What's the difference between "cold" and "hot" mixes for filling potholes?
EDINA, Minn. – From slowing and swerving, to slamming into potholes, this winter has dragged on – taking our roads with it.
In Edina, crews are trying to keep up.
"Even though it's steaming right now just because it's warm, because it needs to be a little bit warm," said Chet Boom, Edina Public Works street maintenance worker.
Though it looks hot, the asphalt mixture Boom and crew are using is actually called the "cold mix," or "winter mix."
"Cold mix is an asphalt product that doesn't have the AC in it, it doesn't have the asphalt cement. It doesn't harden," said Edina Street Supervisor Shawn Anderson. "But it sheds water and it's pliable, and it's like asphalt, so it's about our only option this time of year in Minnesota."
Filling potholes with the cold mix is as easy as scooping it up and dropping it down. But this fix sometimes only lasts a few days.
"It's very temporary. It may not stay in there. Fingers crossed we don't plow snow because that usually takes it all out and throws it on the side of the road," Anderson said. "Traffic also pushes this cold mix right out of the holes."
It's merely a road bandage, until the weather warms, and cities can start using the "hot mix." The temperature range to use this mix is generally above freezing, between 40-50 degrees.
So, what's the difference between the hot and cold mixes?
"Hot mix is asphalt with a tar substance in it, and that allows it to hold, stick to the ground, stick to the base of the road, and to be more impervious to water," said St. Paul Public Works Director Sean Kershaw.
Cities can usually start picking up hot mix from the St. Paul plant in March, but this year they'll have to wait until April. Until then, they're relying on getting hot mix from one of the few contract vendors who have opened their plant.
The sooner they get the hot mix, the faster they can catch up, and patch up.
The St. Paul plant provides hot mix to about a hundred municipalities. Crews will be able to use that mix until it gets cold in November.
Most cities encourage drivers to report potholes. You can do that online or through 311.
