City of Black Hawk – Road Cut Stability

Summary Statement:

The city of Black Hawk used EdenCrete® in shotcrete to reinforce new roadcuts necessary to make safe passages of travel through the mountains for the motoring public.

EdenCrete® Purpose:

When Summit GEO explained the application challenges, Peak Materials recommended EdenCrete® to provide a more cohesive mix with better adhesion and pumping/shooting. Traditional fiber shotcrete was an option but the headache of increased water demand, difficulty in carving, and clearing hoses which become obstructed during the project was unappealing. The added durability and crack resistance provided by EdenCrete®, combined with the improved rheology, made the project a good fit.


When roadways are cleared over top of mountains and through the valleys below, slope stabilization is very important for safe passage of the motoring public. Steep, vertical roadsides require engineered solutions to ensure public safety for years to come. In Colorado, the city of Black Hawk completed a slope stability project on Bobtail Road to reinforce the mountainside. The surface of the mountain to receive the shotcrete was very irregular and required a mix with good cohesiveness and adhesion. During the project, the stretch of Bobtail Rd. was closed to traffic and created additional traffic in the downtown area. Doing it right the first time is essential to avoid future road closures and inconvenience, and it was requested that the mix be extremely durable to weather and cracking.


Concrete Producer
Peak Materials
Black Hawk, CO | September 2019
Summit GEO Structures

Volume & Dosage:

EdenCrete® at ¼ gal/yd3

Project Details and Conclusions:

The face of the mountainside created significant challenges stacking the shotcrete from bottom to top. There were several areas where steel plates and bolts needed reinforcing and the shotcrete could not be built upward from the bottom. As the placement began, the pump operator noticed how well the mix was pumping and reduced his pump pressure from 3800 psi to 2400 psi, ~100 Barr. After reducing the pressure, the nozzle operator was able shoot the areas to be reinforced from the top downward, which is opposite of traditional shotcrete application and extremely difficult to do with traditional mixes at high pressure.

The shotcrete with EdenCrete® adhered very well to the mountainside. The reduced pressure resulted in less dust and waste from rebound and gave the nozzle operator the flexibility to shoot from the bottom upward, or from the top downward, to easily accommodate the shot.

During a follow up visit to the job site, the contractor commented on how quickly the placement went without segregation or clogged lines slowing down the operation. The ability to shoot the top first and then move downward saved additional time and money, and there was no cracking to mention. The project involved 600 cubic yards of shotcrete dosed with EdenCrete® at ¼ gal/yd3.

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