Variability of laboratory fatigue life of asphalt mixes using four point bending test results

Abstract

The fatigue life of a bituminous mixture is usually obtained by fatigue testing or a surrogate model, conducted at relatively large strain levels and using few strain levels in order to minimize the required laboratory testing time. The accuracy of this bituminous fatigue life depends on the number of laboratory fatigue tests and number of strain levels used to obtain the fatigue life – strain level relationship. This paper presents a study where the variability of fatigue life is studied to define the number of strain levels and replicates for each strain level. Eight bituminous mixture fatigue laws, each obtained using three strain levels and up to 12 replicates for each strain level were assessed. It is recommended that fatigue life should be obtained using 3 strain levels and at least 3 test replicates for each strain level.