What Mixture is Used To Help De-Ice Iowa’s Roadways? Is it Different?

For numerous cities in Iowa, it has been safer to stay off the roadways when possible these past week. When you get the amount of snow most of Iowa saw last week and then combine that with negative temperatures, driving can be an absolute nightmare. The snow becomes compacted and then the temperatures, basically, turn the snow to ice.

Plow drivers have been working endlessly to help keep the roadways as safe as possible because we know all too well in Iowa, that the world doesn't just stop because of tough road conditions and freezing temperatures. Some still need to get to work and have places they need to be every day.

Have you ever been driving and noticed a giant plow that has a certain mixture falling behind it to try and help make the roads safer? Most people think this is simply salt and in Iowa, that's sort of true.

Anti-Icing in Iowa

The state of Iowa uses brine to help keep you safe on the roadways. Brine is a combination of salt and water. The Iowa DOT uses precise concentrations in the mix that you see trucks spreading on the roadways. This is different from some of Iowa's neighboring states.

Minnesota uses only salt, Wisconsin uses a cheese brine (of course Wisconsin uses cheese), and certain areas in Illinois, Missouri, and Nebraska use salt and beet juice. North Dakota uses a combination of salt and sand. Why does Iowa use salt and water instead of one of these other methods?

Why Iowa Uses Brine

Tina Greenfield works with the Iowa DOT's Office of Maintenance and she said Iowa doesn't lay down dry material. She told Transportation Matters,

We don’t lay down any completely dry material. We always spray granular salt or sand with brine so that it sticks better. When the material is dry, there is too much waste because dry salt and sand bounce off the road. When vehicle tires come in contact with dry material, it tends to just blow off the road surface instead of bonding to the road reducing ice and frost.

For Iowa's liquid brine, the DOT uses a combination of 2.2 pounds of salt for every one gallon of water. This creates 23.3 percent of the brine concentration. According to Tina Greenfield

Mixing the brine ourselves allows us to take advantage of brine’s tendency to stick to things. This tendency actually reduces the amount of dry salt we use. Dry salt bounces a lot when it lands on the pavement; some studies estimate up to 30 percent soon ends up in the ditch when applying completely dry material. We spray the dry salt or sand with brine as it is dispersed from the truck so it sticks to the road better. Since more material stays put, we can use less and reduce waste.

To fully understand how Iowa's de-icing chemicals work, watch this video from IowaDOT on YouTube.

The Iowa DOT will often plan ahead of time for snow and ice conditions. If you happen to see a plow truck spreading brine on a sunny afternoon day, you may see frost or ice on untreated roads overnight.