A case study on pavement performance due to extreme moisture intrusion at untreated layers

Previous studies reveal that a loss in Modulus of Resilience (Mr) has an adverse effect on pavement performances. However, no study investigated this during extreme moisture intrusion at granular and subgrade layers, which may be compared with a flooding situation. This study has aimed to assess the impact of change in Mr due to moisture increase on pavement performance using the HDM-4 and AASHTO 2008's roughness prediction models. As a case study, the paper utilises seven selected flexible pavement road groups of Queensland, Australia that cover 50% of the major road network. Both the results match closely when pavement strength data are accurate. The deterioration predictions are verified with actual after flood data and t-tests for two major roads in Logan City, and found consistent. The study has observed some interesting findings on change in degree of saturation, pavements flood resilience and life-cycle performances with flooding scenarios. It is believed that these results would be useful in obtaining accurate Delta IRI change at varying Mr values due to a flood to select appropriate post-flood rehabilitation. A road authority can use pavements flood-resistance and life-cycle performance results for deriving a maintenance strategy. Moreover, pavement flood resilience, relationships between Mr loss and strength and Mr loss and deflection would help in pavement design, estimating existing structural strength and rehabilitation design. Finally, the paper highlights major assumptions and suggests some useful future works.