http://www.fhwa.dot.gov/engineering/geotech/pubs/05037/07a.cfm
7.1 Introduction This chapter includes: In this chapter, design details for the specific pavement features of base materials and drainage systems are provided. Compaction, one of the key geotechnical issues in pavement design and construction is also covered. Special challenges generally relate to poor subgrade conditions that occur due to the type of soil and environmental conditions.