Abstract

Improper drainage of subbase and base course materials is considered as one of the major defects in the structural elements of flexible and rigid pavement. The present work represent a primary attempt to evaluate the coefficient of permeability of five types of base materials confirmed with S.O.R.B. specifications, (State Organization of Roads and Bridges) issued in Iraq in l986. The tests were performed under constant head condition within the range of validity of Darcy’s Law and laminar flow. The results of the regression analysis revealed that the coefficient of permeability is a function of the void ratio, mean particle diameter and degree of backing. These parameters are presented in the form of equations and can provide a quick estimation of the coefficient of permeability of the granular soil