Micro and Slurry Primer
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NASA Mill-n-Fill Demos Fiber
Make Trenching Safer Fall 2019 WWW.THEASPHALTPRO.COM 1 www.TheAsphaltPro.com
Editorial Here’s Why Cold Practices Are Hot Right Now
As I mentioned in the Summer Preservation Pro, some state agencies are still reluctant to allow high reclaimed asphalt pavement (RAP) contents the closer we get to the surface of the pavement. If you think about it, we’re removing the asphalt at 100 percent right now and putting it back at up to 30 percent on the high end. The other 70 percent waits at the yard for use in another mix. By generating more RAP than we can put back into the mix, we’re creating stockpiles of RAP. Industry is responding with cold in-place recycling (CIR) methods. The Asphalt Recycling and Reclaiming Association (ARRA) represents multiple disciplines, including the CIR methods currently growing in popularity. As a side note, cold central plant recycling (CCPR) seems to be growing in popularity as well. With this method, the contractor doesn’t have to heat any material, and the method lets you use 100 percent of the removed pavement at a central location. Another advantage to CCPR is it opens the agency up to more flexibility in project options. For example, you can peel the roof off the road, fix the road underneath with something like full depth reclamation, and put the CCPR back all from one location. Then put an overlay on top of the newly created and strengthened course. Part of the reason for the growth we’re seeing in CIR is its range of depth. It’s more of a preservation process. Due to funding shortfalls on a national level, we’ve neglected our roads’ maintenance and preservation, so CIR and full depth reclamation are options agencies need in order to get down to the problems in a pavement system without resorting to an expensive reconstruction. This speaks to the budget benefits of CIR. Then, the preserved system can be overlaid with a hot-mix or warm-mix asphalt or sealed with a chip seal, depending on what agencies have the budget for. In an ideal world, my favorite cold process for agencies to use would be the multi-unit train to ensure they achieve proper gradation. The multi-unit process makes CIR much more controlled. Now, that’s kind of the Cadillac of processes, more suited to large projects with multiple lane miles to correct and preserve. The smaller, single-unit recyclers may require a more skilled crew and operators, but they offer more flexibility in project size and are therefore the market that is growing the fastest right now. – From ARRA’s Eric Baker
Eric Baker is the 2019-2020 ARRA president. He has been at Roadtec Inc., Chattanooga, for 15 years working in different roles in the marketing and sales department covering all product lines. Some of his duties include managing sales, training, product management and product development. For ARRA, he previously served as the Cold Planing Technical Subcommittee chair as well a on the board of directors. For the National Asphalt Pavement Association, he currently serves on the Associate Member Council as well as the World of Asphalt committee. Baker attended Iowa State University and has his Bachelor of Science in computer engineering. He has three kids with his beautiful wife Courtney and lives in Chattanooga.
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Fibers Strengthen Mill and Fill Outside Kennedy Space Center By Sandy Lender
V.A. Paving produced a FC12.5 mix with PG76-22 at 335 degrees F about 12 miles from the job site. The company uses a 300 TPH Dillman unified counterflow drum with three 250-ton silos. Photo courtesy V.A. Paving.
The 50th Anniversary of Apollo 11’s historic mission to the moon brought extra excitement to the Kennedy Space Center (KSC) this summer. As luck would have it, maintenance work on the roads belonging to NASA fixed up avenues to the visitor’s center prior to celebrations and paved the way for a fancy entrance, thanks to asphalt, V.A. Paving Inc. of Cocoa, Florida, and some innovative demo with fiber reinforcement. Take a look. Kennedy Parkway (SR3) was due for repairs in June 2019, according to Eugene Hajdaj, the construction manager at KSC. Al Mallard, a vice president at V.A. Paving, explained how the company got to perform those repairs. “We had a project at NASA with Silver Mountain, a North Wind Company, to repair roads in various locations,” Mallard shared.
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“The project consisted of milling and paving 2 inches on Kennedy Parkway (SR3). We were about to start our second phase of work, which was to pave about two and a half miles northbound lane on SR3 from NASA property line to 5th Street, when Brevard County Road and Bridge contacted me about them using fiber reinforced asphalt on their future projects. We had several meetings on fiber reinforced asphalt and Brevard County had a residential street they were going to try some fiber reinforced asphalt ton, but they asked me if V.A. Paving could use the second fiber company for a test strip on one of our current projects. That’s when we asked NASA if we could do a one-mile test strip in one lane using fiber and the adjacent lane without fiber so that it can be monitored for years to come. We sent a deviation waiver to NASA for approval, which con-
The V.A. Paving crew placed 2 inches of mix over an NTQS1 trackless tack, using a Cat A1000F paver fed by a Roadtec Shuttle Buggy. Their tonnage for the first day was 1,291 tons—800 tons with fiber and 491 without. Photo courtesy Forta Corp.
sulted with Jones Edmunds Engineering, and it was approved by Jesse Salazar and NASA Design Manager Christine Hartett to proceed with test and follow-up with test results.” Scott Nazar, the engineering services manager for Forta Corp., Grove City, Pennsylvania, shared how the demonstration project began from their end. He stated there was a lot of interest in fiber reinforced asphalt at the American Public Works Association (APWA) conference held in Daytona, Florida, April 15-18, 2019. “Molly Anderson, technical engineer, and Roger Linde, sales representative, were working the FORTA-FI booth and spoke with some of the folks from Brevard County who were interested in the benefits they could get with fiber-modified asphalt.” With encouragement from Anderson, Linde set up a meeting with Brevard County during which Nazar presented “The Benefits of Using Fiber Reinforced Asphalt” for the Brevard County engineers. “The meeting and presentation seemed to go very well,” Nazar said. “This project [on Kennedy Parkway] was a demonstration for the county as well as NASA. Brevard County is considering doing a couple projects with fiber hopefully this year.” The timing was fortuitous. Not only did Brevard County get to see FORTA-FI in action on a real-world project, the road to the visitor’s center at KSC got a facelift prior to summer celebrations. “The road was in bad shape,” Hajdaj said, but it wasn’t being milled and overlaid specifically to prepare for the Apollo 11 celebrations. Hajdaj said it was up next on the construction facility’s schedule. He also said it was ideal for the side-by-side comparison Forta and V.A. Paving proposed. “Forta was the company we used for the test strip,” Mallard said. “We contacted Brevard County, NASA, Cape Canaveral Air Force,
and FDOT to come and see the fiber being injected into the asphalt and go to the job site to see it being placed. Everyone was impressed by the application to mix and how it laid on the roadway. There was no impact to equipment or testing. All of our density passed and other lab test passed.” To accomplish fiber injection, V.A. Paving worked hand in hand with Forta team members. Nazar explained how Forta’s director of operations jumped in to help. “Chris Lovett and Bill Surrena, also in operations, flew down to Florida and picked up the Voyager fiber feeder at our office in Sarasota. They hooked up the feeder to the plant in less than an hour without interfering with the plant operation.” V.A. Paving uses a 300 TPH Dillman unified counterflow drum with three 250-ton silos. The plant manager, Denny Sheppard, has been with the company for 28 years and the assistant plant manager and operator, Jeremy Black, has been with the company for 17 years. They didn’t report any worries, according to Mallard. “The Forta Voyager hose fed into the RAP inlet chute; they told us that was the best way,” Mallard shared. “The Forta Voyager had a wireless controller from the fiber feeding bin to our control room, which let our operator control production speed to fiber machine. We run the plant at 200 tons per hour and the fiber machine run the same at one pound of fiber per one ton of mix. We did not see any change in our asphalt production. No change in temperature, no damage to equipment, no clogging. Just add to existing mix and run.” Nazar explained: “The Voyager comes with a remote-control box that sits in the plant operations room. The plant operator can start/ stop and adjust the feed rate to match the production rate of the asphalt plant at the touch of a button. WWW.THEASPHALTPRO.COM 5
“The Voyager is on load cells and accurately meters the fibers based on loss in weight,” he continued. “The technology is a trade secret, but it involves a special rake and minimal moving parts. The fiber blend itself plays an even bigger part in preventing bridging and clogging. The feed rate in real-time is measuring the amount of fiber that’s blown into the drum plant via the RAP collar. At the end of the day, you can print off the feed rates and the total production for the day.” To place the fiber-enhanced mix, it was business as usual. The paving superintendent for the job was Josh Moores, who has been with V.A. Paving for 17 years. After MILL-IT Corp used two Roadtec cold planers to mill the existing roadway, the V.A. Paving crew placed 2 inches of mix over an NTQS1 trackless tack, using a Cat A1000F paver fed by a Roadtec Shuttle Buggy. “For this project, longitudinal fatigue cracking was the issue to resolve,” Nazar shared. “FORTA-FI has shown to reduce fatigue cracking by up to 95 percent in both laboratory testing and side-byside field evaluations. So the goal was to reduce cracking and extend the life of the overlay by three to five years.” Mallard provided the specs for the project, stating that the mix was FC12.5 with PG76-22. They produced it at 335 degrees F about 12 miles from the job site. Their tonnage for the first day was 1,291 tons—800 tons with fiber and 491 without. “The material had no issues,” Mallard shared. “The only way you could tell it had fiber was when you shoveled it or raked it; then you could see the fibers hanging onto the blade. Place and rolling was no issue; it did not affect the material.” They achieved compaction with two Cat 534W rollers, a Bomag traffic roller and a Cat CW34 pneumatic roller. 6 FALL 2019
The Voyager is located on load cells within a portable trailer. The feed rate in real-time is measuring the amount of fiber that’s blown into the drum plant via the RAP collar. Photos courtesy Forta Corp.
“We are delighted that V.A. Paving offered us this opportunity to experiment. We cannot wait to start measuring the difference in performance and the long term change to life cycle costs,” Hajdaj said. Nazar spoke kindly of the project: “V.A. Paving is really open to innovation and new technology; they embraced the fiber reinforcement concept and wanted to bring that to NASA, who, like them, are also innovative.” “Special thanks to Brevard County John Denninghoff, Susan Jackson, Bruce Black and Daniel Blackburn,” Mallard said. “They are the reason this all came together. And thanks goes to NASA for letting us use their project for a test site. I believe this product does make roads stronger; it has thousands of fibers holding all the asphalt particles together.”
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Software for Emulsion Control Blythe Construction, based in Charlotte, North Carolina, opened its first emulsion plant in the United States in early 2011. The company is a construction firm and subsidiary of the Hubbard Group of Companies, and needed the plant to support its paving operations. Blythe turned to MINDS Inc., Boisbriand, Quebec, to deliver a plant automation solution for its mix controls and software to handle its loadout and ticketing needs. MINDS installed its EmulTronic plant control system, which is a Windows-based automation solution for emulsion and modified bitumen plants. EmulTronic is based on the same platform as MINDS’ other asphalt plant automation systems, DrumTronic and BatchTronic, and is designed to control all the phases of the emulsion or modified bitumen manufacturing process, including the unloading of trucks carrying raw materials, mixing and blending, storing, and heating. MINDS worked closely with Blythe team members to design a system that was fully integrated with the new plant. The system has four display monitors that operators can review: the first screen shows operators the status of the emulsion tanks and related equipment; the second displays any production-related information that they need, such as the state of aqueous and anhydrous phases; the third shows bitumen tanks and related equipment; and the fourth is the ticketing and loadout display. EmulTronic is a highly visual system, designed to
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be easy for operators to understand. The process is controlled on the screen only, and both the continuous and discontinuous processes can be controlled with software that displays 3D graphics of the plant. “MINDS designed graphics for the system off of P&ID drawings, and the graphics were spot on,” said Randy Turner, Blythe’s emulsions plant foreman. “When they downloaded the graphics into the system they pretty much matched the actual physical piping in the plant.” Turner said he appreciates the valve graphics, which are color-coded depending on their status, making it intuitive for operators to understand. EmulTronic’s many levels of safety features were also integrated into the plant to prevent pumps being turned on without the operator’s approval and give the operator visual control over the entirety of the operations. Sensors installed on all the tanks and filling devices prevent tanks and trucks from being overfilled. To address Blythe’s ticketing and loadout needs, MINDS installed its Tessera software, which can be integrated with production management. Tessera was integrated with Blythe’s controls to allow staff to print tickets after material was loaded onto a truck. The ticketing system allows users to print tickets and invoices easily and to store information on customers, haulers, jobs, materials and trucks. The Tessera software is built on the MySQL database management system—a standard for the industry—and integrated seamlessly with Blythe’s SAP enterprise software. MINDS’ modular add-on architecture allowed Blythe to customize its import and export functions to accommodate adding or exporting data into or out of the system. Turner said he appreciates the work MINDS put in on adding conversions to their systems that Blythe needed. As the density of emulsion changes from batch to batch, Blythe needed to choose a specific gravity that would work on every batch. “There’s a lot of conversions that we do from tons to gallons and they had to do that for all the chemicals and raw materials,” Turner said. “On the Tessera system, they also had to convert specific gravity over to volume, and they did a tremendous job doing that for us.” Rick Owens, Blythe’s former emulsion manager, said MINDS’ solutions played a big role in the success of the company’s new plant. “MINDS was an integral part of this project from the beginning,” he said. “Without the close support from the MINDS team, we wouldn’t have been able to accomplish this.” Eight years later, Turner said the company is extremely satisfied with the software. Blythe also had MINDS install another system for them, Turner said. The system, only used during extremely busy times on the loadout side, is a copy of the ticketing monitor and the loadout screen, which allows one operator to run the plant as normal while another can handle all loadout functions. “They did that for us and we’ve only used it a few times,” Turner said. “That was a special request that they came up with for us. Their ability to take your needs and actually deliver it to you is just tremendous. They’re great systems,” he added. “I would use them again and I’d put it in another plant if we had one.” For more information, contact MINDS at (866) 505-8893. – From MINDS Inc.
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How to Excavate Safely A variety of industries rely on excavators. To dig a trench or utility cut safety, trained professionals are a fundamental part of the excavator work. Let’s take a look at important safety tips all excavator operators—of large or smaller machines—should follow.
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Inspect Basic Components Understanding is vital when it comes to construction equipment. As an operator, you should have comprehensive knowledge of the following components. Take the time to inspect each one before you get started. • All safety devices, including horns, lights, guards, shields, fire extinguisher, glass and wipers • Engine and hydraulic fluid levels • Boom, stick (or dipper) and bucket • All controls needed for proper function • Check for hydraulic leaks, loose bolts and cracked welds. Examine belts for proper tension and wear, radiator hoses for cracks, and the drive sprocket for work or cracked teeth. More thorough inspections should be don eon a more periodic basis, such as once a month. Operator’s Responsibilities Safety goes beyond physical inspections; only by taking the proper care in our actions can excavators reduce their risk of injuring themselves or others. • Keep the cab clean of dirt, grease and objects which could interfere with its safe operation. • Clean the glass of the cab regularly to increase visibility and to avoid glare. • Test each control before beginning work to ensure they’re all functioning correctly. • Grease the bucket hinge pins as needed; this is dependent on weather conditions and the type of material being excavated. For example, sandy or powdery materials may require two to three greasings per shift. • When climbing into or out of the cab, use the standard three-points-of-contact method. Always enter and exit while facing the machine. Do not jump out. 10 FALL 2019
• Keep footwear clean of excessive mud or grease to prevent slipping. • Buckle your seatbelt when inside and operating the excavator. In addition to these basics, operators need to take notice of their environmental factors. Fatigue, hunger, weather, emotional levels and physical health can all impact or impair the safe operation of an excavator. While the machines we’re talking about in most pavement maintenance or preservation applications are smaller pieces of equipment, excavators can weigh up to a staggering 185,000 pounds. With max digging depths that range from 7 to 31 feet, they offer hidden dangers below the surface. You must remain aware of each inch. • Take note of your working conditions. Work sites can be a bustle of activity, so operators must be able to block out such distractions while operating a machine, yet be aware of other workers. • Be aware of other workers: access to the job site by unauthorized persons needs to be controlled. Barricades should be placed to notify others where the safe and unsafe zones are. • Make sure you know where power line and other utilities are located before you start to dig. Most areas have a one-call number, which will contact local utility companies in your location to delineate dangers. Making a mistake or skipping the above steps can be deadly, given the right circumstances. Excavating Excavators are designed to dig holes and move earth. These tips regarding the act itself will make sure no imbalances or caveins occur. • Material excavated from a trench should be placed a minimum of 2 feet from its edge, although distance may need to be greater depending on soil type. Make sure the slope of the soil pile is flat enough to prevent material from sliding back into the trench. • Beware of undercutting. The operator must always be aware of where the machine is in relation to the edge of the ex-
Whether it’s an attachment or a fullfledged excavator, tools for digging and trenching require safe operation, as illustrated here with this Toro Dingo TX 1000 compact utility loader. Photo courtesy Performance Marketing.
cavation. As a safeguard against cave-ins, your excavator’s tracks should be perpendicular to the trench. • Know the load limits of your machine. Overloading the bucket with too much material can cause the excavator to tip over or become otherwise unstable. Never exceed the capacity laid out in the load chart at any time, for any reason. At the end of the day, the best safety feature on an excavator is its operator. You have the ability to pay attention to each component and ensure it is in good health, and you are capable of maintaining certain standards that mitigate the risks of the job. As long as you’re attentive and committed to following proper safety procedures, your days of digging can be accident-free. Doug Miller is the owner of Mini Final Drives, Salisbury, North Carolina. – By Doug Miller
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Southwest Slurry Seal micro surfaces with Bergkamp’s M1E Continuous Paver in Phoenix, Arizona. All photos courtesy of Bergkamp, Inc.
Upgrade Micro Surface and Slurry Sealing Operations By Sarah Redohl
In part one of our two-part series on the best practices of micro surfacing and slurry seal applications, we share all of the basics and best preparation practices. Part two, forthcoming in the Spring 2020 issue of Preservation Pro, will dig into the best practices on the job site. Experimentation with slurry sealing may have begun in the U.S. in the 1930s, but it wasn’t until the 1960s—with the advent of truck-mounted slurry seal pavers and the development and integration of quicker-setting cationic emulsions—that the treatment began to grow in popularity. The surface treatment is designed to protect the pavement from oxidation and raveling, provide skid resistance, and stop moisture intrusion into the asphalt pavement, while minimizing disruptions to the traveling public with its quick construction times. Its sister surface treatment, micro surfacing, didn’t reach the U.S. market until the 1980s, but has also grown in popularity since its introduction—both for its leveling capabilities and quick set capabilities. “In the last one or two years, we’ve had customers who used to bid every micro surfacing project they could find having to pick and choose because there’s so much of this work out there now,” said Jimmy Ken-
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drick, Director of Sales at Bergkamp, Inc., Salina, Kan. “The more educated people become on these applications, the more popular we’ve seen them become. They just need to see the benefits of it.” What is Slurry Sealing? What is Micro Surfacing? Both slurry seal and micro surfacing are specifically-designed mixtures of asphalt emulsion, aggregate, water, mineral filler and additives, mixed in set proportions, and uniformly spread across a prepared surface. Slurry seal is about one stone thick, just under ¼ of an inch or smaller, while micro surfacing is usually applied at multiple-stone thickness. Although slurry sealing can contain polymer-modified asphalt emulsion, micro surfacing always contains polymer-modified asphalt emulsion. When to Micro Surface or Slurry Seal Slurry seal and micro surfacing is ideal for pavements suffering from flushing, polished aggregate, raveling, oxidation and light to moderate cracking, said Dr. Andrew Braham of the University of Arkansas. Micro surfacing can also fill minor rutting and prevent cracks from growing
wider, due to its use of polymer-modified emulsion. However, neither treatment will prevent cracks from returning, Braham said. Despite their benefits, these treatments have no effect on the structural capacity of the existing pavement. As such, they should only be used to extend a roadway’s service life, not in the hopes of repairing structural damage. Benefits of Micro Surfacing and Slurry Sealing Both slurry sealing and micro surfacing are cost-effective treatments that will seal the pavement surface, fill small top-down cracking and restore surface friction. They are suitable on a variety of asphalt pavement types experiencing various levels of traffic, from highways and collector streets to residential streets and culs-de-sac, according to the Pavement Preservation and Recycling Alliance (PPRA). Both treatments maintain drainage patterns and curb reveal. Additionally, slurry sealed surfaces can be returned to traffic usually between one and four hours after application, and micro surfaced pavements, typically within one hour. “Another benefit of micro surfacing is that it can be used alongside other applications,” Kendrick said. For example, it can be used alongside a cape seal, where a chip seal is covered with a slurry seal or micro surface. Slurry sealing can extend a pavement’s service life between five and seven years, when applied correctly, and micro surfacing can extend service life between six and eight years.
Materials for Micro Surfacing and Slurry Sealing There are five primary materials in micro surfacing and slurry seals: emulsion, aggregate, mineral filler, additives and water. According to Pat Denney, Micro Surfacing Manager for Road Science, Tulsa, Oklahoma, slurry seal emulsions can be produced with a cationic quick-set emulsifier (CQS), a cationic slow-set emulsifier (CSS), or an anionic slow-set emulsifier (SS). CSS and SS emulsifiers depend largely on evaporation for curing, making them much slower to cure. “By contrast, a micro surfacing CQS emulsifier will have a chemical break that begins to kick water out of the system,” Denney said. “Basically the system is stabilized during mixing, and then destabilized chemically to trigger a quicker curing process.” Aggregates used for these treatments should be highly angular with minimal dust or clay, high resistance to abrasion and high soundness. • Type I (#200 x 1/8 in. [3 mm]) offers maximum crack penetration and seals minor raveling and is used in low traffic areas. • Type II (#200 x 1/4 in. [6 mm] stabilizes moderate to severe raveling, provides a smoother surface and quieter ride than Type III, and is used in moderate traffic conditions. • Type III (#200 x 3/8 in. [9.5 mm]) corrects severe raveling, offers high skid resistance and structure for leveling, and is used in heavily trafficked areas. These are the aggregate types, as outlined by the International Slurry Surfacing Association (ISSA). However, many state specs use their own aggregate types, which may differ from ISSA’s.
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Check out AsphaltPro’s article “New AASHTO Pavement Preservation Standards, Explained” at www.theasphaltpro.com.
The mineral filler, additives and water are the same for slurry sealing and micro surfacing. Mineral filler, such as portland cement, hydrated lime or limestone dust, can adjust breaking properties and improve mixture consistency. Additives, such as emulsifier and aluminum sulfate, can accelerate or decelerate the break time Water should be free of contaminants or harmful salts. “Water can have some effect on mixture characteristics,” Denney said. “The use of pond water in a micro surfacing application is not recommended due to increased risk of the presence of deleterious materials or other types of contamination that could negatively affect mixing and cure rates.” Mix Designs for Micro Surfacing and Slurry Sealing To ensure proper performance of a project, a mix design must be conducted to determine the compatibility of the aggregate, emulsified asphalt, water, mineral filler, and other additives. Mix designs should be used to determine the compatibility and ratio of the above materials. They should be performed according to ISSA A105/ASTM D3910 for slurry sealing and ISSA A143/ASTM D6372 for micro surfacing. For project success, the lab performing the mix design should have experience in mix designs for these treatments and should be aware of your project’s parameters. Since temperature, humidity and wind can affect cure time, these variables should also be considered. Micro Surfacing and Slurry Sealing Equipment These treatments can be applied either with a truck-mounted paver or a continuous paver. Truck-mounted pavers are typically used on projects with shorter pulls, while continuous pavers are used on longer pulls, such as highway jobs and can minimize construction joints. Typically, jobs with truck-mounted pavers use two or more on the job, since they must load material at the stockpile. Mobile support units, or nurse trucks, deliver materials to the continuous pavers, which can load materials while continuing to apply the material. Truck-mounted pavers require a smaller crew and can drive to the jobsite, while continuous pavers minimize construction joints. That’s why it’s important to have enough trucks on hand to maintain a steady supply. Both types are equipped with a spreader box, which may or may not have augers to move material and may or may not have a drag on the back to texture the material. The job may also require a distributor truck if tack is required, or a rubber tire roller if required. Calibration and Test Strips “You can have the best crew and the best site preparation in the world, but if the calibration isn’t right, you will have problems,” said Tim Harrawood of Vance Brothers, Inc., during a Transportation Research Board webinar. Calibration ensures compliance with the approved mix design, and the factors determined through the calibration process aid in application rate verification and overall material usage. 14 FALL 2019
Both slurry seal and micro surfacing are specifically-designed mixtures of asphalt emulsion, aggregate, water, mineral filler and additives, mixed in set proportions, and uniformly spread across a prepared surface. Here, Southwest Slurry Seal micro surfaces with Bergkamp’s M1E Continuous Paver in Phoenix, Arizona.
Hudson Construction micro surfaces with Bergkamp’s M1E Continuous Paver from Bergkamp.
“It’s extremely important that application equipment is calibrated in the presence of an agency representative,” Harrawood said. “This could help eliminate potential issues caused by proportioning of the materials.” Generally, Harrawood said, calibration will take place only once per project, though some agencies allow the transfer of calibrations. It can be performed on truck scales or platform scales, but all scales should be certified. He said a seasoned crew can perform the calibration in less than two hours. Each manufacturer has their own preferred calibration method, so consult the manufacturer’s manual. Harrawood also recommends placing a test strip for evaluation and agency approval. “Test strips assure adequate workmanship, aesthetics, and cure time of the mixture is achievable when applied with the personnel, equipment, and materials intended for use during execution of the project,” Harrawood said. He said the test strips should be performed in similar conditions as those expected during actual application. For example, test strips for a daytime project should be performed during the day. Stockpile Success For micro surfacing and slurry sealing jobs, the contractor will set up a staging area for the stockpiles of materials, equipment storage and maintenance.
“Your stockpile location is key,” said Zach Jensen, Product Support Manager at Bergkamp. “When the stockpile is so far away, it’s going to take longer for trucks to get back to the job site.” The stockpile site should also be arranged for safe and optimal traffic flow. The delivery site for the aggregate should be flat and free of vegetation. Denney recommends a gravel, cement, or asphalt surface. “A lot of these jobs will be in remote areas where a concrete pad for your aggregate isn’t available,” Jensen said. “Use the first few loads to make a flat base for the rest of your aggregates to avoid digging into the underlying material.” Regardless of the underlying material, loader operators should take care to avoid contaminating the aggregate with dirt, vegetation or other contaminants. Verify that the onsite stockpiles of aggregate have not become segregated by wind or rain or contaminated with deleterious materials. Denney suggested conducting occasional checks for stockpile moisture content, as well. Ensure the screening deck is free of contaminants and is in good working order. Any oversized stones could create drag marks in the mat behind the paver. When screening the aggregate, Harrawood recommends screening it directly into the nurse truck. “This is absolutely the best method to limit exposure to oversize aggregate,” he said. Some states with strict dust abatement rules, particularly western states, may not allow screening. “If that’s the case, work closely with the trucking firm to ensure the aggregate isn’t contaminated with oversize particles.”
It’s also important that the delivery transports, transfer tanks, and tanks on the project that will be used for the emulsion are also free of contamination, and that the screens on equipment are cleaned daily. Additives may include both wet and dry additives. The storage area for these additives should be clean and dry and additives should be covered by a tarp to protect them from moisture. It’s also important to ensure that the tanks, drum barrels or totes are contaminant-free. There should be enough materials at the stockpile site and enough mobile support units to transport it to the job site to constantly supply the micro surface machine with material. This both maximizes production and minimizes transverse joints. Stay tuned for the Spring 2020 issue of Preservation Pro to learn about the best practices of micro surface and slurry seal applications on the job site. Sources • FP2 Preservation Toolbox • Federal Highway Administration (FHWA) and FP2’s slurry sealing and micro surfacing pocket guides • Pavement Preservation and Recycling Alliance’s RoadResource.org Treatment Center • Transportation Research Board’s micro surfacing and slurry sealing webinar • AsphaltPro’s “How to Micro Surface” article • Jimmy Kendrick and Zach Jensen of Bergkamp, Inc.
WWW.THEASPHALTPRO.COM 15
Her e ’ s how i t wor ks
Step 1
Pull down on the spring-loaded bolt to unlock the pivot arm. Step 2
Swing the arm into position.
Step 3
Remove hose and spray wand from cradle.
Step 4
Use the lever on the wand to blow the patch area clean. Step 5
Once the appropriate valves on the wand are open, the pressurized tank pushes tack through the hose and out the spray nozzle.
Bergkamp’s Pivot Tack System for the FP5 Pothole Patcher When spraying tack into potholes for increased adhesion, that tack can also end up sticking to equipment hoses. Hoses can also present a tripping hazard on the job site. That’s why the team at Bergkamp Inc., Salina, Kansas, engineered its new pivot tack/air hose system for its FP5 flameless all-in-one pothole patcher. Here’s how it works. The pivoting arm, which holds the tack hose off the ground and parallel to the hopper, is located on the back right side of the FP5’s hopper body. During transportation to and from the job site, a spring-loaded bolt locks the pivot arm in the stowed position.
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When the FP5 arrives to the job, the operator pulls down on the spring-loaded bolt to unlock the pivot arm and moves it into position anywhere within its 180-degree pivot range. The working distance with the hose fully extended is 20 feet from the back wall of the FP5. Once the arm is extended, the operator uses the tack wand to blow the patch area clean of any remaining debris using compressed air. Then, he or she turns on the tack, as outlined in the OEM’s instructions, and the pressurized tank pushes the tack through the hose and out the spray nozzle. The operator will spray tack into the pothole
to prepare it for patching. After tacking each pothole, the operator should depress the lever for 15 seconds to pump the remaining tack in the hose back into the tank and then wipe down any tack buildup on the nozzle. To stow the tack wand for transport, return it to the cradle and lock the pivot arm back into position. At the end of the shift, the operator should follow the OEM’s cleaning instructions for the tack system. The pivot arm can be retrofitted onto the FP5 pothole patcher in only a couple of hours. For more information, contact Bryant Lovin at bryantl@bergkampinc.com.
THINK OUTSIDE THE TOOLBOX At Ergon, we’re developing innovative ways to help you stretch your budget and treat more miles in your network. Our growing family of products provides the options you need to expand your toolbox and maximize impact on your roads. Contact our experts today to learn more about the right tools, for the right roads, at the right time. go.ergon.com/toolbox
ergonasphalt.com WWW.THEASPHALTPRO.COM 17
Saved By The Stripe
How 1-877-FIX ASPHALT helped a property manager save his job after a disastrous stencil incident. Picture this scenario: I am working on the landscaping in my yard on a Saturday morning. When I come back into the house, I find I have three missed calls from a client...on a Saturday. I immediately know there is a problem. This particular client managed 370 properties in New Jersey, Pennsylvania, Delaware and New York. I am assuming it’s something typical, like a collapsed catch basin needing to be barricaded. This problem turned out to be far more urgent. Outside the corporate headquarters, right next to where the CEO lands his helicopter, the in-house maintenance crew was trying to help the facilities department and created a situation. The CEO requested “Reserved” parking stalls be striped outside his office for himself and visiting VIPs. The in-house maintenance crew did the best job they could by using paper stencils purchased from Home Depot. On a windy day with stencils intended for a onetime use, it’s easy to imagine what the finished product looked like when it was complete. My client told me he needed to have them fixed before Monday, because he and his boss feared they would lose their jobs. When he exclaimed this to me, I am embarrassed to admit, I kind of chuckled and asked if the stenciling was really that bad, to which he replied, “I am dead serious. I will most likely lose my job Monday if anyone sees this.” Initially, I proposed sending the striping crew to blackout the old stencils with a symmetrical square and restriping the “Reserved” stencils. However, because the asphalt was older and very gray, my client was nervous it would just accentuate the issue. I told him the only option would be to seal coat the parking lot. “Picture the helicopter flying overhead and seeing this nice slate black finish with fresh white stripes on Monday morning,” I said. The client said, “Go!” Here was the issue. They were forecasting a 75 percent chance of rain Sunday, and I had one seal coating crew four hours away, and my second seal coating team had worked 15 days straight and I’d given them the next four days off to rest. With the clock ticking, I was prepared to suit up in work clothes and enlist friends and fam-
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ABOVE: After an unsatisfactory self-stencil job, a property management client asked 1-877-FIX-ASPHALT to rapidly repair its mistake. BELOW: The crew was able to clean, crack seal, cover up the old stencils, apply two coats of sealer, stripe, and re-stencil the parking stalls in less than five hours.
ily if need be to help get the job done. I broadcast a group text to the seal coating crew, asking anyone who wanted to work to report to the South Jersey office in the next hour. Amazingly, all seven team members responded they wanted to come into work—and that was before they even knew they would be getting paid double time for the last-minute effort. Within two hours of the client’s call, I had enough equipment, workforce and resources to seal coat the 35,000-square-foot executive parking lot: two Neal Manufacturing seal coating trucks, two 18 HP walk-behind blowers, four airless line striping machines, a 110-gallon Crafco crack sealing machine, and seven experienced craftsmen.
The crew was in and out in less than five hours. They knocked it out of the park, to say the least. We were able to clean, crack seal, black out the old stencils to prevent them from bleeding up, apply two coats of pavement sealer, stripe, and—most importantly—stencil the “Reserved” parking stalls well in advance of the rain and in time for everyone to report back to work on Monday. What I love about working in the pavement industry, both in the office and in the field, are the challenges it presents and the ability to solve problems—especially customers’ problems. When those solved problems result in a client keeping their job? Then I really love to help. It is a win-win for everyone.
–By Steve Brahney
Steve Brahney is the President of Brahney Paving and 1-877-FIX-ASPHALT, which performs asphalt paving, repair, sealcoating and pavement management in New Jersey, Pennsylvania, Delaware and Maryland. This article originally appeared on the Fix Asphalt blog and has been reprinted here with permission.
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