Colorado D.O.T. – Central 70 Project

Summary Statement:

EdenCrete’s® specialized shotcrete mix with reduced cement was used in the Colorado DOT’s Central 70 project, which completely reconstructs the re-envisioned I-70 corridor through north Denver.

Thorcon Shotcrete and Shoring installed approximately 4,500 cubic yards of shotcrete with EdenCrete® to reinforce caissons and abutments supporting the newly expanded bridges and their underpasses, soil-nail walls stabilizing the on/off ramps and sidewalls along the portions of I-70 which have been taken below grade, and in the construction of the tunnel. The decision to use EdenCrete® shotcrete in place of the originally-specified mix saved 675,000 lb of cement, resulting in 17 fewer bulk tanker deliveries of cement to the concrete plant.

Use EdenCrete® to lower the CO2 footprint for your next project and leave a better environment for our children.

EdenCrete® Purpose:

Using the EdenCrete® shotcrete mix significantly reduced the carbon footprint of the Central 70 project by requiring less cement than originally planned. As a result, ~314 fewer tons of CO2 was released during the project’s construction.

During placement, the nozzlemen for Thorcon experienced the benefits of EdenCrete® including a reduction in dust and waste from rebound because of the enhanced adhesion provided by EdenCrete®. The mix did not get clogged in the pump or hose and did not require the addition of water when emptying the truck, saving time.

The increased resistance to cracking and reduced permeability is anticipated to improve the long term durability of the shotcrete placed along I-70, reducing maintenance repairs and headache for the motoring public.

Challenge:

Shotcrete is being used to reinforce new and existing caissons and abutments supporting the many bridge spans and elevated green spaces, as well as for the soil-nailed walls along new on and off ramps. The shotcrete mix needed to pump easily in order to keep up with the placement schedule while being extremely durable.

Specifications:

Concrete Producer
Aggregate Industries
Location/Date
Denver, CO
December 2018 start
December 2022 end
Contractors
KIEWIT and Thocron Shotcrete & Shoring
Volume & Dosage
~4,500 yd³ of shotcrete containing EdenCrete® at ¼ gal/yd³

Project Details and Conclusions:

As the contractor, Thorcon Shotcrete & Shoring, began shooting the mix, the pump operator immediately commented on how well it was pumping compared to the original 5000 psi CDOT shotcrete mix. After a short conversation regarding improved rheology, the pump operator reduced the hydraulic pressure of the pump from ~3800 to ~2400 psi. The EdenCrete® mix pumped and stacked much better than the original mix, producing significantly less dust and waste from rebound. At the end of the first day, the Thorcon nozzleman commented “My shoes are clean!” The mix did not segregate or pack sand in the line, eliminating lost time to disconnect and clear the hose lines. Thorcon was very pleased with the EdenCrete® mix and has since adopted the EdenCrete® shotcrete mix as their standard shotcrete mix for the majority of their Colorado projects.