C+S May 2020 Vol. 6 Issue 5

Contractors working with the Colorado Department of Transportation utilized more than 6,100 EPS geofoam blocks to quickly fill in the roadway along a stretch of US 36. Photo: Insulfoam

In just 20 days, six Insulfoam EPS plants manufactured and coordinat- ed logistics for more than 200 truckloads carrying in excess of 6,000 blocks of EPS geofoam during the busiest months of the year. Shortly following the installation, the U.S. 36 roadway was fully operational. Geofoam offers lightweight performance According to CDOT, engineers specified geofoam because it is “very strong, which means it can safely support highway loading and also lead to improved slope stability. Of the different options considered, (EPS geofoam) provides the best factor of safety.” A defining feature of EPS geofoam is that it is ultra-lightweight com- pared to other fills. Geofoam weighs approximately 0.7 to 2.85 pounds per cubic foot, depending on the product type, compared to 99 to 116 pounds per cubic foot for soil. This is also significantly less than other low-weight fills such as cellular concrete (24 to 90 pounds per cubic foot) and wood chips (15 to 30 pounds per cubic foot). Unlike other fills, EPS geofoam offers predictable engineered density values, which simplifies design and construction. Although it is lightweight, EPS geofoam has better bearing capac- ity than most foundation soils. The material’s compressive resistance ranges from about 317 to 2,678 pounds per square foot at a 1 percent strain. As long as combined dead/live loads do not exceed 1 percent strain, the material will not creep or experience plastic yield.

EPS Geofoam supports rapid repair of major Colorado highway By Tom Savoy

When cracks appeared on the eastbound lanes of the heavily trafficked U.S. 36, which connects Boulder, Colorado with Denver, crews quickly found that they were facing a full-blown sinkhole. The sinkhole ap- peared in the middle of the high-traffic summer season for the popular stretch of highway, and a quick repair was critical to getting traffic moving again and also beating the impending winter weather. Construction crews created an aggressive timeline to rebuild the dam- aged roadway in just three months’ time. In order to meet this tight schedule, the project’s team turned to expanded polystyrene (EPS) geofoam from Insulfoam to meet the structural requirements of stabi- lizing the roadway. By utilizing EPS geofoam, the Colorado Depart- ment of Transportation (CDOT) and its design team of RJ Engineering and Consulting, Inc. and David Evans and Associates, Inc., were able to keep the project on track.

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