Gravel Roads Better Than Pavement on Permafrost

The Research Section of the State Department of Transportation and Public Facilities (DOTPF) has released a Research Note which casts doubt on the practicality or advisability of paving all the rural roads in the north. In many instances, they note, a well-built gravel road is preferable.

The primary benefit to gravel roads is that they are relatively immune from frost heaving and have less of a tendency to thaw underlying permafrost. Studies showed that on very poor foundation material, such as thawing permafrost, the patching, pothole filling and repaving required by paved roads resulted in maintenance costs more than twice that for a good gravel surface.

This is not to say, however, that all gravel roads are inexpensive to maintain--note the word "good" in the previous sentence. Few gravel roads in Alaska are consistently safe for travel at high speed, and where improper materials are used in their construction, or where the footing is stable, such as on bedrock, they are more expensive to maintain than an asphalt pavement.

DOTPF suggests that "high-speed" gravel roads may provide a solution. Such a road would use hard, crushed, well-graded gravel with enough fine material to act as a binder. It would be further treated with a substance such as calcium chloride, waste oil, or asphalt, which would act to hold down the dust while at the same time alleviating potholes, washboarding and gravel loss problems.