Impact of subsurface water on structural performance of inundated flexible pavements

The assessment of the structural performance of inundated pavements is crucial to reduce the induced damage in the aftermath of flooding. The objective of this study is to present a simplified approach to investigate the impact of different subsurface water levels on the performance of pavement structures. The flooded conditions and subsequent water recession were simulated by slowly lowering the subsurface water from the pavement surface down in depth. A hydrostatic water pressure distribution was assigned above and below the water level for different cross sections with different subgrade types. Layer Elastic Analysis was performed to predict the surface deflection, stresses and strains at the bottom of asphalt layer and at the top of subgrade layer to evaluate the impact of saturated and unsaturated pavements. Finally, the influence depth for subsurface water level at which the road can withstand traffic with zero to minimum deterioration was discussed given the pavement structure and soil type. The results showed that the pavement structural capacity decreases significantly when the base and subgrade layers are fully saturated. The pavement starts to regain its strength once the subsurface water level dropped below the base course layer.