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How ‘clean’ incentives change the playing field for asphalt innovators.

The right pickup line can be quite the conversation starter. And if trying to catch the eye of a federal government in pursuit of environmental objectives, one simple line rolls off the tongue with particular effect: “Asphalt is America’s No. 1 most recycled product.”

Such is the boast the National Asphalt Pavement Association can make again, with its survey released in January 2023 showing 95% of reclaimed asphalt pavement (RAP) is reused in new pavement. Less than 1% winds up at a landfill. The percentage of RAP in mixtures also continues to rise (almost 21% in 2021). The reduction in greenhouse gas emissions (2.6 million metric tons) were equivalent to removing 570,000 passenger vehicles from the road.

The industry’s ability to literally remake itself was part of the pitch to then-President-elect Joe Biden’s transition team in late 2020, as the framework was already being laid out for an infrastructure during the new administration. And the innovations extend well behind recycling product.

Asphalt paves 94% of the country’s roads and bridges, and innovations within the industry, such as RAP and use of greener materials, make it increasingly agreeable with efforts to care for the environment. And now, federal agencies are employing financial incentives to give the progress an added boost.

“With this opportunity to incentivize some of these efforts and with some of the technologies in assessing cracking performance of mixtures coming on, it really creates a nice nexus of opportunity for these innovations to take root and people to use them,” said Richard Willis, vice president of engineering, research, and technology at the National Asphalt Pavement Association.

The Infrastructure Investment and Jobs Act and the Inflation Reduction Act included victories for the asphalt pavement industry and offered incentives — rather than requirements — to use greener materials. Industry leaders have already been making remarkable scientific advancements on their own, but they may be uniquely positioned to benefit from a changing landscape.

“It is a massive shift,” said Austin Hohmann, product manager at Colorbiotics in Ames, Iowa, which has already developed a hot mix capable of using up to 50% RAP.

He sees a different playing field in the government’s plan to favor greener materials, an area where Colorbiotics is already pushing the envelope.

“The conversation shifts from cost effectiveness to performance,” Hohmann said. “One of the biggest things you have to compete with is cost. Well, if it’s no longer about cost as much and more about meeting emissions, that’s one last thing that you have to worry about. That’s drastic. That’s massive.”

Willis agrees: “It’s almost a paradigm shift,” he said. “In the past it’s all been cost, cost, cost, and now we’re starting to try to figure out how we evaluate these [other criteria].”

Evaluations are getting more detailed and verifiable concerning the engineering, the environmental and the economic perspectives. Willis notes the industry is acquiring the tools to make these assessments possible, such as analyzing the performance of products through balanced mix design programs and NAPA’s Environmental Product Declaration (EPD) tool to quantify the environmental impact of an asphalt mix.

Far from going to the lab to start tinkering, 2020 newcomer Colorbiotics has an asphalt line called Invigorate that explores what is possible using bio-based solutions for pavement and treatment. The products include an asphalt hot mix additive and a sealcoat rejuvenator. Invigorate was designed with parking lots, city streets and roadways in mind. Invigorate Plus is suited for heavily traveled highways and interstates. They are examples of an industry poised to make use of greener materials while still making performance gains.

Their latest Invigorate Plus additive uses a soybean-based polymer that enables up to 50% use of RAP, compared with other solutions that enable closer to 20%. The lower percentage with competitive additives is a reflection that RAP alters the binder’s performance grade. When that is exceeded, a binder bump is required, which has a knock-on effect of needing enough rejuvenator to bring down the grade so it will come back up to the appropriate one when RAP is added.

The breakthrough with the Invigorate Plus additive product is that it improves the chemical properties of lower-quality binders rather than superficially changing the viscosity of the binder.

The first demonstration project started in 2018 at the National Center for Asphalt Technology (NCAT) test track in Auburn, Alabama. It showcased the difference between the biopolymer and the respective SBS polymer control group.

The three-year test resulted in minimum rutting of 2.5mm for Colorbiotics’ section. The Invigorate Plus additive sections did not show small surface cracking, though the control roads did. The product has also been used Missouri, Indiana and the company’s home state of Iowa.

But Colorbiotics is among the companies which sees opportunity for much larger projects with the emphasis shifting to performance. Last year, the EPA announced it would begin a “buy clean” policy for federal aid projects. The agency was charged with developing a labeling system for low carbon construction materials, with the General Services Administration and the Federal Highway Administration being allocated funds to help offset costs.

In many cases, the scientific development on cleaner products is already set to go. The wait is for projects employing them to get a green light.

Colorbiotics’ latest offering, Invigorate Plus sealcoat, offers something unique to the industry while being environmentally friendly. The soybean-based spray-on solution is like a makeover for asphalt highways and major arteries, and as a bonus, it reverses the oxidation of asphalt molecules.

“Colorbiotics is the only one that actively restores oxidized asphalt,” Hohmann said. “Everybody else is essentially playing a solubility game of putting one fraction back in of the four to help stabilize. We found a molecule that can navigate asphalt that won’t react with anything except for what causes oxidation.”

The product distributes micron-sized particles that spread through the top inch of the pavement’s pore structure. The depth itself is notable — reaching four times deeper than other topicals — and then the particles set to work reacting with the aged asphalt binder to extend the lifetime of the pavement and improve the appearance.

One of the hurdles in the past has been appropriately classifying and quantitatively measuring the success or failure of new technologies, Hohmann observed. But that is now a focus with bio-based rejuvenators and topicals, and the National Road Research Alliance project with the Minnesota Department of Transportation has been pursuing this data.

Hohmann is keen to demonstrate in an efficacious way that the Invigorate Plus sealcoat is not a fog seal. Fog seals are a topical aesthetic treatment designed to seal up most of the surface. The sealcoat product penetrates the asphalt to seal and restore it.

Hohmann’s hope for new, specific classifications in the industry are starting to take shape. In response to the infrastructure law, the federal government last year took a foray into trying to encourage the asphalt industry to use greener materials.

The GSA identified land ports of entry for rebuilding and reconstruction. As part of that, the GSA implemented what it called an Environmentally Preferred Asphalt standard. To qualify as a contractor, applicants had to be able to quantify the environmental impact of the mix and check a few boxes, and one of those boxes could be using more than 20% RAP in the mix.

In January of 2023, The Environmental Protection Agency released its determination of what a low-carbon materials are, which will again help identify who secures the work. However, the wrinkle is that the federal law opened up more than state departments of transportation. Cities could also in on the funding and pass the incentives on to contractors doing smaller-scale projects. That provides additional opportunities for project managers and contractors to push the envelope.

Hohmann speaks about his projects at Colorbiotics with enthusiasm, looking at an industry making significant changes.

“All I can tell you is our products work really, really well, and they’re environmentally friendly,” he said.

High performance and use of greener materials are ever more the criteria, and innovators in asphalt will find increasing opportunities as civic leaders set priorities for future projects.