Denver International Airport is the nation’s fifth busiest. Over the years, concrete at nine gates in two concourses had deteriorated, allowing water to pond and seep into the basement. At the same time, airport officials noted the need for expansion and asked the contractor to create two additional gate aprons for future flights. Also needed: upgrades to jet bridges, utilities and the jet-fueling system.

The work included demolition and removal of 44,523 sq yd of old pavement, which was hauled off site and crushed into aggregate for future pavement, saving an estimated $500,000. The paving included Portland cement concrete, hot-mix asphalt and asphalt-treated permeable base. But soon after the first concrete was placed, it began to shrink and crack. The project team investigated and found the culprit—the summer heat, which had raised the temperature of the subgrade to 120 degrees Fahrenheit.

And as temperatures cooled, the newly placed concrete shrank and cracked. The paving contractor, quality experts and the concrete-mix designer worked together to develop new curing and placement processes that eliminated the cracking.

Those processes worked, but the project was now off schedule. In the contractor’s words, it was “all hands on deck,” with crews working day and night to get the schedule back on track. Even without the concrete issues, completing a major project with 16 subcontractors at an operating airport was complex, to say the least.   

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