The Highways Agency has apologised after night work over-ran on the A14 in Cambridgeshire because workers used the wrong type of concrete.
The delays on Wednesday saw some drivers taking an hour to travel the 15 miles between Cambridge and Huntingdon.
The work was to install new traffic lights at the Brampton Hut interchange but the concrete used did not dry in time
The Agency apologised saying the wrong type of concrete had been sent.
More roadworks are planned for the A14 over the weekend as resurfacing work takes place.
A section of the road will be closed during four nights and the Highways Agency is hoping disruption is kept to a minimum.