Asphalt: from start to finish (line)

For a motorsport enthusiast there are few experiences that top spending time with your favourite ride on a winding ribbon of fresh asphalt. When planning our road circuit we wanted to give drivers the feeling of going somewhere, catching glimpses of asphalt as you round a corner. That’s where the similarities between a road and our circuit end, and one of the main differentiators is that beautiful asphalt – with every step we took to get here.

Preparation: grade, compact, repeat

Carving a new track out of raw land can appear impressive in those first few weeks, when enormous amounts of earth are displaced and we can see the form taking shape before our eyes. That’s one of the fun parts, and it goes by quickly. For a good portion of the summer our site appeared (to those of us who don’t speak construction) fairly uneventful. It was anything but.

While pouring curbs and walls brought activity and definition, the 4.83km track was being prepped for its paving date: beneath the surface are layers of compacted sand, natural to the location. “Sand compacts well and helps prevent shifting”, explains Lake Excavating president and Area 27 co-founder Trevor Seibert. “Fortunately, we have a good quality subsoil here.”

The crew spent weeks on the final grading, working within precision single-digits to meet design specifications. Loaders dumped material on the rack surface and a grader with a GPS guided mid-mounted blade did the finesse bits before the compactor passed, the entire process repeated until the surface was at just the right grade.

Precision equipment, large scale, has the final say before things get paved.

Tack coat on turn 7.

Gravel was spread on the carefully compacted track, then the surface was coated with an oil substance (applied in liquid form and left to harden or ‘cure’) to create a ‘tack coat’. The treatment isn't always used on road and highway construction, but it helps achieve uniformity for asphalt application and strengthens the bond with the lower surface. Ultimately, it’s the right thing to do on a premium circuit.

Tech Talk: the science of asphalt

Public road asphalt is a mix of one third rock, sand, and recycled asphalt. Area 27 had a custom blend created to handle desert heat and winter cold. “It’s a polymer modified asphalt that in the lab can withstand temperatures as high as 78C and go down to -28C without cracking”, says Brent Traxel, owner and senior technologist with Kam Tech Quality Management. “The composition is 26% rock and 44% MF (manufactured fines) with natural sand, RAP (recycled asphalt product), and 5% is a thick oil that looks like it has the consistency of liquid rubber.” Flexibility.

Brent and his crew were tasked with ensuring the asphalt plant run by Peters Bros. produced raw material within the established specifications throughout the project. “We work with them on most of their jobs”, explains Brent. “Some pavers have in-house quality assurance, and that’s okay too. We like that there’s a level of separation here. We get to know the crews, but it’s easier to be impartial because we’re not employees of the company.” Brent has five mobile labs that serve from Dawson Creek and north (his partner’s region) to Kamloops and south (Brent’s).

Side profile of the bottom lift (bottom layer) shows the composition when compressed.

In the lab with Brent's crew as they burn-test to establish the integrity & quantity of the components.

Raw materials on site at the asphalt plant: RAP (left) and sand (right).

Starting at setup and continuing to the last bit of asphalt goes down, quality assurance was on site for every stage. Brent tested the raw product three times each day, taking samples of hot asphalt directly from the track (in a small lunch cooler) to a lab/trailer beside the asphalt plant. Although the lab was stationed beside the mobile plant, it’s important the samples went through their route before being tested: from plant, to truck, into the paver, and on the track. “Sometimes we have to tweak the plant during the project to match the original formula”, says Brent. When asked if there had been any adjustments after six days of paving, he replied with a smile and a happy “nope.”

The Tricky Part: paving a racetrack

Highways and roads are paved in two passes to help avoid delays. By applying asphalt one lane at a time, crews can keep one lane open and traffic moving – albeit slowly. “Paving like that leaves a centre seam”, says Trevor. “They can use a bitumen to seal it, but it’s susceptible to water ingress.” Environmental considerations are one of three elements that cause asphalt to deteriorate, so to mitigate this factor we used ‘hot joint’ or echelon paving.

Two pavers, running staggered across the surface of the track, lay two strips of asphalt while it’s still hot and cover the entire width of the circuit. The progress was slow but steady, and was followed by a series of compactors to force the 140C asphalt together without that pesky seam. “It’s the ideal way to pave”, explains Trevor. “It takes away a significant portion of the environmental risks causing damage. Highways can’t shut down entirely or they’d probably pave this way.”

Approaching turns 4 and 5 (Jacques' corners) with the echelon paving. Double the fun.

Trevor and Ryley help keep the bottom lift (bottom layer) clear as the pavers approach turn 4.

Careful application of raw asphalt on turn 7.

The crew at Peters Bros. is in demand and we’re fortunate they made time in their crazy-busy schedule to accommodate our unique project. “We’ve been in Hope on a job and were pulled off to do this”, said paving pro Dennis as he walked between pavers. “We’ll go back as soon as we’re done and then we’re booked until Christmas.” He’s earned the admiration of his peers and is known as the best in his industry.

After considering the tight turns and banked corners needing his expertise, Dennis merely shrugged. “For me it’s just another day at the office.” Those days involved disengaging a sonar guided automatic leveling  system, leaving Dennis to pave each of our 16 corners using only his judgment and years of experience to guide him while ensuring consistent asphalt depth along the way. Easy, right? Not so much. Especially when one of those corners is Turn 7. 

First Laps: the custom NASCAR

It could be argued that two very slow echelon pavers had the first hot laps (incredibly hot laps) at Area 27 as they were the ones to lay the asphalt itself. Or maybe there’s a case for those compactors who drove on the new surface for the very first time, slowly and methodically. In reality the first laps go to Trevor and Ryley Seibert, our father / son build team and race car drivers, who drove Trevor’s custom built NASCAR that was specifically designed for this track. It was a goosebump moment for motorsport fans and anyone who loves a good story.

When asked how it felt to drive on the circuit he physically built with his son, Trevor replied with an enormous grin – because that’s all he could say while buckled into his racing seat, helmet strapped on, and ready to go another lap.

Ryley and Trevor pose while the last of the echelon paving goes down. Longest victory lap ever.

One week later: test lap day. Ryley plays pit crew and helps secure Trevor in the driver's seat.

With Ryley buckled in the passenger side, father and son are off for the first hot laps.

Pulling into the pit lane after a few father-son laps. Success.

 

NOTE: photo credit Jeannette Montgomery, subject to copyright

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