January 24th, 2011
DESIGNED TO LASTOptimize Mobility, Preserve Infrastructure, by Catherine Higgins.
I-15 CORE pavement layers stack up to a durable, weather resistant, low maintenance, 40-year life.
Traffic has switched to new concrete pavement between Lindon and American Fork, marking I-15 CORE as twenty-five percent complete. The new smooth ride is a predictor of good things to come.
More than just a pretty surface
“Any pavement design is a multi-layered system,” says John Butterfield, UDOT Materials and Pavement Engineer on the I-15 CORE project. I-15 CORE pavement consists of four layers from the bottom up: granular borrow, drainable granular borrow, asphalt base and Portland Cement concrete.
The amount of material in each layer is adjusted according to different factors, like drainage requirements, availability of materials or project budget. Traffic volume is the most important factor engineers consider when designing pavement.
Where the rubber hits
“The main thing that drives pavement design is traffic,” says Butterfield. ”It all has to add up to the structural value that is predicted from traffic volume expected on that road.”
The forty-year pavement design on the I-15 CORE project is a value-added feature that the contractor, Provo River Constructors, included in their winning proposal. UDOT asked for 30-year pavement, “they gave us forty,” says Butterfield.
UDOT prefers concrete on high-volume roads. “Under heavy interstate traffic, concrete is the best investment,” Butterfield explains, because it’s smooth, rigid and less maintenance is required compared to asphalt. “We just know it works and it will last if it’s done right.”
Concrete is also weather resistant. In engineer-speak, concrete has “an air void system to allow for the pressures generated when internal water freezes.”
Translated, that means potholes are exceptionally rare!
VIDEO: This KSL story below shows concrete installation, and the video after the story shows the layers that make up the pavement.