He says utilities in the state have been hard at work replacing network cables and power conduits in continuous trenches that are 18 inches wide. The utilities immediately fill the completed repair with a sandy concrete so the roads can be opened to traffic. He says state law in Washington requires some construction or repair work on main roads to be done at night, so it's especially important that AA Asphalting's crews be as productive as possible during the restricted work times.
"We follow the utility companies and whatever they rip up, we replace," Alcorn says. "We come in with the maintainer and grind down 3 inches and 18 inches wide and we just keep moving on the repair. We can do anywhere from 1,000 to 1,500 lineal feet a day."
Alcorn says that while it's difficult to say when the asphalt maintainer will or will not be used on a job, a job with a 2-foot-wide trench running 300 or more feet long would almost certainly benefit from a maintainer.
"We would bring it in on something like that for sure," he says. "Doing it by hand would be so much slower. We can do 1,000 feet in four hours with the maintainer."
He says the maintainer is also valuable when utility cuts are deep enough to require two or more lifts of mix. Without the machine smaller patches would have to be constructed, but because the maintainer can deliver mix at a higher rate of speed, larger patches can be completed each time out, making the job more profitable for the contractor and making the utility and the driving public even happier.
"This is a production machine, it's too much trouble for smaller patches," Alcorn says.
Versatile spray patchers
Another approach to higher production pavement repairs is spray-injection patching, which is available from several manufacturers in a variety of trailer and truck-mounted units. While the machines have their differences, they operate on variations of the same theme: the equipment cleans the pavement to be repaired, applies an emulsion tack coat, and stone is fed into the hopper from an aggregate holder. The stone is coated with a proprietary emulsion, and the coated stone is sprayed into a pothole or onto a repair with a high degree of force. This high air velocity provides compaction and density.
"This is not necessarily the ultimate or optimum repair, but it is a very quick and effective pavement repair," says Mark Manning, vice president of Crafco Inc. "Contractors selling this repair have to know exactly what they're repairing and why."
Crafco, for example, manufactures three spray patching units: the Magnum, an auger-fed higher-tech, higher production machine and the smaller air-fed AirStream and AirStream Truck-Mounted units. The towed AirStream can place 4 ½ tons per hour while the truck-mounted unit can place more than 5 tons per hour and the Magnum 7 tons per hour. Manning says the auger-fed Magnum moves roughly 50% more material than the AirStreams, though all models can be used for most types of general spot repairs, including potholes, failed chip seals, skin patches, repair of alligatored areas, sunken areas, and repair of crumbled shoulders.
"To determine whether or not buy a spray patching machine contractors need to take a good look at the type of work they're doing and are likely to do," Manning says. "The profitability of the machine depends on the applications it's going to be used for."
He says contractors also need to determine an hourly rate for running the equipment, and then they need to realistically apply that rate to their expected production.
"A rate per hour, regardless of what it is, only indicates what a piece of equipment will produce for the hour it's working, but you can't necessarily project that out across a full day," Manning says. "If you're repairing potholes on a roadway, for example, all the potholes are not in one place. So you fill one, then drive down the road to the next, and you might only have one pothole every mile or so. And while the unit is moving from pothole to pothole it is essentially not being productive."
But he says the versatility of spray patching machines is what can make them so valuable to contractors and agencies alike.
"This type of repair equipment is ideal for cities and counties and for contractors who do a good amount of work for cities and counties," he says. "It's not a piece of equipment that does only one thing or that can be used on only one type of repair."