Here’s how to succeed in a town where slurry seals have to go down fast at competitive rates, and they have to look great.

In Las Vegas and surrounding areas, a pavement maintenance/slurry surfacing contractor is keeping image-conscious customers happy with peerless pavement surfacings, a consistent product, and a dedication to quality. And it’s doing it with motivated, uniformed crews, aggregate from its own pit, and high-performance laydown machines that keep projects moving and clients delighted.


A slurry machine operator plays a critical role in ensuring that the slurry mix is being applied correctly.

"Las Vegas is different from other places we’ve worked because this town maintains its prestige," said Eric Reimschiissel, general manager, American Asphalt & Grading Company, Las Vegas, Nevada. "Nearly all the pavements are crisp and clean. Not only do we have to look good, but we have to adhere to stringent quality control programs instituted by the local governments, including material, hand work, and seams."

All slurry seals in the Las Vegas area — for both public and private sectors — are latex-modified, Reimschiissel said. "A lot of that is because we have proactive customers who know the latex modifier helps the product withstand the scorching heat, provide longevity, and enhance aggregate retention," he said. The latex is not derived from crumb rubber or tires, as may be seen in the Phoenix area, but is co-milled with an asphalt emulsion dubbed LMCQS, for latex-modified cationic quick-set, with modifier incorporated at a hefty 3% by weight, compared to 2 to 2.5% conventionally.

AA&G’s fleet is made up entirely of Macropaver Model 12B slurry machines from VSS Macropaver, a division of Reed International, Hickman, California.

What are slurry seals?

Water-resistant slurry surfacings (or seals) are thin overlays which seal minor pavement cracks and oxidized pavements, restore surface texture and skid resistance, correct raveling, reduce noise, and allow overlays where weight restrictions and curb heights apply.

A dedicated slurry surfacing truck applies slurry to a residential street in suburban Las Vegas, Nevada.

The Washington State Department of Transportation’s Interactive Pavement Guide defines a slurry seal as a homogenous mixture of emulsified asphalt, water, well-graded fine aggregate, and mineral filler, with a creamy, fluid-like appearance as applied. Setting occurs very quickly — allowing traffic and access — and the seal cures over a period of time.


Squeegee men are an essential part of the slurry crew.

There are three configurations of slurry seals.

- Type I (fine) has the finest aggregate gradation (most are smaller than the 2.36 mm/No. 8 sieve) and is used to fill small surface cracks and provide a thin covering on the existing pavement, WS DOT says. The International Slurry Surfacing Association recommends Type I aggregate slurries for low-density/low-wear traffic areas. The cities of Las Vegas and Henderson, Nevada, use Type I surfacings on new streets.

- Type II (general) is coarser than a Type I aggregate slurry, with a maximum aggregate size of 0.25 inch, and is used to treat existing pavement that exhibits moderate to severe raveling due to aging, or to improve skid resistance, WS DOT says. Type II aggregate slurry is the most common type used. AA&G’s market area uses Type II surfacings on older residential streets and collectors.

- Type III (coarse) has the coarsest gradation and is used to treat severe surface defects. Because of its aggregate size, it can be used to fill slight depressions to prevent water ponding and reduce the probability of vehicle hydroplaning, WS DOT says. In AA&G’s market, they’re typically used in major thoroughfares and highway applications.

- Slurry seals are applied to an existing pavement surface by means of a spreader box linked to a slurry mixing unit or pug mill. Slurry is introduced into the spreader box, which then places the slurry surfacing material over the width of a single traffic lane in a single pass as the mixer/spreader unit moves forward, sometimes at considerable speed.

Keeping quality paramount

AA&G differentiates itself from the competition on the basis of the quality of its product, Reimschiissel said, but quality has to be achieved while also making money on a project.

"If you’re laying 25 to 30 pounds of Type III slurry per square yard, a quarter to a half-inch thick, you lay a lot of material, but you don’t get a lot of area covered. So the faster the material can come out, the more area you can cover, and after all, that’s how we get paid. If you can have a machine that’s half or one-third faster than what someone else’s will place, it makes a big difference in what you can get done in a day."

"Every contractor should put down a quality product," said Okeda Goodloe, slurry crew supervisor for AA&G. "That’s our bottom line. The market is tight no matter where you are, but when you cut corners, it hurts all contractors. And we don’t cut corners.

"A quality mix is a uniform mix that’s not runny, with a beautiful texture," Goodloe said. "When your box and drag mop go over it, a beautiful texture will result. You can go too fast and, depending on the aggregate and the oil, you will not have a good placement. The machine is only as good as the operator."

Goodloe said a number of clues to a failing placement are evident when the operator looks into the box, where slurry is mixed before deposition on the pavement. "If the mix is separating, the aggregate and oil will not be bonding," Goodloe said, "instead, they will be running away from each other. If there is too much water, some will be floating at the top. If there are inconsistencies, the operator will see it in the box before it gets to the pavement."

Once in place, indications to problem placements may be evident. "The operator won’t see it, because he’s looking in the box, but the squeegee men or supervisor will see it," Goodloe said.

Streaks or scratches can be caused by a number of issues. "You can have oversized aggregate caught in the box," Goodloe said. "Or if you work eight hours and the product is curing really fast, pieces can adhere to the burlap drag and that will cause streaks. If it’s a scratch the squeegee men can take it out by hand. Most good operators will sense that something is going wrong and will stop to correct whatever is causing the scratch."

True and steady lines

One key to slurry surfacing productivity is keeping the Macropaver true and steady. "The line driver puts a straight line on the edge of the slurry seal and is one of the most important persons on the crew," Okeda said. "If he is crooked, it makes more work for everyone behind him, especially the squeegee men. If he is straight, it will look good to the eye, and cleanup and repair are minimized."

Slurry surfacings are a popular pavement preservation treatment in the American West and Southwest.

Optimum speed is variable and depends on the size of the project, he said. "Most inspectors like the machine to move between 300 and 500 feet per minute," Okeda said. "If you go faster than that, they begin to squawk. Speed is dictated by the line driver and the box operator."

Eliminating variables is a key measure to success, Goodloe said. "You need trained personnel," he said, "but you also need consistent product. One thing helping us maintain consistent product is that we have our own aggregate plant and our own pit, so we know our rock. The Macropaver is a piece of equipment that’s consistent, too. When we go to work, we know that we will be able to work. I worry about supplies getting to the job, but my Macropavers are there."

Advanced electronic controls on the pavers also help maintain consistency and productivity, AA&G’s Reimschiissel said. "The new controls on our trucks are all electronic, so you know exactly what you’re laying," he said.

Equipment keeps projects going

AA&G’s fleet incorporates Macropaver Model 12B, said to be the fastest slurry machine in the world, with an application rate of up to 4.4 short tons per minute. "I’m familiar with all the manufacturers, and we looked around at different machines before settling on the 12Bs," Reimschiissel said. "We’ve had very good luck with them."

The distinctive chocolate brown color of slurry quickly changes to black after placement.

There are cheaper machines out there, but the Macropaver difference is internal, he said. "In these difficult work environments, we like a completely hydraulic machine — without the chains — like the VSS Macropaver," Reimschiissel said. "They’re easier to maintain, and they’re overbuilt with improved electrical systems. The bottom is double-seamed; the steel is butted together and welded, then another lap is provided at the bottom. Emulsion tanks can be problematic; they can crack or rust or wear out, and the double-seam takes care of that."

Despite having to get used to it, Reimschiissel’s operators now like the Macropaver’s joystick box control panel, Reimschiissel said, adding, "with the joystick, the operator can keep an eye on the slurry while being able to move the stick and control the whole machine."

Macropaver self-loading of emulsion is another advantage, Reimschiissel added. "The way the machine self-loads is very good," he said. "When we are pumping emulsion and our stockpile pump goes down, the machine can load itself. The pump on the machine will pull material out of the tanker and fill itself. There are times that the pump will go down and the backup capability will keep us going. It’s even more important when we’re out of the Las Vegas area. If you’re in Ely, Nevada, and your pump goes down, what are you going to do? You’re certainly not going to find another pump up there."