Sections of Loop 101 in the Tempe, Scottsdale and north Phoenix areas will be restricted at times in the coming months for work to smooth the freeway’s concrete pavement.

Diamond grinding, which involves the use of specialized machines with diamond-tipped blades on rotating drums, is designed to smooth concrete pavement while also creating grooves to limit vehicle tire noise, according to a release from the Arizona Department of Transportation. The process has been used this year to replace older, worn sections of rubberized asphalt along Loop 101 Price Freeway south of US 60 and Loop 202 Santan Freeway east of Interstate 10 in the East Valley.

ADOT is extending the use of diamond grinding on Loop 101 between US 60 and Loop 202 Red Mountain Freeway in Tempe as well as Loop 101 where the freeway is being widened between Interstate 17 and Princess Drive.

Upcoming restrictions for diamond grinding are scheduled as follows:

• Northbound Loop 101 (Price Freeway) narrowed to two lanes between Baseline Road and Rio Salado Drive from 8 p.m. Thursday to 5 a.m. Friday, July 24.
• Northbound Loop 101 (Price Freeway) narrowed to three lanes between Baseline Road and Rio Salado Drive from 9 p.m. Friday to 5 a.m. Monday, July 27. Both US 60 ramps to northbound Loop 101 closed. Northbound Loop 101 off-ramps at Broadway Road and University Drive closed. Detour routes include northbound Dobson Road or McClintock Drive.
• Westbound Loop 101 (Pima Freeway) closed between Tatum Boulevard and Cave Creek Road from 10 p.m. Friday to 5 a.m. Monday. Northbound SR 51 ramp to westbound Loop 101 also closed. Detour routes include westbound Deer Valley Road or Union Hills Drive to Seventh Street to connect with Loop 101.

ADOT is expanding its use of diamond grinding in partnership with the Maricopa Association of Governments, the Phoenix region’s freeway planning agency. As part of this effort, ADOT will research different pavement surfaces, life cycle costs and efforts to limit noise along regional freeways.

Much of the region’s urban freeway system is covered with a 1-inch top layer of noise-reducing rubberized asphalt, with a majority of sections extended beyond their anticipated 10 year service life, the release states. As a result, ADOT and MAG have faced decisions about long-term costs associated with pavement wear over time, including whether to resurface a freeway with rubberized asphalt or use an alternative surface treatment such as diamond grinding.