Pavement Distresses Due to Truck Platoons: A Holistic Analysis

<p>Currently, AASHTOWare Pavement Mechanistic Empirical Design (PMED) does not contain a framework to compute distresses for loading scenarios like truck platoons. Truck platoons reduce fuel consumption and improve safety; however, they increase pavement damage because of a reduction in wander and rest period. The important parameters of truck platoons are wander, rest period, and penetration level. Unlike wander, the effect of reduced rest period on permanent deformation are not well documented. Rest period (i.e., truck spacing) is a critical parameter in platoons that could be controlled to reduce damage and to improve fuel savings. Shorter rest periods resulted in lower permanent deformation through conventional repeated load triaxial testing. However, the test does not entail a representative load stress pulse because of moving loads. This study used modified triaxial testing equipment to simulate different load pulses. Reduced triaxial compression was critical over the conventional load stress pulse. For all representative pulses, the effect of rest period was similar (i.e., increasing rest period increased permanent deformation). Consequently, a framework was developed to compute pavement distresses as a function of truck platoon parameters. Truck platoons distributed uniformly on sublanes resulted in the lowest damage, even lower than a conventional trucking operation. Truck spacing of 60 ft is optimal in terms of safety, as the difference in distresses were minimal compared to spacing at 18 ft.</p>