As the end of the season nears in cold climates, a lot of pavement gets put down in temperatures colder than 40 degrees. There is sometimes a slight frozen crust on the ground. It's not desirable, can can be done with satisfactory results. Results get poorer the colder the temperature and thinner the mat.
A long time ago I was working at a Nuclear Power Station in Illinois. We had a lunatic Navy Admiral running the show. In December the Board of Directors were coming for show and tell. So Lunatic Admiral ordered that asphalt be put down over the gravel roads so they could be pretty. There was a protest that asphalt couldn't be put down in the cold and besides, the asphalt plants close for the winter. He ordered that the plants be opened (they were happy to do that) and the asphalt installed.
It lasted through the meeting and that's about it. Big waste of money.
Each state DOT has its own standards, but what I'm familiar with here on most of the east coast is 40 degrees and rising. Private work specifications usually reference DOT specs, but sometimes weather forces you to do things in a less than ideal manner. How well it holds up depends on the roadbed soils and base material. I've put binder course asphalt on frozen ground and had it hold up perfectly. I've also had it come apart during the spring thaw.
I had the opportunity to see a shoulder paved for the Interstate in Wisconsin in 30 degrees below zero. This was done so the road cold be opened on schedule Date about 1961.
the snow was plowed off and the asphalt put down, at the usual temp.
That pavement held up fine through many years.
The main trouble I have seen with asphalt paving is getting on it with rollers too late in cool weather. Of course too early is not good either.
Up in Wyoming, back when I was working in the field, the spec was ambient temp of 35F and rising before October 15. After October 15, ambient temp had to be 40F and rising.
The soil or base temperature is more important than the air temperature, that is really short term. - Specs and standards do not always reflect this, but an engineer can over-ride if the has the information and data to back him up.
It is always is easier to blame God and Mother Nature for a late completion.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
