Modeling the Postflood Short-Term Behavior of Flexible Pavements

Abstract

The January 2011 flood in Queensland caused severe damage to road infrastructures, which presented new challenges for the efficient management of the roads. To date, no deterioration model can accurately predict the impact of floods on pavements. To understand the impact of the January 2011 flood on the structural performance of flood-affected pavements, falling weight deflectometer (FWD) deflection data on flood-affected roads managed by the Brisbane City Council (BCC) and Roads and Maritime Services, New South Wales (RMS, NSW), Australia, were collected and examined. This paper proposes a deterministic model that expresses structural strength of pavements as a function of time. The model predicts the short-term behavior of a flexible pavement immediately after flooding. A comparison of before- and after-flood data, and flooded and nonflooded sections of the same road, indicates a consistent trend of decrease in strength due to its sustained submergence under flood water. The literature review indicates that structural strength deterioration was also observed for the pavements in New Orleans and Louisiana following Hurricanes Katrina and Rita in 2005. However, a trend of strength gain and even, in some cases, strength loss was also observed in the BCC data, which were collected 2 and 4 years postflood. The flood-affected pavements lost their structural strength faster than the predicted deterioration rate for which the road was designed. Importantly, the proposed model would facilitate the pavement engineers to quantify the postflood rapid deterioration of the structural strength. The model is sufficiently robust and can be adapted to other regions by calibrating for the local condition.