Diamond Grinding Pavement Treatment

The Arizona Department of Transportation is exploring another option for smoothing out the ride along Valley freeways where the rubberized asphalt has aged and is wearing down. Diamond Grinding is a technique for preserving and rehabilitating the concrete pavement surface of a highway. This technique has the potential to reduce costs of rehabilitating our aging infrastructure, while still providing travelers with a smooth, quiet ride.

Closely spaced diamond blades remove about ¼ of an inch of the roadway surface, providing a consistent and smooth texture that resembles corduroy fabric. The small groves run in the same direction as the driving surface.

Why explore diamond grinding?

ADOT has partnered with the Maricopa Association of Governments on an analysis of pavement treatments used to limit noise generated by tires as vehicles travel on freeways throughout the MAG region. Although rubberized asphalt has been successful at reducing freeway noise levels, it wears down over time and must be replaced every 10 to 15 years. Costs associated with replacing rubberized asphalt are projected to increase by nearly 300 percent in the coming years:

• Between 2020 and 2024, rubberized asphalt replacement and pavement maintenance costs for highways in Maricopa County are estimated at nearly $200 million.
• That number is projected to increase between 2025 and 2029, to nearly $800 million.

Diamond grinding could save millions of dollars in pavement-rehabilitation costs and free up funding for future freeway improvements.

Potential Benefits of Diamond Grinding

In addition to saving money, diamond grinding could result in less highway maintenance. For example, rubberized asphalt has a service life of 10 to 15 years. Over time, it wears out because of traffic and the elements. Diamond grinding is a longer-lasting solution.

Drivers on a surface treated with diamond grinding will enjoy a smooth ride, much like a new rubberized asphalt surface. Also, as rubberized asphalt ages and wears down, noise levels associated with highway traffic increase. However, noise levels have not been shown to increase over time on freeways treated with diamond grinding.

Diamond grinding on the Loop 202 (Santan Freeway)

In early 2020, ADOT used diamond grinding to replace older rubberized asphalt overlays in three areas along the Loop 202. In those locations, the rubberized asphalt pavement had been in place well beyond its planned service life, resulting in rough highway surface conditions. Diamond grinding provided a much improved, smooth concrete driving surface on the Loop 202 between Interstate 10 and the Loop 101 (Price Freeway). View photos of this diamond grinding work on ADOT’s Flickr page or watch a video to see how the work was done.

Diamond Grinding on the Loop 101 (Price Freeway)

In May 2020, ADOT announced it will diamond grind 6.4 miles of the Loop 101 Price Freeway - between Baseline Road and the Loop 202 Santan Freeway -  in conjunction with the widening and improvement project in Mesa, Tempe, and Chandler.

Questions or comments?

ADOT welcomes your questions or comments about diamond grinding:

• Telephone: Call the ADOT Bilingual Project Information Line at 855.712.8530
• Online: Visit azdot.gov/Contact, and then select Projects from the “Select An Issue” drop-down menu.
• Mail: ADOT Communications, 1655 W. Jackson Street, MD 126F, Phoenix, AZ 85007