Fatigue cracking is important type of damage in Dutch asphalt pavements. Determination of fatigue characteristics of asphalt mixes is usually based on large number of load repetitions. An investigation has been made to find whether frequency sweep tests and direct tensile tests can be used. Material parameters which are linked to fatigue performance are determined from these. These parameters are the slope of mix stiffness master curve, uniaxial tensile test and Mode I fracture energy. The parameters are used to compute the constants in Paris' fatigue law. Since constants are material parameters, influence of geometry is represented only by stress intensity factor. This offers the opportunity of combining Paris coefficients with the stress intensity factor from classical fatigue tests. Dutch engineering standards for fatigue are based on four point bending tests; development of the stress intensity factor during these tests was therefore determined by FEM simulation. Combination of the stress intensity factor with Paris coefficients produced a fatigue relation; there was good resemblance between this and fatigue line from Dutch standard. The relation between fatigue coefficients enables the determination of fatigue relation using only the results from the frequency sweep test. Whole data processing procedure simplifies to solution of a set of equations. Fatigue lines in Dutch standards can therefore be determined by a relatively simple procedure.
Abstract