Modelling Rapid Deterioration of Flooded Pavements

Abstract

This paper presents a deterministic model to predict the rapid deterioration of pavements within six weeks of a flood. The model expresses pavement structural strength ratio as a function of time lapse in deflection measurement after flooding, subgrade strength as California bearing ratio (CBR) and design traffic loading. Further, the paper proposes a guideline to implement a systematic approach for investigation and long-term monitoring of the flood-affected roads. Additionally, the research evaluated the impact of the increased frequency of extreme weather events such as flooding and intense heavy rainfall on the pavement structure. The study examined the structural and surface condition (roughness and rutting) data of floodaffected roads in the Brisbane City Council, the Roads and Maritime Services, New South Wales, and the Department of Transport and Main Roads, Queensland. The flood-affected pavements were found to deteriorate rapidly, rather than gradually, within six to eight weeks of the flood. The local roads that have thin asphalt concrete (AC) pavements (thickness less than 60 mm) with gravel base were significantly and more severely affected by the flood than the AC pavements (thickness 15-75 mm) with cement-treated base. Four types of deterioration trends were identified as a result of the impact of the rapid deterioration phase of flood on pavements. A direct and practical application of the study relates to providing quantifiable engineering knowledge for strategic plans to manage the flood-affected roads. The research will improve the long-term policy making for flood-affected road management in Australia. Road agencies can identify the adaptation option of building resilience into future roads to reduce the impact of such events, or predicting the cost-benefit model in case resilience is not possible to be built-in.