NCDOT Uses Innovative Cement Solution On U.S. 70 Improvement Project

Lightweight cellular concrete reduces construction time

JAMES CITY, N.C. – The N.C. Department of Transportation is in the process of upgrading U.S. 70 from Raleigh to Morehead City to the future Interstate 42, including a 5-mile section in Craven County where the highway will be elevated at five new interchanges.

The location of the future I-42 in James City presented unique challenges due to its proximity to the river, railroad and airport. Poor soil conditions in the area made traditional fill materials less viable, requiring innovative solutions to ensure timely construction.

“We were going to have such a degree of settlement that it was going to be hard to overcome. In some situations, we were looking at almost 20 inches of settlement once we loaded the section,” said Deputy Division 2 Engineer Cadmus Capehart.

The team looked at several options for building on the existing highway footprint and concluded lightweight cellular concrete was the best material for the job.

“With a traditional fill material that the department would use, we would have 280 days just in settlement time. This lightweight cellular concrete that we’re using actually reduces the settlement to about 90 days,” said Wendi Johnson, Resident Engineer.

Lightweight cellular concrete is a mix of cement, water and a foaming agent. While NCDOT has worked with it before, this is on the largest scale in department history.  

The lightweight cellular concrete is also mixed on site, minimizing the number of trucks to the project site by about 20,000 loads and reducing congestion through the corridor.

Two of the five interchanges are currently under construction with a final completion date expected in 2028.