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Editorial Maintenance Contractors Prep for Best 2019
From the Asphalt Recycling and Reclaiming Association (ARRA) perspective, some of the key developments for the best use of recycled asphalt materials in preservation methods this season are coming from the federal level. The biggest game changer for ARRA was really the MAP-21 Highway Bill that was enacted back in 2012. The bill required states to develop and implement an asset management system and through this we have seen states shift their focus to preventative maintenance and preservation of the national highway system. This has created substantial growth for our member companies and new markets that did not exist prior to this. The other development at the federal level is what are called Environmental Product Declarations (EPDs). You can think of these like nutrition facts for food, but in this case it is the environmental impact from cradle to grave of a pavement process. Asphalt pavements and their ability to be recycled in so many ways excel in these sorts of declarations and the higher the recycle content, typically the better you are going to do in these, which really plays into the ARRA disciplines and pavement preservation. The biggest thing that our members are specifically doing is building awareness of our disciplines through our new website roadresource.org. This site is quickly becoming the one stop shop for agency personnel who want to learn how to prolong the life of their pavements by using cold planing, cold-in-place recycle, hot-in-place recycle or stabilization and full depth reclamation. We hosted “Super-User” training in March for representatives of our member companies who will be utilizing the site in their day-today discussions with specifiers and designers. This will allow them to train these people to use the powerful tools on the site such as the different life cycle cost calculators and selection guides. With some state agencies still reluctant to allow high RAP contents the closer we get to the surface of the pavement, it stands to reason that we are going to generate more RAP than we can put back into the mix. Therefore, we have seen some new creative uses for RAP such as using it as aggregate out in front of a CIR process to improve the structure of the resulting mix. We have also seen a growing interest in cold central plant recycling either utilizing a mobile train in a stationary setup, a dedicated CCPR plant or modifying a hot mix plant to produce cold mix. These are just a few of the creative best uses of recycled asphalt. – 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 as 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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Pave me n t P re s ervat i o n R o un d up MoDOT Rubberizes Chip Seals In the November 2018 final report “Field Implementation of Rubberized Chip Seal” for the Missouri Department of Transportation (MoDOT), five authors offered findings from their field research through the Department of Civil, Architectural and Environmental Engineering at the Missouri University of Science and Technology in Rolla. The executive summary states: “Recently, the research team developed a rubberized chip seal where natural aggregate is replaced with crumb rubber obtained from recycled tires. During this study, laboratory chip seal specimens and a field chip seal section with different crumb rubber replacement ratios were prepared. A total of 108 chip seal laboratory specimens were prepared to investigate aggregate retention using six tests: the standard sweep test, modified sweep test, Vialit test, modified Vialit test, Pennsylvania test, and modified Pennsylvania test. The crumb rubber showed a remarkable performance in aggregate retention measured using the Vialit and Pennsylvania tests. “The macrotexture of the laboratory specimens was investigated using the sand patch and image processing methods and how that reflects on the skid resistance. The values of the mean texture depth (MTD), which is a measure for pavement macrotexture of rubberized chip seal specimens, were significantly higher than that of the conventional chip seal. However, a reduction in the British Pendulum Number (BPN) was recorded with an increase in the crumb rubber replacement ratio. However, after a period of more than a year of service life in an experimental section road, the chip seal segments with 25 percent and 50 percent crumb rubber replacement ratios recorded much higher BPN compared to that of the conventional chip seal segment. A rubberized chip seal section, having up to a 50 percent crumb rubber replacement ratio by volume, was constructed successfully using standard procedures and equipment. However, it was necessary to use a steel roller compactor instead of a rubber tire compactor to compact the chip seal. This section was monitored for its texture, skid resistance, and aggregate dislodge over a period of one year. The MTD increased significantly with an increase in the rubber content where the MTD of rubberized chip seal with 50 percent replacement ratio was increased by 77 percent compared to the conventional chip seal. Raveling distress was also observed due to snowplowing actions. No damage or any sort of distress was observed in the wheel paths due to traffic loads. Therefore, this study concluded that crumb rubber can be used in the chip seal as a partial replacement of mineral aggregates up to 50 percent. It is recommended also to increase the curing time for chip seal, regardless of aggregate type, to at least six hours to improve the performance of the chip seal.” For more information, read the full report on https://www.modot.org/ sites/default/files/documents/cmr18-012_0.pdf. Road Science Gets the Credit Road Science, a Division of ArrMaz, announced that it successfully completed a comprehensive American Association of State Highway and Transportation Officials (AASHTO) On-Site Assessment and Quality Management System Evaluation of its research and de4 SUMMER 2019
Road Science’s Tulsa Laboratory
velopment and customer support laboratory in Tulsa, Oklahoma. The review was conducted by AASHTO re:source over a four-day period, the outcome of which confirmed Road Science’s Tulsa laboratory’s continued compliance with the AASHTO Accreditation Program (AAP). “With our Tulsa laboratory’s longstanding AASHTO accreditation, our customers can confidently rely on our data and recommendations to build their products and grow their businesses,” James Barnat, vice president, Innovation, said. “Achieving and maintaining accreditation for the past 18 years required considerable diligence and resources, demonstrating our ongoing commitment to the asphalt paving industry.” The Certificate of Accreditation and all accreditation details for Road Science’s Tulsa laboratory can be accessed online through the Directory of AASHTO Accredited Labs. AEMA Awards Hemsley, Inducts Guiles J. Michael Hemsley has received the 2019 AEMA Recognition of Achievement Award for his considerable contribution to the Asphalt Emulsion Manufacturers Association (AEMA) and the asphalt emulsion industry, including eight years as chair of the AEMA International Technical Committee. This award is presented to an individual, active or retired, who has made a significant contribution to emulsion technology or the advancement of the emulsion industry. Hemsley has participated in dozens of technical committees in his more than 25 years of service to the industry. He has worked continuously through his career to improve asphalt emulsion binders and mixtures through innovative design methods, process control, laboratory analysis and formulation chemistry. He has given much of his time and effort to improving the quality of the treatments and materials that all members of AEMA are engaged in producing. Hemsley has a B.S. in Chemical Engineering from Mississippi State University and has been employed with Paragon Technical Services Inc. since June 1995. AEMA Past President Neil I. Guiles was honored for his lengthy and considerable service to the asphalt emulsion industry and to AEMA when he was inducted into the AEMA Hall of Fame. The hall of fame award is given to a person who has made a substantial contribu-
In 1991, he developed for international licensing, the POLYMAC Microsurfacing Systems & Technology. In 1993, he submitted a white paper on The Effect of Variables on Schulze-Breuer and Ruck Procedure. In 2000, his became the first private lab in New York to be recognized with the AASHTO Accreditation for highway material testing. In addition, Guiles has served as a board member and past president of both the Liquid Asphalt Distributors Association of New York and the Pennsylvania Association of Asphalt Materials Applicators. These gentlemen received their awards at AEMA’s 46th annual meeting, Feb. 18-21, 2019, in Cancun, Mexico. AEMA President Mark Ishee presents the 2019 Recognition of Achievement Award to Mike Hemsley, Paragon Technical Services. Photo by Tom Kuennen, courtesy of FP2.
tion over a long period of time to the development of AEMA or the advancement of the emulsion industry. Guiles is the president of Vestal Asphalt Inc. and has been a significant contributor to the association for more than 30 years, serving as president in 1997. His involvement in manufacturing and applying liquid asphalt emulsion dates back to the 1970s when he founded his first company, Neil I. Guiles Excavating & Paving. In 1983, he incorporated as Vestal Asphalt Inc.
Partner for Cold Patch Crafco, Chandler, Arizona, released in February the HP Asphalt Cold Patch Producer Partner Program to let qualified companies produce and market bulk Crafco HP Asphalt Cold Patch at their own plants. Through this opportunity, asphalt manufacturers can generate a new revenue stream while filling seasonal capacity voids. The Crafco Producer Partner program is designed to be a collaboration between Crafco and asphalt companies. For more information, contact Jim Slatten at (480) 435-1624 or email jim.slatten@crafco.com. Established Crafco customers can direct inquiries to their territory manager.
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N.B. West’s Steve Jackson explained, “We targeted the areas where we were going to place WinterPave, then put a regular mix on the areas around it.
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Summer Maintenance Helps Winter Drivers Route B in Jefferson County, Missouri, features a curving hill that once offered motorists a challenge in winter. Ice and snow made the steep grade treacherous during storms. To lessen danger for drivers, Missouri Department of Transportation (MoDOT) officers looked into an additive from Cargill for the maintenance of the 1,200-foot section. MoDOT Senior Materials Inspector, SL District, Mitch Huskey explained the situation. “Essentially, it was a dangerous part of the road. It was a steep grade, which made it a good candidate to try the material. The pavement was two years old and the original treatment had some issues, primarily because it was such a steep grade. We had to fix it anyway; we plugged the WinterPave® product into that repair.” MoDOT has a standing, on-call maintenance contract with N.B. West Contracting of Sullivan, Missouri, so Huskey worked with N.B. West’s Steve Jackson and Joe Schroer to put a plan in place. N.B. West crews milled approximately 2 inches deep from the shoved and raveling pavement on the problem roadway. Then they placed the entirety of the WinterPave mixture on a hill section with numerous curves approximately 1,400 feet in length and two lanes wide, in one lift. Remaining repairs were made with a standard BP-2 mix. “The way we did the repairs wasn’t like it would be on a normal project out for bid,” Huskey said. “For this, we could write a work order, and work out getting the product.” Jackson sat down with AsphaltPro at the 2019 National Asphalt Pavement Association (NAPA) annual meeting to discuss the project’s success. “MoDOT procured the WinterPave additive and stored it in 2,000-pound bags in a salt shed until we could pave the project in June.” The timing might sound odd at first because the additive is named WinterPave, but let’s take a look at the pieces here. The granular additive replaces a percentage of fine aggregate in the mix to influence the final pavement’s performance during winter conditions. Roger Wilson, district manager for Cargill Salt—Road Safety, stated: “In general, WinterPave replaces 5 percent of the aggregate by weight, typically the sand or fine gradation material.” Huskey explained that it took a little over a year to get the funding worked out to purchase the product. Then it took a couple months to get all 21 totes arranged because that much material wasn’t stored in the United States at the time. They had it shipped over from Italy and stored it until paving season. Wilson explained: “WinterPave is currently manufactured in Europe and shipped to the U.S. East Coast. We are working towards having the ability to manufacture it here in the United States. Current delivery time is approximately 8-10 weeks after receipt of order.” “N.B. West is a good contractor and we’ve had the opportunity to work with those guys through the standing contract,” Huskey said. “That made it very easy to get the material and have them work up the mix design. We delivered the sacks of material out to their plant.” Schroer is the construction materials engineer for N.B. West, and he explained the process for getting the JMF and plant ready to go.
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ABOVE: Personnel used the tines of a fork lift to hold the totes over the RAS bin, which metered the material into the mix at a target rate of 5 percent of total weight.
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TOP: The team at N.B. West prepared the MoDOT BP-2 by 35-blow Marshall method with natural sand, and substituted a portion of the sand with WinterPave. The mix was produced at 290 degrees F with no modifications. BOTTOM: Personnel used a fork lift to unload totes of additive.
TOP: Mitch Huskey of MoDOT described the WinterPave additive as a granular material with the consistency of a laundry detergent. The contractor adds it to the mix at about 100 pounds per ton of asphalt. BOTTOM: MoDOT ordered and stored the WinterPave material in totes, and then delivered it to the N.B. West plant for mix production.
“The JMF was developed by us for a mixture using all virgin material,” Schroer began. “The MoDOT BP-2 was developed by 35-blow Marshall method with natural sand, of which a portion was substituted with WinterPave. There were no problems developing the design. The mixture was produced at 290 degrees F with no modifications. There were no noticeable changes in operation or mixing. It was noticed that compacted specimens had an oily feeling, such as felt when contacting calcium chloride.” Jackson shared that the team used the tines of a fork lift to hold the totes over the RAS bin, which metered the material into the mix at a target rate of 5 percent of total weight. “Bags were raised over the bin with a fork lift,” Schroer confirmed, “then the bottom was cut open to empty the contents into the bin. It was easy to maintain the rate after calibration of the bin. Charlie Hayes was the project manager; Rob Neier was the plant operator. Except for the addition of the WinterPave, it was business as usual on both ends of the project. There was no mention of the mix behaving any differently than normal mixtures.” “They did a great job getting their plant ready,” Huskey said. “The guys from Cargill came in and gave us some additional insight for putting the material through the plant, instead of it being trial and error.” “For batch plants, WinterPave is shipped in 44-pound low-melt bags that are added after the aggregate is dried and just before the hot liquids are added,” Wilson explained. “For continuous drum plants, WinterPave is currently shipped in 2,200-pound bulk bags, and added using the RAP/RAS bin.” He explained these bins are typically monitored to allow a good control of the amount of material being
added to the mix. “We discussed with the NB West folks at the end of the project the possibility of using a mineral feed system to introduce WinterPave into the production stream. There are other means that we are planning to investigate further as well.” Since the 2018 summer paving, Huskey has seen a few weather events put the section to the test. “In 2018, we had cold temperatures, but no snow. Basically, I just monitored the road. This winter, the building that takes care of the area has monitored it. What we’re seeing so far is that the snow and ice is not bonding to the pavement. We’ve had two really good storms. The temperatures were cold in this second round. The product itself...people have to understand it’s not a hot plate. There will be snow on the pavement, but it keeps the snow and ice from bonding. It doesn’t thaw the road, but we have an easier time plowing. Our crews plow along and then when we get to that chunk, it cleans right off, real easy.” Huskey shared that the agency wouldn’t pave a long stretch of miles with the product, due to its price point, but he also said it’s something he values for targeted areas. “It’s good for use on an intersection, a hill, curves, targeted areas” where weather-related safety issues plague an agency. “Problem areas (busy intersections/elevations/sharp turns) where winter snowpack and/or black ice is an ongoing safety issue would be ideal target areas to incorporate this product,” Wilson shared. “WinterPave is also appropriate to help address similar winter safety issues in parking lots and asphalt walkways.”
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– By Sandy Lender
The new standards prepared by the ETF cover a variety of emulsion treatments, including chip seal, micro surfacing, tack coat, fog seal, scrub seal, sand seal and slurry seal, among others.
AASHTO Publishes Pavement Preservation Standards The pavement preservation and emulsion treatment standards recently published by the American Association of State Highway and Transportation Officials (AASHTO) have been a long time coming. With the 2012 passage of the Moving Ahead for Progress in the 21st Century (MAP-21), state DOTs could begin to use federal funds for pavement preservation. That legislation, along with the passage of other maintenance-related legislation over the past few decades, has made the necessity of national standards for pavement preservation treatments increasingly apparent. That’s why the Emulsion Task Force (ETF) was established in 2008, with support from the Federal Highway Administration, FP2 Inc., the National Center for Pavement Preservation, International Slurry Surfacing Association, Asphalt Emulsion Manufacturers Association and Asphalt Recycling and Reclaiming Association. “In the past, emulsions have not been given as much importance and technical support as hot-mix asphalt,” reads the task force’s website. As such, emulsion technology lagged behind the mainstream hot-mix asphalt technological improvements made in the early ‘90s through the SHRP (Strategic Highway Research Program), said ETF
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Co-Chair Colin Franco. “It is well known that for a technology to be widely accepted by state and local agencies, national standards for that technology must be developed and made available.” The ETF is comprised of industry professionals from state DOTs, contractors, material and equipment suppliers, and academia.
During the past couple of years, the task force has begun to draft the pavement preservation standards it has developed over the past 10 years for incorporation into AASHTO standards. AASHTO standards for any given material or treatment normally require material standards, material test methods, material design practices, and construction guides. See the chart accompanying this story to see the treatments and their corresponding standards. The goal is that all of the standards for each treatment come together to give agencies and contractors “a high level of confidence that they will have a quality job,” said Larry Tomkins, chair of the
“If they’ve been using a spec for years, it’s always a challenge to encourage change,” Tomkins said. “We have to show them that there might be something better out there that could give their projects a better chance of success.” Benefits To Be Had Tomkins said some of the chief benefits of the new national standards is that they are formalized, up-to-date and have been thoroughly vetted. “They’ve been through numerous committees, they’ve been voted on by all the DOTs, they’ve been scrutinized and commented on,” he said. “They’re vetted and they’re up-to-date.”
Agencies may already have specs in place for more common pavement preservation treatments, such as micro surfacing. However, the new standards prepared by the ETF could offer a number of benefits.
ETF’s Marketing Subcommittee and vice president of sales and marketing for the southeast region of Ergon Asphalt and Emulsions Inc., Jackson, Mississippi. “That’s the whole objective of what we’re doing. We want to raise the bar and increase the quality of work that’s going on in the pavement maintenance world.” Agencies Adapt and Adopt “These treatments are being used all over the country, but there was no national standard,” said Jim Moulthrop, executive director of FP2 Inc., and co-chair of the ETF Subcommittee on Design Group: Mixtures. “A lot of agencies already have their own specifications for many of these treatments.” Moulthrop estimates that most agencies already have their own specifications for more common treatments, such as chip seals, cold in-place recycling, micro surfacing, slurry seal and fog seals. Where the standards put forth by the ETF are more eagerly adopted is for treatments that are newer or less familiar to various agencies, such as scrub seals and sand seals. Although the agencies aren’t required to adopt the national standards, Franco hopes that states will see the benefits the new standards could bring. The AASHTO standards are also useful as a reference for local agencies, who can follow state DOT specs or the AASHTO standards. “We expect adoption of these standards to take some time,” Franco said. “Although they are two years old, two years in our industry is still very new.” To get the word out that the standards are done, Tomkins said the task force plans to present the new standards at regional and state DOT meetings and AASHTO meetings. In a recent survey, around 30 percent of state DOTs said they intend to follow the AASHTO standards set forth for these preservation treatments. Some agencies (between zero and 12 percent, depending on the treatment) have already begun to use the new standards from AASHTO. One of the most significant challenges to adoption of the new standards by various agencies is that many DOTs already have specs for some of the treatments.
The provisional standards were approved by two-thirds of all state DOTs in 2016, 2017 and 2018 (denoted by the last two numbers in each standard). They will remain provisional for eight years, during which time they’ll be revised and reconfirmed every two years. Any standards not in use will be dropped from the book of AASHTO standards. Full standards are reviewed every four years.
He also sees it as a matter of educating the next generation of DOT staff and preservation crews. “In the past, agency personnel had a wealth of experience that they didn’t need much direction,” Tomkins said. “They knew what to do. But those people are retiring and that institutional knowledge is gone. These specs help close the knowledge gap on some of these processes.” Franco said that the national standards also establish a consistent baseline for comparison, as well as further technology improvements, that isn’t possible if every agency has its own spec. The standards can also help agencies establish quality incentives and disincentives for these types of jobs. National standards for these pavement preservation treatments can also streamline processes for contractors and reduce the number of emulsion grades being manufactured. Franco, who is also Associate Chief Engineer at the Rhode Island Department of Transportation, gave an example of the DOTs of Massachusetts, New Hampshire, Connecticut, Rhode Island and Maine. Each may have its own chip seal spec, requiring a particular type of liquid. In that case, regional contractors may have five different liquid grades in stock, which can be a production, storage and logistics issue. “The national standards make things consistent so that contractor in the northeast may only need to have one or maybe two grades of liquid available for a particular treatment type,” Franco said. For contractors, Tomkins sees the new standards offering a clearer outline of what they can do to maximize quality. “I don’t think the material or design practice specs will directly affect them,” Tomkins said, “though they may indirectly see a higher level of confidence in the materials they use and the process they’re using.” However, Tomkins sees the forthcoming construction guides as a valuable resource. “You can have the best materials in the world that meets spec and the design works, but if it isn’t applied following best practices and it isn’t tested right, the chances of having a quality project go down,” Tomkins said. WWW.THEASPHALTPRO.COM 11
Emulsion Treatment
Material Standard
Design Practice Standard Construction Guide
Chip seal
MP 27-16
PP 82-16
NCHRP 14-37
Micro surfacing
MP 28-16
PP 83-16
NCHRP 14-37
Tack coat
MP 36-18
PP 93-18
Fog seal
MP 33-17
PP 88-17
Scrub seal
Tabled by ETF
PP 91-18
Sand seal
MP 34-18
PP 90-18
Slurry seal
MP 32-17
PP 87-17
NCHRP 14-37
Bonded surface treatments Draft submitted to SOM
Draft submitted to SOM
Cold recycled mixtures
PP 86-17
MP 31-17
Emulsion Binder Standards
Material Specs
Emulsified asphalt
M 140-16
Cationic emulsified asphalt
M 208-16
Polymer-modified cationic emulsified asphalt
M 316-16
Emulsion/surface performance grades
Draft submitted to SOM
The construction guides will also be helpful for inspectors, offering them guidance on how often to pull samples and how to check the job quality. “It almost comes full circle,” Tomkins said, “from the agency developing the design and specifications to the contractor applying the process and then back to the agency to ensure the specifications were followed.” Collaborate on Construction Guidelines Although the task force is not directly responsible for preparing the construction guides, the idea to put them together was born from within the task force, Moulthrop said. The task force submitted a request to the National Cooperative Highway Research Program (NCHRP), which is funded by AASHTO, to produce a document outlining best practices for each of the preservation treatments it had developed material and design practice standards. In 2016, AASHTO voted to fund construction guides for chip seal, micro surfacing and fog seal applications, NCHRP 14-37, for which Moulthrop is one of the authors. Franco hopes construction guides for the remaining treatments will be completed within the next year. The guidelines would help agencies and contractors utilize best practice guidelines for any given preservation treatment and could be used to help demystify issues that may be decreasing the performance or lifespan of their preservation treatments, Moulthrop said. The construction guidelines also include commentary outlining exceptions to rules or giving additional detail on the advice outlined in the guide. For instance, it recommends agencies in colder climates who typically use a PG 64-22 base binder for emulsions may consider using softer grades, such as PG 58-28. Another example from the guide is to consider using additional water when micro surfacing if the placement conditions are very warm, as long as the extra water does not affect the consistency of the mixture. Franco said that for contractors who have already integrated quality control into their operations and are performing pavement preserva12 SUMMER 2019
NCHRP 9-62 Legend: M stands for material specs, MP stands for provisional material specs, PP stands for provisional design practice standards, SOM stands for Subcommittee on Materials
tion treatments properly, the information outlined in the construction guides may mirror the best practices they already use in the field. “For contractors who aren’t using best practices in the field, the standards hold them accountable for doing the work well and helps the agency ensure each job is done correctly,” Franco said. But before any of these standards could even begin to affect the way pavement maintenance contractors operate, the task force has its work cut out for them to get agencies to adopt the range of standards: material, design practice and construction guides. “We really need to show them the value of the new specs, compared to what they’ve been using for 20 years,” Tomkins said. “It’s our job to make them comfortable with the new spec and help them understand why it is important to them and how it could improve their projects.” – By Sarah Redohl
Austroads Specs for Sealing Austroads, the organization of Australasian road transportation and traffic agencies, has already established sealer standards. It mandates selection and design of sprayed seals (publication no. AGPT04F-17) and bituminous binders (AGPT04K-18). The guides were originally published in 2008 and 2009, respectively, and updated in 2018. AGPT04F-17 provides information on the fundamentals, properties and testing of bituminous materials. AGPT4K-18 gives guidance on how to select a suitable treatment based on traffic volume; pavement composition; roadway speed, mass, turning, acceleration and deceleration movements; existing surface conditions; performance requirements such as skid resistance and surface texture; and availability of equipment, materials and expertise. The guide also outlines preferred time between initial and secondary applications and recommended cure times.
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Her e ’ s how i t wor ks
Step 1
Step 2
Asphalt is loaded into the Thermo-Layʼs hopper, where its temperature is maintained via a closed heat transfer oil system.
At the site of the repair, the operator will raise the arrow board and turn on all safety lights.
Step 3 The operator uses the tack wand to apply tack to the clean repair area.
Step 6 The operator stores the roller and arrow board before driving to the next pothole. Step 4 Step 5 The operator unloads the roller via hydraulic lift to compact the patch.
The auger directs asphalt into the chute, which can rotate 180 degrees.
Thermo-Lay’s Pothole Patcher Leaving a pothole unpatched not only opens that pavement to further water penetration, but it can also be a liability for the agency in charge of that road. The Thermo-Lay truck-mounted pothole patching machine from Thermo-Lay Manufacturing LLC, Billings, Montana, aims to solve both of those problems. Here’s how it works. Asphalt is loaded into the Thermo-Lay’s hopper, where its temperature is maintained via a closed heat transfer oil system with one propane burner and one electric heater. Digital thermostats read the temperature of the asphalt and regulate day and night temperatures. Although monitored by a separate thermometer, the same heat transfer oil that heats the asphalt also maintains the tack oil temperature via a copper bypass, to prevent its temperature from exceeding the temperature set for the mix.
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On the jobsite, the operator will raise the arrow board approximately 36 inches above the truck and engage all safety lighting. The arrow board is visible from as close as 10 feet behind the truck to as far as 2 miles in daylight. Any asphalt collected while cutting off or cleaning the repair area can be placed in the Thermo-Lay’s two bins, each more than one cubic yard. Once the repair area is clean and free of debris, the operator can use the tack oil wand to tack the area. This acts as a base coat or primer for the repaired area. A two-speed auger motor directs the asphalt into the chute, which pivots 180 degrees to angle the asphalt directly into the pothole at rates up to two cubic yards per minute. The motor starts out at high speed, low torque and will automatically shift down to low speed, high torque when the motor senses the need for more torque.
When it’s time to compact the repair, the operator uses the hydraulic lift to unload the vibratory roller from behind the cab. The Thermo-Lay can accommodate a variety of brands of vibratory rollers and plate compactors. Depending on customer preference, the placement of the hydraulic lift could instead be at the rear of the machine. When the roller is returned to the lift and stored, it is automatically locked. The operator will lower the arrow board before driving to the next pothole location. Once the day’s repairs are complete, the operator can pull a lever housed on the right rear of the machine to switch from tack oil to cleaning fluid and clean the system. The operator will also flip a switch to clean or lubricate the hopper with a 25-second blast of biodegradable release agent, coating the entire inner surface. The bins on each side can be dumped hydraulically. For more information, contact Brian at (406) 259-9525 or brian@thermo-lay.com.
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Gorman Group Makes Asphalt Emulsions Easier Due to sub-optimal system performance, 2017 was a “tumultuous year” for making asphalt emulsions. That’s the way Brian Jones described it. He’s the technical services director for The Gorman Group, headquartered in the Northeast. The problem wasn’t lack of demand. It was a milling system that didn’t perform as needed. “We had a tremendous amount of issues [that] year with our old mill,” Jones said. “You can’t even make up half the stuff that happened to us…with our old mill. Even with those types of issues happening we had zero support. It got to the point where we’re tearing apart the mill to replace bearings and having to drive down to pick up the replacements. So it was a very tumultuous year. We were running around 18, 20 hours a day to keep up with our construction group. Most of the time it was hand-to-mouth. We were making it and they were taking it. We were just barely keeping up, which is not good. Emulsions really like to be made and set in the tank for a night to mature and digest. And we just weren’t able to do that.” Lab Manager Tim Roser added, “We had a lot of issues with the previous mill. And that was the same type of mill that we had run here since 1975. It was the same model. We’d had a total of four mills over the course of that time. On the last one nothing seemed to go right and it had a lot of issues with mechanical things breaking down. That system was a lot more manual. Almost all the valves had to be manually turned open or closed for soap solution, asphalt, solvent, latex, or anything.” Founded in 1917, The Gorman Group is a highway construction company that covers the Northeast, primarily New York, Vermont, Connecticut, Massachusetts, New Hampshire, Maine and Pennsylvania. They serve towns, counties, municipalities and states like the New Hampshire Department of Transportation. “My grandfather and my father helped to build Mohawk Asphalt Emulsions [Mohawk Asphalt Emulsions was purchased by The Gorman Group in 1985] and in 1975 we made our first gallon of emulsion,” Jones said. “I’m third generation at this company. My father still works here part time and I’m here now so I’ve got black running through my veins.” With their long history and experience in this industry, Jones and his team unsurprisingly took a savvy approach to find the best solution for what they needed in a new milling system. “I did some extensive research on mills before we went to purchase our next,” Jones said. “I did a matrix of all the different mills that are out there. I compared the pluses and minuses to all the different mills and did a cost analysis on all the different features each one had to offer.” Some of the features The Gorman Group looked for in a new milling system included semi-automation, versatility, quality and support. Jones and company think they have found what they were looking for in the Barracuda™ emulsion mill skid from Heatec. “When we started looking, we saw different types of mills and the different types of automation available. We liked how it was easier for the mill operators because everything is controlled from a central control panel and much more automated,” Jones said.
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With a new mill in place, the emulsion production plant for The Gorman Group is seeing increased production with fewer man hours, and that’s none too soon. “This year I see a significant uptick in demand for emulsion,” Brian Jones said. All photos courtesy Heatec Inc., Chattanooga.
The Barracuda emulsion mill skid is installed in the mill room at The Gorman Group.
The Gorman Group makes around 30 different recipes of asphalt emulsion, so it was important for the system to be versatile. “We took into consideration the types of emulsion we make and the production levels the mills were capable of.” Jones said. Because they make so many recipes, they have to be able to switch back and forth. A semi-automated system makes switching between recipes much easier. Jones explained, “It’s all on demand. We try to stay with cationic, if we’re making the cationic emulsions, and make as much as we need. But if we are required to flop over, we’ve got a really good system in order to transfer. It really takes very little time, the transfer, it’s semi-automated. It’s a flushing procedure that we go through. We flush the mill out, we flush the tanks out. And we go. We don’t flop back and forth if possible, but if we have to, we do.”
“This year, we’ve actually been able to make a couple of emulsions that in the past few years we haven’t been able to make because of the old system’s limitations,” Roser said. “That mill was not capable of making certain blends with the combination of the mill plus the asphalt chemicals. This year, we’re able to make it with no problems.” “We also looked at where the mill was manufactured. There are other mills out there, but the fact that a lot of the parts are made in Europe kind of was a drawback to us,” Jones explained. “We really like the fact that Heatec products are American-made in Chattanooga, Tennessee. If we need parts, I can have them by 9 a.m. tomorrow morning…. They’ve got a lot of sister companies that have experience in the construction world and they understand the sense of urgency.” “Right from the start, it was not a customer/supplier relationship,” Jones said. “It was a partnership type of relationship. Everything that we asked for, within reason, they were able to do. And I think they were learning from us and we were learning from them what the unit can do. So it was never a customer/supplier relationship. I think, right from the start, it started off as a as a partnership, which is good.” Jones specifically mentioned Drew Bryson, Josh Patterson and John Gage from Heatec as being instrumental in the design and support for their new system. Bryson, construction project designer, and his team worked closely with Jones to design the system to meet the needs of The Gorman Group. Patterson, a PLC programmer, custom designed the computer controls for their system. Both Patterson and Gage, a service technician, were onsite during startup and didn’t leave until Jones and his team felt comfortable running the unit on their own. The support continued after they got up and running. Jones said, “Josh can be anywhere in the country, and he can dial in and see what’s going on in my mill and do troubleshooting from there. And that’s huge. I can’t tell you, we’ve used him at least two or three times with programming issues or things we wanted to change, and he doesn’t have to be here. I’m on the phone with him and he’s in Chattanooga logging into the system saying ‘yep, I see what you’re talking about, I’m going to make this change.’” In addition to support, the quality of The Gorman Group’s new mill has provided significant changes to production and productivity. “This mill’s production levels have reduced our hours of operation,” Roser states. “With the old system, you always had to run 18 to 20 hours a day in order to keep up. [2017] was even worse than that. So with the new mill, compared to [2017], we’re almost—not quite—double the production. You don’t have to have somebody here running the thing 20 hours a day. We can keep up or stay ahead with the mill only running 12 hours versus 18 to 20. That’s a big improvement. You don’t have to have somebody here and you’re not fighting with things all the time. It’s a much, much smoother operation too. It’s easier on the guys running it versus the old system. Plus we were always up against it trying to keep the tank levels up. And it seems like this year with this system it’s much, much easier for us to keep product in the tank and keep enough so that we’re ahead of the crews more than we ever were before. “I know some other companies don’t make as many varieties of emulsions; we make 28 or 29 kinds of emulsion here. So we’re constantly going back and forth and changing formulas and everything. The guys that are running it seem to be much happier with this system. Changing back and forth formulas, putting formulas in. And to be honest, we really haven’t had to tweak our formulas as much as we did in the past because of the inconsistencies that we were experiencing. Now it’s more of a consistent product. You don’t have to keep changing this and that up and down.” With the new mill in place the future looks bright for The Gorman Group. Brian Jones sees the emulsion business growing.
Brian Jones is the technical services director for The Gorman Group.
Some of the storage tanks at the plant
“I think more and more towns, counties and the public are starting to understand the value of pavement preservation. So I see emulsion sales growing year to year. “We’re a member of AEMA, which is the Asphalt Emulsion Manufacturers Association. Their goal is to double the emulsion sales by 2020 as an organization and they’re working to educate people. They’re working to teach the public and the folks that are making the decisions on road repairs that it doesn’t always make sense to go worst first. Let’s protect the good roads so they last longer. You spend a lot less to protect the good road than you do to have a complete rebuild. I think that education is going to help grow emulsion sales. “We’re starting to see more interest in what we do. We’re doing research and development on different types of emulsions and we’re trying to develop our emulsions to make them better. If it’s more polymer or polymerizing certain emulsions that haven’t been polymerized, we’re working on that. We’re working on new materials that use emulsion. So, we as a business, we see some very good potential for growth on the emulsion side. The last three years or so we have been fairly stagnant, give or take a few hundred thousand gallons, but this year I see a significant uptick in demand for emulsion.” “I think the expectation was to have something that was easier for everybody to run and that makes a better product,” Roser said. “We’ve met the expectations that I had. Increased production, less man hours. I think those were the expectations. To make life easier for everybody. And it seems to have accomplished that.” – By John Flynn
WWW.THEASPHALTPRO.COM 17
FORTA FIber Shores Up Slurry Seal A properly-applied slurry seal or micro surfacing treatment will last an average of three to five years, depending on the state of the underlying surface. However, a new product from FORTA Corporation, Grove City, Penn., aims to extend the life of slurry seal and micro surfacing treatments by an additional three years. Surface-EXT is an alkali- and acid-resistant glass fiber that increases pavement durability and flexural strength. “Not only does Surface-EXT reduce cracking and distresses, but it also holds the crack together tighter and longer so there’s less water penetration,” said FORTA Regional Manager Garrett Lovett. “It works before, during and after the crack. That fiber is always working for you.” In January of 2017, two test sections were placed atop the asphalt parking lot of the Texas Station Hotel and Casino in northern Las Vegas. One test section was micro surfaced with Surface-EXT added to the mix, while the other was micro surfaced without the use of fiber. After one year, the lot was surveyed and it was found that the section where Surface-EXT was used showed less cracking than the section without fiber. According to flexural tension testing performed by MWV Specialty Chemical, the average flexural bend of standard mix without added fiber is 9 mm with a range between 5 to 15 mm. When Surface-EXT is added, the average flexural bend increases to 54.5 mm with a range between 35 and 95 mm. In August 2016, Surface-EXT was integrated into the mix used for a test section paved on MnRoad, a test track operated by the Minnesota Department of Transportation. When the test sections were revisited in August of 2018, the test section containing fiber had a cracking percentage of .5, compared to 11.6 percent for the control section. Its rut percentage, in millimeters, was 2.2 percent compared to 3.2 percent for the control section. Although Surface-EXT has been used on jobs across the country for a few years, it wasn’t until recently that FORTA finalized its feeder system and began to market Surface-EXT more widely. Surface-EXT is incorporated into the mix through FORTA’s patented fiber dispenser, known as the Ranger. FORTA’s fiber dispenser can be mounted to any continuous or truck-mounted slurry or micro surfacing equipment in about one and a half hours. It can stay on the machine at all times, whether or not fiber is being used on that project. Once installed on the machine, contractors can simply fill the feeder with Surface-EXT pre-chopped fiber, set the dosage of the dispenser, and the feeder will dispense the fibers into the pugmill of the paver. FORTA’s recommended dosage is between .15 and 4 percent of the dry aggregate weight. Most users use about .2 percent Surface-EXT of the dry aggregate weight according to Brian Engstrom, FORTA’s Pavement Preservation Consultant. The feeder is controlled with the same controls as the rest of the pugmill components. “As soon as you turn the mixing machine on, everything comes on at the same time,” Engstrom said. Beyond attaching the feeder, Engstrom said contractors will not experience any differences in workability, paving process, or mix design.
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Incorporating Surface-EXT into micro surfacing or slurry seal applications does not require any change to mix design and does not change the way paving crews operate.
Surface-EXT, seen in detail here, distributes evenly throughout the mix and creates a matrix to hold aggregate together.
“Surface-EXT can’t absorb anything, so it doesn’t require more material to coat it,” Engstrom said. “Everything is the same for the contractor. It doesn’t make any difference to the guys using it.” “If you ask municipalities to change the mix design [to accommodate the fiber], things get too complicated,” Lovett said. “The chemistry behind Surface-EXT makes it simple to incorporate into the mix design without any changes. It’s sort of a no-brainer because it’s so simple to do. It’s even becoming common practice in some regions.” The fiber is added on the front side of the pugmill, at the same time that the AC is added to the mix. To prevent the fiber from falling to the bottom or rising to the top of the mix, Surface-EXT has the same density and weight as the asphalt mix, Engstrom said. This allows for even dispersion through the mix. “Surface-EXT is distributed uniformly in the mix and bonds to itself, creating a matrix that holds the aggregate together,” Lovett said. “It’s sort of like a very strong spider web, catching and holding together rocks that are thrown into it.” Both Surface-EXT and the Ranger feeder are available through FORTA Corporation.
— By Sarah Redohl
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