Each year, Mother Nature leaves her stamp on state highways, city and county roads, and even parking lots in the form of potholes. Born from both harsh, cold winter and dry, hot summer weather, potholes show up many times throughout the year and in all regions and climates – no area is immune.
Furthermore, there’s no way to stop them. Regardless of a road’s design and build quality, virtually all asphalt pavement will eventually crack, either from extreme cold, or dry, hot weather. And that crack, combined with heavy traffic, will eventually turn into a full-blown pothole. But those seemingly small holes pack a lot of punch. Potholes potentially cause major damage to vehicles, and since prevention is an impossibility, management becomes key. Cities, counties and states are faced with developing plans to manage pothole repair.
There are numerous methods to repair potholes, from the most basic “fill-and-go” techniques to most complex, where a large area of pavement is removed and replaced. While each offers the same general end-result, the processes, labor requirements, equipment used and final product quality are quite different – and one method has proven itself to be the leader in several areas.
Introduced in the early 1980s, spray injection patching has emerged as the choice method in terms of efficiency, quality and cost-effectiveness. The technique offers several benefits and a considerable potential for return on investment (ROI). Because pothole repair is an ongoing process, and one that has to be dealt with in every city, it only makes sense to consider the method that will offer the greatest productivity, durability and potential for ROI.
Spray Injection Patching
The National Research Council’s Strategic Highway Research Program (SHRP) Report deems spray injection patching as “the most economical and longest lasting method of pothole repair.” It’s also the safest method, as the entire process is done from inside the machine’s cab. The operator doesn’t have to exit the machine and enter a busy roadway to repair a pothole. This is also a major benefit in cold weather operation. Pothole repair, spray patching included, can be done year-round, in a variety of ambient temperatures. Bitter wind chills and freezing temperatures don’t exactly build excitement in crews assigned to head outside and manually fix potholes. Finally, spray patching machines, despite their great size and perceived complexity, are actually very-user friendly. Most untrained workers can learn the process quickly and become proficient at pothole repair.
Spray patching is done via a low-pressure system, which delivers the necessary air, aggregate and emulsion at a rate of just three to four PSI. It includes four basic steps. First, all water, dirt and any debris are removed from the pothole. Next, the hole is sealed with a coat of liquid asphalt to help ensure a strong bond between the aggregate mix and existing asphalt. The hole is then filled with the mix, typically consisting of hot asphalt or liquid-covered rock, which bonds to the existing pavement. Finally, the patch is sealed with a dry coat of aggregate to enhance durability and longevity.
The technology has been around for decades and spray injection is a widely accepted form of pothole repair. In fact, several cities and state agencies across the country have adopted the method. The City of Houston and Tulsa County public works departments are just two examples of southern-area entities, while up in the northeast, both the Pennsylvania DOT and Tri-Borough Bridge Authority in New York have adopted the method as well.
When evaluating the ROI impact of purchasing a spray-patching unit, several questions must be considered. First, what are the major benefits? What’s the overall cost and production compared to the way the process is currently being handled? How will this change the way the current workforce is being utilized? And finally, perhaps most importantly, how do all these benefits translate to ROI?