"What we suspect ... is that it's the extreme weather conditions that we had the past two weeks ... caused the concrete to literally explode and crumble," said Transports Quebec spokeswoman Sarah Bensadoun.
Transports Quebec reports the overpass was last inspected and secured less than two months ago, on Nov. 27. Bensadoun said the weather fluctuations are the most likely explanation for the overpasses's rapid degradation.
Traffic is flowing again on Highway 40 this morning after officials closed it overnight to inspect the overpass and remove 4.8 square metres of superficial concrete.
Transport Quebec is reminding the public that removed concrete was purely aesthetic, meant to hide the structure's inside.
"Be assured that if it was dangerous, the traffic would be not allowed," Bensadoun said.
She said she expects there will be another closure of Highway 40 tonight, so that inspectors can complete their work on the overpass.