Structural design of low-volume roads

This report synthesizes current structural design concepts and methods for such roads. The first two chapters treat the fundamentals of road design and performance (including design and performance phases, structural and functional failure, stress distribution, serviceability and performance, distress mechanisms, and equations for predicting road roughness) and the relation of economic considerations to varying design philosophies. The next four chapters discuss key design factors: (1) traffic patterns (through mixed-traffic analysis); (2) soils and subgrades; (3) the effects of moisture and frost on the strength and volume of construction materials; (4) road surface materials, especially the granular materials and and bituminous surface treatments characteristically used for low-volume roads; and (5) improvement of material quality through compaction and chemical stabilization. The last two chapters present and illustrate structural design methods used by the U.S. Army Corps of Engineers, the U.S. Forest Service, and the United Kingdom Transport and Road Research Labooratory. Included are 33 tables and 38 figures.