John Thomas Maloney, 81, a mechanical engineer who was president of a company that made the concrete used in the building of the Metro system and other projects in the Washington area, died of kidney failure April 19 at Suburban Hospital. He lived in Bethesda.

Mr. Maloney was a native Washingtonian who headed Maloney Concrete Co. for more than 20 years before it was sold to Genstar Stone Products Co. in 1989.

Maloney Concrete, which was founded by Mr. Maloney's father, Charles, in 1929, grew into a well-known entity in the region. The company's fleet of concrete trucks, including one painted to look like a football in the burgundy and gold colors of the Washington Redskins, rumbled down streets delivering water-sand-cement mixture produced at its three plants in Washington and others in Bethesda and Rockville.

The concrete was used to form the Metro subway tunnels, government buildings, commercial properties, sidewalks and highways at a time of rapidly expanding real estate development.

In some ways, Mr. Maloney appeared to be a victim of his own success. In the 1980s, he engaged in an ongoing debate with developers and owners of tony retail shops over whether his downtown Bethesda plant, a squat and dusty facility, should be moved. For years, he successfully resisted their efforts as upscale restaurants sprouted up near the plant. A Mexican restaurant now occupies the plant's old site.

Mr. Maloney was a graduate of St. John's College High School and Catholic University, where he received a degree in mechanical engineering.

During World War II, he served in the Army Air Forces as a fighter pilot in England. He received a Distinguished Flying Cross for his missions in a P-51 Mustang over Germany and France.

He was on the board of directors of Royco, a family owned real estate business in Silver Spring, an usher at Little Flower Catholic Church in Bethesda and a member of Columbia Country Club, the National Redimix Association and the Rotary International Club.

Survivors include his wife of 54 years, Thelma Iager Maloney of Bethesda; two children, Kristin I. Nesline of Towson, Md., and John Thomas "Tom" Maloney Jr. of Honolulu; two sisters, Ann Murray of Chevy Chase and Gertrude Viner of Silver Spring; and four grandchildren.