DISTRESS - A CRITERION FOR DESIGN OF FLEXIBLE PAVEMENTS

The paper briefly discusses various types of distress conditions which affect flexible pavements as well as the design methods based on the prediction of such conditions. Apart from load consideration, properties of materials of each pavement layer as well as the subgrade are considered in determining pavement thickness and environmental conditions in order to predict pavement design life. Not only rigid pavements but also flexible pavements are susceptible to temperature variations likely to cause cracking in the asphaltic concrete layers. So far as Indian conditions are concerned, permanent deformation (rutting) can be considered as the principal type of distress suffered by flexible pavements so that design procedures should take into consideration factors governing the formation of ruts such as stiffness of bituminous mixes and axle loads. (TRRL)