By Marty Muenzmaier, Cargill’s sustainability and external affairs lead for the Bioindustrial group
Historically, many in manufacturing believe going with bio-based ingredients for various manufacturing applications from wood panels and furniture adhesives, foams and flooring, paints, inks and coating, asphalt hot-mix additives to dielectric fluids for electrical transformers means a loss of quality and performance compared to conventional petroleum-based ingredients.
In reality, however, bio-based manufacturing applications are delivering the same reliability and performance results that uphold products and additive solutions the same way petro does. But, in addition to meeting and exceeding performance expectations, plant-based solutions help businesses achieve an overarching sustainability objective while lowering costs over the long-term.
Two industrial areas that are seeing impressive performance year-over-year with plant-based applications, while helping deliver sustainability advancements, is road construction and power generation.
Road construction firms around the world are finding cost savings, reliability and environmental benefits by moving to a recycled asphalt pavement method, compared to using only virgin aggregate for paving needs. A plant-based rejuvenator, like Cargill’s ANOVA, allows state departments of transportation, municipalities, commercial road owners and contractors to realize budget savings as road projects use more recycled material, reducing waste and producing high-quality surfaces that last over time.
Wisconsin Town Paves the Way with Recycled Asphalt Using Plant-Based Rejuvenator
One such case study that road owners should consider as they strive to maintain highways during uncertain financial times is that of the City of Janesville in Wisconsin. Located in the south-central part of the state, just north of the Illinois border, the City of Janesville is responsible for maintaining approximately 345 centerline miles of municipal roadways and alleys that serve a population of 65,000. In addition, the city performs routine maintenance on 11 centerline miles of state highway that are within city limits. In 2014, Janesville was rehabilitating its streets at an average of 6.3 centerline miles per year — 5.2 miles resurfaced and 1.1 miles reconstructed.
The city was rehabilitating asphalt pavements every 54 or 55 years on average, according to Lisa Wolf, Janesville assistant city engineer. “This is a completely unrealistic expectation, especially in our Midwest climate where we have multiple freeze-thaw cycles and older infrastructure within the city that’s already been milled a few times,” she said. In Wisconsin, the average service life for an asphalt surface is around 18 years for new pavement and 12 years for an overlay, according to Wolf. By the time she joined the city in 2014, the average condition of the city’s streets was declining. The city council decided that more yearly rehabilitation work was needed before the overall condition of its streets declined further.
In 2014, the Janesville City Council committed to funding 12 miles of street rehabilitation annually, doubling its program. Part of the strategy to rehabilitate more miles per year is adjusting the mix designs for the pavements and “increasing the use of recycled materials in the asphalt,” said Wolf.
The city began working with a local firm based in nearby Beloit to develop new mixes that would incorporate higher recycled content into Janesville’s asphalt pavements. The firm also helped revise the city’s specifications for resurfacing and reconstruction projects, streets in new developments, new street extensions, and more. The revised specifications increase the use of reclaimed asphalt shingles (RAS), RAP, and fractionated reclaimed asphalt pavement (FRAP) in Janesville.
“The first season of production included trial sections that used softer virgin binders and various additives to offset the harder asphalt from the RAP, FRAP and RAS,” said Wolf. “Subsequent tweaks to the specifications included requiring additives in surface mixes where the ABR is over 30 percent.”
Since the revised program went into effect in 2016, Janesville has been reaping the benefits. Performance testing specifications ensure the high recycle mixes are resistant to cracking and rutting. In addition, prior to 2016, Wolf said, prices for hot mix asphalt were steadily rising per year. After increasing its use of recycled asphalt material, Janesville saw the price per ton for a typical local road asphalt mix drop about 6 percent from the 2015 price. “There are real cost savings in utilizing more recycled asphalt material,” said Wolf.
Recycled asphalt, through the use of a plant-based rejuvenator, contributes to a circular supply chain and economic system. From supporting farmers producing a renewable, raw ingredient year-over-year, that then allows old aggregate to have a second life instead of going into a landfill, the circularity process creates a mutually beneficial outcome for multiple economies and long-term environmental benefits.
“From smaller towns in the Midwest to large metro areas around the world, rejuvenated RAP is not only consistently proving to be a reliable performance solution, but real cost savings are also being realized,” said Dr. Hassan Tabatabaee, global technology manager for asphalt solutions with Cargill’s Bioindustrial Group. “We’re excited to see results like the city of Janesville is experiencing. This data, captured over a long period of time in real world applications, can help inform the industry when developing asphalt rehabilitation strategies for the future.”