Balancing GTR, RAP, WMA over failing concrete proves successful for Missouri taxpayers

Early June 2023, the team at NB West Contracting, headquartered in Pacific, Missouri, began work on a complex overlay. The main goal was to cover up a 15.3-lane-mile, potholed, concrete section of Route 63 in Maries County and make it a smooth, safe driving surface for the taxpayers. The Missouri Department of Transportation (MoDOT), Ingevity, National Center for Asphalt Technology (NCAT) and NB West partnered to exceed that goal.

Steve Jackson, the vice president of asphalt plant operations and sustainability for NB West spoke of combining ground tire rubber (GTR) and 20% recycled asphalt pavement (RAP) as one aspect of the warm-mix asphalt (WMA) project.

Jackson took infrared images of the project to double-check consistency of mat temperatures and confirmed that consistency coming from the plant to the jobsite.

“It was a balanced mix design, performance spec, SP095C (9.5-millimeter,) Superpave with ground tire rubber and RAP, warm mix, placed through a spray paver, and bonding to a concrete pavement,” he said. He listed off all those moving parts of the project like it was business-as-usual for the production and paving personnel. For a team that’s been on the scene since 1956, it almost is a walk in the park, yet they pulled out the quality control/quality assurance (QC/QA) and safety best practices to make sure everything flowed smoothly for an award-worthy project. In the end, they garnered the Missouri Asphalt Pavement Association (MAPA) 2023 award for a primary route under 50,000 tons. Here’s how they accomplished it.

Familiar Parameters

In 2012, NB West had successfully performed a project bonding an asphalt layer to concrete with the company’s Roadtec spray paver, and saw an opportunity to apply that technology again. Jackson explained the DOT originally was letting the project with the 19.0 mm mix and a 12.5 mm mix for the surface layer, but his team wasn’t excited about that because both layers would have been placed at less than four times the nominal maximum aggregate size.

“The thickness of the layer didn’t allow for the 12.5 mm to work smoothly,” he said. “In 2012, we’d done something similar bonding concrete with the spray paver, so after we were awarded the [Maries County] job, we did a value engineering proposal to bond to the concrete. We suggested two lifts of 9.5 mm Superpave with an overall reduction of 1 inch in the overlay. We’ve been trying to get back to realistic lift thicknesses that can get good compaction and DOT agreed with that.

The Relationship Between EPDs, BMD, RAP & Plastic

“We also proposed using ground tire rubber to delay the cracking coming back through the mix. The other reason for the GTR is we were doing our performance tests, and when we’re using the GTR in those mixes, our IDEAL-CT numbers have just been off the charts. Our performance tests are the IDEAL-CT and the IDEAL-RT.”

Good Numbers: For the Maries County project, the team saw an average CT-Index of 168, an average RT-Index of 77 and Hamburg rutting result of 7.0 mm.

The unconfined joints were on the outer edge of a concrete roadway that had a rock shoulder. The NB West crew paved the mainline and used a non-Superpave asphalt layer over the rock to cover up the shoulder.

Making Mix

Jackson credits the elasticity of the GTR for aiding in pavement performance. “We’re putting the ingredients back in that gives it a little flexibility.”

To add the GTR, NB West uses the dry process, adding Elastiko® engineered crumb rubber asphalt (ECR) manufactured by Envirotx and supplied by Asphalt Plus. N.B. West’s Joe Schroer, P.E., materials and support engineer, explained the dry process is considered mixture modification. Performance testing measures the interaction of GTR, aggregates and binder as a system, and allows a more innovative approach to designing asphalt mixtures, he shared. Additional enhancements to mixture performance can be made by adjusting the grade of the binder.

A groundman brings the 2,000-pound tote of Elastiko material to the feed bin of a modified Hi-Tech Fiber machine with a forklift. From the bin, the machine feeds the material to a 6-inch-diameter flexible hose and to the portable Astec Double Barrel.

Balance Your Mix Design for Asphalt

“We blow it right into the drum,” Jackson explained. “The control unit’s inside the control house and it’s tied into the tons per hour you’re producing.” In this manner, the plant controls the addition of the GTR product as it would cellulose fibers being fed in.

This project ended up with a variety of additives in the production process, but Jackson said it was business as usual for the team. “We had the normal challenges. This still had our normal Superpave testing in it; we were still running volumetric testing and adding in the performance testing. So, it was a lot of testing.”

Jackson shared a testing tip for working with GTR. “When you’re making pucks up, if you put a weight on your mold top (with the GTR in there), it keeps the GTR from rebounding while cooling. If you don’t do that, you get some kinda strange results.”

The unconfined joints were on the outer edge of a concrete roadway that had a rock shoulder. The NB West crew paved the mainline and used a non-Superpave asphalt layer over the rock to cover up the shoulder.

Smooth Quality

In the field, the crew worked with temperatures below 300 degrees F. Even with the Evotherm WMA additive in play, they elected to have temperatures closer to HMA to accommodate the Elastiko. “The manufacturer told us not to go below 280 with the GTR,” Jackson said. “We went down to 270 and didn’t have any problems.” A longer haul—approximately 40 minutes from the plant—for this project allowed a longer dwell time for interaction of the GTR with the binder at the reduced temperature, according to Schroer.

Jackson took infrared images of the project to double-check consistency of mat temperatures and confirmed that consistency coming from the plant to the jobsite. “I took my FLIR camera out there…the good thing is I think the ground tire rubber holds the heat in the mixes. It was about 40 minutes to the job, and we were on a two-lane road where we had to flag the traffic, so it was challenging getting the trucks in and out. But we didn’t lose a lot of heat in the mixes.”

One of the best practices Jackson recommended was staying on top of the rolling pattern. “We were keeping our rollers right up on the screed. Because we were already dropping our temps below 300.”

The mix design used all the moving parts. “We used 20% RAP in this mix and 10% by weight of AC was the asphalt plus Elastiko product. The idea was that we had our baseline AC, which was a 64-22 and 10% of the Elastiko was in there to bump it up to a 76-22. It was the same mix on both lifts.”

Is Your Lab Ready for Balanced Mix Design?

The Missouri DOT allows whatever percentage of RAP the contractor wishes to use and still meet performance specs. “Technically, there’s no limit,” Jackson said. “Our problem is availability. We can’t run maximum RAP in our mixes because we don’t have it. There was nothing to mill on this project, so we had to bring RAP from other locations to put in this mix.”

For the NB West team, that’s just one more solvable problem. Jackson spoke of the “can do” willingness to put a puzzle together when it comes to the crew, starting with Plant Operator Clay Pitts.

“Number One is just the general attitude of not saying ‘we can’t do that.’ Yeah, we’ll try that. That’s huge. Clay’s great about that. Always willing to try something new and make it work.

“Dustin Hollis was the foreman and Juan Marquez was the general superintendent; they manage several jobs at a time.”

Jackson also described the effort the quality control/quality assurance (QC/QA) team had to put forth, given the changes to the contract after it was bid.

“Our quality control dept came up with these mixes and tried new things and really kind of pushed the envelope. The performance testing, the way we did this, that wasn’t set up in the contract, so we still had to do all the volumetrics testing and add the performance on top in a BMD situation. We’ve never run this mix so we were going live on the road with what looked in the lab like it would run well and do its performance testing. We had to go behind the spray paver and dig a sample behind the screed in a mat that has a polymer in it. It was a monumental challenge for our QC team.

“We have our plant people and our QC people coming up with this crazy stuff and then we go execute it and we still have to make money at it. I think we did a slight tweak to the mix after the first day or two to take advantage of the performance test because we could reduce our air voids using the performance test.”

The final result gave an average international roughness index (IRI) of 32.

“On concrete pavement that they didn’t have enough pavement repairs for, to come out like that, I think it was great,” Jackson said.

Not only did the project win a MAPA award, the traveling public noticed the good work. Jackson has received unsolicited comments about the work. “I’ve had somebody call and say, ‘that rides real good.’ People see that [kind of result] and they’re more likely to support the gas tax.”

Balancing Mix for Optimum Density

One of the reasons NB West uses a warm-mix additive in every mix they can is to get the compaction aid assistance.

“We run Evotherm in every mix that we have to get density on,” Jackson said. “We don’t run it on Novachip, but every other mix, we’re putting it in there.”

One of the factors that changes when developing a balanced mix design (BMD) and doing your performance testing is the number of gyrations.

“You’re dropping your gyrations,” Jackson said. “You’re making a mix that’s got more AC in it. So, you can take advantage of some of those mixes then of making them more compactible in the lab so when you go to the field, it’s easier to get compaction.”

Take a typical interstate mix as an example.

“We started off at 125 gyrations on interstate mixes. When you’re trying to compact that, you’re breaking rock trying to get density. Then we backed off to 100 gyrations, then to 80. I think we’re at 60 with BMD.

“To keep your voids in mineral aggregate (VMA), you end up putting some more AC in it. So, you have a mix that will compact, and it’s got binder to hold it together. Now instead of breaking rock to get to 92%, you’re rolling this and getting 96%. That’s what FHWA wanted: higher density. We get higher density by going to balanced mix design.”

Learn More

Step 1: The forklift brings the tote of ground tire rubber product to the bin.

Step 2: The GTR product is fed through the 6-inch-diameter, flexible hose.

Step 3: The plant’s controls meter the product just as it would any cellulose fiber being fed to the Astec Double Barrel drum.

About every 11 years, the world experiences a peak in solar activity with the next maximum predicted between 2024 and 2026.

During these periods of heightened solar activity, the resulting ionospheric disruptions may negatively impact the quality of global navigation satellite system (GNSS) signals and degrade positioning accuracy. That’s why Trimble, Westminster, Colorado, has developed a new technology to mitigate GNSS signal interruptions caused by ionospheric activity: IonoGuard™.

Although the effects of ionospheric disruption are typically minimal or isolated to certain geographic regions, according to Trimble, “it is during the peak where global disruptions can bring construction and mining operations to a costly halt when they are dependent on precise positioning.”

Trimble’s new IonoGuard technology aims to mitigate ionospheric disruptions in positioning and navigation by minimizing performance impacts caused by scintillation or signal noise. This graph shows the extent to which IonoGuard was able to improve positional accuracy at a site in Sweden.

Planning for a High Peak

The upcoming peak is the fourth solar maximum Ed Norse, portfolio manager of Trimble’s GNSS original equipment manufacturer (OEM) modules, has experienced since joining the industry. “The first one I experienced in the late ’80s was quite large,” he said. “It was significant enough to shut down some electrical grids.”

The next two peaks, in 2001 and 2014, were relatively mild in comparison. “We don’t expect the upcoming peak to be as bad as [1989], but it does look as though this peak will be larger than the last two,” Norse said. If that’s the case, it could create problems not only for the areas familiar with ionospheric disruption—latitudes along the equator and near the poles—but also mid-latitudes such as the continental United States and Europe. “It’s possible some customers in the mid-latitudes who require the highest possible accuracy could experience problems that may occasionally shut down their operations.”

Trimble SiteVision Brings Augmented Reality to Asphalt Paving

This can occur during a period of high sunspot activity, which usually lasts for a few days. “However, the problem is not constant during those days,” Norse said, and may last anywhere from a few minutes to a few hours.

Not only were the past couple peaks less intense than what’s anticipated for 2025, but there were also far fewer customers relying on Trimble’s highest-precision positioning technique, real-time kinematic (RTK) GPS. “Our number of RTK users has doubled every decade,” Norse said. “The levels were lower and we had fewer users [in 2014], but the applications then didn’t require as high of accuracy as they do today.”

For example, he added, “One of our biggest problems right now is running autonomous trucks in mines in South America. We weren’t running trucks autonomously 11 years ago, but autonomy is a big thing now and that requires centimeter level accuracy.”

Trimble Announces Strategic Partnership for Cloud Solutions

How the Sun Cycle Impacts Positioning Accuracy

The solar cycle is a periodic variation in the Sun’s activity, measured by changes in the number of sunspots on the Sun’s surface. Sunspots are regions of the sun with temporarily reduced surface temperature, caused by active magnetic flux reducing convection.

Sunspots can eject material from the sun, known as Coronal Mass Ejection. If the material is ejected toward Earth, this can sometimes be observed as the Northern (or Southern) lights—in addition to impacting GNSS performance. During more intense storms, the Northern lights can extend to the continental United States, as can the impact on GNSS signals at these lower latitudes.

“The more sunspots, the more areas with magnetic activity,” Trimble writes in an IonoGuard technical paper. These areas can eject particles, which may be carried to Earth. “As more particles hit earth, the layer of atmosphere known as the ionosphere becomes more charged, and the GNSS signal delay resulting from the ionosphere increases.”

“In general, GPS and GNSS rely on very faint signals coming through the atmosphere,” Norse said. “We need a good signal from at least four satellites, and if the signal is affected in any way, that can affect our positional accuracy.”

Union Concrete and Construction Gives Buffalo Airport a Lift

Peaks Pose Challenges

According to Norse the degradation to positional accuracy as a result of ionospheric disruption can reach as much as a meter. “In some applications, like a car navigation system, that might still be okay,” he said. “But for an operation requiring centimeter accuracy, a degradation of even a couple centimeters is a deal-breaker.”

Trimble supplies its users with an accuracy estimate so the customer knows what level of accuracy under which they are currently operating. “Then, they can decide whether or not they want to proceed,” Norse said.

For example, surveying operations require accuracy to 1 or 2 centimeters. “Depending on the application, grading equipment might need blade accuracy of 1 to 3 centimeters,” Norse said. “Compaction is an application growing in popularity that also requires centimeter accuracy.”

“We’ve already seen some issues with construction operations in Alaska and grading applications in Brazil,” Norse said. “Although we’ve seen some small levels of ionospheric disruption in the mid-latitudes already, it hasn’t been enough to shut down operations.”

Securely Track Vaccination, Test Status on the Job Site

So far, the applications most affected by the upcoming peak include mining and agriculture along the equator and northern Canada. “Mining activities running autonomous machines and mining applications in general are a high-cost application where downtime is very expensive,” Norse said. “If a mine goes down for even a couple hours, that could be hundreds of thousands of dollars lost.”

And, unfortunately, ionospheric disturbances are difficult to predict and, therefore, difficult to schedule around. Although winter is generally worse than summer and nighttime is generally worse than day, Norse said “there will be good days and bad days, with the number of bad days increasing as we reach the peak—and there’s no way to know when these bad days will occur.”

Enter IonoGuard

Although Trimble has been adjusting its technology in regards to the solar cycle for decades, the company began to prepare for the 2025 peak in earnest five years ago. Trimble installed raw radio frequency (RF) recorders at multiple equatorial and high latitude locations to capture both regular seasonal ionospheric activity in addition to activity during some major solar storm events.

The company then replayed this raw data to test the effectiveness of its new signal processing techniques and RTK algorithms before loading this updated firmware into onsite receivers for real time evaluation—to much success.

“For example, in a scenario with 10 or 20 centimeters of error, IonoGuard can generally get the accuracy back to 1 to 2 centimeters,” Norse said. “We had customers in northern Canada and Alaska running beta versions of IonoGuard, and it greatly helped.”

Selecting Your xD for Mill-and-Fill Workflow

Trimble also has established a global ionospheric measurement network (gnssplanning.com), which allows users to see current ionospheric disturbance and plan ahead for times when higher disturbance is anticipated.

According to Trimble, multipath, jamming and other factors can cause similar outcomes as ionospheric disturbances. Trimble’s IonoGuard firmware features a traffic light system of green, yellow, orange and red icons to indicate the current level of ionosphere disturbance that the RTK base station is experiencing on each satellite, so users can more easily pinpoint if that might be the cause of any issues. “If that seems to be the case, please download the latest firmware to all roving receivers,” Norse said. “If the problem persists, there’s something else that needs troubleshooting, such as a problem with the base station, a bad cable, etc.”

“Ionospheric disturbance doesn’t affect all satellites at once,” Norse said, adding that the receiver web interface will show which satellites are most affected. “IonoGuard will automatically de-weight the satellites most affected compared to the satellites that are not passing through the problem area.”

According to Norse, Trimble plans to continue honing IonoGuard leading up to the 2025 solar maximum. “We were under time pressure to get the technology out because customers are already having problems,” he said. IonoGuard was released in November 2023 as a free downloadable firmware update for Trimble GNSS receivers utilizing the ProPoint^® GNSS positioning engine. “Once affected customers install the new firmware and test what IonoGuard can do, they’ll see that it results in a significant improvement.”

Schlouch Incorporated is a heavy civil site work contractor in Blandon, Pennsylvania. Although the company’s services range from excavation, utility installation, drilling and blasting, to design build services, concrete work and asphalt paving, Schlouch isn’t too big to benefit from offering niche asphalt paving services.

The company is known for its quality work paving running tracks for high schools and colleges throughout eastern Pennsylvania. Although the area in which Schlouch performs running tracks is fairly consistent with the region in which they perform asphalt paving—which accounts for roughly one-fifth of the company’s annual sales—the company will sometimes travel outside their usual area of operation to pave sport surfaces.

Powell stresses the importance of adhering to tight tolerances when milling out old asphalt, “or you won’t be able to adhere to those tolerances when you put it back in.”

Glen Powell, Schlouch’s paving department coordinator and project manager, estimates the company has paved around 60 running tracks, as well as around 100 sport courts, since it began going after that type of work 20 years ago.

Schlouch Inc. was founded in 1983 by Barry and Deborah Schlouch, who own the company to this day. Today, the company employs 285 people.

John Reinhart, an estimator and project manager for Schlouch, brought the idea of doing sport courts and tracks with him when he joined the company 20 years ago after having experience with these types of jobs at his previous employer.

Reinhart estimates that there are only a handful of contractors in eastern Pennsylvania who pave tracks and sport courts. He explained that such jobs require tight tolerances, and Schlouch employees take pride in delivering a product within those required tolerances.

It’s also a niche market with a tight network of contractors, Powell said, and one heavily based on referrals, Reinhart added. Most of Schlouch’s referrals come from architects the company has worked with in the past and surface coatings contractors, who subcontract the paving portion of the work to Schlouch.

“The reason surfacing contractors stick with us is the quality of the product we turn out,” Powell said. “We turn out quality they can count on. More than anything, that is what’s helped us grow in this niche.”

At Schlouch’s most recent running track job, at Bensalem High School, the track was around 15 years old. Although the underlying asphalt was still in good shape, the surface coatings had delaminated from the pavement.

Meet Sanctioning Bodies’ Specs

On average, running tracks last anywhere from 10 to 20 years. At Schlouch’s most recent running track job, at Bensalem High School, the track was around 15 years old. Although the underlying asphalt was still in good shape, the surface coatings had delaminated from the pavement.

“The most common reason tracks are redone is because of the wear on the surface or its delamination from the asphalt,” Powell said. Often, he said, the schools are just replacing the asphalt to ensure the surface coatings have a good pavement to stick to and to ensure the asphalt remains in tolerance.

Reinhart said the track plans are usually prepared by the engineer in accordance with national high school or collegiate standards. The line striping, which requires certification from the sporting body, is usually performed by the surfacing contractor. In Schlouch’s case, the surfacing contractor is often the general contractor on their track jobs, and so the surfacing contractor is also responsible for accepting the pavement tolerances.

“With high school tracks, you have tight tolerances because you have to meet certain requirements from the sports’ sanctioning bodies,” Powell said, citing Pennsylvania Interscholastic Athletic Association Inc. (PIAA) or the National Collegiate Athletic Association (NCAA) as examples. “The quality has to be very good because of those tight tolerances.”

Upsell Recreational Site Managers with Multi-Purpose Sport Courts

Tennis courts and tracks require a slope of ⅛ of an inch per 10 feet, said Schlouch Paving Field Coordinator Rob King. “For context, that means when you put down a 10-foot straightedge after paving, there shouldn’t be any light visible under that straightedge or you’re out of spec,” he added.

To pave running tracks, the Schlouch crew relies on Cat AP-555F pavers equipped with Cat’s Grade and Slope Control System. Schlouch has been using that system on all its jobs since the system was launched, and used Topcon’s Grade + Slope Control System prior to that. In the future, Schlouch plans to get into 3D paving.

“We use Cat’s Grade and Slope Control System while paving and perform spot checks with a laser level and straightedge,” Powell said, adding that they perform surveying work in house to check the layout for tracks. “Being able to check grades across the tracks prior to paving is key, but it’s also important to check grades every step of the way.”

With such tight tolerances, Powell stresses the importance of starting from step one with the end goal in mind. “Whether it’s a new track or a rehab project where the existing pavement is milled out, everything from a quality and tolerance standpoint starts at the beginning,” he said. “You can’t do a lesser quality job in preparation and expect a  quality result from the paving at the end.”

For new track projects, Schlouch uses Cat Grade Control System on its graders. For rehab track projects, the company relies on its milling subcontractor, Rota-Mill, Oley, Pennsylvania. “They do most of our milling,” Reinhart said. “We’ve worked with them a long time.”

How to Surface & Stripe a Pickleball Court

Before milling can be done, the surface coating has to be removed. “The reason the surface has to come off is because the rubber in that coating cannot be recycled at the asphalt plant,” Reinhart said.

“It’s important to make sure you’re adhering to those tolerances while you’re taking the material out,” Powell said, “or you won’t be able to adhere to those tolerances when you put it back in.”

That’s exactly what Rota-Mill did when it milled 1.5 inches off the track at Bensalem High School before Schlouch’s crews replaced it with 1.5 inches of new asphalt.

After paving, Powell said, the architect, designer and surfacing contractor typically walk the track to perform a tolerance check. In the case of Bensalem High School, there were no corrective actions to the tolerance.

“The pavement was good to go and move forward with the coating,” Powell said. “We always provide that feedback to the crew who paved the job because they put all the work into it.”

The Bensalem High School track required 450 tons of asphalt. “We also rebuilt the runways in the D zones,” King said, referring to the area between the goal posts and track where events such as the high jump, throwing events, and pole vault take place.

King said Schlouch normally uses a 9.5 mm asphalt for its tracks and courts, which are usually 4 inches thick: 2.5 inches of base course and 1.5 inches of wearing course.

Tackling Track Challenges

King said an average running track is 4 inches thick, usually paved in two lifts: 2.5 inches of base course and 1.5 inches of wearing course. “Some of the tracks are designed as if you’d have tri-axles and tractor trailers driving on them,” he said, adding that it’s common for school maintenance vehicles and utility vehicles to drive on the track, as well as tractors and trucks for events like homecoming.

Schlouch normally uses a 9.5 mm asphalt for its tracks and courts, King said. “And one of the keys is to ensure it’s a virgin mix,” he added. For their region, “[t]he reason for that is if you’re using a mix with RAP, there’s the potential for small pieces of metal to be in it. That metal can rust and come up through the rubberized coating on the surface.” Most of the vendors Schlouch works with do not have magnets where the material is entering the plant process, King added. Although it’s mostly a matter of aesthetics, he said, it could delaminate the coating from the pavement.

Powell said they usually don’t have problems sourcing virgin mix for these jobs within a reasonable distance to the project. However, he added, it is a consideration the company needs to make in the bidding stage.

One challenge Schlouch’s crews often face when paving tracks is access, often a fence with only one entry/exit. In the case of Bensalem High School, the track had only one entry point and was otherwise surrounded by a 30-foot berm.

How to Pave a Tennis Court

“We only had one spot to get in and out and it wasn’t the best spot to get in and out,” King said. “It limited the way we could pull the job, and the way we ended up having to pull it wasn’t the best to maintain tolerances so it required more handwork.”

The optimal way to pave a track, King added, is to end at the edge of the sprint track. “If you imagine the track as an oval, there’s a section where the 100-meter race is run that extends straight past the radius of the oval,” he said. “That’s usually where you want to finish your pull.”

Powell said the crew is typically matching a concrete curb or drainage system on the inside of the track, which makes paving the curves of the track easier.

In terms of density, Powell said the crew is aiming for the same density as road jobs, between 94 and 96%. However, he added, the compaction process must also factor in tolerances: “As you compact, you have to be very careful you don’t overcompact in some areas to the point that you’re out of that tolerance.”

“It really comes down to having good roller operators,” Powell said, adding that Schlouch has several roller operators with 10 or more years of experience and one with more than 20 years of experience. “These jobs are not the jobs you want to put a new roller operator on. They definitely call for someone seasoned.”

“That goes for every role on the crew,” King added. “The whole team you assemble for these types of jobs needs to have experience for a job like this to come out to spec.”

Glen Powell, Schlouch’s paving department coordinator and project manager, estimates the company has paved around 60 running tracks, including this one at Muhlenberg College, since it began going after that type of work 20 years ago.

Slow and Steady Hits the Spec

Powell said it usually takes three days for Schlouch to pave the average running track.

“To be competitive in paving, you often have to pave fast and look for high production,” Powell said. “But paving tracks is the complete opposite. You can’t bid on a running track like highway paving.” He estimates they’re paving at about 20% of the speed they’d usually pave on a highway job.

However, Reinhart said, being able to pave running tracks well is a matter of prestige for Schlouch. “Not everyone takes the time to do this type of work,” he said. “Our company is proud that we have the skills to do this type of work. ”

How to Pave a Sport Court: Practice Really Does Make Perfect

“You have to take pride in what you’re doing,” Reinhart said. “The more pride the crew has, the better the job will be. The better the job will be, the more people will notice and the more referrals we’ll get.”

Often, Powell added, this type of work leads to other maintenance activities at local colleges and schools. “It’s not uncommon that we pave a running track and then get called back to repave the parking lot a year later,” he said. “Good work leads to more work.”

However, he added, “it’s important to remember even though you’re paving on a track, it’s not a race.”

It’s an unfortunate fact that vehicle intrusions are one of the leading causes of death in the road construction industry, resulting in tens of thousands of work zone crashes and hundreds of fatalities each year.

What’s even more devastating is that many of these fatalities could have been prevented.

The National Highway Transportation and Safety Administration estimates that 80 percent of all accidents are due to distracted drivers, looking away from the road to check a text (4.6 seconds), change the radio station (2 seconds) or search for a dropped cell phone (10+ seconds). All while their vehicles travel the length of a football field every 3.7 seconds.

Here’s another number: 6 seconds.

That’s how long it takes a worker to run five lane widths—more than enough to avoid an oncoming vehicle.

When it comes to work zone safety, every second counts.

That’s why Oldcastle Materials has developed its AWARE system. The system, which stands for Advanced Warning And Risk Evasion, tracks traffic and crew members within a work zone and sounds alarms and alerts both to drivers and to workers at risk of a collision.

Oldcastle, the largest asphalt manufacturer in North America, started to develop its AWARE system after experiencing a handful of fatalities in 2013 and 2014 due to lane intrusions.

“We were following all the regulations and recommendations at federal, state and association levels to make our organization safer, but at the end of the day, we were still having catastrophic events,” said Curt Davison, director of AWARE technology at Oldcastle Materials. “So, we asked ourselves what we could do beyond best practices and beyond regulations to make our workers safer.”

So, they began to develop AWARE with nothing more than a sheet of paper, a pencil, and an end goal: keep workers safer in the work zone.

Davison hopes to begin implementing the system company-wide in May of 2018.

How the AWARE System Works

As you can learn when watching the AWARE video in the link below, the system includes one or more sensors, a GPS-based alert unit for the worker, a number of threat deterrents, and a base station app for iPhone and iPad.

The sensors use radar to track the position and trajectory of vehicles within a range of up to 600 feet. When a vehicle is about to enter the workzone—when the sensor detects it as a threat—the sensor triggers audio and visual warnings for the driving public and individual alerts for workers who might be in harm’s way via their GPS-based units. The system will also begin recording video with an onboard camera for use in accident investigations, if necessary.

Today, there are two different types of solutions within the AWARE system, Davison said. One is a freestanding cart to set up by the flagger and the other is dedicated to safety in the work zone.

The system can be used for a number of applications, from line striping and traffic control setup, to multi-lane construction, flagger safety or lone-worker scenarios like road maintenance and sign placement.

Within the typical paving train, Davison recommends including in the system the paver and each roller. The QA/QC tech should also have one on his truck, since he’s often quite a ways back from the rest of the crew. The system can also include other operations such as milling and maintenance equipment.

When the system detects a threat, it will automatically trigger audio and visual warnings for the driving public and individual alerts for workers who might be in harm’s way. It will also begin recording video with an onboard camera for use in accident investigations, if necessary.

The system works to reduce false alarms, preventing desensitization in workers. When a real threat has been identified, the threat deterrents will activate, emitting whatever sound and strobe pattern the AWARE user has chosen.

Worker and equipment locations can be viewed in real time via the system’s companion app for iPhone or iPad. With the app, users can control basic functions of the system, including lane width, work zone type, minimum and maximum speeds, and conservative and aggressive reaction times for warnings.

Implement, Adopt and Stay Safe

The AWARE system’s sensor monitors traffic within a 600-foot range. Additional sensors can be mounted to other pieces of equipment in the work zone.

Last year, Oldcastle piloted the system in eight states on 13 different crews to continue to refine it, and one of the major improvements has been in usability.

“Our crews have a hard, hot job and they’re busy doing what they’re doing,” Davison said. “So we had to make it super simple.”

Davison estimates it takes about two hours to install the system on each piece of equipment in the work zone. After that, the AWARE system is very easy to use on a daily basis. The AWARE sentry for the flagger station takes less than a minute to set up and the entire work zone solution takes only a few minutes.

Other improvements in usability include reducing the weight of the sentry to less than 50 pounds and making the user interface of the app easier to use.

Davison also conducts an hour of training about the system before sending it out with new crews. He also recommends making the system a part of each crew’s morning safety talk, to discuss the best exit strategies and other emergency procedures for the job.

“You may only have seconds to respond after the system goes off, so that isn’t the best time to ask yourself where you should go,” Davison said. The system gives between one and six seconds of notice, depending on the situation. “One second may be enough, but you have to have a plan in place.”

Although making the AWARE system easier for workers to use is important, the real proof is in the pudding.

Davison shared a story about a flagger who wasn’t sold on the system when they deployed a threat deterrent next to him on the job. Then, a semi came towards him at a high speed. As it barreled closer to the flagger, it wasn’t slowing down. The system sensed its speed and the lights began to flash. Still, the semi didn’t slow down. The system’s lights started flashing brighter. When the semi still didn’t slow down, the alarm sounded. By that point, the flagger could see inside the cab and noticed the driver’s eyes go wide as the alarm sounded, apply the brakes, and come to a stop only inches from the flagger’s original position.

“Please understand that this technology, the AWARE system, does not replace the need for safety best practices in the work place,” said Oldcastle VP of EHS Lee Cole. “Rather, the two should work together to provide the safest work place possible.”

AWARE, Beyond Oldcastle

During presentations at industry events, Davison has realized how important a system like this is to all paving operations, as well as in other industries.

“A lot of people from a lot of industries–construction, police, truck drivers–have come up to ask me if the system will be available outside of Oldcastle,” Davison said. And it will–eventually.

“We want to refine the system a bit before releasing it outside of Oldcastle,” Davison said. “Right now, the sensors are still learning and rating threats, from false alarms and alarm-no-harm situations to near misses and minor and major incidents.”

Davison expects to refine the system internally throughout 2018, but hopes to make it available to other companies and industries in 2019.