John Ball shares a quick tip for paving smoothness, preventing material segregation

When charging the hopper, our main objective is to get the mix out of the truck, uniformly, without segregation. This takes communication with the haul truck driver, which we discuss in several articles you can find on TheAsphaltPro.com website, including “Prevent Fatalities with Better Truck Driver Training, Best Practices.” By communicating with the haul truck driver, you can prevent him from bumping the paver when he stops in front of it.

The next thing to worry about is whether he’s stopping in front of a paver that’s ready to receive him.

How to Set the Augers

When the paver operator brings the tractor forward and brings the push rollers to rest against the truck tires, they’ve got to be clean. If the push rollers up front are caked with material and unable to roll freely, that’s the first indication the paver’s not going to go smoothly down the road. The wheels will be hopping, and the paver will rise up and fall down going down the road until the wheel breaks free and moves freely.

The bar that holds the push rollers on has a pin in the middle that oscillates. It has a 3-inch radius to help turn the push roller. It’s not a straight solid bar; it turns with the truck. It doesn’t cause restriction on the tires of the truck or on the tires or on the paver. It can smoothly turn. It’s oscillating in the middle, but only if it’s clean of asphalt material buildup.

In this picture, you can see the asphalt has built up on the push rollers and the bar. Not only are the rollers gummed up to cause problems, mix will leak out through the holes in the rubber dams.

Maintenance on the paver is always important, but especially at the reception of the truck. Once we start to go forward, we want the pace to be smooth and not hiccupping down the lane.

In the field, no one thinks cleanup is a high priority, but it really is. Asphalt builds up on this front area and can affect the tow arm. It can cause the tow arm to pump up and down if you’re hiccupping down the lane. The tow arm is hooked to the tractor and could cause restriction. Or, if you’re using automation or sonics, it could cause something not to work properly if the push rollers are hitching and hiccupping.

Prevent Fatalities with Better Truck Driver Training, Best Practices

A 3-pound hammer can hack this material loose; you can fracture it and break it off. Sometimes you need a torch but if you whack it with a hammer, being careful to avoid the bearings that allow it to roll, you can fracture and knock the caked material loose.

What’s better is to use a shovel or rag to scrape or wipe the material off when it’s still warm immediately after the paving shift. If you can wipe the material easily in a few minutes at the end of the paving day, that’s so much easier and better than banging at hardened material before startup the next day.

However your crew has to do it, you want to have push rollers that turn smoothly to smoothly push the haul truck forward and to pave a smooth mat.

John Ball is the proprietor of Top Quality Paving & Training, Manchester, New Hampshire. For more information, contact him at (603) 493-1458 or tqpaving@yahoo.com.

Asphalt paving training tips to control the head of material and screed performance

Constant, ongoing observation and evaluation, then timely intervention, is critical to maintain a consistent head of material. This is the bedrock of accurate, repeatable, consistent quality results when paving. To me, it seems a lot of operators aren’t sure when to intervene and make adjustments to the material feed sensors. This directly results in inconsistent outcomes, variable depths and noticeable mat texture differences. Here, we’ll get a proper understanding of what to do, when to do it and how to do it for confidence in the paving process.

Top Tips to Nail Your Paver Start‑Off Every Time

Establish and Maintain Good Levels

Establishing and maintaining a suitable amount of material in front of the entire screed (including the extensions) is in my view the single most important skill set required to build high quality, smooth asphalt mats consistently. The head of material directly impacts the screed’s behavior, your ability to control it, and everything that passes beneath the screed plate.

I routinely refer to the U.S. Army Corps of Engineers’ “Hot-Mix Asphalt Paving” handbook published in 2000, AC 150/5370-14A Appendix 1. It reinforces the importance of managing the head of material. This excellent reference states that approximately 90% of all mat defects can be traced back to both an unmanaged head of material and poor screed set up.

Frequently I observe people who either don’t appreciate the importance of this paving fundamental or don’t consider the downstream negative effects an uncontrolled head of material invariably leads to. Being that it is such an important procedure to both understand and master, I think it’s timely to have a bit of a refresher on it.

Screed Influences

There are several forces acting upon the screed which influence its behavior and the resulting mat quality and texture. Some of these things we may not have too much control over, such as weather, trucking delays, mix temperature and the existing grade, but the head of material is absolutely within our control, and it is the screed operator’s responsibility to manage this process.

If your head of material is both erratic and variable, this directly alters one of the primary forces acting on the screed. We need to manage that. Failure to do so will lead to inconsistent mat texture and thickness, and creates a lot of avoidable quality issues.

You can fit all the automation you want to control the thickness, slope or grade, but it will not be consistent if the feed isn’t consistent.

For some reason, I often observe people uncertain about what to do on this matter, and it appears on occasion they think because the paver has sonic auger feed sensors installed it should control the feed automatically by itself. But it doesn’t work like that.

Every time you extend or retract the extender(s), increase or decrease paving speed or alter the auger height, this fundamentally alters the view the sonic feed sensors have. In other words, if you have done a great job establishing a consistent head of material (about halfway up the auger shafts along the full length of the screed) but then something changes, you must also make adjustments to the feed sensors to accommodate those new circumstances. You must readjust the sensor.

The screed is a precision tool and feeding a consistent amount of material to it is paramount to success. When the surface to be paved has dips or poorly milled areas, the screed operator has to make adjustments to the material feed. In this picture, you can see how the paver is being used to pre-level or shape-correct an area that was too far out of spec to correct in one lift. In this instance, the left-hand side of the screed is dragging to zero on the existing grade. This will harm the screed and cause problems for precision paving in the future. Dragging the screed plates on the grade is not good.

Remember, the sonic feed sensor needs to be pointed at a 90-degree angle to the pile of fresh asphalt being augered out. When the screed extenders are shifted in or out, it often results in a change to the sensor angle. You need to adjust it and refocus how it sees the head of material. If the original circumstances it was set up for change, its setting must change, too.

I find using something like an 18-inch-long object such as a straight edge or retractable tape measure can help to indicate that the sensor is angled correctly. Place it next to the auger sensor tube so you can see how it’s aimed.

Once you start pushing the extenders out more than about 50% of their travel (typically 19 inches with an 8-foot screed), it is important to mount both tunnel guards (or hydraulically extend them out if you have this feature) and install at least 16 inches of bolt-on auger extension to allow you to confine the head of material and to properly auger the material out to the endgates without overloading the center. You ideally want to aim for a distance of 16-18 inches from the ends of the auger shaft and tunnel guards to the endgate. Don’t have it too close to the endgate, though; it needs a bit of room to work properly and steadily. If it’s too close, it’ll be typically running on-off instead of a nice, consistent and steady speed like 20-40 revolutions per minute (rpm).

Auger Prototype to Prevent Segregation

Width vs Speed

Trying to pave too wide without installing mainframe and auger extensions usually overloads the head of material in the center of the machine, and you will see it rocking the tractor side to side, behaving more like a boring machine than a paver. Don’t allow that to happen. Having far more material in front of the screed creates multiple problems and typically results in:

• an excessively large pile of material that puts a lot of unwanted and undesirable forces on the screed. Often too much material will tend to make the screed rise because there is a lot more resistance acting on the screed than it both requires and should have. It also creates a steep-sided pile of excess material that will segregate because it’s not confined or contained in a tunnel.
• excess mix. If you are doing a lot of short pulls like 100-foot-long runs in a car park or commercial job, you are going to have a lot of excess mix to pick up at the end of each pass.
• material segregation. If you are paving longer runs, a lot of that excess head of material will basically stagnate in front of the extenders and not be consumed, nor will it pass under the screed. That’s a bad idea and it’s not going to do anything good for your mat, quality-wise.
• stress on the components. Consider the enormous and unnecessary stress and load a larger than required head of material also directly puts on the tractor, screed and material handling system; fuel burn goes way up, as does wear and tear on the augers and the extender bushes.
• loss of traction. If you are trying to drag a lot more material than the screed actually needs to float properly on a soft or marginal base, often this can cause the tractor to spin out or lose traction; particularly on a wheel paver or when paving up a steep grade or on wet tack.

If you are not confident or familiar with how to adjust the position of your auger feed sensors on the fly, the best idea is to practice. Say you have a wet day and you’re in the yard cleaning the paver. Request from your manager if you and the crew can use it as a training day and run fine crusher material through the paver and practice. You can also use this as an opportunity to hone the entire crew’s capabilities on running the screed so you have some additional members of your team who get to understand how the screed behaves and reacts. Cross training is very beneficial.

QUICK TIP! The material you use for “training day” should be fine crusher material such as <7mm or ¼-inch nominal maximum aggregate size (NMAS) dust to prevent extra wear and tear to the paver. You want to avoid running something like a 2-inch NMAS basecourse or gravel through the paver for this extra training as this leads to accelerated wear on the feeder components.

There is further excellent related training material and courses to complement and enhance this subject with AsphaltPro Magazine’s Asphalt Paving 101 resources with John Ball III, as well as Caterpillar’s Paving by the Numbers with Todd Mansell.

The reason why I consider it so important to discuss the issue of managing the head of material is because it’s arguably the primary factor in determining a consistent, quality outcome. And it’s completely within every screed operator’s ability to control.

Benjamin Everett is the owner of About Asphalt Ltd., and has worked in the asphalt industry for nearly four decades. For more information, contact him at bjeverett@aboutasphalt.co.

Buck Brothers commits to new technology across its fleet and operations

The Buck family has been involved in asphalt and concrete paving services for the Toledo, Ohio, metropolitan area since 1947. As 5th generation owners of Buck Brothers Asphalt Paving & Concrete, Chad (founder), Jacob and Zach Buck have a solid foundation in asphalt paving and milling tools and techniques as well as a clear understanding about the importance of continuous improvement.

Recently, the company sought to resolve some inefficiencies that had begun to emerge in the firm’s paving practices. For many years, crews relied on manual lasers and an old asphalt paver to achieve grade. However, a diminishing workforce created some real challenges when performing fine grading in the company’s conventional way.

Jacob explained, “We didn’t have graders or dozers at the time, so we would run stone through an old asphalt paver to achieve grade. While it worked, it was difficult to achieve a perfect grade. It became a ‘guess and check’ process that requires considerable skill.”

He knew the company needed to find a better way to fine grade, particularly on larger projects.

“It was either learn machine control or learn to manually operate a grader/dozer. It made more sense to go the machine control route,” he said.

After perfecting the workflow, Jacob Buck trained team members to survey a project and send the data back to Trimble Business Center, where it can be modeled for action.

Technical Transition

In 2023, Jacob reached out to the SITECH® Ohio team, his local Cat® dealer, to get started.

He said, “They initially suggested a laser system, because, at the time, I had no AutoCAD® or 3D experience. I didn’t even know what a data collector was or how to use a total station. But I wanted the full experience.”

After some discussion, Jacob opted for a Trimble® SPS930 Universal Total Station (UTS) because it’s both a survey and machine control instrument, providing precision measurements (in the 3-mm range). The robotic and reflectorless solution is ideal for capturing field conditions like parking lots with speed and accuracy.

After a quick training session, he immediately put the instrument to work on a job. Jacob surveyed an entire project and then sent the data back to Trimble Business Center, where he modeled it.

“Remember, I went from no 3D experience to creating a full survey and grade model, plus learning machine control,” he said. “The instrument was easy to use but I needed to think more carefully about model development.”

His next step was to connect with Trimble and SITECH specialists as well as Alan Sharp from Rockpile Solutions, an authorized software development and consulting partner for Trimble. Jacob added, “With help from all of them, I was able to get a model built in one day and begin establishing a good surveying and modeling workflow.”

He would spend the next year perfecting that workflow and is now teaching other team members.

NDDOT Trials New Technologies on Hwy 14

Efficient Flow, Paved to Spec

For new construction, Jacob will set up the UTS and survey existing curbs and surrounding surfaces and structures. He explained, “I shoot everything including curbs, drainage, flush surfaces, utility lids, etc. I send that data to Trimble Business Center to be cleaned and modeled. Then, I can establish a grade off of that model.”

That model is then sent to a compact grading machine equipped with the SPS930 UTS for blade control. “The finished surface is always accurate because I’m working directly from as-built conditions, so our drainage, flushes and transitions are all going to be exactly right.”

For a reconstruction, like a mill and overlay, the process is somewhat similar.

Jacob continued, “Before we mill it, I’ll survey the existing lot and then model it in Trimble Business Center, again paying particular attention to drainage.”

Subsequently, the crew mills with Trimble 3D Roadworks on a Cat PM820 and then paves to depth with Trimble 2D Roadworks on a Weiler P385B asphalt paver with sonics.

Not every job is modeled. Jacob said, “If it’s a sizable job, 25,000 square feet or more, or a more complex job with drainage issues, then I’ll model. There are many times I’ll model seemingly simple driveways, because drainage was not considered in the initial design. We can fix those problems with re-grading.”

In the two short months before the season closed in 2023, Buck Brothers was able to fine grade over 300,000 square feet of stone base before paving. Jacob said, “We literally cut our prep time in half and delivered effective drainage in every situation.”

Those benefits continued in 2024. For instance, Cornerstone Church in Maumee, Ohio, had a 20-year-old parking lot that deteriorated quickly and a number of drainage issues that led to potholes and unsafe conditions. When complete, the Buck Brothers crew had regraded the 100,000-square-foot area to 1/16-inch precision. The curbs and islands were optimized for drainage, and they had created 24-foot drive lanes for improved access and safety.

Another project was a 50,000-square-foot freight yard, which was a unique effort because instead of asphalt, the surface was all stone, and well above grade. Conventional methods would have required the crew mill and pave multiple times to achieve the desired thickness. Jacob recalled, “I knew we needed to come down about 4 inches—but what would that do to the drainage?”

Instead, he surveyed the existing conditions with the Trimble SPS930 UTS and modeled the final surface, drainage included. A Cat PM820 cold planer equipped with the Trimble Roadworks 3D Paving Control Platform was then used to mill the parking lot to the specified grade.

He added, “Since we are able to mill 3D, it is considerably easier to pave to depth than using traditional paving methods such as checking depth with a dipstick or using sonics. We completed the work on time and to exact specifications, all while working around the client’s ongoing operations.”

The Buck Brothers crew paves with a Weiler P385B asphalt paver with sonics equipped with Trimble 2D Roadworks.

Sustainable, Precise, Efficient

When asked about measuring the success of the company’s technology enabled workflows, Jacob noted he hasn’t run any official numbers. “For me, it’s more of a reality that I can’t do things the way we did before anymore; I needed a different solution. That said, I see value every day in this current workflow.”

He pointed to greater efficiency of materials. “With this modeling workflow, I know we’re not going to be over on asphalt. The cost savings on materials alone likely pays for the technology investment.”

Arguably, the greater benefit is confidence in the results. He continued, “Our old methods were inefficient, and sometimes inaccurate, which required rework. Now I know that everything we pave is at the right thickness and is going to drain correctly—and that’s big in the asphalt world. I can’t picture us ever going back to the way we did it before.”

Selecting Your xD for Mill-and-Fill Workflow

The satisfaction and comfort of using the 3D-modeling workflow has prompted Jacob to begin training others in the organization in how to build the models. He’s also looking to invest in other machines including a dozer and excavator.

Customer satisfaction is at an all-time high. Jacob concluded, “My customers, both owners and general contractors, are kind of in awe of what they’re seeing. Many people assume this technology is only for large scale construction sites and workflows, but we’re finding it has huge benefits for smaller sites where precision and material yields are equally important.”

Kevin Garcia is the general manager of civil specialty construction for Trimble.

Asphalt paving contractor and consultant shares tips and techniques to start each lift successfully

In the July training department, we discussed investigating the screed and paver and looked into maximizing the grade and start-off point for your best paving success. This month, we’ll dive into placing the mix.

First, I’m not going through the full suite of every proper start-off step when there is plenty of excellent established material that covers this at TheAsphaltPro.com, within the Asphalt Paving 101 online training course, and in Caterpillar’s “Paving by the Numbers” method. Instead, I’m sharing tips and techniques I’ve learned over the years that may be new and helpful to you.

1. Start with temperature.

The screed must be at proper temperature to place any hot mix. This means each section of the screed—mains and extenders. The heating elements must all be working properly to allow the screed to float properly and to behave in a controllable manner. A cold screed will always dive immediately after coming off the take-off reference. It will be next to impossible to achieve the target thickness and finished profile if the screed is not up to temperature or has some heating elements not working.

Top Tips to Nail Your Paver Start‑Off Every Time

I’ve been on several pavers in the last few years that were in very poor condition, and it’s next to impossible to hold target grade and finished height when the screed doesn’t heat properly. You can put the tow points way up and end up with the screed planing like a surfboard and still not be able to get target depth until the screed has heated up properly.

It can take at least 150 feet or more before the screed starts to plane properly and start floating on the mat as it should. You need to watch it like a hawk, because once it starts heating up, the depth will increase quickly as it comes up to target temperature. Before you know it, you’ll be chasing your tail and having to reduce depth fast.

QUICK TIP: Remember to install auger and mainframe extensions (aka tunnel guards) to within 18 inches of the endgate inside. If you don’t, you will have an inconsistent material feed, an erratic mat texture and a difficult time managing the screed. Basically, remember, “Control the feed; you control the screed.”

Fresh Pavement for Pago Pago

2. Get the settings right.

Check your screed extender match height and slope, main screed crown and extender angle of attack relative to the main. (NOTE: This last adjustment you should have dialed in during step 1 on the flat, workshop floor before it came to the job site.)

Set your screed width and try to always balance the screed by having each extender out the same amount on both sides. I’ve found that some screeds are quite sensitive to being used with one side out more than the other; try to keep it symmetrical if you can. If you must have one side out more than the other for job site conditions, I always prefer to have the lower side out more than the high side. It’s a lot easier for the material to flow downhill to the lower side of the mat than it is to try and push it uphill.

When we remove the tarp from the start-off joint, we reveal a clean edge. We take loose material left on the tarp to the next lane over and place it where the paver will begin, compacting it in a thin layer while preparing the starting boards for the next lane’s pull.

3. Measure and calculate.

Physically measure the true depth of the start joint. Oftentimes it might be a milled edge from a previously placed mat. Sometimes, the depth may be quite a bit thinner or thicker than it should be, and this requires you to carefully tailor the starting boards to the right thickness to ensure the roll down is right and to avoid having to stop after 15 feet to fix the joint, which we discussed in part one in July.

Most repetitive work like asphalt paving is 99% preparation and 1% execution. In other words, the effort you choose to invest each time by following a well thought out, repetitive step-by-step set-up process directly translates into success or failure. This is why airplane pilots must follow a checklist every single time they take off. The act of following a known, established and proven process almost always results in a safe, successful takeoff. If you want to enjoy consistent, repeatable and predictable results every time you take off from the joint, then follow a good process. (If you’re still not sure what that process should be, refer to the AsphaltPro Magazine’s online course, Asphalt Paving 101.)

To place a quality longitudinal joint, we must pave a straight, sharp line or replicate a nice, smooth curve or radius. The key to doing this is twofold. First, ensure you paint a nice, sharp clear paint line to give the paver operator a good reference. Second, set out an accurate reference for the paver operator to follow said paint line. The best way is to use an adjustable steering guide or pointer or guide bar that they use to trace accurately the line they need to follow. Make sure these things are in good shape and not bent or broken or difficult to adjust. Recently, manufacturers have released aftermarket devices that mount on the paver and point a colored beam of light along the painted line, centerline or other reference point.

4. Square up.

Once you have the correctly calculated starting boards under each side of the main screed and in the center of the main, be sure to back the paver up square to the joint. You want the machine lined up properly for a straight longitudinal joint to be placed.

QUICK TIP: You also want to place starting boards under the extenders if those are out more than about 20 inches.

Don’t accept or allow the paver to be crooked. Back it up so the foremost part of the screed frame is about 4 inches behind the edge of the take-off joint. Next, I recommend setting the tow points at the approximate correct height for the mat depth you are placing, taking into account the need to keep the line of pull as close to being parallel to grade as you can.

Not every paver will be able to be set to pull in an exactly horizontal plane. I’ve found some screeds are not well balanced. They may be heavy on the front or the rear, or the height of the screed pivot point isn’t on a similar plane to where the pull point is. Oftentimes you have to experiment to find a happy medium that gives a good mat. (See the picture of the Proper Line of Pull for notes.)

This picture shows the proper line of pull between the tow point and screed pivot point.

Lower the screed onto the take-off boards (or starting reference) and be sure the screed switch is in “float.”

Next, be sure to slowly (at low engine speed) creep the tractor forward about 2 inches to take up the slack at the tow points and to introduce a load on the screed. This is a critical step that, if not done properly, invariably leads to a poor takeoff with a dip or bump.

If you did everything right so far, the leading edge of the screed should now be about 1 inch behind the edge of the start joint.

Next, null out your depth screws (if you have them on your screed) so you are sure both sides of the screed are relaxed or nulled. Then, one side at a time, introduce about 1/8- to ¼-inch slight “nose up” angle of attack with the depth cranks. Remember that earlier you should have already set your extender vertical height relative to the main screed. This will act as a means to help set that approximately 3/16-inch angle of attack, because once you null the screed out, it tends to rest on the extender section. Similar to a plane flying through the air or a boat on water, the screed nose must also be slightly “up” to provide lift.

Now, lower the endgates so the skid plate is lightly contacting the grade on the leading edge. But make sure to have enough “space” with the spring so there isn’t too much down pressure, as that can interfere with the ability of the screed to float properly on the mat. If the other side is matching a previously placed pass, set that side plate at a suitable height to avoid it digging into the mat. (See this “Float the Endgate” article.)

Fresh Pavement for Pago Pago

5. Half-fill the auger chamber.

Next, I fill one side of the auger chamber at a time with the engine at low idle and the augers and conveyors at slow speed. Try to fill the area in front of the extender to the level that you would normally have it when paving; about halfway up the auger shaft is a good rule of thumb. It helps to have someone carefully shovel mix out by hand to avoid the temptation to power it out with the augers and overload it.

QUICK TIP: Don’t overfill this area (it’s easy to do this) as this will affect the screed when you pull off the joint. Also remember safety! Ensure laborers working near the augers are kept safe and their limbs and clothing are well away from moving parts. Shut the augers off once “full.”

Once both sides are full, choose your target paving speed and ensure the trucks being pushed by the paver (or the MTV operator) are informed you are about to start so they are ready and can anticipate how much brake pressure to set and so on to avoid spills. If everyone is on point and working as a cohesive team, many big mistakes can be avoided, and we can have a good day.

Some operators prefer to start in automatic, while others like to stay in manual until they validate that the mat depth is on target. If you know your screed well and how it behaves in all circumstances, and you have performed the set-up steps correctly, start in auto. Typically, I prefer to start manually and switch to automatic after one to two paver lengths; once I’m satisfied I’m on the target mat depth.

To assist me both at startoff and for matching joints or adjacent structures like a concrete channel lip, I use a bobbin and chain. I like to have a visual, tangible reference for fast and accurate feedback as to whether I’m at target depth. Also, although I always advocate for and prefer to use dual grade averaging, there can be some occasions on almost any job where that just isn’t feasible.

10 Screed Setup Steps for Better Mat Control

On car parks and many siteworks or commercial jobs, it’s typically less about achieving a “billiard table” smooth ride and more about matching adjacent equipment or structures such as concrete channels or light stands and other things of this nature. Frequently, these things we need to match can be at a different elevation or level to the paving thickness we have to meet. Therefore, discretion and a solution are needed. This requires quite a lot of forward thinking and planning to ensure water will still run off the right way and not create a bird bath. If you have the bobbin and chain calibrated to your target loose mat depth, when you need to deviate to carefully match to something on the fly, it’s great to have a trusty reference you know is already right that you can use to quickly get back on grade.

When we have the auger chamber dialed in right, the screed set up per industry best practice and everyone’s ready to go, it’s time to pave.

When we remove the tarp from the start-off joint, we reveal a clean edge. We take loose material left on the tarp to the next lane over and place it where the paver will begin, compacting it in a thin layer while preparing the starting boards for the next lane’s pull.

6. Pull off the start-off joint.

I pull off the joint at the same speed I’m intending to pave, and I focus solely on hitting target depth, having a consistent, steady 20-40 RPM auger speed and a smooth mat without irregular texture. I make sure to trim the extender heights if required to take out any transition lines.

We all know the goal is a consistent mat texture free from segregation and defects. I have a couple of skilled laborers who work as a team and lift up the start-off tarpaulin, fold it in half lengthwise, then carefully place the mix from the tarp on the grade at the next lane over and screed it out fairly thin by hand, then compact it by walking on it. There is usually no need to touch the transverse take-off joint this way.

If you did things right—if you made sure the screed starting reference was carefully calibrated for the thickness at the joint, set up the screed properly, and took the slack out of the side arms to preload the screed so it behaves in a predictable, controllable way—then the breakdown roller can get onto that joint immediately after the starting tarpaulin and laborers are out of the way. He can start getting density. That roller needs to nail that joint in a timely fashion and then keep up with the paver following the pass pattern.

When we remove the tarp from the start-off joint, we reveal a clean edge. We take loose material left on the tarp to the next lane over and place it where the paver will begin, compacting it in a thin layer while preparing the starting boards for the next lane’s pull.

I’m not going to do a narrative on how to compact the transverse properly; others have covered this very well many times over. If you’re still not sure about it, look at the AsphaltPro Magazine online course, Asphalt Paving 101, for some helpful tips from industry veteran John Ball III or Caterpillar’s Todd Mansell with “Joint compaction and roller operations” and “Transverse joints—avoiding the bump!”

These two installments of Start Paving Off Right offer tips and techniques I’ve learned and used over decades in the field. These are some of my “go to” tips to keep the screed from nosediving when coming off the starting reference, thus they are tips for avoiding re-work and achieving success. Let me know which elements you found helpful or which you’re going to try out on your next project. Let’s continue to learn not only from the training courses offered around our industry and in these pages, but from one another as well. I look forward to connecting with you on TheAsphaltPro’s social platforms to share ideas.

Benjamin Everett is the owner of About Asphalt Ltd., and has worked in the asphalt industry for nearly four decades. For more information, contact him at bjeverett@aboutasphalt.co.

Asphalt paving contractor and consultant shares tips and techniques to set up each pull successfully

Do you ever get frustrated after setting up the paver and pulling off a start joint only to realize you are too low or too high after just the first 13 to 16 feet (4 to 5 meters) or so? We all take pride in delivering the best outcomes we can and need to do so repeatedly for our good reputation and good pay. Let me share a few “go to” tips for achieving consistently great results that avoid re-work, stopping the paver, or having to fix low spots because the screed took a dive immediately after coming off the starting reference.

Quick Primer on the Starter Plate and Fluff

Low or high spots created by an improper takeoff cause handwork that affects the quality of your lift. Typically, it takes the crew at least 10 to 15 minutes to correct a poor start-off defect. And no matter how good your guys are (and I’m blessed to have several incredibly talented team members who possess excellent handwork skills), handwork always shows up as a different mat texture. It usually doesn’t look as nice or as “ironed” as a well compacted, homogenous lift placed by a paver that’s been set up properly and operated correctly.

Let’s talk about how to start off correctly.

Typically, it takes the crew at least 10 to 15 minutes to correct a poor start-off defect. And no matter how good your guys are, handwork always shows up as a different mat texture.

Irregular areas must be filled by hand prior to paving. You want to pre-compact these areas with a plate compactor or tamper, so you get the entire patch compacted. If you attempt to roll these areas with a steel drum roller, you may bridge the internal area and fail to achieve proper compaction.

Standing on the Shoulders of Giants

First, I would like to reference some excellent steps from Caterpillar with their “Paving by the Numbers” step-by-step process. This is an effective and good method to follow. Most paver manufacturers such as Blaw-Knox, Bomag, Vogele and Roadtec/Astec have their own similar but unique guidelines that are well worth carefully studying and adopting.

In addition, John Ball of Top Quality Paving & Training, Manchester, New Hampshire, has excellent best practices and on-site training. I have attended many of his classes at industry events and can recommend them.

Complex Warehouse Lot Provides Training Opportunity for Commercial Paving Crews

Just so you know, even after 39 years in the asphalt industry, I still attend at least three refresher or new education sessions at events like World of Asphalt (WOA) and CONEXPO-CON/AGG and attend Todd Mansell and Caterpillar’s excellent courses annually. It’s important to stay sharp, up to date and on point with new industry lessons, new techniques and new material types. Plus, one can never have enough good old-fashioned refresher courses. Let’s face it, we don’t always remember every single thing, especially if you don’t do much of a particular technique.

High areas that won’t allow proper depth of paving need to be leveled with the mill. You might think it’s acceptable to leave these “high” areas alone and let the screed scrape across the top of them, saving yourself the cost of material, but these will be areas of low quality in the mat where the compaction train will encounter problems.

Mandatory Start-Up Steps

We want to apply the new practices to our quality paving while remembering the important basics to start off every job right. My go-to start-up steps that I use every single time, no matter what type of job I’m doing, include those discussed here.

I would rather take an extra five to seven minutes at the set-up stage of each pass to be sure these small but critical details are right, than cutting corners and getting caught with a bad start.

Mark low spots, outlining the area with a color that indicates the repair to be made. On large enough projects, you may wish to write out the tonnage required for repairs.

1. Check the screed and paver.

Ensure the screed plates are not warped or out of shape from being overheated or being hung up coming off a lowboy that didn’t have long enough ramps for a paver. This is surprisingly common.

You cannot expect to deliver quality outcomes with a damaged screed or paver that isn’t within tolerance. A screed is a precision tool that must be treated as such. It needs to be operated professionally by competent people and maintained and repaired as required.

Think of it this way: a professional musician wouldn’t mistreat or neglect their prized guitar or piano, nor would a sportsperson wreck or damage their tennis racket or golf clubs. I’ve never seen a first-class fitter turner or skilled tradesman treat their lathe or other essential tools of trade in a bad manner. We are professional craftsmen; a screed needs to be treated the same way. Respect it and operate it like a pro.

Get a Straight Line of Pull

Get underneath it every morning and have a look at it. Don’t just assume it’s okay; verify it! Don’t allow it to be slammed into obstructions trying to avoid the tiniest bit of handwork. Professionals don’t do that.

* Remember: safety first. Be sure to engage the screed locks, apply the parking brake, chock the wheels/tracks etc. before inspecting the equipment.

If you put down a starting tarp, you can avoid having excess material to clean off the existing surface, and you can provide a clean, well-defined starting transverse joint. This allows the breakdown roller to get onto the mat quickly and efficiently. Place your take-off boards (which need to be about 40 inches long) in the correct position on top of the tarp. One of the single most important determiners of nailing a professional take-off joint is sizing the thickness of the take-off boards correctly.

2. Inspect the screed more closely.

Assuming your screed and paver are in acceptable condition to place a great mat, if it’s the first time you’re using this machine (maybe it came from another crew), you need to physically check the screed for the following:

• Check for correct flatness front and rear of the main and extender plates. Use either an aluminum straightedge or a stringline and 3 X equal size nuts to verify the leading edge and trailing edge are essentially flat transversely and if required, a slight positive lead crown. (Check with manufacturers recommendations regarding lead crown; don’t automatically assume it is required.)
• Examine the strike-off plate condition. These often get bent or damaged on ironwork on mill-and-fill jobs, or caught on a lowboy when loading/unloading.
• Check the strike-off plate vertical height. You’ll refer to your screed manufacturer’s recommendations; often it’s ½- to 1-inch (12.5- to 25-mm) above the bottom of the screed plate, but this depends on your material thickness, nominal maximum aggregate size (NMAS) and viscosity of the binder, etc., as these all affect the screed’s ability to float on the mat and one size doesn’t fit all. You have to experiment on different jobs to find the sweet spot for that screed, on that material and thickness that allows the screed to float properly at the right angle of attack.
• Check the extender slope stops are correct, and the scales or gauges for crown, slope and match height are calibrated correctly. Most manufacturers have a step-by-step screed adjustment and set-up process that guides you through these critical checks. You wouldn’t believe the number of times I’ve come across pavers and screeds with bent or missing delta plates, warped or bent screed plates, and screed frames in a poor state of repair.

You cannot achieve precision asphalt paving with a screed that isn’t fit for purpose or in a proper condition for the intended use. Get these basics right first, before even thinking about placing a mat. It’s best to perform this screed check the day before in a workshop with a clean, flat concrete floor and with the assistance of a competent mechanic or fitter. Follow the OEM steps methodically.

Here’s a quick tip! Be sure you lay the tarp down neat, square and straight just back from the edge of the take-off joint, leaving the joint exposed ¾ to 1 inch (19 to 25 mm). This is to allow just enough overlap of material onto the existing grade to form a proper, tight and dense transverse joint, but not so much you then have to go back and start bumping the joint or tempting well-meaning laborers to try to push the edge back. We need to avoid that.

3. Assess the grade.

After you have ensured the tractor and screed are both calibrated and in proper, serviceable condition, you may think you’re ready to go lay some mix. But wait! Have you checked the grade?

A number one mistake we often fall victim to is assuming that the surface we are going to place mix on is flat, smooth and free from high areas and low spots. That’s the exception in my experience; it’s hardly ever within spec. If it’s a commercial car park with grader placed or skid steer placed granular base like stone or base coarse, invariably that will require careful inspection. You may have to check with a straightedge and correct by hand to fill low areas.

Remember: asphalt generally compacts approximately 22 to 25% after the full compaction process. Therefore, if you are placing a 2-inch (50-mm) compacted mat, this means you need to pave it about 2.5 inches (62 mm) loose from the paver to allow enough compaction. When you find those random low spots that are about 1/2- to 1-inch (12.5- to 25-mm) or more, which I guarantee most jobs have, mark them out with spray paint, fill them by hand and compact them before you even think about using the paver.

Prepare Tomorrow’s Transverse Joint for a Fast Start in the Morning

As an example, on a recent FAA resurfacing project my team and I were on, the pre-leveling generally took between 20 and 60 minutes to complete before paving began. This was on an area of around 3,109 square yards (2,600 square meters) per day. We had to comply with less than a 1/4-inch (6.4-mm) finished level tolerance, and as we were only placing a single layer of asphalt, it was essential to ensure the grade we placed it on was level.

You want to plan for a similar 20- to 60-minutes depending on the extent of the areas to be filled. High areas need to be cut off with a milling machine on milled surfaces and cut down by the motor grader on granular base and reprepared and recompacted.

This should be evaluated and identified by the paving supervisor or other competent individual well prior to the crew, paver and gear arriving on site. Inspect each site one to two days prior and preferably rectify these problems before you turn up to pave it.

Get the client to attend the site walkover or pre-handover visit with you so there is no doubting what the situation on the ground is. Preferably get a surveyor to take levels to validate the low areas. Then ensure the client or client’s representative agrees with you on the additional make-up material and time and labor for the fix. You need to get this in writing, or it’s going to be on you after you have paved the project to try and recover the extra costs later. This is such a fundamentally important step in the process for a quality outcome and a happy client.

Avoid having to touch the start joint by hand by using a length of truck tarpaulin—or similar tarp material—at the start-off point. You want to place it about 1 inch from the joint and have it extend about 1 to 2 feet wider on each side of the lane.

4. Plan to minimize handwork.

You’ve ensured the paver and screed are in good condition and you’ve ensured the project area is ready for the paving crew to do its best work. Now let’s eliminate handwork at the takeoff joint. Place a tarpaulin at the start point.

It’s all about working smarter, not harder.

A procedure I like to use on any job, whether it be a commercial parking lot, city street or an airport, is to try to avoid having to touch the start joint by hand. I want to avoid having to “fix it up” after the paver’s pulled off the joint. No matter how good your best laborers are, the moment you touch material by hand, some degree of segregation is going to occur, and it will stand out.

Not only that, but handwork also compacts differently than paver placed material due to not having the weight of the screed imparting a degree of pre-compaction on the material. The paver placed mat always has a nice, ironed appearance to it and is always going to be more homogeneous in appearance than handwork if it’s being set up and operated properly and the feed system operating in a consistent, steady manner.

How to Set the Augers

Try to minimize the amount of handwork you need to do, by paying more attention to the set-up steps for the screed, which I’ll share next month.

The tip I’m sharing right now is to use a length of truck tarpaulin—or similar tarp material—at the start-off point. It needs to be at least 1 to 2 feet (305 to 610 mm) wider on each side than the width of the lane. It also should be at least 40 inches (1 m) deep (front to back) to allow enough coverage to avoid material having to be picked up by hand. Just before you are ready to set the paver down to place each pass, lay this tarpaulin down on the grade at the take-off joint.

Place your starting or take-off boards (which need to be about 40 inches or 1 m long) in the correct position on top of the tarpaulin. One of the single most important determiners of nailing a professional take-off joint is sizing the thickness of the take-off boards correctly. If the milling crew didn’t cut that transverse take-off joint quite deep enough, you need to reduce the thickness of your starting reference accordingly. Otherwise, you’re going to be too high and losing time rushing back to fix it by hand.

I would rather take an extra five to seven minutes at the set-up stage of each pass to be sure these small but critical details are right, than cutting corners and getting caught with a bad start. The bad start could take 10 to 15 minutes to sort out and will never look as nice as a joint that was completely placed by the paver.

With these basic start-off tips in mind, you’re set for a successful beginning to each pull. What’s next? See you next month for the sequel to “Start Paving Off Right.”

Benjamin Everett is the owner of About Asphalt Ltd., and has worked in the asphalt industry for nearly four decades. For more information, contact him at bjeverett@aboutasphalt.co.

Maui Paving offered an asphalt update for the island’s Haleakalā Highway

Maui Paving, a joint venture formed by Goodfellow Brothers and Grace Pacific, recently completed the reconstruction of Haleakalā Highway for the Hawaii Department of Transportation (HDOT) ahead of schedule. Tyrone Pullman, foreman and construction manager for Maui Paving, shared in a video interview this highway is one of the biggest on the island. It connects the densely populated valley with the surrounding rural areas.

A&A Paving Invests in its First Mill for Mega-Growth

The team from Maui Paving removed and replaced 4.2 miles of divided highway at a depth of 8 inches. They used two Wirtgen milling machines—a W 210 Fi and a W 200 Fi—as well as a SUPER 2000-3i paver from Vögele among other equipment on the project.

“It is the demolition of 4 inches of ultra-thin white top and 4 inches of asphalt treated base, and then placing back 6 inches of asphalt treated base and 2 inches of Mix IV,” said Zack Gonzales, general manager of Maui Paving.

The SUPER 2000-3i highway class paver from Vögele with an engine rated output of 186 kW (250 hp), in combination with the VF 600 paving screed, was used to place the PMA with 20% RAP in lifts of 6 and 2 inches.

Gonzales shared in a video interview that the plan was originally to cut up and remove those sections with an excavator, but Maui Paving had a better idea. It was more sustainable to mill the highway and recycle all that material. And with the Wirtgen cold planers, they were able to mill the full depth in one pass.

“It’s a hundred percent recyclable,” Gonzales shared. “We’re recycling the material that we’re demoing out and then also our asphalt that we’re placing also includes 20% RAP, which is a recycled asphalt pavement as well.”

How to Mill for Profit

Members of the DOT provided the details, with Brandon H. Hee, the Geotechnical and Pavement Design and Shoreline Section Head for the DOT, explaining the 16-year-old pavement’s condition prior to project start. Hee shared that the 4 inches of ultra-thin white topping (UTW) placed in 2008 over the existing 3 to 5.5 inches of ACB placed in the 1970s was failing. “The failure appeared to extend into the underlying ACB, and this is why the cold-planing was done to 8 inches deep,” Hee explained.

“The highway had a Pavement Quality Index (PQI) of 78. “78 is rated at fair and would be in the range of warranting minor rehabilitation.”— Kyle Suzuki, P.E.

Kyle Suzuki, P.E., of HDOT Highway Division, explained the department doesn’t use pavement condition indices (PCI) to assess structures. “We use internal indices to characterize pavement condition and performance. The closest index to the PCI is HDOT’s Pavement Quality Index (PQI), which this road had a score of 78 out of 100. 78 is rated at fair and would be in the range of warranting minor rehabilitation.” He also shared the pavement had an average IRI (MRI) of 163 in/mi as measured on Jan. 19, 2023.

Tyrone Pullman, foreman and construction manager for Maui Paving, shared details of the projects progress and the crew’s experience with the new equipment.

To replace the pavement, the Maui crew used the Vogele Super 2000-3i to pave a 2-inch polymer-modified asphalt (PMA) Mix IV over a 6-inch ACB with polymer, Hee explained. “We use the SBS polymer.”

Kristi Grilho, Bituminous Engineer for HDOT, discussed the mixes in more detail. “Mix IV is a ½-inch dense-graded mix. Both ACB (also called Hot Mix Asphalt Base Course (HMAB)) and Mix IV used PG64E-22 asphalt binder. From mix design submittals, both used 20% RAP. HDOT doesn’t require additives or other accommodations for RAP percentage allowed (up to 20% for surface, and 40% for HMAB (drum plant).”

New Equipment on Maui

Wirtgen Group reported: The deployment of this paver was a première on the Hawaiian island of Maui. To enable Maui Paving’s personnel to exploit the full potential of the machines, they all received appropriate training from Wirtgen America before the start of the project. The familiarization of the crew with the machines went off without a hitch for everyone, from the mechanic to the operating personnel on the site.

All three machines deployed on the project [paver and two cold planers] impressed the construction crew with powerful performance, precision and low noise levels.

“The transition to the Wirtgen milling machines has been so smooth and seamless, not only due to their efficiency, but also to the fast delivery of parts by Pape, (the local John Deere/Wirtgen Group dealer) and the training provided by the Wirtgen Group,” reported Zack Gonzales, general manager of Maui Paving.