The retired president of a Northern Virginia paving company was fined $25,000 by a federal judge yesterday on a conspiracy charge stemming from a wide-ranging investigation into bid rigging among highway contractors in Virginia and other states.

Jack A. Mansergh, the former head of General Paving Corp. of Manassas, was also sentenced to a suspended two-year prison term and two years' probation and ordered to perform 500 hours of community service. The sentence was imposed by District Court Judge Richard L. Williams in Alexandria.

Mansergh, of Hartly, Del., pleaded guilty last month to a single count in an indictment alleging that officers of several paving companies have submitted "collusive, noncompetitive and rigged bids" to the Virginia Department of Highways and Transportation since 1977. General Paving has been fined $250,000 under a plea agreement with the Justice Department.

Mansergh is among six officers and five paving firms that have pleaded guilty to bid-rigging charges in Northern Virginia in the 11-month investigation of highway contracting in the state. The federal corruption probe extends to at least 16 other states.

Mansergh also faces prosecution on a separate conspiracy charge accusing him of bid rigging in connection with a $1.3 million paving contract for work in 1978 on Interstate Rte. 66 in Fauquier and Prince William counties.

Mansergh offered to plead guilty to the charge yesterday. But Judge Williams refused to accept his plea, citing discrepancies between federal allegations and Mansergh's account of the incidents. It was unclear when a trial date might be set on this charge.

In imposing the sentence yesterday, Williams rejected requests from prosecutors that Mansergh be imprisoned as well as appeals from Mansergh's lawyers that he be sentenced only to performing community service. Mansergh had faced a possible maximum sentence of three years' imprisonment and a $100,000 fine on the charge.