Rutting, or permanent deformation, is known to occur in hot-mix asphalt (HMA) pavements. Higher rut rate typically occurs at pavement temperatures higher than 40 degrees Celsius. Heavy traffic loadings are the leading cause for permanent deformation in HMA pavements in hot climates. Rutting performance of HMA pavements is simulated in laboratory using different procedures, techniques and devices. In this paper, a new rutting model to fit laboratory rutting performance data obtained from the Hamburg WTD test is presented. The new rutting model developed in this paper is a three-stage model that describes the three different phases of HMA rutting normally occurring during the rutting test: consolidation (or primary stage), permanent deformation (or secondary stage), and flow (or tertiary) stage. A polynomial of the third order was the basis of such model. The constants of the polynomial model were then related to the asphalt binder properties. The asphalt binder properties where found to exhibit high correlation with the Superpave rutting parameter. The model was expressed in terms of the asphalt binder property and load cycles. Given the asphalt binder, the model may be used to evaluate the rutting performance of HMA pavements and identify the three different stages of rutting. (a).
Abstract