The role of thermal ratcheting in pavement failures

Although recognised to be a factor in certain failures of pavements, there is evidence that alternations in solar energy may be contributing to considerably wider classes of pavement distress than is currently acknowledged. Restrained expansion or contraction during alternations in heating and cooling often result in forms of distortion that are not fully recovered at the end of each thermal cycle. Over time a form of thermal ratchet leads to an accumulation of failure that can have serious consequences for pavement integrity. This paper attempts to describe a representative range of these thermal ratchet-induced failures. It aims to provide a classification system for failures according to the dominant material failure or mechanical process responsible for the cyclic accumulation of distress. It is suggested that greater recognition of the thermo-mechanical processes responsible for these various types of pavement failure could have important implications for improving future design and maintenance strategies.