Dorset Highways will be returning to Goulds Hill, between Martinstown and Upwey, next week.
Two weeks work was completed earlier this month to rebuild and strengthen the edges of the carriageway and resurface a 1800m stretch of road.
Tests of the surface material have shown that it is unlikely to perform as expected and needs to be replaced.
Jack Wiltshire, Dorset Council Head of Highways, said: "Our priority is the safety of road-users and we need to replace this 40mm of surface material. We've identified the earliest opportunity in our programme to carry out the work – which is next week.
"We appreciate that this is terrible timing for residents and commuters, who have been unable to use the road this week because of sewer works by Wessex Water, but we will minimise disruption by overlaying the new material and carrying out the work outside of commuting times."
Goulds Hill will be closed 9am to 5pm on Tuesday 16, Wednesday 17 and Thursday 18 July for a new surface course of material to be laid through the site.
The cost of this remedial work is being met by Dorset Highways partner Hanson UK.
Until this work can be carried out, an advisory 40mph speed limit will be in place.