Moving Mountains: Blasting complete for the I-17 Improvement Project

PHOENIX – If you’ve recently traveled along Interstate 17 north of the Phoenix metro area, you’ve undoubtedly noticed that the landscape looks a lot different. Entire sections of the mountainsides have been removed through controlled rock blasting, and this major earthwork operation is now complete ahead of the start of the summer travel season. 

This tremendous effort was necessary to make way for the additional lanes from Anthem Way to Sunset Point. That includes 15 miles of widening and 8 miles of flex lanes along the entire 23-mile I-17 Improvement Project corridor. 

Controlled rock blasting began in December 2022 and required full closures of I-17 in both directions to keep everyone safe, including the traveling public. Because I-17 is such a heavily traveled highway, blasting took place at 10 p.m. during the weeknights and involved a very tight schedule. Crews had just one hour to close the highway, carry out the blasting operation, clear the debris, and then reopen the highway. 

The team conducted a total of 62 blasts at seven different locations along the project corridor over the course of a year. That’s far less than the initial estimate of 120 blasts. In many circumstances, crews were instead able to “rip” or excavate rock in certain areas using heavy equipment. Ripping is the preferred method of rock removal because it lessens the impacts on traffic. Areas where the rock material was too hard to be ripped needed to be blasted instead.

Blasting operations were a success not only because the I-17 project team was able to reduce the number of blasts and the associated full closures of I-17, but also because the team was able to complete most blasts in less time than the scheduled hour-long operation. In many cases, traffic was only stopped for about 20 minutes.

Approximately 177,000 cubic yards of rock and material was removed during the blasting process, then hauled to another area of the project to be reincorporated into the new roadway. A large portion of the blasted material is crushed and then used as aggregate base, embankment and rock mulch along the 23 miles of new lanes. The construction team is using everything that is removed by putting it back into the project. This eliminates the need to outsource material and cuts down on construction costs. 

The entire 23-mile stretch between Anthem Way and Sunset Point remains under construction throughout 2024 and into 2025, as the new lanes are constructed and paved and a dozen bridges are either widened or replaced. The 15 miles of new lanes between Anthem Way and Black Canyon City are expected to open by the end of 2024, and the eight miles of flex lanes between Black Canyon City and Sunset Point are expected to open in 2025. 

Once fully complete in 2025, this major design-build project will help alleviate congestion and improve safety and traffic flow along a Key Commerce Corridor that is crucial to the state’s travel, tourism and economic development opportunities. 

As a reminder to all drivers, ADOT lowered the speed limit to 65 mph along the entire 23-mile construction zone between Anthem Way and Sunset Point as a safety measure to reduce crashes due to excessive speed. The Arizona Department of Public Safety is partnering with ADOT to enforce the reduced speed limit. Both agencies strongly urge drivers to slow down, pay attention in the work zone, and watch for construction workers, vehicles and equipment. 

For more information about the I-17 Improvement Project, visit improvingi17.com. 

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