A mile-long construction maintenance project on Interstate 985 set to begin Tuesday must be done at daytime because the concrete can’t be poured when the temperature is too cold.

The northbound right lane of a portion of the interstate in Gwinnett County, about one mile from
Interstate 85, will be closed from 8 a.m. to 4 p.m. Tuesday and Wednesday.

Because of damaged concrete slabs, state Department of Transportation crews will be pouring concrete, which has to be done during the day, DOT spokeswoman Teri Pope said.

“It’s not just the temperature, it’s also the time because as concrete gets harder it strengthens as it cures slowly,” she said.

One slab is about 20 feet long, 12 feet wide and usually about 12 to 8 inches thick, Pope said.

Crews had been keeping an eye on the sections of the interstate for several months and DOT officials expected to hold off on the project until the spring, Pope said.

But the slabs degraded faster than expected and required maintenance.

“It’s been degrading rapidly over the last month, so before winter hits we need to replace these three slabs,” she said.

Another issue working against crews is the location of the
slabs, which are in a shaded area, causing temperatures to be even lower.

“There’s really a lot working against this particular slab area trying to get concrete removed and then re-poured, so that it can dry fast enough and strong enough,” Pope said.

Although not applicable to this particular project, road projects done at night typically cost more, Pope said.

Because crews must use extra traffic controls, set up lights and various other factors, nighttime work brings added costs.

“Anything at night costs more than during the daytime, during the normal business hours, because you’re paying a premium for the labor,” Pope said.