Most of New York City’s largest construction projects ground to a halt or near-halt on Tuesday because of an unanticipated strike by more than 400 cement-truck drivers.

With the bulky, noisy ready-mix concrete trucks largely disappearing from the city’s streets, the walkout affected scores of projects, including the Freedom Tower; the Second Avenue subway; the new Yankee Stadium; Citi Field, the ballpark that will replace Shea Stadium; and many high-rise apartment buildings.

The concrete companies hit by the strike predicted that the walkout would last at least through Monday and perhaps considerably longer, putting thousands of construction workers temporarily out of work.

“The strike was a surprise because it seemed that the negotiations were going well until the 11th hour and then it fell apart,” said John Quadrozzi, president of the Quadrozzi Concrete Corporation, which has 50 trucks and calls itself the city’s largest concrete company. “At a time when the city is complaining about construction being behind at the World Trade Center site and the economy being in a downturn, we feel it’s not the right time for the union to take such a strong position in this type of negotiations.”

Carolyn Daly, a spokeswoman for the striking union, Local 282 of the International Brotherhood of Teamsters, said the main issues were wages and working conditions. She said the union expected the strike to last only a few days, adding, “The posture is positive; it’s not angry.”

Joseph Greco Jr., treasurer of the Association of New York City Ready Mix Concrete Producers, saw the situation in a more negative light. “The union has informed us that they will not be contacting us to have additional negotiations until next week,” he said.

As a result of the drivers’ strike, construction was all but shut down Tuesday on a project to erect a six-story building for New York Law School at West Broadway and Leonard Street. Across the street, concrete work on the fourth floor of a planned nine-story condominium building had also been halted.

Victor Buono, a foreman on the condo project, said it looked as if a lot of workers would be forced to prematurely begin a very long July Fourth weekend.

“A good group of the guys, 30 or 40 of them, aren’t coming in tomorrow,” Mr. Buono said. “We’re just having a skeleton crew.”

The two sides engaged in intense bargaining until 12:30 a.m. Tuesday at Local 282’s headquarters in Lake Success, N.Y., but then the union informed the concrete companies that it was walking out. The contract expired at 12:01 a.m. Tuesday.

“Teamsters Local 282 regrets that it was unable to reach an agreement,” Bruce Levine, the lead lawyer for the union, said in a statement. “Local 282 is particularly disappointed because in the past month, it has succeeded in reaching innovative, far-reaching and fair agreements with hundreds of employers” that handle demolition as well as lumber, steel and other non-concrete building materials.

Construction is continuing at nonunion projects, which are generally smaller than the unionized sites affected by the strike. Work continued at some unionized sites where all the concrete had been poured, allowing laborers to do interior work or work on heating and air-conditioning.

Mr. Greco, who is also the secretary-treasurer of the Greco Brothers Concrete Corporation, said that under the expired contract, drivers earned $33.11 an hour, rising to $59.01 when health insurance, pension contributions and other benefits are included.

He said the union earlier this week demanded raises of $5 an hour in the overall compensation package each year for three years, although the union did not specify how much would go to wages and how much to benefits..

Mr. Greco said that during Monday’s bargaining, Gary La Barbera, Local 282’s president, reduced that demand to $3.50 an hour.

“They didn’t give us a chance to answer the $3.50 package before they walked out,” Mr. Greco said.

That $3.50 would represent a 6 percent increase in the drivers’ $59-an-hour compensation package.

“That is absolutely not a correct number or a correct version of events,” said a member of the union’s bargaining team, who insisted on anonymity because union officials said they would not negotiate in the news media. “And I’m surprised that a member of management’s bargaining team would be saying these things in public.”

Local 282 had long been notorious because the Gambino crime family controlled it for decades. But government officials placed it into trusteeship, and Mr. La Barbera was brought in to help root out corruption. Government officials say the cleanup has been quite successful.

Mr. Quadrozzi voiced keen frustration on Tuesday because his company is the primary concrete supplier to the Freedom Tower and PATH station at the former World Trade Center site.

“We’re shut down,” he said. “We have 50 beautiful trucks just sitting there in our parking lot.”