A January 14 winter roadwork article in The Detroit News quoted Beton’s Kevin MacDonald. 
Evidently, counties and the Department of Transportation in Michigan are pushing roadwork into colder months, which is requiring extra protective measures to ensure the concrete doesn’t freeze.
MacDonald said that for every dollar spent on a road project in July, the cost jumps to $1.30 to $1.50 in the winter.
“Modern highway construction in cold, wet climates requires highly durable, as well as high-strength concrete,” he said. “”This can be achieved in cold weather, so long as precautions are taken to ensure that the concrete has adequate strength.”
Beton Consulting Engineers writes cold weather concrete specifications for large-scale winter roadwork projects.
The lengthy article describes cold weather concreting techniques using heaters and blankets, and the risks of placing concrete on a frozen base.