Fatigue life prediction of asphalt pavement based on cumulative damage

Abstract

Splitting fatigue tests of AC-25 asphalt samples were carried out in stress control mode, and samples are suffering from one freeze-thaw cycle and without frozen-thaw. The stress fatigue equations are obtained with the result of the tests, and the strain fatigue equations are acquired on the base of above. The maximum tensile strains at the undersurface layer of the typical asphalt pavement are obtained through finite element calculation. The concept of cumulative damage is introduced, and the necessary parameters and detail steps for fatigue life prediction base on cumulative damage are proposed. The fatigue lives of asphalt pavements in rich rainfall area with water damage seriously (simulation by freeze and thaw) and drought climate area with no rain damage are predicted. The results of the paper are as following: 1) Strain fatigue equation for asphalt mixtures has nothing to do with temperature, and strain fatigue equation at different temperatures can be regressed with a single strain equation and the correlation coefficient is 92%. 2) Fatigue life of asphalt pavement in rich rainfall area is about 60% that of drought climate with no rain, and this proportion decreased with the increases thickness of the undersurface layer of the asphalt pavement. 3) Fatigue life of asphalt pavement is improved greatly as the thickness of the surface layer increase. The action effect is closely related to the rainfall where the pavement located. Compare to the pavement in rich rainfall areas, the effect is more noticeable for pavement in less rain or no rain areas.