Asphalt is a science just as much as it is a trade. I saw this first-hand when I recently visited the brand-new, state-of-the-art asphalt quality control laboratory built in Mansfield, OH. What drew me to them was a simple question: what motivated them to invest in this new lab?
Over the past three years, I've had the pleasure of visiting many jobsites and learning how to operate all kinds of machines. Early on, I made it a personal goal to learn everything I could about how to actually do the work that the people in our industry perform day in and day out.
For the most part, my focus centered on the laydown crews—the finished product, how the mat gets paved and compacted, and how it gets milled up and recycled. Asphalt plants, where the production happens, remained something of a blind spot for me—one I am now turning my attention toward correcting.
About The Company
Founded in 1951, Kokosing, Inc. is now a third-generation family-owned group of construction and materials companies operating across a wide range of civil engineering and infrastructure sectors. They pride themselves on being one of the few remaining family-owned construction firms in the Mid-Atlantic region.
According to their website, “Kokosing’s primary business lines include industrial, transportation, pipelines, water and wastewater, marine, and renewable energy. Additionally, aggregates and asphalt material suppliers are part of the Kokosing family of companies.”
Their group of companies includes Kokosing Construction Company, Inc, Kokosing Industrial, McGraw Kokosing, Integrity Kokosing, The Olen Corporation, and Kokosing Materials Inc. which was the particular company I visited for this story.
Getting Into The Lab
I’ve only ever been inside two previous “labs” for asphalt testing, and both were trailers set up on site at asphalt plants. KMI has multiple “field labs” too, as they call them, which are similar to what I’ve seen before. But their new QC Mix Design Laboratory is massive, clean, and filled with machines I had never seen before—one seemingly tucked into every corner.
It almost felt like I was in the Willy Wonka chocolate factory of asphalt. And if that were true, the asphalt chocolatier at KMI would be Matt Anderson, their Quality Control Lab Manager. He started in the asphalt industry in high school, and twenty years later, he’s still here.
“I thought this was just a high school job for me,” he told me. “My first job was taking temperature readings at the plant. Then they started training me to do new things, then they paid for me to get state certified, and now, here I am.”
Matt follows the same schedule every day. Starting at 6:00 a.m., he pulls the day’s sample mix designs from a large oven and starts making asphalt—literally by hand in a small drum mixer, adding the correct amount of AC and any additional additives called for in the mix design.
Working alongside a team of about ten employees with their own roles in the QC department, they focus on two primary responsibilities. The first, and by far the most significant, is testing mix designs for various jobs, many for the Department of Transportation (DOT) or the Federal Aviation Administration (FAA), to ensure that the plant’s output meets the required specifications. That makes up about 95% of their workload, with the remaining 5% being QC tests on on-site samples.
All told, they estimate that at least 150 different mix designs go through the lab each season before being sent to the DOT or FAA for final checks and approval. Once the mix designs are properly created, they go through a curing process before being compacted into either a Marshall “pill” or a Superpave “puck,” depending on the project.
“Once the designs are finalized and approved, I’ll load them into a mix data sheet, and the plant manager will run off that,” Matt said. “Everything we create is a job mix formula, or JMF. What they have to use is all predetermined—what parameters they need to hit. We come up with a design here, it goes through its required tests, then it gets sent to the agency, and once it’s approved, we pass it off to the plant.”
Everything begins with the QC lab, heads off to the DOT or FAA, returns to the QC lab, and finally gets handed off to the production crew.
A Quality Upgrade
Many firms this year are taking a measured approach to finances and investments due to economic uncertainty in the industry. But KMI went against the grain, deciding to greatly expand and upgrade their quality control facility and operations. I was curious what drove the decision to expand while others are playing things closer to the chest.
“I think it’s the advancement of balanced mix design (BMD)—just having space for everything,” said Mike Matheny, Director of Quality Control. “Now we have room for things like the Hamburg Wheel Tracker.
Balanced mix design, also called performance-based design, has been driving a lot of conversation and change within the industry for years. If you attend any asphalt industry meeting, it’s a frequent topic.
The industry advocates for BMD for one major reason: If you want to work with federal agencies and access federal funding, you need to be on board with BMD. Doing so, as KMI has, typically requires investment in new lab equipment and in additional staff training.
Different agencies, however, have clear preferences for one method or another depending on the project and specifications. A modern QC lab must be equipped to meet all of them.
The FAA’s standard specifications for airport pavements are based on the Marshall method. They require designing mixes using the Marshall procedure and achieving criteria such as minimum stability values in the lab. For heavy aircraft (gross weight ≥ 60,000 lbs or high tire pressures), the FAA specifies a 75-blow Marshall design targeting a stability of at least ~2,150 lbs and a flow between 10–14 (0.01" units). The agency also mandates field verification test strips using plant-produced mix before full paving can begin. In practice, nearly all FAA-funded asphalt runways and taxiways still use Marshall-designed mixes.
State highway agencies, by contrast, have overwhelmingly moved to Superpave for road and highway mix designs. Following FHWA guidance in the 1990s, by the early 2000s most states had adopted Superpave binder specs and mix criteria. Today, if you bid on a DOT paving job, the mix design will almost certainly need to be a Superpave design meeting that state’s adaptation of AASHTO M 323, complete with binder grade requirements, traffic-level criteria, and tests such as Hamburg wheel tracking for high-volume roads.
As we turn the corner into the new year, the industry’s landscape is changing, and competition for projects may become increasingly fierce. Those best prepared to meet evolving demands will be positioned to make the most of the federal and state dollars available. While it remains to be seen what the focus will be for the next surface transportation bill, it's likely that the critical quality standards aren't going anywhere.
Like KMI, the companies making the future-oriented investments into training and equipment to support these higher standards will find their ROI on such investments to be much higher than those who lag behind. Because making these sorts of upgrades and changes, isn't something that happens overnight.
