Why is a 10-mile stretch of California's Interstate 10 so special to many contractors and engineers in the concrete pavement industry? Constructed in 1946, this extraordinary section of I-10 is the oldest existing concrete pavement rehabilitation project in the United States. Stretching from Colton through Fontana, the pavement also is the first to be rehabilitated by diamond grinding.

The road has been restored three times, and after 53 years, is still going strong. Diamond grinding played a major role in all three rehabilitations and, some say, in the longevity of the pavement. Since the first rehab project in 1965 to the most recent in '97, diamond grinding technology has changed dramatically. In 1965, small 2-foot-wide grinding machines sporting 120-hp Ford industrial engines tackled 112,000 square yards of I-10, taking 8 months to complete the job. In 1983, with the project expanded to cover 198,900 square yards, crews used three 400-hp grinders to cut 37-inch-wide paths. In 1997, an even larger 300,000-square-yard rehab was completed in 50 days, with crews using two grinders with 4-foot-wide heads.

Caltrans' Pavement Management System played a large role in the longevity of I-10 and many other California roadways. "We evaluate the pavement every 2 years using this system," explains Ben Ramirez, Caltrans' district division chief for maintenance. "It prioritizes our needs, and when a pavement meets certain criteria for deterioration, one of which is a rideability score, we go in and grind it."