The A1 southbound between Harlaxton and Little Ponton will close overnight for the next month.
The closures will be in place at night time from 8pm to 6am on weekdays only, starting on Tuesday, April 6 and lasting five weeks.
The diversion route will be via the B1174 through Grantham, rejoining the A1 at Little Ponton.
More work will be needed on the road before the new Grantham Southern Relief Road junction fully opens later this year, with additional closures penned in for June.
During the current batch of works, drainage and ducting installation will take place, as well as the construction of a new surface water channel and the fitting of more street lighting and signage.
Progress on the full Grantham Southern Relief Road project is going to plan, and is still expected to be fully complete by 2023.