Assessment of flood risk to performance of highway pavements

Highway pavements generally perform poorly after flood events. However, no study has addressed this in detail, so the aim of the current research was to evaluate pavement performance before and after a flood. Roughness against time data for the last 10–12 years for 34 000 km of roads in Queensland, Australia, were used to obtain an abrupt jump in roughness, which was termed a flood, and the time gap between two floods was considered as the likelihood of a flood. The distribution changes in roughness data before and after a flood were used to calculate flood consequences and then risk scores. The results revealed that a strong and high-traffic-loading road of high standard performed the best, which is consistent with previous studies. This information could thus help to identify flood-resilient pavements and upgrade flood-damaged roads to flood-resilient pavements. The flood consequence and risk scores were validated with actual data for two road groups, and reasonable agreement was found. The paper highlights key restrictions of the study, recommends a comprehensive flood risk assessment by comparing pavement performances of road groups with the same flood frequency and similar initial conditions, and incorporates road grouping based on risk rating to obtain more robust results.