runs near a high school football stadium. This one-quarter-mile section gets lots of bus traffic.
He observed the north lane had a normal amount of cracking while the south lane was noticeably less.
Returning to the office, Aaron found that Greg Hayes, a Senior Engineering Technican for the City, was present during the street’s overlay in 2013. Greg shared that the mix design was PG 64-22 for NE Grant St…but with a twist.
FORTA-FI ® Fiber undergoes a 9-year test
There was one clear modification made by the City in 2013 regarding the mix design: they chose to work with Pacific GeoSource (PGS) to design the asphalt mix using FORTA-FI ® Fiber for one lane. This would give them a clear comparison of traditional overlay vs. the FORTA-FI ® reinforced overlay to clearly see any benefits over time.
The south lane was reinforced with FORTA-FI ® Fiber while the north lane was not.
FORTA-FI ® Fiber is known for extending asphalt pavement life by up to 50% through increased crack resistance and tensile strength. At only $12/ton, adding FORTA-FI ® Fiber helps owners like the City of Hillsboro keep more money in their pocket for future project use.
Since 2013, the control lane has recieved a crack seal treatment and continues to show cracking while the reinforced side holds strong with no crack seal treatment needed.
Findings, Nine Years Later
After Aaron’s discovery, the City did an investigation and found the north (control) lane had 2035 ft of cracking, while the south side reinforced with FORTA-FI ® Fiber had only 751 ft of cracking – a difference of 63%.
The City documented the 2021 ADT and truck percentages for each lane as well: the southbound (FORTA-FI ® Fiber) lane was higher with 2829 vehicles/day (vpd) and 4.74%, respectively, while northbound (control) lane was 2179 vpd and 4.4%.
Greg says the City will do a crack seal during Summer 2023 on both sides of the roadway. Aaron notes, “The FORTA-FI ® Fiber reinforced lane has definitely stood up better than the control side under the higher bus traffic loading.”
PGS celebrates the City of Hillsboro
“I have such appreciation for the City of Hillsboro for being open to new and innovative ideas that can benefit their community,” says Mike Haas at PGS. “We’re glad to see the City be such great stewards of their assets, watching the long-term performance of their roadways and documenting results.”
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