Institute for Transportation

About the research

The erosion of limestone rock due to water ingression is not an uncommon event, nor is it entirely preventable. Situations where limestone subsurface material comes in contact with water can be responsible for the erosion of subsurface support. In instances where roads are constructed on top of limestone outcroppings, this erosion could result in voids underneath pavement, resulting in potentially unsafe conditions.

Such an instance has occurred on U.S. Highway 67 in Scott County Iowa. The erosion of the limestone subsurface has created voids underneath the paved barrier rail and possibly the driving region of the highway. The area to be inspected would be that portion of the shoulder adjacent to the railroad area, with limited access to the side of the roadway.

By completing this research into the limestone erosion of the roadbed under U.S. Highway in Scott County, Iowa, the number and size of voids under the paved road will enable the Iowa Department of Transportation to access the extent of the erosion, and take measures to ensure a safe and effective road environment for continued use.