Impact of pavement layer properties on the structural performance of inundated flexible pavements

The assessment of the structural performance of flooded pavements remains complicated due to the lack of structural data in the aftermath of flooding and the fact that information about the pavement structure and materials is not always readily available. The objective of this study is to acquire a better understanding of the structural response of pavements that have been inundated and the foreseen changes in capacity using two approaches: a mechanistic approach using layer elastic analysis and the AASHTO empirical approach to determine the structural number. The relative impact of parameters such as unbound material type, layer thickness, traffic loads, and interlayer bond conditions on the reduction in expected strain values at critical locations were evaluated. The results show increases of 15-80% in vertical strains at the top of subgrade layer for low volume and interstate sections and 6-15% increase in horizontal strain at the bottom of asphalt layer for low volume sections and 3-8% for interstate sections. Accurate information on the layer thicknesses, traffic type, and interlayer bond condition were found to be most important for the evaluation of the change in expected horizontal strain. The types of base and subgrade materials are the most important factors for evaluating the change in expected vertical strain. The results of this study provide guidance on the type of information that is most important to collect for the assessment of the structural capacity of a pavement following inundation.