Innovative Design-Build Project Achieves Significant Reuse and Recycling of Materials 

This project was selected for innovative contracting so CDOT and the transportation construction contracting community could partner together to effectively utilize the principles of innovation and continuous improvement—to keep costs down while accelerating delivery and protecting the environment.

We weren't disappointed! In addition to coming in 10 percent under budget and ahead of the original schedule, this transportation construction project provided significant environmental benefits, including the following.

1. For years, transportation agencies like CDOT have struggled with how to make more use of recycled hot mix asphalt (HMA) pavement. This material is used in up to 25 percent of new HMA but couldn't be used for class six road base. The issue was controlling the quality of millings due to the variability of the product and the presence of asphalt.
   Up to now, we haven't been able to control the density of the material or adequately document quality. In this design-build project, using the Alternative Technical Concept (ATC) process, the contractor and CDOT worked through concerns and found a way to use a new crushing and screening process employed by the construction contractor to allow us to use a significant amount of HMA in place of virgin material.

2. Large retaining walls on the southeast and northwest quadrants, which would have been removed in a conventional project, are being re-purposed as excavation support. Keeping them in place saves removal and replacement costs, extra material use and disposal of waste materials.

3. The old concrete roadway, which would have been removed in a conventional project, was rubblized in place and used as embankment for the project.

4. While not a new concept, the steel girders, and rebar from the old bridge were recycled as well.

5. The quantities of recycled and reused materials from this transportation construction project include the following:

   • The project removed, processed and recycled 26,000 tons of existing 6th Avenue pavement, and placed it as road base for eastbound and westbound at Garrison.

   • The new Brannan HMA asphalt mix used contains approximately 25 percent—or 2,600 tons—of recycled asphalt.

   • The project removed, processed and recycled 6,300 cubic yards of old concrete from the old bridge and 6th Avenue.

   • The project will recycle 176,300 pounds of steel locally.

   • Reuse of the existing cast-in-place walls as temporary shoring areas to complete the new walls kept 1,800 truck-round-trips off Denver highways.

In recognition of the terrific results achieved through innovative methods used to protect the environment and increase reuse and recycling of materials, the team responsible for this Project received the 2016 CDOT Environmental Award in the Transportation Project Category. CDOT's Environmental Awards foster an environmental ethic in all we do at CDOT by recognizing efforts that exemplify our commitment to environmental excellence.