Well designed and built pavements must resist various types of distress due both to traffic and weather and maintain an acceptably smooth and quiet riding quality for an extended period of time. The modulus and permanent deformation properties of the base course play an important role in how well a pavement serves this intended purpose It is even more important for performance that a base course can be evaluated at the time of construction for its ability to resist the changes that will be imposed on it by moisture, freezing and thawing and traffic stresses. In addition, the distortions to
1.1 Design of pavements
Pavements are designed to carry traffic loads by arranging the layers to have a modulus and thickness that will carry the traffic loads well for several decades. In both asphalt and concrete pavements, the base course provides a major load-bearing component of the pavement. In addition to assuming the modulus of the base course, the designer also assumes the permanent deformation properties of the base course and uses these assumed values in predicting the development of rutting and roughness with time. The assumed values are usually based on laboratory or field nondestructive testing measurements to which the designer has access.