Since 1990, the LCPC carried out three "semi-scale"experiments on its test track aimed at studying the fatigue behaviorof asphalt mixes in the aspect of the influence of the natureof asphalt.

The large amount of laboratory tests carried out on the sixdifferent tested materials show that, if the modulus is a valuerelatively independent of the measurement method, the fatiguebehavior in the laboratory strongly depends on the test procedure(frequency, temperature, two or three points bending, controlledforce or displacement, with or without rest period). The resultsobtained don't allow to choose one type of fatigue test as morerelevant than another one in all cases.

A systematic study carried out in laboratory in order to betterdefine the data obtained from the fatigue tests highlights theenergy dissipated in the form of heat during the continuous tests.It also points out that the differences in the results betweenthe continuous and discontinuous tests are probably not attributableto an actual healing of the material during the rest periods.