Asphalt pavement resilience to flooding: conventional vs inverted pavement structure

Abstract: Conventional pavement structures are vulnerable due to degradation of unbound materials after water inundation. Inverted pavement structure has been proven to be cost-effective and energy efficient, while its resilience has not been investigated. This study is aimed at assessing the resilience of inverted pavements to flooding events using an integrated hydraulic and mechanical modeling approach. Two-dimensional hydraulic models were established to analyze flooding-induced moisture variations in the pavements with different subgrade soils and initial groundwater tables. Based on the moisture distribution results, three-dimensional mechanical models that considered the moisture-stress-matric suction dependent modulus of unbound materials were developed to calculate critical pavement responses under moving load. The increases in critical responses of inverted and conventional pavements due to flooding were compared and analyzed. The results show that the moisture content of granular base layer in the inverted pavement was relatively stable because the drainage facility removed the water coming from the unpaved area and the cement stabilized base layer separated water from the subgrade. The subgrade with higher groundwater table or larger hydraulic conductivity was more likely to be invaded by water during the long-period inundation. Compared with conventional pavement, the increases of critical pavement responses were significantly smaller after long-period flooding, which indicates the potential benefits of inverted pavement in enhancing the resilience to flooding impact.