FATIGUE AND FRACTURE IN PAVEMENT

This paper we present what is fatigue ?and what is fracture? we will discuse on design aspects related to fatigue failure, an important mode of failure in engineering components. Fatigue failure results mainly due to variable loading or more precisely due to cyclic variations in the applied loading . A fatigue failure begins with a small crack; the initial crack may be so minute and can not be detected. The crack usually develops at a point of localized stress concentration like discontinuity in the material, such as a change in cross section, a keyway or a hole.for design pavement flexible or regid pavement cycle life or how many percentage of material damaged.one parameter of design in all branch of engineering is standard of test of fatigue and fracture.for example in pavement number of axles ,number of tires ,thickness of pavement ,kind of Load is effect on fatigue and fracture