CHARACTERIZATION OF THE EFFECT OF MIXTURE PROPERTIES IN THE PERMANENT DEFORMATION OF ASPHALT MIXTURES USING THE MEPDG

摘要

The hot mix asphalt (HMA) rutting prediction model within the Mechanistic-Empirical PavementDesign Guide (MEPDG) utilizes a relationship that includes effects of mix characteristics onlythrough the resilient strain, which in turn is a function of the dynamic modulus (∣E~*∣) of the mix.However, increasing evidence suggests that use of ∣E~*∣ alone may be insufficient to completelycharacterize the HMA permanent deformation behavior. This paper analyzes the effects of mixcharacteristics on permanent deformation in addition to those already considered by the MEPDGthrough ∣E~*∣, using repetitive axial permanent deformation test results from laboratory compactedHMA specimens. Results from multiple linear regression analysis indicate that binder type,effective binder content, and air void content have a significant effect on the permanentdeformation model parameters.The potential effects of mix characteristics on the permanent deformation modelparameters are analyzed using the MEPDG with an HMA pavement section compacted at fourdifferent levels. Scenarios where the mixture characteristics are incorporated solely by means of|E*| are compared with scenarios where the effect of air voids and asphalt content are alsoincorporated within the rutting prediction model by adjusting its parameters using therelationships established in the laboratory.The empirical laboratory evidence supports the hypothesis that universal values forpermanent deformation model parameters regardless of mixture properties do not fully take intoaccount mixture specific contribution to rutting, and that other mix characteristics such as airvoids may be needed to supplement ∣E~*∣ for the appropriate permanent deformationcharacterization of asphalt mixtures.