Effective road pavement rehabilitation design for local government roads within the Sunshine Coast region

The Sunshine Coast is located in Southeast Queensland and has one of the largest local government road networks in Australia. The region has been developed on soft estuarine deposits with highly expansive or collapsible soils. The Sunshine Coast Council is continually looking for more effective pavement rehabilitation treatment options to manage the poor subgrade behaviour of the region. Unbound pavements and subgrade replacement are traditionally the dominant pavement rehabilitation methods used within the region. This dissertation critically evaluates the effectiveness of Sunshine Coast pavement rehabilitation treatments through the analysis of road condition survey data and falling weight deflectometer testing. Initially, seven (7) sites were subjected to surface deflection testing. The surface deflection of pavements under an applied load provided a good indication into the structural integrity of the pavement. The pavement strength of these sites was assessed via plotting measured pavement deflections at various chainages against measured rut depths. Incorporating laser road condition survey data such as roughness and rutting provided a robust dataset to understand pavement conditions. Eight hundred and sixty-six (866) road segments which have been constructed or rehabilitated within the last ten (10) years were tested to assess the long term effectiveness of various pavement types within the region. Council has been proactive in its approach to pavement rehabilitation, trialling new technologies and searching for cost saving initiatives where appropriate. Council practices are generally sound and in accordance with the latest Austroads and Department of Transport and Main Roads standards and specifications, aligning with current world best practice for pavement design and rehabilitation. The effectiveness of pavement rehabilitation treatments are case-specific, however, Sunshine Coast practices could be improved by considering sustainable rehabilitation methods including stabilisation, plant mixed foamed bitumen and further use of geosynthetics. Further recommendations include aligning the Sunshine Coast Council Planning Scheme more accurately with Austroads and Department of Transport and Main Roads documentation, accompanied with internal practices for specific subgrade conditions