ADOT testing concrete pavement treatment along Loop 202

PHOENIX – Arizona Department of Transportation engineers are exploring another option for smoothing out the ride along Phoenix-area freeways where the asphalt pavement showed its age and was wearing down, especially after last winter’s heavier wet weather.

It’s called diamond grinding – where a specialized grinding machine uses diamond-tipped saw blades to both smooth and add small grooves in a freeway’s concrete-base pavement. Concrete industry contractors developed diamond grinding to improve ride quality, limit noise and provide increased surface friction to enhance stopping on the pavement.

The Arizona Department of Transportation will evaluate a section of eastbound Loop 202 (Santan Freeway) in Chandler where diamond grinding was done as part of a recent pavement repair and preservation project.

The diamond grind test section is along the eastbound Loop 202’s right two lanes near Dobson Road. Crews last month removed a 1-inch layer of rubberized asphalt that was worn out by time, traffic and Mother Nature.

“This is another tool in our pavement-improvement tool box,” said Randy Everett, senior administrator of ADOT’s Central Construction and Maintenance District serving the Phoenix area. “This is an opportunity to explore options and see how the diamond grind performs in an area where the rubberized asphalt finally wore down well after its expected lifespan of 10 years.”

Much of the Santan Freeway’s rubberized asphalt surface between the US 60 interchange in Mesa and Loop 101 in Chandler also was given an asphalt-based sealant treatment recently. That fog seal treatment, which has been used on several other Valley freeways, is designed to extend the life of the existing asphalt pavement.

ADOT maintenance crews used weekend closures along the Santan Freeway last month to fix potholes or make repairs to other sections of worn pavement.