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caption: SR 544 buckles near Everson, Wash. amid an intense heat wave June 26-28, 2021. 
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SR 544 buckles near Everson, Wash. amid an intense heat wave June 26-28, 2021.
Credit: WSDOT

There's no concrete solution for roads buckling in the heat ... it's actually asphalt

The recent heatwave has meant trouble for Washington's roads. Stretches of I-5 have actually buckled, a stunning sight in the Pacific Northwest.

The simple explanation is that concrete expands with heat. The record-breaking high temps pushed cracks through the roadway. But as odd as this may sound, these incidents actually came at the best time.

Of course, there's never really a good time to interrupt the flow of highway traffic.

Still, Tony Black with the Washington state Department of Transportation says parts of I-5 buckled when it was most convenient for repair crews.

"I mean, this is construction season for us, so we had a bunch of crews that were out there," he explains. "So, it was almost like a perfect storm. If it was going to happen, this would be the time for it to happen, when we have tons of people that we can get out there and address them as quickly as possible."

And there's another reason crews were able to work as quickly as they did to repair the cracks: the difference between concrete and asphalt.

"We're usually filling [cracks] with asphalt, which is a lot quicker to dry, cure, cars can start driving over it immediately," he says.

That was the case as four large cracks appeared along I-5 in Seattle Monday, all at about the same time — two southbound and two northbound. The cracks struck as evening commuters hit the road en masse.

Yet crews were able to fill those cracks relatively quickly, Black says, and without diverting traffic. Drivers were slowed, but still flowed around the roadwork.

If they just used more concrete, as they have with projects like Revive I-5, Black says WSDOT would have had to close stretches of the highway.

"That's because we're laying down this concrete that needs at least 50 hours to cure before cars can start rolling over it," he explains.

Whatever you're rolling along on, Black is reminding drivers to look out for any additional crews as hot temps continue. Slow down and give them plenty of space to make sure everyone gets home safely.