Work crews trying to fix a botched paving job on the Chesapeake Bay Bridge have won a race against the cold weather, and weeks of unanticipated delays for motorists will soon end, Maryland officials said yesterday.

The last of the concrete was poured at 7:30 p.m. Wednesday, allowing transportation officials to open the middle westbound lane during daytime hours. The left lane is scheduled to open a week from today after the concrete cures, road barriers are removed and the lanes are restriped. Both lanes will remain closed from 10 p.m. to 5 a.m. to complete that work.

Officials said the bridge's five lanes (two eastbound and three westbound) will be open through the New Year's holiday period, when scheduled work that is part of a four-year, $60 million refurbishing project will continue.

But more inconvenience and delay loom for travelers because of the faulty paving, as parts of the middle and right lanes will need to be redone, said Maryland Transportation Secretary Robert L. Flanagan.

"It has been painful for our customers, and it will continue to be painful," Flanagan said. He said the extent of the additional work will be determined in the next several weeks.

The multiple-lane closures, in effect for about three weeks, caused miles-long traffic tie-ups in both directions, and drivers complained that there wasn't enough roadside information about what was going on.

The roadway problems stem from the use of a type of concrete, called microsilica, that is easier to pour during cold weather. Officials used it so they wouldn't have to shut down a bridge lane during the heavy summer travel season. But the concrete had to be removed after severe cracking was discovered, and it was replaced by a more standard latex-modified concrete.

Flanagan said an independent team hired to look into why the original concrete didn't work has not reached any conclusions about whether the fault lay with the state, the contractor or engineers. He also reiterated that the cost of fixing the problem would run well over the original $7 million estimate.

Workers had been racing against the weather to lay a new roadbed on the left lane because the concrete could not be poured in temperatures below 45 degrees, in winds above 15 mph or in rain.

Officials had hoped to be able to do all of the work at night, but a run of bad weather prevented workers from making much progress. So they chose to close two lanes during all hours except the morning rush and added extra work crews to try to finish the job before the heavy Thanksgiving travel weekend and the onset of winter cold. If they hadn't finished the job, the left lane would have been closed until spring.