Pavement structure can be inadequately designed to withstand the progressive increase in load applications that takes place at advanced service times. The progressive increase in load applications has been related to a stage design strength ratio using a two-stage design analysis approach. The stage design strength ratio is defined as the ratio of the relative strength change to the design relative strength associated with a design load applications level. The relative strength change is determined as the difference between the design relative strength (first-stage design) and the stage relative strength (second-stage design) associated with a stage load applications value that is less than the design load applications level. The presented sample results indicate that the stage design strength ratio is relatively low compared to the corresponding increase in load applications especially at advanced service times. This could be a major contributing factor to the accelerated deterioration of flexible pavement. Three popular design methods of flexible pavement are investigated in the analysis: the California Department of Transportation (Caltrans) method; the American Association of State Highway and Transportation Officials (AASHTO) method; and the Asphalt Institute (AI) method. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Abstract