MARVIN JOLES
IN THE MIX
Compaction Matters:
3 Keys to Better Asphalt Patches
MARVIN JOLES
T or asphalt maintenance contractors, patching is one of those services that can look simple from the outside. Remove the failed material, put hot mix back in, compact it, and move on. However, anyone who has done enough patching knows there is a big difference between a patch that looks good when you leave the job and one that still looks good years later. Whether you are performing a traditional remove-and-replace hot-mix patch or using an infrared heater to repair existing asphalt, compaction is one of the biggest factors determining the life of that repair. With 22 + years of asphalt maintenance experience with Wis-Coat, I can honestly tell you, I have had both versions. Education was the main thing that helped our patches get better. Most maintenance contractors aren’ t showing up with a fullsize paving train. We are working with plate compactors or compact ride-on rollers. That makes getting the fundamentals right even more important. Here are three things to consider when trying to get the best possible compaction from your asphalt repairs as an asphalt maintenance contractor.
1. Temperature Is Your Working Window
Hot mix doesn’ t wait for you. As asphalt cools, it becomes increasingly difficult to achieve proper density. That means your compaction process needs to be planned before the mix hits the patch, not figured out as you go. Have your plate compactor or roller ready, fueled and positioned before placing the material. Once the mix is down, get it leveled and begin compaction while it is still workable. The same principle applies to infrared repairs. After heating and scarifying the existing pavement, don’ t waste the temperature you just worked to create. Add rejuvenator or supplemental mix as required, properly blend and grade the repair, and get to compaction. Weather matters too. Cold pavement, wind and lower ambient temperatures can shorten your available compaction window considerably. So, plan on a warmer day, if you can. We use a dump trailer at Wis-Coat and keep the mix double tarped once it is in the trailer. We haven’ t insulated ours yet with foam and wood, but if we were going a long distance or needed it to stay hot longer we would have to. The hotter and more workable the material is when compaction begins, the better opportunity you have to achieve density.
2. Control Your Lift Thickness
One of the easiest mistakes to make is trying to compact too much asphalt at once. A plate compactor or small roller only delivers so much compactive effort. If you place a deep patch in one thick lift, the surface may look tight while material deeper in the repair remains inadequately compacted. For deeper repairs, build the patch in manageable lifts and compact each lift before adding the next. Your lift thickness should make sense for the mix being used and the compaction equipment available. The goal isn’ t simply get-
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