Plans to carry out temporary repairs on the A53 flyover at Etruria have been postponed.
The road has been closed since 9 July, after a driver reported what they thought was a pothole.
A specialist was brought in to look at the problem, which was found to affect the area around an expansion joint.
It is an original part of the flyover, built in 1988.
Early indications were that temporary repairs could take place to reopen the road, and further work could then take place overnight during the summer schools holiday to fully resolve the problem.
That first hit a snag last week (17 July), when structural engineers said some of the roadside barriers also needed to be replaced, which would have to be custom made before they could be installed.
But work on the carriageway itself that was due to start has now been halted.
David Stubbs, Engineering Manager at Stoke-on-Trent City Council said: "We were in a position where we were able to undertake an interim repair to the flyover joint.
"The contractor came on to undertake that repair, unfortunately when he removed the joint it exposed a much bigger problem that what we had first seen.
"Looking at the condition of the concrete we were not able to pursue that interim repair, it was far too big a problem.
"We now need to take one step back and do some proper testing and analysis of the concrete to find out why."
David Stubbs on the A53 flyover, which is to remain closed to traffic until problems are resolved
Experts are now being brought in to assess the joint, along with a second one on the other half of the bridge.
A contractor will then be appointed to carry out necessary work to repair it.
The road is expected to remain closed for several weeks while the issue is addressed, and cannot reopen until all work is completed.