Nearly 100 building and paving projects in Northern Virginia were disrupted yesterday when the Teamsters union went on strike against Virginia Concrete Co., the region's largest concrete supplier.

Most of the 250 Teamster drivers, mechanics and maintenance workers walked picket lines at the firm's Springfield headquarters and 11 concrete plants.

Management employes were able to make only a small number of the deliveries expected at construction sites throughout the booming Northern Virginia suburbs.

The strike, which started at 12:01 a.m. when the union contract expired, could be long, company and union officials said, and, as of last night, no talks had been scheduled to resolve it.

"It is going to have a heck of an impact. A lot of people won't be able to get concrete until this is over," said Chuck Shepherdson Jr., the company's executive vicepresident.

The dispute revolves around wages, pension benefits, and a union demand for a limit on the use of outside subcontractors to do jobs formerly performed by union members, according to Phillip Feaster, president of Teamsters Local 639.

Tony Ahuja, technical services director of the Northern Virginia Builders Association, said that construction projects in Fairfax and Loudoun counties, as well as other Virginia areas, would be affected. He said scores of firms would have an "extremely difficult time" finding alternative supplies because the building boom has already stretched concrete suppliers to their limit.

"This is going to cost a lot of people a lot of money if the strike lasts" because builders have hired crews and ordered materials depending on concrete deliveries, Ahuja said.

Most of the jobs canceled yesterday were residential and commercial construction, road-paving, and parking lot construction. "We've already canceled seven jobs . . . and sent some of our people home," said a spokesman for Baird Concrete, one of Virginia Concrete's customers.

Feaster said that Virginia Concrete has enjoyed "fantastic" profits and could easily afford substantial increases in its current $10.50 top hourly wage.

He said the company's parent firm, Florida Rock Industries Inc., of Jacksonville, has been expanding and has recently granted 50 percent wage increases to some key executives.

"We are demanding a reasonable contract and we believe they can afford it," Feaster said.

Shepherdson said the company's drivers are already the highest paid in the region's concrete industry and said the firm would lose its competitive edge if it were forced to pay substantially more. He characterized the Teamsters' wage demands as "absurd," but neither side would disclose its specific offers.

On the picket lines, Teamster drivers said that wages and job security were their major concerns. "We don't have a guarantee of a job tomorrow," said Willard Killion, a 48-year-old welder from Alexandria. "The money is fine, but I want to make sure I have this job tomorrow."

Killion and others said that the firm is using more nonunion subcontractors for the many construction and maintenance tasks needed to build and run concrete plants.

Joseph Woodward, who said he earns about $18,000 a year, said he has lost substantial income because the firm uses lower-paid subcontractors instead of employes to work Sundays, which pays double.

Shepherdson said the firm needs the flexibility to hire outside contractors for special tasks such as new construction, but he said the subcontractors have not been used to replace the firm's own workers.

Office Cooley, 47, a truck driver from Camp Springs who earns $7.35 hourly after one year, said he lost his last driving job because of a two-year strike in Maryland, but said he is willing to strike again "because that's the only way we are going to get anything decent."

Cooley said that at the company's current 60-cent per hour pension contribution, he expects a monthly pension of about $450 per month. "I feel we ought to have more," he said.