Heat causes road "blow-ups"

MoDOT crews fill in a "blow-up" on Highway 63.

Crews with the Missouri Department of Transportation worked on a section of southbound Highway 63 in Callaway County Monday to fix a "blow-up" caused by the heat.

Blow-ups happen when the concrete underneath the pavement heats up. As pressure builds along road joints, the asphalt buckles, causing a ripple in the roadway.

"Traffic drives over that and sometimes when it pushes up...with traffic hitting that it'll blow that asphalt out and cause a pretty good pot hole," MoDOT Maintenance Supervisor Jim Williams said.

Williams and his crew Monday provided a temporary fix to the blow-up. The procedure is similar to filling a pot hole.

"We come in here, we hammer the joint out, relieve that pressure, and then we put this temporary patching material in there just to let traffic get over it for now," Williams said.

"And then we're going to come back in and we'll do a more permanent repair with concrete."

That permanent repair involves actually sawing out the joints in the road to pull up the bad concrete and replace it with new concrete.

While blow-ups do not usually cause too much of a threat to drivers, it is important to report a blow-up or visible ripple in the roadway to MoDOT as soon as possible.

"The more the traffic drives over it, the more of a chance of the asphalt popping out and creating a pot hole. You know, it's just not real comfortable for drivers to go across," Williams said.

Williams said you cannot predict when or where a blow-up may happen, so MoDOT workers are constantly on the lookout.