A review of the structural performance of flooded pavements

Abstract

This paper presents the effects of flood on the structural performance of pavements. Severe floods occurred in 2010 and 2011 in Southeast Queensland which prompted a need to monitor road pavements subject to frequent flooding. The long-term observation of pavements subject to flooding can provide answers as to why some roads largely survive flooding but others can be greatly impacted by flooding. A study conducted by ARRB Group and Griffith University, with Austroads funding, commenced in early 2013 to quantify the impacts of flooding on pavement deterioration. The study examines the structural and functional performance of flooded pavements using the Falling Weight Deflectometer (FWD) and surface condition data sourced from Brisbane City Council, the Department of Transport and Main Roads Queensland, and Roads and Maritime Services of New South Wales. The FWD deflection and surface condition data collected prior to and after the flooding events were used in modelling pavement deterioration. The deflection data was analysed using the CIRCLY5 program to back-calculate the stiffness moduli of the various pavement layers including the subgrade CBR. With the stiffness modulus, the Structural Numbers of pavement sections could be calculated. The preliminary results obtained from several road sections indicate a consistent trend with increased FWD deflection and reduced structural strength immediately after the flood events, as expected. However, strength gains were observed in a number of pavement sections several months after flooding mainly due to post-flooding rehabilitation work. A literature review of pavement deterioration under extreme climatic conditions of flooding in other regions of the world is also presented. The study is expected to provide valuable information regarding building resilience into future road pavements and predicting the cost consequences for when this resilience cannot be built-in.