Determination of fatigue characteristics from laboratory testing

1 Determination of fatigue characteristics from laboratory testing 

CEN EN 12697-24 (2012) considers the number of the load applications when the complex stiffness modulus of the asphalt has decreased to half its initial value as a conventional criterion of fatigue failure. 

Alternatively, ASTM D 7460 (2010) considers as failure point the number of cycles to failure that corresponds to the maximum (or peak) normalised complex modulus x cycles 

The fatigue point depends not only on the asphalt composition and its properties but also on the magnitude of the applied stress, the test temperature and the loading time. 

The general equation defining the fatigue life in terms of tensile strain, as a criterion, is as follows  

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