How Iowa State University Repaved 4.5 Acre Parking Lot Using 100% Recycled Asphalt

Massive project only had a week to get it done, and they managed to do it using the asphalt that was already there.

Invigorate Plus re-binder is a bio-based liquid topical that seals millings to create a smooth, final surface.
Invigorate Plus re-binder is a bio-based liquid topical that seals millings to create a smooth, final surface.
Provided by Colorbiotics inc.

Jon Klein, the project manager at Gee Asphalt Systems, expected to hear a job proposal, but he didn’t have specifics. It was a Friday in the late summer of Ames, Iowa, in the 4.5-acre parking lots between Jack Trice Stadium and Hilton Coliseum, where students would soon return for the fall term.

General contractor Andrew Gatto with the Elder Corporation met Klein and said, “I have a project for you,” motioning toward the expansive lot used for student parking during the week and for fans attending events at the adjacent football stadium and indoor arena on nights and weekends. Klein was immediately interested in the job. Then came the curveball: “I told him it needed to be done by the next Friday,” Gatto recalled with a wry smile. “Any sort of fix for a lot that size would be a very quick turnaround, but to redo the entire parking lot — that’s unheard of.”

“I thought he was kidding, of course, because normally we’re working weeks or months out,” Klein reflected on the request. He got on the phone with the home office to see if such a timeline would even be possible with labor and equipment assignments. Coincidentally, another job had just been postponed, so the assets could at least attempt to meet the timeline.


Klein and his team had an advantage to take on the accelerated timeline. The product they chose enabled them to use 100% recycled asphalt pavement (RAP). Even better, the RAP to be used was already on site in the form of the existing parking lot. The contractor decided to handle the urgent job with Invigorate Plus re-binder, which applied to RAP makes a hard new surface without an ounce of virgin asphalt. 

“It’s as easy as laying out your millings at a four-to-six-inch depth, topically applying this Invigorate Plus cold mix product and then compacting it,” said Brayden Lester, the asphalt territory manager at Colorbiotics. “We can use 100% RAP. That’s pretty unheard of in the industry.” 

Because of the time crunch, the contractor was not able to use a pugmill. Workers simply spread out several inches of RAP across the parking lot, graded it and used a water truck system to spray the Invigorate Plus re-binder. Then the recycled asphalt was rolled into a new surface.

“You can imagine if we were forming a new pavement somewhere else and we had to go get the materials, the logistics and the carbon footprint would result in a lot more time and money,” Klein says. “Because it’s all on site, we could do it in place, and it saves a great deal of time, energy and money.” The deadline inside a week became less daunting.


Once the old asphalt parking lot was milled, the crew laid down four-to-six inches of RAP millings across more than 200,000 square feet. The project required 14 totes — 28,000 pounds — of Invigorate Plus re-binder. The cold mix solution applied on top is designed to seal the surface of the aging RAP and restore microfractures. Because the product is soybean-based rather than petroleum-based, it did not require a permit for spraying, which also aided the contractor in meeting the quick deadline.

“It went quite fast and really turned out well,” Klein said, adding that higher RAP content is becoming ever more popular as people look for economical and environmentally friendly options. 

He also appreciated the cold mix product that enabled the project to meet quality standard, uses bio-based materials. “It’s soybean based, and being in the Midwest that has some appeal,” he said. “I’m always interested in new technologies and new ways of doing things.”

The general contractor at Elder Corporation was pleased, if not surprised, that the project came together within the requested timeline. “We were looking for an affordable solution that would hold up for a long period of time,” Gatto said, reflecting on the unique request to complete such a large scale project within a week. “I was honestly blown away by it. It came together well. It’s a hard product and made that parking lot basically like any other asphalt surface.”


On the far side of the parking lot north of Hilton Coliseum, the parking lot pavement had no need to be replaced; it was only three years old. But that age falls within an ideal window to extend the life of good pavement. The contractor deployed a different soybean-based product for that job. Invigorate Plus sealcoat is designed to reverse oxidation of asphalt molecules in order to extend the life of pavement between five-to-seven years, and its soybean-based polymer seals the surface to prevent moisture intrusion.

The process began by cleaning the pavement using brushes and blowers to remove debris from the surface. Then a tanker truck with a spray bar on back covered the pavement at a specific calibration. The tanker made a single pass over the lots, and two hours after application, the cones were removed for vehicles to return.

While the product does offer colored sealcoats (black and other colors), the Invigorate Plus sealcoat comes as a clear option, meaning contractors are not required to re-stripe the asphalt. Gee Asphalt Systems selected the clear sealcoat for the Iowa State job given that the existing striping remained plainly visible. Klein noted that was a big advantage to both save time for his crew and to reopen the lot as soon as the surface was dry.

“Whether you’re in a city or county —  it’s instinctive to not do anything to your asphalt until it shows signs of distress or age, but that’s a reactive strategy, and it’s the least fiscally sound,” said Klein, who is a strong proponent of asphalt management. “It’s the most expensive way of doing it because the repairs, patches, and repaving are so expensive. But if you keep up the pavement by putting on a rejuvenator, sealing cracks it can double or triple its life. That this sealcoat is eco-friendly as well is just an added benefit."


Innovative, bio-based products within the asphalt industry are poised to shake up the traditional factors determining new jobs. Increasingly, lower cost is not enough to win bids. The Inflation Reduction Act only expedited a focus on low-carbon materials with significant financial incentives for meeting those demands. Environmental product declarations (EPDs) are already required for many asphalt projects, a trend likely to expand rapidly. 

The federal government is willing to pay a premium for low-carbon materials through reimbursements to state and local agencies. “This is really a profound change in my mind because historically we’ve always been constrained on low-cost procurement, especially with federally funded projects,” said Joseph Shacat, director of sustainable pavements at the National Asphalt Pavement Association (NAPA). “This changes that rubric.”

Producers who make quality, low-carbon products are finding an audience with large transportation departments looking to capitalize on the federal incentives. “Our soybean-based products are allowing us to get up to the platform,” Lester said. “Greener agendas help that.”


For the Iowa State University jobs, Gatto acknowledges he was previously unaware of a soybean based re-binder that could allow for 100% RAP and quickly turn it into a new pavement. After the seeing the completed job, he became an advocate.

“It was not something I’d seen before, so I had no expectations coming in,” he said. “But I was stunned. Projects that need a good turnaround should definitely explore this route.”