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Road Management & Engineering Journal
Copyright © 1997 by TranSafety, Inc.
April 1, 1997
TranSafety, Inc.
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Sealing Cracks Extends Life of Asphalt Pavement
Pothole Was Repaired after Louisiana Parish Notified of Hazard; Parish Not Liable Without Knowledge of Recurrence
Article Outlines Six Steps to Patching Potholes


















Automated Pothole Patching--Better Patches for Less Money

How can a highway maintenance crew of one person make pothole repairs that last an average of 43 months--even when the work must be done in temperatures of -25 degrees Fahrenheit? Dickinson County, Michigan is doing just that with a self-propelled, spray-injected pothole patcher.

In an article called "Dickinson County Automates Pothole Repair," the January 1995 issue of Better Roads described the County's experience with their self-propelled pothole patcher. The new equipment is repairing potholes more effectively than traditional methods, saving the County money, freeing people to attend to other jobs, and improving safety for maintenance crews.

THE EQUIPMENT

The one-person pothole-patching operation is made possible by the self-propelled unit shown in the photograph below. A fully equipped patcher like this one cost the Dickinson County Road Commission just over $100,000 almost two years ago, and Superintendent Tim Hammill thinks it was a good buy. Hammill observed, "I never thought I could propose spending over $100,000 on a pothole patcher, but these days we have to look at equipment that will be cost-effective in the long run."

Hammill first saw the patcher at a convention, and he learned more about it when he talked with maintenance officials in Anchorage, Alaska, where three of the machines were already in use. He told the Reporter that recently when agencies in Minnesota were interested in the pothole patcher, representatives came to Dickinson County for a demonstration. They happened to show up when temperatures were -30 degrees F. They were concerned they would not see the machine at work because of the cold, but they were able to watch as pothole repair continued--at 30 below. The Minnesotans were so impressed they ordered three machines--that day.

Rosco Manufacturing Company of Madison, South Dakota makes the pothole patcher used in Dickinson County. Rosco estimates 200 to 250 units similar to Dickinson County's are operating across the United States. A representative from Rosco told the Reporter that more than 3,000 automated pothole-patching units from various manufacturers are now in service. This includes trailer-mounted units and units that mount on dump trucks as well as the self-propelled equipment. Operating trailer- mounted and truck-mounted patchers requires a crew of two or three people.

FOUR-STEP REPAIR PROCESS

With a self-propelled patcher, one person controls the entire pothole repair process from the cab of the truck. Dickinson County's Michael Timbrook operates their pothole patcher. After training and a week or so of practice, he perfected his skills. Timbrook said the biggest challenge was that "you are filling a hole that is 20 feet (6 m) away from where you are sitting, but once you get it figured out it does an amazing job."

Better Roads described the four-step process:

  1. The hole is cleaned. A high volume blower provides a blast of air to remove loose rock and debris.
  2. A tack coat of hot emulsion is applied to the area to be patched.
  3. Aggregate and hot emulsion are combined with forced air and shot into the hole.
  4. A dust coat of aggregate is applied. Traffic can flow immediately.
LONG-LASTING REPAIRS

Miller-Bradford & Risberg in Negaunee, Michigan is a distributor of the pothole patcher. According to their branch manager, Tom Martin, follow-up studies show that repairs made with automated patchers are lasting two and three times longer than repairs made by traditional methods. The automated pothole patcher boasts repairs that are staying in place for an average of 43 months.

Furthermore, the machine's ability to fill potholes in cold temperatures means crews do not have to wait for warmer weather to make repairs. Previously, weather delays allowed potholes to degenerate and made the crews' work more difficult. When they could do winter repairs, crews generally had to use cold-mix materials. The automated pothole patcher holds emulsion and chips in separate containers and heats both before blowing material into the cleaned hole. A hot water regenerative heating system heats the emulsion, and the engine exhaust system heats the chips.

IMPROVED SAFETY

Pothole repair endangers maintenance crews, who frequently have to stand in the path of traffic behind a dump truck. Hammill explained that one of Dickinson County's reasons for purchasing the new equipment was the safety of its workers. He said, "We've had too many close calls with the traditional patching crews. When the guys on the crew have to dive for cover to avoid inattentive motorists, it's time to do something different."

Now when Michael Timbrook repairs potholes, he never leaves the cab of the truck. To alert traffic, he activates a four-foot-by-eight-foot, flashing-arrow panel from the cab. On four-lane roadways, where traffic can easily move around the equipment, the County operates the patcher by itself. On two-lane highways, flaggers accompany the patcher to direct traffic.

Reporter staff asked about using crash attenuators on the back of pothole patchers. Although Dickinson County's patcher does not have a crash attenuator, Hammill agreed an attenuator would be a good idea. Rosco Manufacturing's representative said some agencies are considering specifying that the patchers they order be equipped with crash attenuators.

Crew safety also improves with the pothole patcher because fewer workers are put at risk. Hammill used to need six to eight people to do pothole repair, and most of them were exposed to the dangers of working near moving traffic. Now, in most cases, only one person goes out, and that person is inside the cab of the truck. Of course, an additional benefit is that Hammill's people can do other jobs while one person repairs potholes.

Reporter staff asked about the safety of pedestrians, crew members, and vehicles in the vicinity of the patcher, especially during the hole-cleaning phase when debris is blown away. Hammill indicated he felt the patcher could be used even in urban areas when pedestrians were present. He said the machine threw debris only four or five feet. The Rosco representative elaborated by saying that debris cleared out of the pothole moves at a very low speed. He added that people could put their hands under the blower without being injured.

WIN-WIN SITUATION

Potholes can cause damage to vehicles or even result in a motorist's losing control of a vehicle and crashing. At the least, potholes are distracting and irritating to motorists. Road maintenance crews are in danger when repairing potholes on busy roadways. The automated pothole patcher allows fewer workers to make longer-lasting, more immediate pothole repairs in the coldest weather. Highway maintenance departments save money and safety improves--a beneficial situation for everyone.

Copyright © 1997 by TranSafety, Inc.


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