Compaction of Forest Roads in Northwestern Oregon – Room for Improvement

Abstract Monitoring the construction and as-built conditions of a low volume aggregate surfaced forest road in Northwest Oregon coupled with detailed laboratory testing of the subgrade soils allowed an analysis of the potential benefits of improved structural road design and construction control. Specifically, subgrade compaction was found to be far below desirable levels that would achieve greater subgrade strength, and based on a common design equation, allow for the use of significantly less aggregate. It is inferred that a combination of inadequate compaction energy and failure to account for the detrimental influence of high field moisture content resulted in poor subgrade densities. This case study showed that a 34 percent saving in aggregate cost maybe possible.