Impact of sea level rise on asphalt pavement responses considering seasonal groundwater and moisture gradient in subgrade

Abstract

Sea level rise (SLR) has been found to have a great impact on the transportation infrastructure in coastal areas. This study developed an analysis approach with numerical modeling to analyze the impact of SLR-induced groundwater rise on critical responses of coastal pavements. The numerical model employed a stress-, moisture content- and matric suction-dependent modulus model to consider the unsaturated characteristics of subgrade soil and non-linear distribution of moisture content. The model results were validated using Falling Weight Deflectometer (FWD) tests in the field. Based on the realistic moisture content collected from Long-Term Pavement Performance (LTPP) database, the critical responses of pavements were evaluated. The in-situ moisture content is non-linearly distributed along the depth, which differs from traditional assumption of monotonic distribution. The seasonal groundwater table (GWT) and subgrade soil type are two factors impacting the critical pavements responses under SLR scenarios. The pavement will be significantly impacted by SLR in the seasons with the higher GWT. The modulus of clay soil is more sensitive to moisture content than that of sandy or silty soil and thus causes the greater increase of pavement responses as sea level rises. On the other hand, the compressive stain on subgrade increases more remarkably than tensile strains at the bottom of asphalt layer under the impact of SLR.