US 24 Westbound – Constitution Ave. to Garrett Rd., Colorado Springs, CO
Contractor: Castle Rock Construction Company
Owner/Engineer: Colorado DOT Region 2

US 24 Westbound connects Colorado Springs and Falcon, CO. The existing asphalt roadway was showing severe deterioration, it was determined the roadway needed complete replacement. The Colorado DOT decided to bid the project as an alternate bid/alternate design.

Castle Rock Construction was awarded the project, which was awarded by a wide margin with the life-cycle cost adjustment. The project had a life-cycle cost adjustment of more than $1 million, and in contrast, the low asphalt bid was $100,000 under the second-place concrete bid. The sections were 7 in. hot mix versus 8.25 in. concrete.

The project included 10,000 SY of asphalt planing and more than 75,500 SY of full-depth reclamation; more than 65,000 SY of 8.25 in. doweled concrete pavement; and traffic signal reconfigurations. During the concrete portion of this project, it rained every afternoon. However, the rain was no match for the project team, which was able to make up the time, so much so that the contractor earned most of the early completion incentive.

The concrete pavement required no corrective action for smoothness, thanks to an optimized concrete mixture and quality paving, curing, sawing, and sealing. Castle Rock used an innovative testing procedure for the aggregates. Combined gradations were done three times daily in a pug mill to assure the mix was within the specified range for coarseness and workability, as well as to attain the amount of free water in the aggregates. This allowed the contractor to adjust batch water to maintain a very consistent batch.

Sustainability was also a consideration with this project, and the contractor demonstrated a commitment to source reduction and recycling in several ways. The cement used featured a 10% lime stone replacement, which lowered the carbon footprint. Fly ash was also part of the mix, which not only yields a stable, durable slab, but also diverts a potential waste material away from landfill. The asphalt FDR materials from the project were crushed onsite and used as road base, thus allowing a significant reduction in trucking and fossil fuel use, as well as a less virgin material.

As a result of the hard work, commitment to quality, and attention to detail Castle Rock completed the project on time and within budget and delivered a quality concrete pavement that will provide excellent service to travelers, residents, and visitors to these two popular Colorado cities.