Eurovia will be rebuilding sections of A17 Newark and A15 Bourne legs of Holdingham Roundabout over four Saturdays in July and August.
Cllr Richard Davies, executive member for highways, said: "Our improvements to Holdingham Roundabout are progressing really well and as planned.
"We're now at the stage where we'll be upgrading all of the roundabout's legs so we can fit new approach lanes.
"In order to carry these works out over the next few months, we'll be closing sections of the A17 and A15 where they exit the roundabout so the team can safely rebuild them."
Below is a list of upcoming Saturday roundabout leg closures:
- A17 Newark – westbound towards Newark
- Saturday 3 July and Saturday 17 July
- 7am to 6pm
- Diversion route via A15 South, A153 West, A607 North
- A15 Bourne – southbound towards Bourne
- Saturday 7 August and Saturday 14 August
- 7am to 6pm
- Diversion route via A17 West, A607 South, A153 East
Cllr Davies added: "Once these works are finished, we don't expect to have any more closures on until September, when we lay the final road surfacing for the roundabout and all its approaches.
"Dates for this are still being confirmed, but we'll share the details as soon as we can.
"There is still a lot of work left to complete, but we're still on track for having the project finished in December."
For more information about this and other major highways projects, visit www.lincolnshire.gov.uk/majorprojects.