Fatigue characteristic of asphalt

The objective of this paper is to research the fatigue characteristic of asphalt. The fatigue characteristic of four kinds of asphalt in continuous loading and loading with rest interval were both researched. DSR was used to measure the rheology characteristic of asphalt. The experiments adopted 15° and stress-controlled condition. Four indexes were used to evaluate the fatigue characteristic of asphalt in different kinds of loadings, they are DER (Dissipated Energy Ratio), DR (Damage Rate), δ and 50% reduction in initial complex modulus (50% G*). The results show that the indexes used in continuous loading test can't reflect the fatigue characteristic of asphalt accurately. Rest periods can lengthen the fatigue life of asphalt, and the modulus of asphalt can recover during rest periods. It is not available to evaluate the fatigue characteristic of asphalt only in continuous loading test. Both the fatigue life in continuous loading and the healing ability should be used to evaluate the fatigue characteristic of asphalt. Copyright ASCE 2008.