SIOUX FALLS, S.D. (KELO) — With temperatures soaring this week, those who take care of our roads and highways say to be on the lookout for concrete blow-ups.

The South Dakota Department of Transportation is currently working on more than a dozen cases of concrete buckling, the vast majority on I-29. Most are not as catastrophic as this one that blocked traffic back in 2019. The blow-ups are ranked and fixed in the order of their severity. Engineer Harry Johnston says with the temperatures headed into the triple digits the conditions are right for the damage caused by expanding concrete.

“So as the concrete grows and it closes up those joints it usually can’t go down because that’s where the gravel is, but it will push up instead.”

Tom Hanson: How much pressure is involved in something like this?

“Oh, I could not give you an exact amount, but the concrete on our interstates is 11 and a half inches thick,” said Johnston.

The pressure needed to crack concrete almost a foot thick can be dangerous. That’s why crews who fix this type of damage use extra caution. The concrete in this region is mixed with quartzite instead of limestone, quartzite is stronger and more durable but it also retains more heat. That’s why we find more blows on the east side of the state. Also, this year I-29 is seeing more blowups than I-90.

“I-29 has more lanes but at the same time is mostly CRC our continuously reinforced concrete and it runs north-south not east-west I don’t know if that makes a difference it is all just whatever that recipe is that heat and that movement that’s where we are going to find a weak spot,” said Johnston.

Johnston says although they have crews patrolling for blow-ups they rely on the public’s help in reporting. The sooner crews can react the lower the chance cars are damaged.