Repairs are underway on concrete roads that are heaving and buckling under the pressure of summer heat in Hays and Ellis County.

So far three roads have showed up with damage, and there’s no telling whether there will be more.

“The heaving is completely unpredictable and random,” said Hays Public Works Director Jesse Rohr. “You usually don’t have a tell-tale sign. Some years it happens and some years it doesn’t.”

Ellis County Public Works Director Bill Ring got a call at 5:15 p.m. Wednesday that there was buckling on Old US-40 highway between Vincent Avenue and Interstate 70.

“This is a July-August event,” said Ring. “There’s a saying around here that the hottest week of the summer in Ellis County is fair week, and just look at the temperatures we’ve had this week.”

The nearly 5-mile section of road between Walker and Victoria where the buckling occurred is the only part of Old 40 that’s still concrete pavement.

“We have one spot break every year,” Ring said. “It’s one of the few concrete paved roads the county has.”

Called thermal expansion, sections of concrete pavement expand as they heat up under the summer sun during the day, Rohr explained.

“There are joints put in when the concrete is placed to allow for expansion and contraction,” Rohr said. “When it expands beyond what the joints can handle, it heaves.”

The joints are just space between the concrete panels, and it can vary by application from a quarter-inch to three-quarters of an inch, and usually spaced anywhere from 6 feet to 12 feet apart, Rohr said.

“This heaving happens when the temperatures rise,” he said. With temperatures this week in the upper 90s and over 100, the temperature of the pavement itself has been anywhere from 120 to 130 degrees, Rohr said.

It’s a phenomenon familiar to public works directors nationwide, said Ring, a product of heat and excess moisture. With all the rain Ellis County and the surrounding areas have had the past few months, there remains a lot of water below the surface of the roadway in the dirt, he said.

“The moisture is trapped down there, and it gets hotter and hotter,” said Ring. “It’s like a tea kettle, with the steam that starts to smoke and hiss. You can’t compress water, as water expands, so something is going to move. It will just push up, which causes the concrete to heave, and then the concrete starts to break and flake.”

Ellis County shop crews on Wednesday evening brought out patching asphalt for the Old 40 break, as well as a skid steer and barricades, and the road was patched by 7 p.m. and reopened to traffic.

“This is the fourth year in a row we’ve had a piece of road pop up on Old 40 between Walker and Victoria. It just lifts up. And now it’s getting hotter and hotter, it’s supposed to be a heat index of 110 today,” Ring said. “My truck thermometer when I was on the scene there directing traffic showed 104.”

On Commerce Parkway south of 13th Street, city crews on Monday cut out a 24-by-24 section of damaged panels that had heaved and adjacent panels, then re-poured the concrete using a fast-setting concrete. The concrete was poured at 11 a.m. and the road was reopened by 6 p.m., Rohr said.

The work at 22nd and Canterbury will take longer because the area is larger and there was more damage, not only to the street, but also to the curb and gutter, he said.

That repair will start at 7 a.m. Monday, with East 22nd Street closed to through traffic at Canterbury Drive during the work.

This September, when temperatures cool down, county crews will replace the asphalt patch on Old 40 with a concrete one, shutting down the lane, removing the asphalt from the damaged area, forming it up, and pouring the concrete. The work should take a couple of days, Ring said.

“We didn’t want to close Old 40, so we’ll wait 'til the end of the summer when it’s cooled off,” he said. “We’ve got so much other work going on with other projects.”

Meanwhile, there’s no predicting the rest of the summer.

“We could see more today, we might not see any more this week, or any more this year,” Rohr said. “But when it does happen, we’re prepared.”