The essential repairs will see the A70 closed between Manse Road, Muirkirk and Glenbuck from Monday, July 18.
EAC are forking out £300,000 to resurface a 226m length at Manse Road and 1300m from Darnhunch to Glenbuck.
Around 1800sq metres of 'deep patching' also will be carried out during the work.
The A70 will be closed for two weeks until Sunday, July 31 to allow workmen access to the site.
Drivers are being asked to follow the diversion route which will see east bound traffic being re-routed from the A70 at Muirkirk via the B743, A71 through Strathaven then at Stonehouse turning right onto the B7078 southbound, before rejoining the A70 near Douglas and vice versa.
At the same time a £380,000 project will be undertaken on the A70 from Ochiltree Mains Farm to Grimgrew outside Ochiltree.
A 2.3km length of road will be resurfaced.
Delays are expected in the first week of roadworks when a single file convoy system will lead traffic through the works.
Then from Monday, July 25 to Sunday, July 31 diversions will be in place as the road will be closed to allow the completion of works.
West bound traffic will be diverted at the A76 Dettingen Roundabout travelling north to Templeton Roundabout at Auchinleck before turning right onto B7083, then right onto C62 Pennylands Road, right onto B7036 Barony Road before rejoining the A70 at Ochiltree and vice versa.
EAC have reminded motorists to allow sufficient time when planning journeys.
A spokeswoman added: "Advisory signs will be erected in advance of the works to alert the travelling public.
"East Ayrshire Council apologises for any inconvenience caused during these essential road works."