REGIONAL- Summertime is not the time one would expect St. Louis County to be applying de-icer to many of its roads, but it turns out that liquid calcium chloride is also an effective agent for keeping dry dirt and gravel road in good shape.
County Public Works District Four Superintendent Dale Johnson said that drier than normal weather conditions can take a toll on the roughly 500 miles of dirt and gravel roads in his district.
“When the roads get dry, they get washboarded,” he said. “Trying to go out there when it’s so dry and blading them does not really do any good. It actually will make them worse. If there’s any compaction at all, we would loosen that up and with the dry roads it’ll just get more washboarded and then end up potholes.”
The calcium chloride acts to control dust, bringing more cohesivenss to the particles on the road’s surface, which helps to maintain the roadbed.
“It helps for our maintenance on the gravel roads when we can put the dust control on them because we aren’t having to be out there and grade them as much as normal. Once we get the chloride on there and we can get a bladed with a good crown and pack it good the road will turn real hard in places that it’ll get dark and almost looks blacktop. Where we would be out grading weekly, we sometimes we only have to go out maybe monthly. We aren’t out there as often to blade them so that it helps in our maintenance costs. And in the long run we aren’t having to put as much gravel down. So it’s a good thing as far as the maintenance aspect.”
But don’t expect to see a fleet of county snowplows rolling down gravel roads applying the treatment. The county has an independent contractor who handles that, Johnson said.
“Most of the time the road supervisor goes out with them in their vehicle and works with them on what roads they need to do,” he said.
Because of cost, every gravel road won’t receive the calcium chloride treatment. Johnson said they focus their efforts on the most highly utilized roads.
It’s also getting to be the time of year when heavy nighttime or morning dew, as well as light rain, can provide enough moisture to help out with gravel road conditions, Johnson said.
“When it gets dry you don’t notice it and you think the chloride has gone away,” he said. “When it rains, it kind of rejuvenates it. When you get the heavy dews it helps bring it back up to the top of the road again.”
And with less maintenance to do on gravel roads, county workers have more time to tend to other maintenance issues.
“Mainly we’re patching holes, patching cracks, we’re putting culverts in, we do more grass mowing and brush mowing, also some ditching,” Johnson said.
This spring’s flooding wasn’t as bad as 2022, but it was enough to reveal the need for more culvert replacements.
“We did quite a number of them with the spring runoff and the water issues we had this spring,” Johnson said. “We did a quite a number of culvert changing where it washed a culvert out or alongside of it. Usually the culvert was in bad condition and so we had to replace it anyway.”