The Rocks Issue
asphaltPRO PRODUCTION – PROFESSIONALS – PRODUCTS
Customize Safe Crushing Residential Paving
• How to: Crush RAP • How to: Crush Cubical • How to: Gather Volumes • How to: Crack Seal Correctly • How to: Get Micro Surface Aggs
AUGUST 2019 WWW.THEASPHALTPRO.COM
UNMATCHED DESIGN
Heatec has been designing and building tank farms for over 40 years and each project has been unique in some way. That’s because each customer is unique. You have your own business model that may be slightly different or dramatically different from the other guys’. That’s why at Heatec we take a comprehensive approach to designing your tank farm. That means we look at the materials you will be using, all the equipment that needs heat, the piping, and even future plans for expansion. Then we design a system that works for you. And we make it efficient and simple to operate. Heatec is unmatched when it comes to designing heating and storage systems for your asphalt plant. To find out more about our approach, visit us at www. heatec.com or give us a call at 423-821-5200.
H E AT E C , I N C .
an Astec Industries Company
5200 WILSON RD • CHATTANOOGA, TN 37410 USA 800.235.5200 • FAX 423.821.7673 • heatec.com
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CONTENTS
asphaltPRO august 2019
departments
20
Editor’s Letter 6 – Protect Your Image
Safety Spotlight 8 – Crush with Custom Safety Features By Sarah Redohl
Mix it Up 12 – Lab Friction Testing Gets a New Standard By Michael Heitzman
Solve Your Problem 14 – Stock Up Micro Surfacing Success By AsphaltPro Staff
Pavement Maintenance
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40
Feature articles
30
16 – Steps to Superior Crack Sealing By Sarah Redohl
Project Management 20 – Drone Program Reveals New Efficiencies for Luck By Thomas Nicholls
Producer Profile 24 – Industry Incorporates Sustainability at Asphalt Production Plants – Part II By Malcolm Swanson, P.E.
Producer Profile 30 – Covia Uses Drones for Better Data Analysis By Sarah Redohl
32 – Big Creek Sand and Gravel Doubles Production From KPI-JCI and Astec Mobile Screens
Product Gallery
38 – Best Practices for Crushing, Screening RAP for HMA Production By Jay Giltz
52 – Find New Parts for Paving By AsphaltPro Staff
New Tech 60 – RoviTracker Tracks Your Tools By Sarah Redohl
Here’s How it Works 62 – Mauldin’s 1560 Asphalt Paver
Off the Mat 66 – Nonstandard Work Impacts Safety By Sarah Redohl
40 – Crush for Cubical By Kelly Graves 46 – Cobalt Preserves Railroad Legacy in Alaska By Julie Andras
The Rocks Issue
asphaltPRO PRODUCTION – PROFESSIONALS – PRODUCTS
Customize Safe Crushing Residential Paving
50 – Job Site Planning for Residential and Commercial Paving Part Three of AsphaltPro’s “Best Practices for Residential and Commercial Paving” series. By Sarah Redohl
• How to: Crush RAP • How to: Crush Cubical • How to: Gather Volumes • How to: Crack Seal Correctly • How to: Get Micro Surface Aggs
AUGUST 2019 WWW.THEASPHALTPRO.COM
on the cover
When producers and OEMs work together on award-winning customizations, safety improves for the whole industry. See related article on page 8. Photo courtesy of Allan Myers, Malvern, Pennsylvania.
editor’s Letter Protect Your Image
The number of less-than-safe construction practices I’ve seen photographed and posted on social media is rivaled only by the number of commenters mocking one another for bothering with personal protective equipment (PPE) in the heat of summer. Both of these trends should alarm human resources directors as well as safety directors, supervisors and any other person with a shred of common sense. I know we all get a kick out of sharing stories such as “crazy things we’ve discovered in the paver hopper.” Those silly pictures don’t necessarily present a safety hazard and certainly don’t have to include a company logo or be accompanied by anyone’s name for shaming. But these pictures and posts beg the question: Should we encourage one another to show off our mistakes or to show off our triumphs? I vote we share the positive, bonus-worthy asphalt images—even if an occasional wacky-things-found-growing-in-the-stockpile stories can be comical. The asphalt industry with its adherence to complex mix design specifications while performing detail work with heavy equipment should be above childish behavior, yet too many company policies apparently allow random paving crewmembers to play with their smart phones while working. They further allow the crewmembers to post the results of their playtime online for competitors and the Occupational Safety and Health Administration (OSHA) to review. Does anyone else in this industry see the folly in letting workers capture mistakes—and even hazardous conditions—for posterity? I put it to you: It is wiser to prepare a policy that forbids the use of smart phones for activities other than work-related and to forbid workers below a set “director” grade to post pictures to social media without a foreman or supervisor’s approval. Posting good pictures that glorify a company’s exemplary work, clean equipment and safe workers in proper PPE is a smart marketing move. That kind of imagery is worth its weight in PR gold. Posting bad pictures that demean a co-worker or subcontractor for mistakes, broken and/or dirty equipment, and inexperienced or apathetic employees ignoring safety protocol is an unwise move. Keep in mind, instructional videos are educational and hopefully aren’t seen as bullying in nature. But pictures posted to entice others to comment negatively are irresponsible. That kind of imagery hurts your company and the industry as a whole. It’s unfortunate to see the level of grumbling and negativity that lives in any community online; a discussion about an improved company policy could go a long way to curing pessimism in our little niche of the Internet. As you work to reprogram your workers to appreciate the job, the company, the industry, you could request they show off the good and the exemplary in asphalt production and paving. In fact, AsphaltPro magazine has a Facebook page with which we try to request positive, good practices for conversation. Join us there and share positivity instead of a company’s marketing nightmare. We’re working toward showing the great side of the asphalt industry. Stay Safe,
Sandy Lender
6 // august 2019
August 2019 • Vol. 12 No. 10
asphaltPRO
602 W. Morrison, Box 6a • Fayette, MO 65248
(573) 823-6297 • www.theasphaltpro.com GROUP PUBLISHER Chris Harrison chris@ theasphaltpro.com PUBLISHER Sally Shoemaker sally@theasphaltpro.com (573) 823-6297 EDITOR Sandy Lender sandy@theasphaltpro.com (239) 272-8613 ASSOCIATE EDITOR Sarah Redohl sarah@theasphaltpro.com (573) 355-9775 MEDIA SALES Cara Owings cara@theasphaltpro.com (660) 537-0778 ART DIRECTOR Kristin Branscom BUSINESS MANAGER Susan Campbell (660) 728-5007
AsphaltPro is published 11 times per year. Writers expressing views in AsphaltPro Magazine or on the AsphaltPro website are professionals with sound, professional advice. Views expressed herein are not necessarily the same as the views of AsphaltPro, thus producers/contractors are still encouraged to use best practices when implementing new advice. SUBSCRIPTION POLICY: Individual subscriptions are available without charge in the United Sates, Canada and Mexico to qualified individuals. One year subscription to non-qualifying Individuals: United States $90, Canada and Mexico $125.00. For the international digital edition, visit theasphaltpro.com/subscribe/.
safety spotlight
After being named a finalist for a 2018 Asphalt Operations Safety Innovation Award, Allan Myers’ John Shabrach said, “We pride ourselves on being better, faster, safer.”
Crush with Custom Safety Features Editor’s Note: Allan Myers was recognized by the National Asphalt Pavement Association (NAPA) as a 2018 finalist in the Operational Excellence Award in Asphalt Operations Safety Innovation. AsphaltPro magazine is proud to sponsor the industry’s safety award that recognizes superior safety practices using creative ideas and practical methods that
8 // august 2019
lead to improved worker safety in a roadway, plant site or quarry setting. When Allan Myers, Malvern, Pennsylvania, looked to buy its first portable crushing plant to yield stone gradation for two of its five quarries, safety was top-of-mind.
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“We started the process early and spent a lot of time researching what equipment would work the best for our operation,” said John Shabrach, superintendent of operational services at Allan Myers. “This is our first portable operation, so it took several months of discussions internally and with the manufacturer to design this plant
safety spotlight
Allan Myers’ custom safety features on its new portable crushing plant focused on safe access for maintenance activities. 10 // august 2019
that meets our values and standards as a company.” Allan Myers reviewed a computer-generated, 360-degree digital display of the portable crusher from KPI-JCI and Astec Mobile Screens, Yankton, South Dakota. The team, consisting of Allan Myers’ health, safety and environmental team; operations team; and purchasing department, worked with the plant manufacturer to customize specific aspects. Shabrach explained the main focus was to eliminate ladders while maintaining safe access for maintenance activities. Allan Myers replaced the ladders with rolling staircases and safety gates. The rolling staircases, with locking wheels, provide access to elevated platforms so workers can safely conduct maintenance. “Allan Myers’ portable plant without ladders creates safe access to any part of our plants for maintenance or monitoring,” Shabrach said. The stairs were made by one of Allan Myers’ vendors to their specifications, are universal, and are used for safe access to the crusher platform, screen plants, and to the electrical center platform. They are built so that there is no gap between the plant and the staircase to eliminate tripping/falling hazards. At the top of all stairs in the plants, self-closing safety gates were also incorporated that shut behind workers once the platform is accessed. Allan Myers also extended the catwalk platform on the screen plants over the drive motors and 6 feet past the screen, alongside the chute work. “In the manufacturer’s original design, the catwalk stopped right at the motor,” Shabrach said. “The design was changed so workers can safely access the sides of the screens to adjust gates and perform maintenance activities.” According to Shabrach, these customizations are now options for all customers who purchase screen plants from the manufacturer. They also resulted in Allan Myers’ recognition as a finalist for NAPA’s 2018 Asphalt Operations Safety Innovation Award. Shabrach applauded the manufacturer for its cooperation, “partnering spirit,” and willingness to adapt its standard equipment to Allan Myers’ goals for its first portable crusher. “We pride ourselves on being better, faster, safer,” Shabrach said. “This operation mirrors our company’s core values.” – BY SARAH REDOHL
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mix it up
Lab Friction Testing Gets a New Standard Some highway agencies still rely on the British Pendulum (BP) test to qualify aggregates for asphalt pavement surface friction. Other agencies specify friction aggregate based on geology and/or mineralogy. Both approaches have allowed agencies to maintain an acceptable level of pavement friction long-term performance. However, the BP polishing and testing procedure evaluates a single size coarse aggregate and requires careful manual adjustment of the pendulum height to obtain the correct length of surface contact. Recent advances in laboratory polishing and friction testing now provide a better assessment of friction that considers the entire gradation in an asphalt mixture rather than a single aggregate source. The dynamic friction tester (DFT) gives a better assessment of the friction of a pavement surface. The DFT procedure, standardized in ASTM E1911, provides a more consistent measurement (no manual adjustment of the device before testing) and records friction over a range of speeds. The National Center for Asphalt Technology (NCAT) developed the Three Wheel Polishing Device (TWPD) in 2006 to complement the DFT for measuring friction on asphalt mixes. The Maryland State Highway Administration modified the TWPD concept to use a large ring of a single aggregate on an epoxy substrate. After polishing with the TWPD, the ring of aggregate can be tested with the DFT to assess the aggregate’s terminal friction value. Under Maryland’s lead, a task group of American Association of State Highway Transportation Officials (AASHTO) agency representatives and NCAT researchers are developing a new standard test procedure using the TWPD and DFT. This standard will provide equipment requirements and testing procedures to rapidly evaluate an aggregate source or asphalt surface mix for long-term friction performance. In addition to the TWPD and DFT, the equipment includes an aggregate specimen preparation device consisting of a rigid mold for the single aggregate procedure. The mix specimen preparation procedure will permit any slab compaction procedure that produces the required size with a smooth surface compacted to a uniform target density. The testing procedure for aggregate polishing and asphalt mix polishing are slightly different but involve the same TWPD. Both procedures use the DFT for measuring friction. This new friction testing protocol allows an agency or aggregate supplier to determine the long term (terminal) friction properties of any aggregate or asphalt mix in about one week for a cost of less than $5,000. A few agencies have used this system to assess the friction performance of aggregate blends for surface mixes at a substantially lower cost and much shorter time period compared to full-scale field test sections with no risk to the traveling public. For more information or a quote from the testing lab, contact NCAT at (334) 844-7328.
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NCAT developed the Three Wheel Polishing Device (TWPD) in 2006 to complement the DFT for measuring friction on asphalt mixes.
British Pendulum (BP) test
– BY MICHAEL HEITZMAN
Michael Heitzman is the assistant director, senior research engineer for NCAT. His specializations include pavement friction, non-destructive pavement evaluation, thin lift surfaces, rehabilitation and more. This article is reprinted from the Spring NCAT Newsletter with permission.
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The dynamic friction tester (DFT), as standardized in ASTM E1911, records friction of a pavement surface over a range of speeds.
A WIRTGEN GROUP COMPANY
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Solve your problem
Stock Up Micro Surfacing Success
As it does with new construction or mill-and-overlay projects, the nominal maximum aggregate size (NMAS) in a micro surfacing mix impacts the project’s success. If your problem centers around the preservation crew getting callbacks to smooth a micro surfacing application’s rough surface, or if your company is getting complaints about loose rock, etc., then you can take a page from the Transportation Research Board (TRB) seminar on Building Better Micro Surfacing and Slurry Seals, held April 24, 2019, with members of the National Center for Pavement Preservation (NCPP). Specifically, Tim Harrawood of Vance Brothers spoke of some best practices that can prevent micro surfacing problems your crew might experience.
The Problem:
After the machines have been calibrated and all materials are deemed to be incompliance with the job mix formula, the mix is proving too thick or full of fines. Alternately, the mix may be coming through the spreader with chunks of larger rock than it should. Either situation is a problem to be addressed before the team puts too much of that out-of-spec material down. Your loader operator could be scraping up material from beneath the approved stockpile.
ENGINEERING
The Solution:
ENGINEERING
Training the loader operator is a big factor in preventing errors, of course. Whether a wheel loader operator is feeding cold bins from stockpiles at the asphalt plant or a skid steer operator is feeding a nurse truck alongside a micro surfacing project, make sure he knows to grab material at least a few inches from the base of the pile. Avoid scraping the bucket along the ground where dirt, detritus or out-of-spec rock can creep into the bucket. When possible, use these best practicesENGINEERING that Harrawood recommended: • “The best QC measure is to screen the aggregate directly into the nurse truck,” Harrawood told the webinar audience. He suggested the loader feed a screen alongside the project and the screen then convey the on-spec product into the nurse truck. You can see that process with a Rawson Manufacturing Inc. Model 74830 screen in this photo from Bergkamp Inc., Salina, Kansas. ENGINEERING • Harrawood also suggested putting the tested and on-spec stockpile on a paved surface when possible. Many times, a contractor will have no choice but to build the stockpile on a gravel or dirt area; in that case, make sure the loader operator is paying close attention to how he collects material to avoid contamination. – BY ASPHALTPRO STAFF
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Pavement maintenance
Crack sealing is the process of placing an adhesive sealant into cracks on the pavement surface, preventing the infiltration of moisture and noncompressible materials into the pavement.
Steps to Superior Crack Sealing Cracks come in all shapes and sizes, and no pavement is immune to cracking. If left untreated, those cracks are only the start of more significant problems, from potholes all the way to subbase failure. According to the Pavement Preservation & Recycling Alliance’s roadresource.org, 75 percent of unsealed cracks develop into potholes within three years, while only 1 percent of sealed cracks develop into potholes in that same timeframe. Considering the benefits gained from reduced vehicle damage, increased driver safety and reduced road maintenance, it’s clear why crack sealing is important. Crack sealing is the process of placing an adhesive sealant into cracks on the pavement surface, preventing the infiltration of moisture and non-compressible materials into the pavement. It is a cost-effective pavement preservation treatment that can slow pave-
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ment’s deterioration and extend pavement life by three to five years. A crack-sealed road can be opened to traffic almost immediately when a de-tacking agent is used.
WHEN TO PERFORM CRACK SEALING
Crack sealing should be performed before a pavement becomes too distressed. Crack sealing can be used for cracks wider than 1/8 of an inch, including block, edge, longitudinal, reflective, thermal or transverse cracking. Pavement experiencing alligator cracking may not be a candidate for crack sealing, as the alligator cracks indicate failures requiring repair beyond crack sealing, as originally reported in AsphaltPro’s 2016 article “How to Crack Seal Right, Step by Step.” Potholes and cracks wider than 1½ inches also should not be crack sealed. “Errantly applied sealant looks unprofessional and can cost road owners hundreds or
even thousands of dollars a year,” said Jamie O’Driscoll of Crafco Inc., Chandler, Arizona. “It can also reduce skid resistance.” If the pavement is a candidate for crack sealing, that treatment should be performed in the spring or fall when cracks are neither completely open (as they are in winter) nor closed (as they are in summer). Most manufacturers recommend a minimum pavement temperature of 40 degrees Fahrenheit. Performing crack sealing at lower temperatures results in reduced adhesion. A hot air lance may be required to warm the pavement if crack sealing must happen when the pavement temperature is below 40 degrees. Crack sealing can be combined with other preservation treatments, including chip seals, HMA overlays, slurry seals or micro seals. However, the crack seal must cure for a minimum of two weeks before any treatment can be placed overtop. Overbanded crack seals require even longer cure times.
When routing, a minimum of 1/8 of an inch of deteriorated pavement should be cut from each side of the crack and the rout should be no less than 3/8 of an inch deep.
PREPARE THE SURFACE
Proper preparation of the surface is key to successful adhesion of the sealant. Some jobs may require cracks to be routed; others will not. There are a number of factors determining whether or not cracks should be routed before they are sealed. Routing offers cleaner edges for better material adhesion and creates a defined reservoir that holds the appropriate amount of sealant to accommodate the anticipated annual thermal movement. When done before crack sealing, routing can improve the likelihood of proper sealant adherence and double its service life, said Brandi Julian, training director at Crafco Inc. The first step is to calculate crack density, which is determined by assessing the linear footage of cracks per square feet of the pavement area. Julian recommends routing if the crack density is not greater than 20 percent. She said anticipated movement is also a factor. “The more a crack moves, the more we encourage routing,” Julian said, “because more material in that crack means it can accommodate more movement.” Routing is also integral for particularly narrow cracks, to allow enough material to get down into the crack. “We know that most people don’t route even though we know it improves sealant performance,” Julian said. She pointed to a survey completed with Texas DOT in which the majority of respondents stated they do not route because they find it is too expensive and requires an extra piece of equip-
ment. “We see the longest sealant service life out of that seal and configuration, but what’s state of the art is not necessarily the state of the practice.” If pavement has a crack density greater than 20 percent or shows fatigue cracking or other severe distress, it may not be strong enough to sustain routing. “You could potentially do more harm than good,” Julian said. When routing, a minimum of 1/8 of an inch of deteriorated pavement should be cut from each side of the crack and the rout should be no less than 3/8 of an inch deep. The exact width and depth of the reservoir will depend on the climate and other factors. Generally, colder climates may require wider reservoirs to allow for additional expansion/ movement, but not greater than 1½ inches. The rout should be centered over the crack for uniform adhesion. Cracks, routed or not, that are more than 1 ½ inches wide need to be filled with a sealing mastic, Julian said. If spalling (the breaking of aggregate at the edge of the cut) occurs, ensure the cutters or pins are not worn. Check that you are using the right type of cutter for the reservoir. Julian recommends a carbide-tipped cutter over a steel cutter for prolonged life. The operator should also slow down his/her operation to see if that reduces spalling. If spalling continues, the pavement may be in too poor of a condition for routing. The length, hub and configuration of the cutters on the cutter head are determined by the reservoir dimension.
Whether or not cracks must be routed, they should be cleaned. Any dirt, grass or other deleterious substances will reduce adhesion. The most common cleaning method is the use of compressed air at a minimum of 90 psi. Direct the nozzle directly at the crack and no more than 2 inches from the pavement surface. It’s important to ensure debris from one crack doesn’t get blown into cracks that have already been cleaned, and to time your operation so cleaning happens just before sealing to avoid debris blowing back into cleaned cracks. Sometimes, more than one pass is required to properly clean cracks, especially for wider cracks. Before beginning, check that moisture or oil isn’t escaping from the compressor into the crack.
If working in an area sensitive to air quality, blowing may not be an option. Vacuum systems can also be used to pick up debris. Some systems incorporate compressed air to blow loose any debris before removing it by vacuum. Moisture will also adversely affect adhesion. In fact, according to roadresource.org, crack sealing on a dry road is often more integral to the success of the treatment than pavement or air temperature. To ensure cracks are dry, use a hot air lance. The high-velocity, high-pressure heated air both cleans and dries the pavement. Sealant applied while the surface is still warm from the hot air lance can also adhere better. However, you must take care not to burn the pavement. Overheating will cause excessive hardening of the asphalt, create early crack surface failures and reduce adhesion. Although slight darkening of the pavement is normal, excessive darkening, smoking or dislodgement of aggregates are signs of overheating.
PREP MATERIAL
Sealants should be selected based on pavement condition, climate, pavement movement, service life needed and sealant properties, as reported in our 2016 article. “As you select sealant, make sure it falls within approved spec and that the sealant lot
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Pavement maintenance number is on hand in case there’s any issue,” O’Driscoll said. “That way a manufacturer can track and resolve it.” Climate will also impact your sealant selection. For example, cooler climates require more flexible sealants than hotter climates. Typically, there is less movement of the pavement in hot climates, so there’s less of a need for a very flexible material. Additionally, using a softer sealant in a hot climate could cause tracking. If you use a less flexible material in a cooler climate, where the pavement will be exposed to greater temperature swings and will have more thermal movement, then the sealant may crack prematurely. Job type is also a factor in determining the type of sealant used. For example, stiffer sealant works better for parking lots, which see more turning vehicles and foot traffic, while a more flexible sealant would be better for roadways. The condition of the pavement is another factor. For pavements with less than 20 percent crack density, use a more flexible sealant. For pavements with higher crack density, use a stiffer sealant. For working cracks (cracks that move more than 3 millimeters), Julian recommends a sealant engineered to accommodate anticipated movement throughout the seasonal temperature changes. Regardless of the sealant used, follow the manufacturer’s recommendations. Sealant, which is melted and applied using a piece of equipment called a melter, should only be heated within the manufacturer’s specified temperatures, usually between 380 and 410 degrees Fahrenheit. Overheating the sealant degrades its properties, while under-heating it will negatively impact adhesion as it won’t flow down the depth of the crack appropriately. It’s important to note that some sealants can be reheated, while others cannot. Check the temperature of the material regularly. The manufacturer’s instructions will also outline proper sealant agitation. Overworked sealant can break down, reducing adhesion and the life of your melter pot, O’Driscoll said. Agitation should be continuous, except when the melter lid is open to add more sealant blocks, to speed up melting and maintain sealant temperature and uniformity.
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When you start heating material in the morning, Julian recommends loading the tank halfway full and maintaining that amount throughout the day. A half-filled tank will heat more quickly. “Most sealants can be reheated only one time,” Julian said. “If it rains and you have to shut down, you’ll have space to add new, fresh material, which resets the pot life back to zero.” She also said not to heat material for more than 12 to 15 hours without introducing fresh material, as most sealants are not meant to withstand elevated temperatures for that length of time. Add sealant blocks one at a time at the rate you are using it. “Adding too many will reduce the temperature of the heated material in your tank,” Julian said. “Too many blocks can also jam agitation paddles in certain melters.” Julian also reminds us to empty the tank completely before adding a different sealant type for another job, because the chemistry of those sealants can be drastically different.
CRACK SEAL APPLICATION BEST PRACTICES
There are a number of crack seal placement configurations, including flush fill, overband, reservoir and combination. Regardless of the method used, take care to fill the crack from the bottom up to ensure a complete seal and use the right wand tip for the job. For flush fill configurations, the material is placed in the crack so it is flush with the pavement. O’Driscoll said this configuration should be used if an overlay or other surface treatment is planned in the near future. With an overband, the material is placed into and over the crack with a sealing disc. It is then either left unshaped (capped) or shaped using a squeegee to create a band that is no more than 1/8 of an inch thin and 2 to 4 inches wide. Squeegeeing can also push the sealant down into the crack to help with adhesion. Overband covers and waterproofs the crack and is ideal for cracks with considerable deterioration along the edge because it will cover those sections in addition to filling the crack. We covered the reservoir configuration in our section about routing. However, reservoirs can be flush or recessed. A recessed res-
ENGINEERING
CONSTRUCTIO
The length, hub and configuration of the cutters on the cutter head are determined by the reservoir dimension.
ervoir is placed lower than the pavement level when an overlay will be placed in the same season as the crackENGINEERING sealing occurs. CONSTRUCTIO There are also combination configurations for jobs where routing throughout is not possible. To combat sagging as sealant cools and shrinks, some material suppliers recommend filling the crack ¾ of the way and then allowing it to cool before filling completely. Other suppliersENGINEERING suggest filling the cracks CONSTRUCTIO to the proper height and returning to any cracks that are too low. If excessive sagging occurs, for sloped pavements, choose higher viscosity sealant to resist sagging/flow. Throughout the job, avoid using too much sealant or leaving behind drips and puddles. Using a drip stopper on the tip can help to ENGINEERING avoid drips and excess application. In the CONSTRUCTIO case of puddles of excess sealant, remove by heating a flat blade and cutting puddle excess without harming the treatment. It is important not to turn the freshly crack-sealed surface over to traffic too soon. However, the exact cure time depends on many variables, including sealant, ENGINEERING weather and volume of traffic on the CONSTRUCTIO road. If a light application of fine sand or a liquid de-tacking agent is applied to the surface, traffic can return to the pavement almost immediately. – BY SARAH REDOHL
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A commitment to service is a commitment to your success. For the Astec service team, education is an integral part of demonstrating that commitment. From PARTS the renowned Astec customer schools, to on-site training sessions, Astec service makes education a priority.
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Project management
UAVs can quickly, precisely and safely map areas in 3D that were formerly difficult to access by foot, such as an elevated terrain in a quarry. Luck Stone engineers can collect aerial imagery to make high-resolution maps and 3D models to visualize how they currently look and what they could look like in the future. Imagery courtesy Delair
Drone Program Reveals New Efficiencies for Luck Luck Stone Corporation, headquartered in Manakin Sabot, Virginia, is a family owned and operated construction aggregates company that has demonstrated a commitment to innovation in all aspects of operations for almost a century. Investing in drone technology was a logical and strategic step for management. Recently, Luck Stone has been using unmanned aerial vehicles (UAVs) powered by the aerial intelligence platform from Delair, headquartered in Toulouse, France, to transform the company’s business decisions and environmental footprint. As a producer and supplier of sustainable aggregates for civil engineering, construction and environmental projects of all sizes, Luck Stone offers a variety of crushed stone, sand and gravel products sourced from its exten-
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sive quarry network in Virginia, Maryland, North Carolina, South Carolina and Georgia. According to John Blackmore, survey and mapping supervisor at Luck Stone, drone data has proven its financial value by increasing efficiency and uncovering untapped reserves of aggregates. “Our fleet of UAVs can digitally map existing conditions and measure stockpile volumes for inventory management, production forecasts and more accurate auditing,” he said. Prior to investing in UAVs, Luck Stone chartered planes to take aerial photos and collect information about site resources twice a year. Upon getting the images, the company made 3D models of the sites and then sent paper copies of the surveys to project managers in various locations, using overnight shipping to ensure that project data was shared in a timely fashion.
“With planes, our associates spent hours on manual surveys and days on data collection,” Blackmore said. “Drone data has helped us determine substantial quantities of reserves and, as a result, helped improve site design.” As early adopters of UAVs, Luck Stone viewed drone technology as a solution to managing inventory; one skilled drone pilot could navigate the UAV to fly over a quarry pit and survey resources from a birds-eye vantage point. Additionally, the mining-specific analysis tools that the Delair.ai platform offers are helping the company harness the full potential of aerial intelligence within the business. Now, site inspections and inventory updates can be done as frequently as four times a year and are done monthly at some sites. UAVs have the potential to quickly, precisely
Project management
Luck Stone use the Delair.ai aerial intelligence platform for detailed volumetrics analysis, which is then used to calculate how much overburden has been moved by contractors. This data enables the company to uncover new insights that can reduce costs.
and instantly share the information with engineers back at the office. Also, broader views of the territory around extraction pits help project designers to place safety berms more effectively in the excavation area. “Through our partnership with Delair, we have learned about the many different types of analysis that are literally at our fingertips now,” Blackmore said. A pioneer of new technologies and processes, Luck Stone aims for the gold standard in worker safety. At the same time, expert engineers and surveyors must be provided with accurate, timely and detailed data. With drones, there is a reduction in time and survey costs; plus, Luck Stone’s project team no longer needs to traverse the quarries to gather data.
ADDITIONAL BENEFITS AND INSIGHTS
The Delair.ai platform gives Luck Stone engineers a way to collaborate on a wide variety of decision-making purposes including volumetric measurements, safety inspections and pit efficiency analytics. and safely map areas that were formerly difficult to access by foot, such as an elevated terrain in a quarry. Also, the ability to access and share job data in near real-time is a valuable business and communications tool for providing progress reports to various internal departments at Luck Stone. “By sharing information with everyone involved in a specific project through the Delair.ai cloud platform, we can address issues related to quantities and costs much sooner,” said Chuck Stilson, mining engineering manager at Luck Stone. “We need to think in 3D and being able to visualize our plants with the Delair.ai platform is very helpful.”
IMPROVE WORKER SAFETY
While the drones are designed to collect data for computer analysis, they also offer flexibility. For example, the drone pilot can pause to take photos or videos of anything that might require closer attention
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One of the most significant benefits of using Delair’s aerial intelligence platform with mapping technology is improved site surveying efficiency. Luck Stone uses UAVs for inspections, surveys, and mapping of current and future projects. From high above the Luck Stone operations, UAVs take hundreds of aerial photos that will be uploaded to the Delair.ai platform, ready for analysis by engineers and project designers. The business intelligence resulting from those images will be used for a wide variety of decision-making purposes including volumetric measurements, safety inspections and pit efficiency analytics. Luck Stone makes use of the Delair.ai platform to manage, process, view, analyze and collaborate around aerial data. “We collect aerial imagery to make high-resolution maps and 3D models to visualize how they currently look and what they could look like in the future,” Blackmore said. Additionally, UAVs have collected valuable information about truck routes and distances. This information is used to optimize Luck Stone’s on-site fleet of loading and hauling vehicles. Drone-assisted volumetrics have also been used to calculate how much overburden has been moved by contractors. Consequently, drone data enables the company to uncover new insights that can reduce costs. Such data can be harnessed to become consumable, actionable and shareable.
PLANNING NEW MINING PROJECTS
Drone data has been instrumental in mining development projects. Detailed maps and contour surveys are combined with geological data to project scenarios and test out designs. Aerial imaging analysis enables Luck Stone to capture and analyze site detail at a more granular level, more than a ground-based survey ENGINEERING team could do. The CONSTRUCTION up-to-date, high-resolu-SERVICE & TRAINING tion, geo-localized images can then be transformed into actionable aerial data. In a recent project, Luck Stone project designers used aerial intelligence from UAVs to choose the route of a road at a site. The optimized route protected significant aggregate reserves, ready to be extracted at aSERVICE & ENGINEERING CONSTRUCTION later date. TRAINING “It’s hard to even put a cap on what’s going to happen with drone technology and the people who are tapping into this,” said Eric Warinner, a UAV pilot for Luck Stone. Companies in the construction and aggregates industry are moving toward a future where drones are used on every jobsite.SERVICE & ENGINEERING CONSTRUCTION For Luck Stone, integrating UAVs into theTRAINING enterprise operations is not on a high-tech wish list—it is a business imperative. Drone technology has permeated the fiber of Luck Stone’s decision-making by delivering cost savings, improving safety and increasing efficiency. In the days ahead, as hardware and software evolve with seem-SERVICE & ENGINEERING CONSTRUCTION ingly lightning speed, drones will continueTRAINING to prove their value and be even more indispensable. As Luck Stone embarks on a period of strategic, accelerated growth through expansion deeper into the Southeastern United States, the company has never compromised on its unwavering pledge to have aSERVICE & ENGINEERING CONSTRUCTION positive impact on people and the commu-TRAINING nities it serves. Drone technology powered by the Delair.ai platform is destined to play a critical role in Luck Stone’s continued pursuit for exceptional quality in its products and customer service. – BY THOMAS NICHOLLS
Thomas Nicholls is CMO at Delair, where he manages the strategic positioning and promotion of the company’s aerial intelligence solutions worldwide. Previously, he was executive vice president at IoT network pioneer SigFox.
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Producer profile
In areas like the southeastern United States with high rainfall, covering stockpiles makes good sense. This is an economically advantageous means of conserving resources, fuel, aggregate and RAP, as well as reducing GHG emissions. In this image, the engineers from ClearSpan Fabric Structures provide the new ArmorShield technology to cover piles. ArmorShield is a 29-ounce architectural vinyl building cover; a protective membrane consisting of seven layers including a base fabric and multiple layers of protective coating. It includes a dual-sided PVDF top coat to increase durability and repel dirt. The company states the cover is mildew resistant and flame retardant. It comes with a 30-year warranty.
Industry Incorporates Sustainability At Asphalt Production Plants PART II Editor’s Note: The asphalt industry works with sustainable practices to lower GHGs and keep an already low carbon footprint in check. Malcolm Swanson, P.E., gathered information for an 11page document outlining some of the industry’s sustainable practices. Part I of the piece appeared in the July edition of AsphaltPro; here we’ll share Part II of Swanson’s paper, in which he gives a deep dive into additional ways to reduce combustion source emissions while reducing your fuel spend at the asphalt plant. Although discussions of energy and materials are going to necessarily intertwine, we focus on energy in this part of the article series. We mentioned in Part I that better combustion, for the purpose of reducing NOx emis-
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sions also resulted in reduction of all other emissions, including carbon dioxide, a wellknown greenhouse gas (GHG) and, at the same time, resulted in a reduced fuel spend for a contractor in California. Here are some more ideas plant managers can implement to save costs and enhance environmental sustainability.
CONTROL EXHAUST GAS TEMPERATURES Better thermal energy efficiency is tied directly to exhaust gas temperature. Better thermal energy efficiency means less fuel will be burned and fewer emissions produced. Asphalt plant exhaust gas temperature is typically around 250oF but, with 5 percent moisture in the incoming materi-
als, dew point is about 160oF, which is almost 100 degrees lower. By reducing the exhaust gas temperature to something around 170oF, the temperature gap is reduced to 10 degrees, instead of 100. That change results in a fuel purchase reduction of about 6 percent and a similar reduction in exhaust gas volume, reduction in all combustion-source emissions, and an increased production capacity. We now have the technology to measure incoming aggregate and RAP moisture contents and to use the data as input for real time calculation of exhaust gas dew point by an algorithm embedded in the plant control computer program. Astec’s V-Pack system, for example, is driven by the algorithm output and can be used to continuously adjust dryer drum speed to control exhaust gas
You want to reduce any radiation and convection heat losses from hot surfaces. Insulating all manner of components and piping makes sense. Photo courtesy Heatec Inc., an Astec Industries company temperature to maintain it just above the dew point. Although almost all plants could tolerate some reduction of exhaust gas temperature with no problem, operating with the exhaust temperature too close to dew point will cause mud to form on the walls of the baghouse and on the bags. The greatest advantage of this technology can be realized when applied in conjunction with a good insulation system for the exhaust ductwork and the baghouse. Look inside the dryer at the flights, which lift virgin aggregate from the bottom of the drum and drop it through the stream of hot gases coming from the burner. Some flight designs don’t produce a uniform distribution (veil) of aggregate across the full diameter of the dryer drum, except possibly when the dryer is fully loaded. When incorporating more than about 30 percent reclaimed asphalt pavement (RAP) into the mix, obviously the virgin aggregate component is less than 70 percent of full capacity. The more RAP in the mix, the less full the dryer is. As the dryer drum rotates, flights that aren’t full won’t shower the aggregate on the uplift side of the drum. That leaves an unobstructed exit path for the hot burner combustion gases. The hot gases will take the path of least resistance, bypassing the aggregate that is showering on the down side of the drum, and taking the heat with them. Although the superheating of the virgin aggregate usually gets the blame for a hot baghouse, it’s actually the incomplete aggregate veil that has caused the problem, wasted fuel and reduced production capacity.
This was the main reason the V-Pack™ system was developed. The flights used in that system have deep v-shaped cuts in them that enable them to produce a complete aggregate veil whether they are lightly or fully loaded. A complete veil prevents heat from escaping via the path of least resistance. Maintaining the dryer and exhaust system in good condition and keeping the burner properly tuned avoids wasting fuel. Tuning the burner with a properly calibrated combustion analyzer will inevitably result in fuel savings. Wasting fuel always results in a higher fuel spend and increased emissions. Worn dryer flights and damaged or missing drum seals have the same negative effect. Leakage air, whether it gets in through missing seals or worn holes, absorbs heat and takes it away from its intended use and makes it necessary to burn more fuel.
STOCKPILE SUSTAINABILITY
The lowest cost and most renewable of available resources are gravity and sunshine. They are resources that can be used to reduce the fuel spend and increase production capacity without the slightest concern about depleting them. In fact, the only way they can be wasted is to make no effort to optimize their use. When aggregate and RAP are stockpiled on paved surfaces, sloped away from the feed bins on a 6 percent grade, much of the water that naturally accumulates in piles will be removed by gravity drainage. This conserves fuel and enhances production capacity more than almost any other available option. The paved surface under the stock-
piles also prevents perfectly good aggregate from sinking into the ground over time and effectively becoming lost. In areas like the southeastern United States with a lot of annual rainfall, covering stockpiles can make a lot of sense, too. Again, this is an economically advantageous means of conserving resources, fuel, aggregate and RAP, as well as reducing GHG emissions.
ASSESS TEMPS
In the first part of this series, we showed that producing WMA in place of hot-mix asphalt (HMA) lowers fuel consumption and reduces all combustion-source emissions because of the lower mix temperature. It should be obvious that this is a good thing. The advantages of being able to get better asphalt cement coating on aggregates, store mix longer, haul longer distances, have mix that remains in a workable condition longer and have mix that is more easily compacted add to the clear evidence that paving with WMA is a smart business move. There is always the FOB customer who will want mix at a high temperature. (You might be better off without that customer.) To avoid loss of margin, you have to get a premium for that mix not just because of the additional fuel burn but also because the additional exhaust gas volume slows your production rate and causes a larger amount of fixed plant cost for the high-temperature mix than for normal temperature mixes. Of course, additional emissions are created. Best practice, for many reasons, is to avoid overheating the mix.
www.THeAsphaltpro.com // 25
Producer profile STORE IT
Having the ability to store finished paving materials in silos enables plant operators to run continuously and at higher production rates, thus increasing plant efficiency. As with other efficiency improvements, this implies reduced energy consumption that translates to lower GHG emissions. Sustainability is further improved by reduced wasting of materials. Starting and stopping wastes fuel and materials. An additional factor is the positive effect on the consumption of diesel fuel by trucks while they wait to be loaded. If the day is started with filled silos, trucks have less wait time and burn less fuel, producing less exhaust gases.
RENEW THE ENERGY
Using biomass fuel to provide heat to the asphalt plant aggregate dryer is attractive because biomass is fully renewable and carbon neutral. While biomass burning does emit carbon dioxide, re-growing the source plants reabsorbs it. Environmental groups consistently oppose the use of biomass fuels based on the misconception that their use will consume forests. In reality, many forests are privately owned and only exist because the owner grows the timber for profit. Without that opportunity, the owner (tree farmer) would remove the trees and grow some other crop on the same land. There are at least three avenues that could be travelled to get to biomass-fired asphalt plants. The first of these is to burn wood chips in a furnace and use the hot furnace exhaust gases as the heat source for the aggregate dryer. All of the necessary equipment and technology for this is either currently available or can be developed in a reasonable period of time. It would probably be best to run any plant configured this way as a 24-hour per day operation, because startup and shutdown of the furnace would require at least several hours. However, capital cost is too high. Another way to use biomass is to reduce the fuel to fine particles and burn it as dust in a suspension burner. The Astec Biomass Burner does this in a rotary dryer. The catch with this approach is that there is no really good and readily available technology to prepare the fuel. Hammer milling is too expensive and the only other way to get there is by steam explosion of the wood fiber. This technology exists and is advancing, but isn’t ready yet on a
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National Average Retail Fuel Prices on an Energy-Equivalent Basis January 2019* Per Gasoline Gallon Per Diesel Gallon Per Million British Equivalent ($/GGE) Equivalent ($/DGE) Thermal Units ($/MBtu) Gasoline 2.27 2.56 19.86 Diesel 2.65 2.98 23.15 CNG 2.19 2.48 19.16 LNG 2.41 2.71 21.06 Ethanol 2.59 2.93 29.57 (E85) Propane** 3.99 4.49 47.78 Biodiesel 2.52 2.86 19.94 (B20) Biodiesel 3.5 3.93 29.89 (B99/B100) *includes public and private stations **includes primary and secondary stations Table 1. Source: Astec Industries scale that would support this demand. However, it’s being developed for use in utility power plants. Once it reaches a level of production to be viable in that industry, asphalt plant demand would be a small side market. If a plant is in close proximity to a furniture factory or other industry that produces sander dust, that can be a source of small enough particle size to burn in the Astec Biomass Burner. Lastly, there is biodiesel. See the table on page xx for comparison of biodiesel to other fuels. Biodiesel is obviously renewable because it comes from plant sources. B20 biodiesel is a blend of 20 percent biodiesel and 80 percent petroleum diesel. B100 biodiesel is 100 percent biodiesel. The other major energy form used by asphalt plants is electricity. With most utility companies you can ask and learn how much of your electricity comes from renewable sources such as wind, hydro and solar, and how much comes from fossil fuel sources and nuclear. You may even be able to request and receive more of your electricity from renewable sources. Whether you can go that route or not, there are many things that can be done, with respect to electricity use, to operate in a more sustainable manner. Here are some of those. Using variable frequency drives (VFDs), along with fan motors, has a significant payback (see the case study https://theas-
phaltpro.com/articles/vary-energy-use-increase-utility-savings/ on www.TheAsphaltPro.com). Without using a VFD on the plant exhaust fan, the fan must run at 100 percent all the time, even though that’s not necessary; plants frequently operate at production rates below maximum capacity. An exhaust fan damper reduces the power consumption a little, but nothing like the VFD. Typically, the next largest fan employed at an asphalt plant is the burner blower. A proportional energy savings is available there, but caution must be exercised. Most burners are not designed to operate with variable blower speed. Never apply a VFD to a burner blower unless the burner was designed to operate with variable burner blower speed. To do so could cause damage to the burner or worse. Using VFDs for drag conveyors and other equipment may still be an advantageous thing to do to improve the plant power factor and for reduction of wear rates on wear liners, chains, etc. Reduction of wear is important in itself because worn parts have to be replaced. Of course, a worn steel or cast iron part can be recycled, but the part of it that has been worn away cannot. The sustainability of iron and alloying metal resources is connected to wear, as is the cost of replacing the part. Proper lubrication is an important factor in minimizing the wear rate of many components of asphalt plants.
EXAMPLE: Electric power savings gained by using a VFD to control exhaust fan volume by fan speed on a 400 TPH plant operating at 80 percent of capacity If a 300-hp fan drive with VFD speed control operates at 50 percent power for one hour, as opposed to one with outlet damper control that operates at 90 percent power for that same hour, the savings is calculated as follows: Electric power savings = ((0.9x300 hp – 0.5x300 hp) x 1hr x $0.11/kwhr) / 1.341 hp/kw = $9.84/hr. Typically a 400 TPH plant can produce at 80 percent of rated capacity, 320 TPH, on this much exhaust fan power. Electric power savings per ton = ($9.84/hr.) / 320 TPH = $0.031/ton Annualized power savings = $0.031/ton x 500,000 tons/yr. = $15,500.00/yr.
Table 2. Source: Astec Industries Consider premium efficiency motors as well. On average, premium efficiency motors save about 3 percent electric power consumption as compared to standard efficiency motors. While that may not sound like a lot, anything that reduces electric power consumption without an offsetting increase elsewhere improves sustainability overall and reduces the size of the power bill. Use a soft start starter where VFDs are not particularly advantageous. A soft start
reduces the current inrush when a motor is being started. This can reduce the demand charges that are associated with instantaneous load on the grid. Most electric power utilities add “demand charges” to the power bills of users that have big inrush events, such as starting a big motor across the line, because they have to over generate to absorb those drains on the grid while maintaining system voltage above a certain low limit.
If there is sufficient land area, wind and sunlight hours, the asphalt plant power source can be complemented by onsite renewable power generation such as solar and wind power. When the plant isn’t operating, at most locations, the power generated by the wind and/or solar systems can be sold into the power grid. There are also battery systems that can store this cheap power to be used during higher rate periods. Nevertheless, we have to be judicious in investing in these resources; there are areas where the average daily sunlight or average wind speed is not enough to justify the investment. This discussion of ways to thoughtfully use renewable energy at the plant leads us to the materials at the plant. In the final installment of this series next month, we’ll look at the different categories of materials in use at any asphalt plant and their sustainability as well as profitability. –BY MALCOLM SWANSON, P.E.
Malcolm Swanson is the vice president, innovative products, for Astec Inc., Chattanooga.
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AND YOU KNOW WE DO THIS... You know Astec for durable, reliable equipment with proven performance. A pioneering team with decades of experience and a culture committed to putting the customer first has culminated in a range of options including drum styles, baghouse styles, and silo styles which allow you to configure the precise plant for your needs. Only Astec offers a complete line of portable, relocatable and stationary asphalt plants from 80tph to 600tph. Astec manufactures both Astec and Dillman brand equipment.
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This photo was captured during one of Covia’s weekly pit surveys last fall using Kespry’s drone-based aerial intelligence platform.
Covia Uses Drones for Better Data Analysis Before deploying drones to measure stockpile volumes, collecting the data required for inventory management and mine planning was a time consuming and expensive affair for Covia Holdings Corporation’s mine in Tunnel City, Wisconsin. Continuous Improvement Manager Nick Dehaan would spend one week each year walking the entire site with a GPS survey system to gather raw data from which he could manually calculate the volume of each stockpile. “I used to have to take a week off from my regular work duties to walk the site and deal with the raw data,” Dehaan said. “Because of that, we would typically measure the sites once a year.” Then, January 2018, Covia deployed a drone-based aerial intelligence platform for aggregates and mining from Kespry, Menlo Park, California. Now, the process can be done within one day, which has enabled
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Covia to measure stockpile volumes on a weekly basis, rather than only once per year. Ultimately, the decision has enabled Covia to improve efficiency in its mine planning and make better operational and safety decisions.
With more than 3,000 employees operating more than 50 plants and 94 terminals, Covia is one of the largest solution providers in the industry. “The big driver [to get the system] was that our business had increased,” said Plant Manager Mark Massicote. “As part of that, we’d taken over our own stripping at the mining site and we needed a quick way to see how our face advance and backfill was progressing.” “The volume we were pushing out created a need for it,” said Covia Operations Manager Craig Johnson. “With the growth
of our business, people were taking on more workload, so the time saved using the aerial platform versus ground-based surveying was big.”
COVIA IMPLEMENTS NEW PLAN
Before Covia could implement Kespry, it got three employees Part 107-certified by the FAA to fly drones commercially. Kespry provided study materials to prepare for the certification test. Within three weeks, Covia staff were certified and had completed four training sessions with Kespry and were able to run the system independently. Once a week, the operator flies the Kespry drone over the mine as it captures pictures and data. The flight process is autonomous. On the drone’s accompanying iPad, the operator will see an ortho image of the mine, upon which they can select the drone’s height and the boundary of where they want to fly and
what they want to take photos of. The tablet will also notify them if they are flying in a restricted area, such as near an airport. “Basically, you set up the drone, hit go, and you don’t have to do anything after that,” Dehaan said. The Kespry box communicates and controls the drone’s flight pattern. The iPad can also be used to track the drone, monitor battery life, and see what percent of the mission is complete. It can also be used to do an emergency landing or prompt the drone to fly back to the operator. Covia typically performs its flights over 50 acres, which can be done on one battery (which has a runtime of 30 minutes). However, the exact time depends on the resolution to be captured. Flying lower altitudes leads to higher resolution photos, but longer flight times. If a battery runs low, the drone automatically flies back to the operator—located a safe distance from all operations—for battery replacement, and then continues its mission where it left off. “Separating people from moving equipment is a pillar of our corporate safety culture,” Massicote said. “Now, we don’t have to have a guy out there trying to survey while operating and we don’t have to stop production to survey either.” Kespry also enables Covia to get the survey points it needs without anyone standing at the edge of a 120-foot wall to identify an offset. Dehaan said the results from Kespry are also more accurate than those they’d gotten from ground-based surveying. “You’re not having to make any assumptions about your offsets if you’re working around a high wall or a berm,” he said. “It encompasses that whole berm. The data points are so much higher than what you can do from the ground.” If the operator is walking on ground with elevation changes, Kespry also tracks that. According to Kespry, the system offers positional accuracy within 2 to 10 centimeters.
DATA COLLECTION VS. DATA ANALYSIS
The data is automatically transferred to the Kespry cloud for processing and is ready within a couple hours of the flight. Although the data analysis is done automatically, the
Previously, the Covia team only measured its sites once a year. Now, an operator flies the Kespry drone over the mine to capture pictures and data on a weekly basis. user still has access to the raw data, should he need it. “The Kespry system doesn’t take any extra work time away from us,” Dehaan said. “We can go work on something else while it’s processing.” The Tunnel City mine team mostly uses Kespry to track its volume of material still on the ground in its quarry and to reconcile the volume calculated by its belt scales. “Kespry’s volume tool is the most useful tool for us,” Massicote said. “Say the belt scales say we mined 100,000 tons in one week. We can do a flight and compare that volume against the survey data. It makes doing those reconciliations very fast.” “Or, if used to project a face avance, you can look ahead to the next 20 acres to see how many tons you expect to mine,” Dehaan said, “and use that information to time crusher moves, conveyor moves, and better schedule it out.” The cross section tool has also come in handy, particularly for determining slope angles of haul roads and planning efficient dozer pushes. “Using Kespry to make sure our dumps are built properly is a big deal,” Massicote said. “We don’t have to do any re-work on reclamation any longer because of improperly-created dump slopes.”
Another reason Covia decided Kespry was the right choice for them was that it is cloud-based. “The other options sell you a license you can only use on one computer,” Johnson said. “It’s not shareable, so those other systems don’t let you collaborate as a team on any of this information.” In addition to collaborating on the data, Covia also uses the photos from Kespry to communicate with staff. For example, they can use aerial photos to show drivers where the haul roads are. “The site is constantly changing,” Dehaan said. “The pictures help our operators understand and visualize the plan and keeps them on track.”
Kespry has not only changed the way surveying is done at Covia’s Tunnel City mine, it is also now used at another Covia mine 60 miles from Tunnel City to survey its stockpiles once a month. “The drones open us up to information we just didn’t have before,” Massicote said. “Instead of having staff spending a lot of time collecting data, they can spend that time analyzing the data so we can make better decisions.” –BY SARAH REDOHL
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Big Creek Sand and Gravel Doubles Production FROM KPI-JCI AND ASTEC MOBILE SCREENS
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Crushing Superintendent Charlie Harvey explained the pit has quite a bit of sand in it. Using the new tripledeck screening plant, they’re able to get better screening capacity than in the past, and can remove more sand than when they used the regular two-deck screen. Photos courtesy KPI-JCI and Astec Mobile Screens
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For Charlie Harvey, crushing superintendent of Big Creek Sand and Gravel in Borger, Texas, achieving the production needed to meet recent demand meant investing in new equipment that could double—and in some cases triple—the operation’s output.
PRODUCTION MEETS PERFORMANCE Big Creek Sand and Gravel, formerly known as E.D. Baker Company, has been in operation for more than 20 years. The company offers a variety of services, including commercial aggregate sales, trucking, asphalt paving, earth work, wind generation work, highway construction and airport construction. Some of its major clients include the Texas Department of Transportation, Brazos Wind Ranch and Conoco-Phillips Company. Knowing the company needed to increase production, Harvey began searching for a crushing spread that was highly portable, durable and high performing. The system that
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The Pioneer® jaw crusher feeds directly into the K300/6203CC, which combines a Kodiak® Plus K300+ cone crusher with a triple-shaft, low-profile horizontal screen for Big Creek Sand and Gravel’s operation. worked for his needs is the 2650 Pioneer® jaw crusher and the new K300/6203CC portable crushing and screening plant, which he purchased from authorized dealer Texas Bearing Company in Amarillo, Texas.
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One of the key features that drew him to the Pioneer jaw crusher was the hydraulic dual wedge closed-side-setting (CSS) adjust, which eliminates manual shims and provides quick adjustment and enhanced safety,
according to the manufacturer. The ability to adjust on the fly increases production by several hundred tons every time an adjustment is needed, Harvey said. He explained that their older crusher took about half a day to adjust manually. With the new crusher, “you’re going within minutes,” he said. At Big Creek Sand and Gravel’s operation, the Pioneer jaw crusher feeds directly into the K300/6203CC, a newly-released plant that combines a heavy-duty, roller bearing Kodiak® Plus K300+ cone crusher with a triple-shaft, low-profile horizontal screen. In its closed-circuit configuration, the K300/6203CC allows producers to use a single chassis to produce up to three finished products or supplement existing demand in a small footprint, reducing the number of auxiliary conveyors they require. Harvey estimated the old system produces less than 40 tons per hour making 3/8-inch minus rock. By using the Kodiak Plus K300+, that number tripled, he said. When making 1-1/4-inch minus material, his production increased so much that his loader couldn’t keep up, requiring him to switch to a larger loader.
“The three-deck screen allowed us to make a product that is in demand that we were previously wasting,” Charlie Harvey said. “We couldn’t feed material fast enough making 1-1/4-inch minus,” Harvey said. “Even our larger Kawasaki 92ZV loader couldn’t keep up. We had to have our other loaders come back in and throw a bucket in whenever they had time.”
SCREENING VERSATILITY The addition of the new crushing spread meant additional screening power was needed on site, so Harvey sought out a mobile screening plant that could keep up with the increase in production.
Already familiar with the GT205S—in 2012, the company purchased the very first GT205S from KPI-JCI and Astec Mobile Screens—Harvey decided to invest in a second unit. The GT205S is a double- or triple-deck track-mounted screening plant designed for producers processing sand and gravel, top soil, slag, crushed stone, and recycled materials. Harvey uses the GT205S to process concrete rock and hot-mix material. By using three screen decks, he is able to make A4 rock, a size of material the company previously had to discard. Now, Big Creek Sand and Gravel is able to avoid wasting material and can offer more products to its customers, he said. “With our old two-deck screening plant, we were limited with the products we could make,” Harvey said. “The three-deck screen allowed us to make a product that is in demand that we were previously wasting.” The GT205S has also proven to double screening capacity, compared to the company’s old two-deck screening plant, Harvey said. “Our pit has quite a bit of sand in it, and with the triple-deck screening plant, we get much better screening capacity and can remove a lot more sand than we could with the regular two-deck screen,” he said.
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BEST PRACTICES FOR CRUSHING, SCREENING RAP FOR HMA PRODUCTION BY JAY GILTZ
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Asphalt producers know that many factors go into making the highest quality hot-mix asphalt (HMA) end product from reclaimed asphalt pavement (RAP). Important considerations include the need for correct size and shape of material, structural soundness, and a minimum of moisture, fines and white rock going into the mix. Additionally, production capacity is a key factor in assuring asphalt drum mixers can operate at the sometimes 24/7 demand that is generated in peak asphalt season. A slip in production capacity at the front end leads to disruption in the whole asphalt system. This article will discuss what producers can do to assure crushing and screening of RAP meets best practices for achieving highest product quality and production capacity goals. There are many choices in crushing and screening equipment to get the job done. When it comes to crushing, jaw crushers, cone crushers and impact crushers all have specific applications. Jaw and cone crushers are popularly used equipment types, but there are key reasons why an impact crusher may be the best choice for achieving the end quality product producers desire, along with providing the necessary production capacity to keep high-quality hot mix flowing. Crushing and screening RAP is a recycling application, which requires very different end product needs than virgin aggregate and even concrete crushing applications. Jaw and cone crushers are highly effective in crushing hard rock. RAP, however, is not hard
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rock, and the unique characteristics of RAP crushing can actually cause cone crushers to negatively impact product output. As cone crushers crush and re-crush the RAP to break it apart, the asphalt can be literally stripped from the RAP, creating white rock, which now requires the extra step and cost of recoating. A jaw crusher in a RAP circuit is used for primary reduction, prepping it for the cone and requiring at least two crushers, and in some instances, a vertical shaft impactor (VSI) to make a spec product. An impactor in most RAP applications typically requires only one crusher. Two may be necessary where very high capacity or special products are required. Cone crushers can work fairly well until heat is added into the equation, but as heat and pressure build, the RAP can become a hardened material, so compressed that it can become uncrushable, resulting in what is called “Bonne Float,” almost metal-to-metal compaction. The forces that can be created are directed down through the bearings and can destroy them, requiring extensive and expensive down time. Impact crushers, on the other hand, use a simpler design comprised of a rotor and two bearings that spin to launch the RAP against a curtain. In my 45 years in the crushing and screening business, 26 of those selling the UltraMax® Impactor for Eagle Crusher Company, I have sold jaws, cones, impactors, hammer-
LEFT: Here the Eagle Crusher 1400 portable impactor plant processes RAP. ABOVE: Here the Eagle Crusher MaxRap® processes RAP at Lindy Paving Inc., Newcastle, Pennsylvania. Lindy Paving is a National Asphalt Pavement Association 2008 and 2009 Sheldon G. Hayes Award winner for a highway pavement exhibiting exemplary quality.
mills, VSIs, roll crushers, and even Wood Hogs. They all have a specific application in which each one excels. The simplicity of the Eagle Crusher impactor’s three-bar, solid-steel rotor works like this for RAP: The action of exploding the material with the force of the blow bars and launching it into the primary curtain at the proper angle, then whacking it again with the secondary curtain liners to prepare it for its final reduction, creates a very consistent mix to be sent on to the drum. The RAP impacting into the curtain breaks the interstitial lattice of the RAP’s binding matrix and creates a beneficiation of the original virgin aggregate—simply put, knocking off the arrowheads and cubing up the product. The result is a minimum of white rock and fines produced by the impactor, and a more structurally sound cubical product. Cone crushers tend to “pancake” the RAP and do little to reduce the elongated aggregate, rather than produce the cubical spec product required for highest quality recycling of RAP. As the impactor separates the binding matrix, the material is aired out and moisture is released, making for a drier material going into the hot mix. Drier material saves energy as it eliminates the need for more gas in the burner. Why, then, are jaw and cone crushers so popular for RAP? Many producers have grown up in quarries where they have seen, firsthand, the ability of jaw and cone crushers to effectively crush hard
rock with wear parts that withstand the crushing process with minimal replacement. This effectiveness and wear-part longevity mindset carries over into the purchase of equipment for recycling of RAP, when recycling RAP is actually a very different application. In my experience, an impactor works best in RAP with an open setting rather than a closed one. The open setting controls the size and production with speed. With that in mind, an impactor can retain its product gradation as well as capacity throughout its wear life. Too many times, only the secondary curtain setting is adjusted because it is easier to do than adjusting the primary curtain. However, for best practice, both should be adjusted proportionately to maintain a correct reduction ratio and highest product quality. When it comes to production capacities of impact crushers compared to jaw and cone crushers for the crushing and screening of RAP, Ryan Freeman, the general manager at Rason Materials, shared his experience. “Rason operates five asphalt plants and four crushing operations, all on Long Island, New York,” Freeman said. “Working with our Rason company management team, I was able to make the switch from an original configuration of three crushers—a jaw, impactor, and cone with two screen decks, the impactor was not designed for the unique properties of asphalt crushing—to a new configuration of two Eagle Crusher impactors with two screen decks swapped out. We were able to double production capacity based on tons per hour with one less crusher and half the labor.” Freeman continued, “There’s a lot less skilled labor out there for cone crushers, so finding good cone crusher help is more difficult. Plus, cone crushers are harder to maintain for the products Rason produces.” One other and often overlooked part of any spec RAP system is the screen. A properly sized and type of screen is critical to any RAP operation. Producers are typically making finer sizes than other types of aggregate and recycling production. For RAP, the screen is the determining factor for net production. Producers can have all the crushers in the world but if RAP can’t be screened, it probably can’t be used. Jay Giltz, Eagle Crusher Company applications manager and sales representative, has 45 years of expertise in the crushing and screening industry.
www.THeAsphaltpro.com // 39
CRUSH FOR CUBICAL BY KELLY GRAVES
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The primary impact crusher produces cubical aggregates from minerals such as limestone or dolomite. All photos courtesy Kleemann, a division of Wirtgen Group
As the nation studies higher-performing bituminous mixes and pavements, attention remains focused on the need to optimize the percentage of cubical-shaped aggregate particles in the mix, and limit to low single digits the amount of particles that are flat or elongated. During crushing and screening, cubical-shaped aggregate particles are created, along with so-called flat or elongated shaped particles, and fines. Since the advent of Superpave mixes in the late 1990s, mix designs have limited the percentage of flat or elongated particles allowed in a mix. That’s because cubical, or angular, and rough-textured aggregates have much greater particle-to-particle contact than rounded and smooth-textured aggregate. The ease of movement of one aggregate particle relative to another is related to the number of contact points between the aggregate particles. If the aggregates are flat and/or elongated, they can fracture, thus creating a void in the mix. Cubical-shaped products lock together better as a skeleton within the matrix, providing a better-performing mat under compaction, while reducing voids in the mix. The cubical shape is a better product for both bituminous asphaltic concrete and Portland cement concrete (PCC), as the cubicity suppresses potential voids that might occur, and provides a better finish for both materials.
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In fact, elongated pieces in PCC can protrude from the surface of the freshly placed slab, and if your finisher strikes it, he may break or move it, creating a void in the surface. Both the power or hand finisher can strike the elongated particle, pulling it up and out of the surface and creating a void while ruining the finish. Quite simply, the cubical shape is strong; cubical aggregates lock together, creating a strong pavement, which is why a very high cubical aggregate content appears in virtually every modern standard pavement spec.
EVALUATE CUBICITY Aggregate characteristics such as particle size, shape and texture influence the performance and rideability of HMA pavements. Crushed or broken surfaces are defined as facets of stone produced by crushing or breaking by natural forces, and are bound by sharp edges. • A totally crushed or broken particle is one with more than 90 percent of its surface crushed or broken. • A crushed or broken particle has more than 50 percent of its surface crushed or broken. • A rounded particle has 50 percent of its surface crushed or broken. • A totally rounded particle has more than 90 percent of its surface rounded.
The percentage of crushed and broken surfaces affects interparticle friction, and hence the shear strength of a mix. It also affects friction and surface texture for aggregates used in pavement surfaces. When trying to optimize a crushing circuit to produce mostly cubical aggregate, it’s important to consider the material being processed and the gradations an operator wants to produce. You have to consider the entire operation in order to achieve one production goal, that of optimized cubical aggregate. You have to start from the very beginning: How you blast material, how raw shot material is conveyed at the plant, what its scalping capability is, and how the equipment delivers material to the primary, secondary, tertiary and even quaternary crushing. Surge control points—such as bins, hoppers and stockpiles—can smooth the flow of material throughout the plant.
apron. When impact crushing is used, the striking of the aggregate by the spinning rotor’s blow bars knocks off or breaks the elongated fractures. This process is repeated by an impactor in the secondary stage.
The impactor blow bars break stone and hurl it against aprons (right) for additional breakage.
Cone crushers create cubic aggregate via compression-breaking of stoneon-stone within the crushing chamber. Know the composition of your material, understand how it breaks, and then choose the right crushing and screening process needed to produce the finished product in the shape or gradation that your state or application requires. The right type of crushing will optimize creation of a cubical product. To begin, we are looking for a deposit with minimal clay or deleterious material. Uniformity of feed encourages creation of cubical aggregates and consistency of gradations and shape. For a feed with deleterious materials a jaw crusher will work without clogging, but jaws tend to produce elongated particles. If you have minimal clay or other deleterious material, a horizontal shaft impact crusher as a primary, and certainly as a secondary, will produce the highest ratios of cubical aggregates. The type of material plays a big part in how you’re going to process the material. Different rock types favor cubical aggregate production. Chert or flint from a sand and gravel pit will fracture into sharp slivers. On the other hand, cubical shape can be created from granite or limestone or natural gravel or dolomite. When you get into the slates or cherts or caliche, that kind of material will create more issues with optimizing cubical vs elongated product. Granite can make a really good cubical shape if you use the right crushers, as well as limestone. When you get into the softer stones, like sandstone, caliche and slate, those can be a little more difficult to make cubical due to their inherent softness.
JAWS VS. IMPACTORS Crushing in an impact crusher takes place when the stone is struck by the spinning impact bars, and by that stone being flung against an
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By contrast, with compression crushing via a primary jaw crusher, the material is smashed between two opposing surfaces, resulting in long slivers and more elongated product. That’s why primary impact crushing always will provide a more cubical shape than primary compression crushing with a jaw. Compression crushing with a higher speed cone crusher is much different. Compression crushing will result in a cubical shape in a cone crusher in a secondary or tertiary application, due to the rockon-rock compression that takes place within the cone as well as being “choke” fed. With the cones, especially the high-speed cones, material is retained in the crushing chamber longer, allowing rockon-rock action, which produces a cubical product.
High-speed cone crushers in the secondary position are perfect for cubic aggregate when paired with a primary jaw or impact crusher. For an abrasive, tough material like an igneous rock, a primary jaw/secondary cone set-up works well, while jaw/impact and impact/ cone crusher sets work well for the softer stones. Thus it is possible for cubical product to use a jaw as primary crusher, and then use an impactor or cone as a secondary. Tertiary crushers can be a cone or horizontal shaft impactor (HSI) or vertical shaft impactor (VSI); any one of those three; or a combination of both. Impact crushers in either primary or secondary position—in particular, HSIs—are ideal for producing a high percentage of cubical aggregates. If you use an impactor as primary, you start the
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The blow bars on an impact crusher rotor break feed into cubical shapes. process of having a cubical shape right there, and the cubical proportion is increased as material moves to the secondary or tertiary crushing stages.
SCREENS HAVE LIMITATIONS The crushers are the determinant of the percent cubical aggregate processed. The best option is to feed crushed, cubical material to the screen, and let the screen decks size the different particles into the desired cubical gradations. The crusher needs to be the device that controls the amount of elongated product in the feed, not the screen. Still, choosing the right type of screen media will help control the amount of elongated particles in the product. For example, any screen with slots in it—allowing material to turn on its side and drop through—will encourage the percent of
Unlike slotted screen media, square mesh screen media will discourage retention of flat or elongated particles in produced aggregate gradations. 44 // august 2019
elongated material produced. Slotted screens may have opening widths of a half-inch wide, but the slots will be 2 to 3 inches long, allowing elongated material to pass through the slot. Square mesh screen media help keep elongated material out of the mix. Square openings in mesh also will allow elongated particles to pass, but it’s less likely that those elongated pieces will pass through, compared to slotted screen media. Small as it is, the square opening is square, not elongated. Elongated particles can pass through a square media vertically, but if positioned horizontally, as most are, as the feed flows down the inclined screen, elongates will roll off and either be re-crushed via the return circuit, or go into a different, non-state spec product like base or fill material, but not asphalt or PCC mixes. With base or fill product, elongated material is acceptable. When material goes to a screen, you are using the screen to size a finished product into individual gradations. Once flat or elongated materials are in the product flow, it’s very difficult to separate elongated material from the cubical material. The best scenario is to make a good cubical product at the crusher, and then allow the screen to size the material out to the proper sizes. Send good cubical material from crusher to the screen and let the screen separate the sizes into the finished gradations. That means you want to have the right crushers up front to make the cubical shape in the feed before sending it to the screen plant. Have the right type of crusher based on the raw material, and the finished product sizes that are required. Make sure you choose the right type of crushing to minimize elongated material and maximize cubical material. Kelly Graves is director of sales for North America, Kleemann div. of Wirtgen Group
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COBALT PRESERVES RAILROAD LEGACY IN ALASKA
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BY JULIE ANDRAS
Jon Rudolph has a long relationship with the railroad, from his father serving as a personnel safety manager in the ’70s to his latest project—a loop for the White Pass Railroad in Skagway, Alaska, designed to allow more people to experience the remote beauty of the north. Rudolph serves as the vice president of operations for Cobalt Construction, the company chosen to work with the new owners of the historic railroad to expand and enhance service for the cruise ship industry. Deemed one of the most popular land-bound destinations for passengers of cruise ships tying up at the port in Skagway, the railroad was originally built to transport those seeking their fortune during the Klondike Gold Rush in the late 1800s. Today it still takes close to 7,000 passengers up 3,000 feet in elevation in just 20 miles each day. The breathtaking route is filled with glaciers, gorges, waterfalls, tunnels and trestles. White Pass Railroad changed hands over the summer of 2018, with new owners who have a unique understanding of the future requirements of the cruise industry, as well as a deep commitment to the historical significance of the railroad and Skagway itself. With the change came the opportunity to expand. They turned to Cobalt Construction, based in Whitehorse, a large-scale earthworks company that specializes in road construction, bridges, mine development, contract mining and mine site remediation throughout the north. “Our expertise has always been around anything that involves moving rock and dirt,” Rudolph said. “Building roads, dams,
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The project scope included clearing the site for the installation of track to create the turnaround, as well as crushing and screening rock for railroad ballast needed for track stability. The project came with unique challenges. Its remote location had the potential to hinder the supply of materials and manpower to get the job done before winter. airports, contract mining, mine reclamation work—all of this served as groundwork for spinoff work with White Pass.” White Pass invested in a new turnaround loop to increase ridership capacity from 7,000 to 10,000 people daily, putting more trains in operation and providing a speedier return to Skagway. The existing system requires trains to decouple and creates a bottleneck. The new loop would fit as many as three trains and allow them to turn around and head down the mountain. The project scope included clearing the site for the installation of track to create the turnaround, as well as crushing and screening rock for railroad ballast needed for track stability. The project came with unique challenges. Its remote location had the potential to hinder the supply of materials and manpower to get the job done before winter. Ironically, while Cobalt has built most of the major highways in Northern Canada, this site is inaccessible by road. “Everything that has to go into that job site—literally everything—goes in by train: The fuel, the explosives for blasting rock, the groceries, everything,” Rudolph said. “White Pass is supporting us 100 percent because we can’t do it without them.” This required any supplies and equipment to be transported in and out either by
locomotive work train or small Casey car with a couple of trailers behind them. Explosives needed to be brought in daily because the contractor couldn’t store much on site due to the proximity to the active railroad. Cobalt management needed a crusher and screener to crush and size the thousands of tons of ballast needed, and the transportation constraints required the contractor to consider not only production requirements but also the load sizes of the equipment to ensure the railroad could transport it. Management sought advice from Bison Iron, a heavy equipment dealer based on the west coast. “We could have used a larger crusher, but we couldn’t have gotten it on the train,” Rudolph noted. “When we started to talk with Bison Iron, they understood the unique challenges, but also saw the great opportunity if the right equipment for the job could be brought in.” Conversations led Bison Iron to recommend two pieces of equipment manufactured by McCloskey International, based in Ontario. Ultimately, Bison Iron and Rudolph agreed that a J40V2 jaw crusher and an R70 screener would be the best fit for the job. After setting up camp, Cobalt got to work clearing a path for the tracks through
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the solid rock mountaintop. The contractor primarily used a drill and blast method, moving a total of about 26,000 to 27,000 cubic meters of granite by the time the project was complete. It wasn’t straightforward, however, as the work site was next to a lake, which required environmental protection measures to be put in place and was constantly monitored for compliance. Crews installed floating silt curtains in the lake to catch blast debris. Cobalt was also responsible for supplying ballast to support the new tracks, which meant putting the new McCloskey J40V2 crusher and R70 screener to work. The crew moved the J40V2 onto the new quarry and used the equipment to crush granite to 2.5-inch pieces for ballast. The material was then sent through the R70 screener to remove fines and create the finished product. The R70 paired well with the crusher; both were self-propelled, allowing maximum mobility around the site. Before the project shut down for the winter, the jaw crusher and screener ran 24 hours a day for 10 days to stockpile ballast for the start-up in the spring. Crews finished with about 20,000 cubic yards of ballast. The site’s remote location brought additional challenges to the project. Emergency maintenance issues occasionally required a mechanic to be brought in by helicopter. In addition, because the site sat on a solid rock mountaintop beside a lake, the team couldn’t install a septic system. Cobalt instead used a storage tank on site which was pumped out weekly and taken out by train to Carcross’ sewage treatment facility in the Yukon. “It’s a very unique site and project, and we have a super crew out there,” Rudolph said. “There’s no room to install a standard camp, so accommodations are comfortable but can be tight. We make do and everyone’s happy to be part of the group.” Challenges presented themselves more as winter moved closer. In mid-November the Casey car, which brought explosives in to the site, couldn’t make it due to large drifts of snow. The team called the work train up from Skagway, 20 miles away, to clear the snow. Normally the train would not be running at that time of year, but the commitment to getting the loop finished was strong among all project team members. Partnerships are key to success, and Cobalt works hand-in-hand with the American work trains coming out of Skagway, which work with the Canadian mainte-
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TOP: The work site was next to a lake which required environmental protection measures to be put in place and was constantly monitored for compliance. BOTTOM: The J40V2 crusher features steep angles on the jaw and a wide opening for enhanced production. Cobalt used the equipment to crush granite to 2.5-inch pieces for ballast. nance. The site sits right at the border, and the cooperation is visually reinforced with the two national flags only a few feet from each other. Cobalt finished its portion of the loop project in December 2018. White Pass wrapped up installation of the ballast and tracks in early 2019 before the trains started April 27. Though the contractor is done with the White Pass loop project, Cobalt will return in spring to build more ballast for White Pass for maintenance and other projects. This will mean continued use of the crusher and screener—equipment Cobalt typically wouldn’t own—allowing them to prove their worth as White Pass has indicated it wants the contractor to work two to three more years assisting with upgrades to the entire railroad system.
The White Pass multi-generation commitment is infusing the railroad with new life. Like Rudolph, Superintendent Rail Operations Mark Taylor at White Pass in Skagway has the rail line in his genes. He’s a third generation White Pass employee. His grandfather worked with Jon Rudolph’s father in the ’70s, while his grandfather was director of White Pass in the States. Rudolph’s father was personnel safety manager in Canada. Now Jon’s son, Shaun Rudolph, runs Cobalt and is a contemporary of White Pass’ owners. As the railroad continues to grow, it seems their legacy will too. Julie Andras is the global marketing & communications manager for McCloskey International. For more information, visit www.mccloskeyinternational.com.
PAVING PERFECT RESIDENTIAL AND COMMERCIAL JOBS Part Three of AsphaltPro’s “Best Practices for Residential and Commercial Paving” series.
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BY SARAH REDOHL
Commercial and residential paving presents its own unique challenges compared to highway paving jobs. Instead of paving long, straight passes, residential and commercial paving crews are often paving short passes and working around parking islands. Although the jobs may be different, there are still best practices to follow when paving residential and commercial jobs to ensure a high quality mat. At World of Asphalt 2019, Brian Hall presented a seminar of best practices for residential and commercial paving. Hall, a territory manager with LeeBoy, Lincolnton, North Carolina, visits up to a dozen paving jobs each week. “No matter where you are, there are DOT guidelines of how parking lots should be made, and that’s what we’re following today,” Hall said. Here, we share some of the insight Hall presented in the final installment of a three-part series devoted to best paving practices for residential and commercial jobs. Our first two segments of the series covered job descriptions on the paving crew and job site planning and are available on www.theasphaltpro.com.
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This crew has knocked down the pile and spread it evenly to build a starter pad for the pull. Notice the fourth worker from the right holds a depth gauge to double-check they have the right level for the screed to set down on. Photo courtesy John Ball of Top Quality Paving & Training, Manchester, New Hampshire
GET DEPTH DONE RIGHT
There are three ways to start at the right depth. Skilled operators can start from zero, putting the screed on the ground, letting the asphalt come under it with a positive angle of attack and coming up to the right depth. However, most operators may not be able to do this, so they use a starting pad or starting blocks. The crew can build a starting pad by dropping enough asphalt for the lute guys to level out to create a pad the same width as the screed and the same depth that the finished product should be. Then, set the screed down on the pad to get started. If using starting blocks, ensure the wood is cut to the exact right depth, float the screed down on the blocks and take off from there. Find the null point in the screed so there’s no pressure on either side, then crank until you feel resistance to introduce some angle of attack. Any time the speed, angle of attack or head of material changes, it will affect the depth of the mat. If the speed changes, the shear factor—the point at which the head of material is cut off by the screed—will change, so the depth will change. At an increased speed, the shear fac-
tor decreases and the depth decreases. When speed decreases, the shear factor increases, as does the depth. The angle of attack is the angle at which the screed meets the asphalt. It is adjusted with electric screws, hydraulic screws, or manual screws. If increased, more material passes under and the screed rises. It will then reach an equilibrium and resume the original angle of attack. However, it takes five tow arm lengths for the screed to fully react to the change. While continuously adjusting the screw may make it appear the operator is working hard, Hall said, it’s actually ruining the mat. If the paving speed, mix, and grade doesn’t change, the angle of attack also should not have to change. The head of material is the amount of material ahead of the screed. The correct head of material is usually half of the way up the augers. This creates resistance against the screed. Constant resistance will result in constant depth. If the head of material decreases, the depth decreases. If the head of material increases, the depth increases. That’s why many of today’s pavers have sonic augers and automatic conveyors to help maintain a consistent head of material.
JOINT CONSTRUCTION
The joint is where the new pass meets the previous pass. When constructing a hot joint, the roller operator must keep the roller off the edge. Hall recommends a distance about the same width as the endgate shoe. Then, on the following pass, the crew will put the end gate flush on that uncompacted edge of the previous pass. Be sure to spray it first so it doesn’t pick up the material. Raise or lower it according to grade, or use an automatic joint matcher. When the roller hits that joint between the first and second pass, it will knead everything together. A cold joint is when those adjoining passes are done on two different days. You will need to overlap the edge of the previous pass by a couple inches when rolling. You will need to allow an extra ¼ of an inch depth per inch of compacted depth, since the other pass has already been compacted.
PAVE LIKE A PRO
Paving in a straight line sounds simple, but it’s always important to have help. All paving operators should have a guide to help them drive straight. Hall recommends placing that guide as far out as possible without it getting in the way of the haul trucks so the paver operator has a longer line of sight. “The farther you’re looking down the road, the straighter you’re going to pave,” Hall said.
ROLL & ROCK
We roll to achieve the density specified for the project. What you’re looking for is a minimal amount of air voids in the asphalt. There are three phases to rolling: breakdown, intermediate and final. Breakdown offers primary compaction and aggregate movement, intermediate offers some additional compaction and binder movement, and finish offers minimal additional compaction and a smooth surface. Hall said breakdown and finish rolling is done with steel drum rollers, while the intermediate is done with a pneumatic roller. Hall recommends using the Minnesota Department of Transportation’s PaveCool 3.0 tool to determine how long after paving before rolling should begin and when it should end. Regardless, roller operators should have a sense of urgency in most instances, Hall said. The speed at which the roller operator travels, along with drum and lane width, will impact the number of passes he should make.
The example Hall offered is this: to achieve 98 percent density, the operator would need to roll six passes at a speed of 500 feet per minute or two passes at a speed of 300 feet per minute. When rolling against the curb, Hall recommends keeping the edge of the roller on the curb. “Originally, I thought the curb would lift the roller up so it wouldn’t get density against the curb,” Hall said. “But since you’re trying to get water to flow to the curb, if you keep the roller off the curb, you’ll create a ridge and the water won’t make it to the curb.” However, Hall adds, the density at the curb will suffer, so he recommends tilting the paver endgate up a bit to allow a little extra asphalt at the curb.
Teach Your Crew What it Takes to Pave a Bonus-Worthy Mat
END-OF-SHIFT MAINTENANCE
Before the last load of the day, Hall recommends spraying the paver with an approved release agent. That way, when the last truck full of hot asphalt hits the paver, any stuck asphalt should slip right off. At the end of the shift, remove all excess asphalt from the paver, clean and spray all components, run the conveyors while spraying with release agent, spray the auger chains and conveyor chains, refuel the machine and grease all parts. “If you don’t schedule time for maintenance, your equipment will schedule it for you,” Hall said. He also recommends backing the paver onto the trailer and never letting the screed bump the trailer or drag on the ground. Loading boards may be necessary.
LEAVE CUSTOMERS SATISFIED
“Your company’s success depends on word of mouth,” Hall said. “The customer has questions and you have answers. Involve them in the process.” He recommends designating one crew member to talk to the customer. If the customer comes out and asks the crew to do something extra and he says they will but doesn’t communicate that to whomever needs to do it, the customer won’t be happy. The entire crew should respect the property. Keep your tools organized. Respect the people working or shopping at your commercial projects. Keep your trucks clean. They represent your company. Walk or ride the job, make a punch list before the customer does, and follow up to make sure the job is done to the customer’s satisfaction.
AsphaltPro magazine joined forces with hall-of-fame paving consultant John S. Ball III of Top Quality Paving & Training to bring you the newest online training resource for your crew: Asphalt Paving 101. The course is available on any device, anytime, anywhere to train your entire crew. Your single subscription to the best curriculum of all time gives you access to train all of your employees, each time you bring in a new hire.
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In this course, your crew will learn: • How to stay safe on the job site • How to build a takeoff ramp • How to determine fluff factor • How to determine yield • How to prep for real paving in the real world • How to maintain equipment the right way • Job responsibilities for each paving crew member • and so much more…
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www.THeAsphaltpro.com // 51
product Gallery
Find New Parts for Paving PCD milling tools are a useful addition to the existing pick range featuring conventional carbide tips. PCD is a synthetically manufactured, strong mass of carbon and carbide. The PCD tip consists of differing layers: A concentrate of diamond particles in the upper layer, the interlayers and a tungsten carbide substrate. Get more details: https://media.wirtgen-group.com/media/01_wirtgengroup/ media/media_00_general_information/W_flyer_PCD_0918_V1_US.pdf For more information, contact Matt Graves at (615) 501-0600.
PHCO The RP-195 rubber track paver is designed for highway work. Manufacturers haven’t slowed their research and development in between tradeshows while you’ve been out paving this summer. If you’re in need of parts, components or a whole new machine, the OEMs who make the goods are hard at work to keep up with demand. The next few pages include a handful of offerings that were provided to make it easier for you to find who’s keeping your bottom line in mind. Let them know you appreciate them making your life easier through AsphaltPro magazine.
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ROADTEC
Roadtec, an Astec Industries company, of Chattanooga, offers its RP-195 rubber track paver. With a 230-horsepower Cummins engine, the RP-195e/ex is designed for highway work. It features Roadtec’s exclusive anti-segregation design of the feed tunnel, feed tunnel discharge and rear augers. A delta plate defines the front wall of the material tunnel, preventing mix from rolling forward under the paver. Augers are kept close to the discharge of the conveyors to keep material moving. Each rear auger and conveyor is driven by its own hydraulic motor. This way conveyors can be wide and close together and6 each can run inde-
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pendently. Electric flow gates give precise control over the head of material. For more information, contact Eric Baker at (800) 272-7100.
WIRTGEN
Wirtgen America Inc. of Antioch, Tennessee, launched the PCD cutting tools for pavement maintenance projects September 2018. Polycrystalline diamond (PCD) milling tools are designed with exceptionally long service life thanks to a highly wear-resistant tool tip. Depending on the application,
PCD cutters from Wirtgen are designed to provide enhanced machine productivity and a constant milling pattern. for highway work.
Process Heating Company (PHCo) of Seattle offers the Patch King pothole patcher, which heats hot or cold mix patching material and keeps it at the desired working temperature, from 50° to 350° F, for at least 10 hours, according to the manufacturer. The unit features Lo-Density® opencoil, drywell-style heaters, evenly distributed across the sides, bottom, ends and discharge doors, which dissipate up to 1 watt per square inch of heat. Operators can either heat the material at the beginning of the day, set a time clock for early morning pre-heating or keep it hot overnight for more efficient use of material and improved worker productivity. It heats without flame.
Available in insulated 3.0-, 4.0- or 8.0-cubic yard models, the Patch King is popular with municipalities and road maintenance contractors because the insulated patch box easily mounts into a dump truck or onto a flatbed.
Your Preferred Asphalt Equipment Resource The Meeker Family
www.THeAsphaltpro.com // 53
product Gallery
The Surface-EXT™ fiber from Forta Corp is designed to reinforce slurry and micro surfacing mixes. Available in insulated 3.0-, 4.0- or 8.0-cubic yard models, the Patch King is popular with municipalities and road maintenance contractors because the insulated patch box easily mounts into a dump truck or onto a flatbed to keep mix hot all shift. In addition to the standard dump model, the Patch King is available in a trailer model and a rotary auger model. For more information, call (866) 6821582 or visit www.processheating.com.
FORTA
Forta Corporation of Pennsylvania, now offers its Surface-EXT™ fiber for use with micro surfacing mixes. Surface-EXT is an AR glass fiber used to improve flexibility and fatigue performance, offering reinforcement throughout the slurry or micro mix. According to a MnROADS study, adding fiber reduces rutting and cracking versus the control, while also proving profitable when compared to the time and cost of using a double preservation treatment. Check out the Here’s How it Works feature in the May issue. For more information, contact Forta at (724) 458-5221.
BERGKAMP
Bergkamp of Salina, Kansas, offers the pivot tack/air hose system for the FP5 flameless all-in-one pothole patcher. Located at the back-right side of the
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FP5’s hopper body, the system’s pivoting arm holds the original tack hose off of the ground and parallel to the hopper, locked in place for transporting with a spring-loaded pin. When in use, the pivot arm also locks into position, allowing the operator to keep the hose suspended and off of the ground. The pivot arm and hose system has a 180-degree pivot capability and provides approximately 20 feet of overall extended reach with the tack wand. For more information, contact sales at (785) 825-1375.
BOMAG
BOMAG of Ridgeway, South Carolina, launched the new BF 300 C-2 track paver for both new asphalt construction and pavement maintenance during World of Asphalt 2019. The paver offers hydraulically variable paving widths from 5.6 to 11.2 feet. BOMAG screed extensions feature Quick Coupling technology to extend maximum paving widths to 16.4 feet. Available reduction skids allow for 2.3-foot paving widths. Equipped with BOMAG’s patented Sideview system, the operating console and seat are fully adjustable. Get more details: https://www.bomag. com/ww-en/machinery/categories/paver-feeder/bf-300-c-2-89117/ For more information, contact Tim Eisfeld at (803) 337-0749.
CARLSON
Carlson Paving Products Inc. of Tacoma, Washington, an Astec Industries Company, offers its new CP60 and CP65 wheeled asphalt pavers, representing the company’s entry into the international 1.8-m city paver market. “The introduction of the CP60 and CP65 marks a historic milestone for Carlson,” Chris Colwell, president of Carlson, said. With its DEUTZ® engine, available in Stage 4 (US EPA Tier IV) and 3a (US EPA Tier III) engine packages, the CP60 and CP65 deliver laydown rates of up to 250 tons per hour with transport speeds of up to 16 kph. The EZC34 electrically heated screed has a standard pave width of 1.8 to 3.4 meters. Available in vibratory and tamper bar models, the EZC34 platform can be built out to 4.5 meters with bolt-on extensions. For more information, visit www. carlsonpavingproducts.com
able with SwingApp functionality, which can transform the unit to an offset feeder by swinging the conveyor belt up to 55 degrees in either direction, and can be mounted in less than two hours, according to the manufacturer.
The MF2500CS models are powered primarily by a Cummins® QSB 6.7-C225 diesel engine and can reach operating speeds of over 80 feet per minute and a transport speed of 2.5 miles per hour. For more information, visit www.dynapac.us.
LIBRA REMOTE PRINTER TERMINALS Are your ticket delivery methods stuck in the past? Consider the efficiencies of keeping the driver in the truck and delivering tickets electronically!
Experience the Advantages: Printer • Document presenter holds ticket for driver and retracts it into an internal box if not taken
CRAFCO
• Loop print presenter ensures jam-free operation by eliminating user access to the document while it is printing
Crafco of Chandler, Arizona, offers the expanded ActionPave® brand pavement sealers at Crafco Pavement Preservation Supply Centers or through a Crafco territory manager. Customers can fill up at the centers or authorized distributor, get delivery to their own tanks, or get tanker delivery at job sites. The sealer is sold in concentrate in a range of grades and mixes. For more information, contact Crafco Sales at (800) 528-8242.
DYNAPAC
Dynapac North America of Fort Mills, South Carolina, offers its MF2500CS material feeder product family featuring two new models—the MF2500CS and the MF2500CS with SwingApp. The feeders boast a capacity of up to 4,000 tons per hour (TPH) and are designed to handle a variety of material applications including asphalt, stone and road base material. It averages less than two and a half gallons her hour of fuel consumption, according to the manufacturer. The Dynapac MF2500CS feeder features a high performance conveyor belt system designed to empty a standard 35ton truckload in 35 seconds. The feeder is 8-feet, 4-inches wide. It has a maximum transport mass of 22 tons. It’s also avail-
• Best reliability of print head, cutter and presenter (2x to 10x over other thermal printers)
• Handles 3” or 4” wide paper and various paper thicknesses • Highest-speed printing • Exceptional print quality
Enclosure • Industrial enclosure designed to house printer and paper roll • Heat shield keeps printer cool in direct sun • Internal heater keeps printer warm in freezing climate • Motion-activated light illuminates when enclosure is opened
For more information, contact Libra Systems via email (sales@librasystems.com) or phone (215.256.1700)
www.THeAsphaltpro.com // 55
product Gallery
Drum mixers
MAULDIN
Mauldin offers three new commercial class pavers this year. The three new models—the 1860, the 1560 and the 650 gravity fed paver—have undergone changes to help increase product performance while maintaining operator convenience. The 1860, which replaces the long-running 1750-C, is powered by a Cummins 110HP Tier 4 Final engine. The redesigned tractor now has a larger 9.5-ton material capacity. The new lower conveyor uses heavy-duty greaseless heat rated bearings designed for longer life. The 1860 is propelled by larger 14-inch poly pad tracks for better traction. The 1860 shares the same Silver 16 screed of the 1750-C, which has been in production for 15 years. The Silver 16 weighs 4,500 pounds and is paired with a 4-auger feed system. The electric heat for the screed still comes from a 16-kw 4-zone thermostatic control system. For more information, visit www.4amauldin.com.
HAMM
www.tarmacinc.com
contact tarmac at 816-220-0700 or info@tarmacinc.com
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Hamm, a Wirtgen Group company, of Antioch, Tennessee, offers the Hamm DV+ Articulated Split Drum Compactors now with split oscillation drums. One of Hamm’s highlights at World of Asphalt 2019 was the DV+ 90i VV-S, a model from Series DV+. These pivot-steered tandem rollers are available in two weight categories (7.7 and 9.9 tons). All of the eight models come with split vibration drums as a standard feature. Brand new on the market in the spring were the new models offered by Hamm with a split oscillation drum. An important factor is the evenly distributed weight of the DV+. This is due to the positioning of the engine in the center of the machine and the two-part water tank distributing the weight evenly in all operational states, according to the manufacturer. The split vibration drums are fitted as a standard feature to get compaction in tight curves. There is a large
The Hamm DV+ is available as a tandem roller with double vibration drums or with oscillation and vibration drums, and also as a combi roller.
Rubberized asphalt for better roads.
CEI for better rubberized asphalt. Trust the most established name in asphalt rubber blending equipment — CEI Enterprises. A market leader since the 1990s, CEI pioneered high-precision, technologically advanced systems that are durable, easy-to-use, field-proven, and have the best service support in the industry. Did we mention the high continuous production rates? CEI’s triple-compartment reaction tanks allow for agitation, reaction, and usage operations to occur simultaneously, while being controlled independently. This 3-stage process offers production rates of 25 to 34 tons per hour of binder that is ready for use. Like all CEI equipment, our asphalt-rubber blending systems are proudly American-made in Albuquerque, NM, and backed by worldwide parts and service support.
Made in U.S.A.
C E I E N T E R P R I S E S an Astec Industries Company 245 WOODWARD RD SE • ALBUQUERQUE, NM 87102 USA • 800.545.4034 • FAX 505.243.1422 • ceienterprises.com
product Gallery turning angle, and the enormous track offset of the pivot steering allows the DV+ to be steered with great sensitivity in four different steering modes, according to the manufacturer. Get more details: https://www.hamm. eu/en-us/products~1/tandem-rollers/series-hd/hd-90i-vv-s.171183.php For more information, contact Matt Graves at (615) 501-0600.
AMMANN
Ammann Group of Langenthal, Switzerland, offers a new line of soil compactors featuring new technological solutions to meet the latest emissions standards, reduce fuel use, and provide data to eliminate unnecessary passes on jobsites. Sustainability efforts center on the new ECOdrop initiative that is being used across the Ammann product line. Among the benefits of ECOdrop are improved machine serviceability and engine efficiency that leads to lower fuel costs. Hydraulic and vibratory components have been optimized to reduce the fluids required to run the system. “The savings with ECOdrop are substantial,” Vlasta Medek, Global Commercial Compaction, said. “For example, with the ARS 70, fuel consumption dropped 22 percent. The required hydraulic oil dropped by 26 percent and the oil needed in the vibratory system was reduced by 10 percent.
The ARS 170 soil compactor from Ammann Group 58 // august 2019
Vogele’s engineers have completely revamped the Big MultiPlex Ski, focusing on simplifying assembly, handling and transport. Customers therefore can expect a corresponding drop in the costs of fluid acquisition and disposal.” Standard on the ARS 70 is the Kubota V3307-CR-TE4 diesel engine. The Deutz TCD3.6L4 engine is standard on the ARS 110 and ARS 130; the Deutz TCD4.1L4 is standard on the ARS 150 and ARS 170. The rollers are compact because of the innovative no-rear-axle concept, which positions the engine, coolers, liquid tanks and
hydraulic components in the engine compartment. Congratulations to Ammann on its 150th anniversary this year. For more information, visit www.ammanngroup.com.
VOGELE
Vogele, a Wirtgen Group company, of Antioch, Tennessee, updated its Big MultiPlex Ski April 2018. This new grade and slope control technology simplifies the process of connecting and using the sensors. It operators as standard with three multi-cell sonic sensors fitted to a beam 16.4 to 42.6 feet in length. Up to five sensors can be connected to it, depending on the application. Vogele’s Niveltronic systems for automated grade and slope control calculates a mean from the measurements recorded across the entire measuring range, making up for any unevenness over long distances, according to the manufacturer. It is designed so one person can attach it completely in just seven minutes. New clamping fasteners allow mounting without tools. Get more details: https://www.voegele. info/en/technologies/grade-slope-control/ voegele_big_multiplex_ski.html For more information, contact Matt Graves at (615) 501-0600.
new tech
RoviTracker Tracks Your Tools Have you or any members of your crew ever set a tool down on the side of the road and accidentally left it behind as the paving train moves ahead? Or maybe a tool gets put back in the wrong truck, something gets stolen, or the paver gets parked hidden behind an embankment. Although some tools of our trade are easier to lose track of than others, every misplaced tool is sorely missed when it’s needed on the next job. And replacing every misplaced $50 grease gun starts to add up. That’s why the team at RoviTracker, West Jordan, Utah, partnered with telematics company CalAmp, Irvine, California. RoviTracker’s asset management software solution is powered with data from the CalAmp Telematics Cloud and smart sensors to manage smaller form factor tools and equipment, such as generators, jackhammers, light towers, pavement saws or skid steer attachments. “The most recent annual report from the National Equipment Register and the National Insurance Crime Bureau states that the annual cost of equipment theft in the United States is up to $1 billion,” a CalAmp representative said. “Since only 21 percent of stolen equipment is recovered, it is imperative for companies to consider implementing IoT software solutions to prevent theft as well as streamline the daily operations and usage of a complex catalogue of assets.” A CalAmp iOn Tag can be attached to equipment. The bluetooth tags are 1.33 by 2.85 by 0.19 inches in diameter—roughly the size of a
H
short stack of cards—so they don’t obstruct the safe use of tools and equipment, and are designed to be safe to use in all weather conditions. The tags are paired with an SC1004 asset visibility gateway placed at a job site or yard, which tracks all tags within 80 meters. If the base station is placed on a moving object, such as the paver, the geofence tracking those tags will move along with the paving train. The user can set up geofences for each job site or yard location within RoviTracker’s mobile app to monitor the movement of assets in and out of those areas. Users will receive a real-time notification through the RoviTracker app when equipment enters or leaves each geofence, or they can view all company assets on a map with RoviTracker’s Maptrac tool. However, assets cannot be tracked if moved outside the range of the base station. In addition to monitoring connected assets’ locations in real time, companies can also access historical data about where their equipment has been and gather reports about its use. Using RoviTracker’s software, companies will be able to see more than just a tool’s location. They can also view engine runtime, battery voltage, solar charge, fuel level, temperature, integrated video surveillance and motion, among other data. Users will need to subscribe to RoviTracker’s software services at a flat rate per device to track all connected assets. For more information, visit www.rovitracker.com. – BY SARAH REDOHL
Help educate future generations about the value of asphalt roads while providing a positive community message about your asphalt facility!!!!!
OPERATIONAL MANAGEMENT Tapping into a lifetime of experiences EXECUTIVE ADVISOR Budgeting · Logistics · Staffing appraisal Research · Special projects
LOG-BASED DOCUMENTATION
Use Asphalt Lane for: • Curriculum ideas for your local school district or your child’s elementary class • A career day activity at your facility • Company Events: picnics, open houses, plant tours • Tradeshow giveaways • Giveaways to local favorite restaurant, church, synagogue.
Design and set-up · Subscription · Manage and train
MANAGEMENT TRAINING Coaching and mentoring · Recruitment and retention
Ken Monlux
kenmonlux@yahoo.com • 209-495-1017
60 // august 2019
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Registration Opens | Tuesday, October 1, 2019 Cost per attendee is $1,450.00 Hotel rooms available @ The Westin Chattanooga | 866.912.1083 $118 + tax. Astec rate available at booking.
WK 1 Jan. 6
TRAINING DATES – Jan. 9
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Here’s how it works
Step 2 The haul truck delivers mix to the hopper.
Step 3 The paverʼs feed sensors monitor the head of material.
Step 1 The operator toggles a switch to begin heating the screed and sets a desired temperature for the screed.
Step 4 As more material is needed, the dual conveyors turn on to deliver mix to the augers, which feed material to the end gates.
Step 5 The thermostat-controlled screed initially compacts the mat.
Mauldin’s 1560 Asphalt Paver M
Maintaining the proper temperature on the screed is key to leaving behind a pristine mat. Cold or unevenly-heated screeds are more likely to pick up material and mar the newly laid asphalt mat. That’s why the team at Mauldin, Taylors, South Carolina, built its new 1560 commercial paver with an electrically heated, thermostat-controlled screed. Here’s how the 1560 paver works. Before paving begins, the operator heats the screed by toggling a switch located next to the paver’s 5-inch color digital display. This display is used to control all gauges, as well as material height and screed temperature. The electrically heated screed draws power from a 14 Kw direct-driven generator mounted directly on the 1560’s Cummins 74 hp engine. The operator then sets a desired temperature for the screed, and in less than 15 minutes, the screed will be at paving temperature.
62 // august 2019
Next, the haul truck delivers mix to the 1560’s 6.5-ton hopper. The paver’s feed sensors, located on each end gate, actively monitor the head of material. As the sensors indicate that more mix is needed, the 1560’s independent dual conveyors automatically feed material on demand to the augers. The conveyors turn off and on, as needed, to maintain a consistent head of material. The 1560 has four augers—two main augers mounted on the screed and one auger on each screed extension—to move material out to the end gates. The dual auger system offers extension flexibility from 8 to 14 feet. The mix then passes under the 1560’s Freedom Fourteen free floating vibratory screed. As the 1560 tracked paver moves forward at speeds up to 140 feet per minute, its 3400-pound screed offers initial compaction of the asphalt mat.
Throughout the job, a thermostat will monitor the screed’s temperature and automatically turn on or off each of the four different heat zones on the screed and two heat zones on the extensions to maintain the temperature set by the operator at the beginning of the job. Each of these heat zones is monitored by one of four temperature sensors. The system automatically detects any faulty sensors and monitors that sensor’s heat zone with the sensor of an adjoining heat zone until the faulty sensor is repaired so paving can continue without downtime. The 1560 is ideal for paving small roads and parking lots. It was introduced at World of Asphalt 2019 alongside two other new Tier 4 commercial class pavers from Mauldin, the 1860 and 650. For more information, contact Brandon Granger at brandon.granger@calderbrothers. com or (864) 244-4800.
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advertiser index Almix . . . . . . . . . . . . . . . . . . . 7
Libra Systems . . . . . . . . . . . .55
Applied Test Systems . . . . . . .34
Meeker . . . . . . . . . . . . . . . . 53
Asphalt Drum Mixers. . . . . . . .36
Minds . . . . . . . . . . . . . . . . . 45
Astec, Inc . . 11, 15, 19, 23, 28, 61 B & S Light . . . . . . . . . . . . . .49 CEI Enterprises . . . . . . . . . . . 57 Chemtek . . . . . . . . . . . . . . . . 9 CWMF . . . . . . . . . . . . . . . . .43 E.D. Etnyre . . . . . . . . . . . . . .54 Fast-Measure . . . . . . . . . . . .65 Gencor Industries . . . . . . . . . . 4 Green Patch . . . . . . . . . . . . . 47
Process Heating . . . . . . . . . . 27 Pugmill Systems . . . . . . . . . . 35 Reliable Asphalt Products . . . . . . . . . Back Cover Roadtec . . . . . . . . . . . . . . . . 3 Stansteel . . . . . . . . . . . . 21, 63 Systems Equipment . . . . . 41, 59 Tarmac International, Inc . . . . 56
Heatec, Inc . . . Inside Front Cover
Top Quality Paving . . . . . . . . .65
Ken Monlux . . . . . . . . . . . . . 60
Willow Designs . . . . . . . . . . .65
KPI-JCI-AMS . Inside Back Cover
Wirtgen . . . . . . . . . . . . . . . . 13
AsphaltPro’s advertiser index is designed for you to have quick access to the manufacturers that can get you the information you need to run your business efficiently. Please support the advertisers that support this magazine and tell them you saw them in AsphaltPro magazine.
www.THeAsphaltpro.com // 65
off the mat
Nonstandard Work impacts Safety Almost one third of all construction workers are considered to be employed in nonstandard work arrangements, according to a recent report by the Center for Construction Research and Training (CPWR), Silver Spring, Maryland. The report found that the construction industry has the second-highest rate of nonstandard work arrangements of all industries, second only to the agriculture, forestry and fishing industry (44 percent). A number of studies have shown that nonstandard employees are at a greater risk for occupational injuries, illnesses and other adverse health outcomes as a result of their work arrangement. That’s why it’s important to understand who among your employees is considered nonstandard and to think about how you might improve the safety of these workers in your organization.
A
DEFINE NONSTANDARD WORK ARRANGEMENTS
“A lot of different words have been used over the last several years to talk about nonstandard work arrangements, from contingent workers to day laborers, the gig economy to contract workers,” said Rebecca Jackson, assistant director of CPWR’s data center. “The unifying idea of all of these terms is that there is no expectation of permanent employment. If you do a good job, that doesn’t mean you’ll continue to have your job. Instead, you expect your work to be temporary.” This can include on-call workers and day laborers, workers provided by a contract firm, temporary help agency workers, and independent contractors/self-employed individuals. “My own experience suggests that 30 percent of construction workers belonging to nonstandard work arrangements is probably an underestimate,” Jackson said. “The reason we’re interested in this from a health and safety perspective is our jobs are how we access legal benefits like workers compensation, unemployment benefits, health and safety enforcement, and social benefits like vacation, sick leave and health care.”
66 // august 2019
Nonstandard work arrangements as a percent of total employment. Source: CPWR’s Quarterly Data Report, “Nonstandard Work Arrangements in the Construction Industry” CPWR’s most recent quarterly data report does not explore health outcomes and injury rates among people engaged in nonstandard work arrangements because such data wasn’t collected in the 2017 Contingent Worker Supplement to the Current Population Survey (CPS), a household survey conducted by the U.S. Bureau of Labor Statistics (BLS), the data from which CPWR used to prepare its report. “We specifically need more information on how this complex web of work arrangements affects occupation safety and health, as well as physical, mental and emotional health,” Jackson said.
DATA SHOWS DISPARITIES
Nonstandard work arrangements are roughly twice as common in the construction industry as they are across all industries. About 30 percent of construction workers were employed in nonstandard work arrangements, 22 percent as independent contractors (9 percent for all industries) and 8 percent in alternative arrangements, including temporary workers, day laborers, on-call workers, and workers provided by contract firms (6 percent for all industries). Half of the construction workers in alternative arrangements would have preferred a different work arrangement; one third said alternative arrangements were the only type of employment they could find. On the other hand,
only 9 percent of independent contractors preferred a different arrangement; 35 percent say they choose this type of employment because they enjoy being their own boss. Workers in alternative arrangements were more likely to be Hispanic, foreign born, and to have less than a high school diploma. They were also less likely to have health insurance from any source. Only half of workers in alternative arrangements had health insurance from any source, compared to 68 percent for standard employees. Only one-quarter of workers in alternative arrangements had employer-sponsored health insurance, compared to 42 percent for standard employees. As Jackson said, more research on the correlation between nonstandard work arrangements and occupational health and safety needs to be done. In the meantime, consider your own employment agreements and how they might impact the safety of your workers—standard and nonstandard. Do you treat workers with whom you have nonstandard work arrangements differently from your standard employees? Do they receive adequate safety training? Are they expected to wear personal protective equipment? Do any nonstandard workers sit on your safety committees? And how might that impact their overall safety? Every crew member—standard or nonstandard—should make it home safely at the end of the shift. – BY SARAH REDOHL
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