The Gore Highway which forms part of the National Land Transport Network and is a major freight route servicing southern QLD and northern NSW. The section between Pittsworth to Millmerran traverses the Condamine River floodplain which incorporates very complex hydrology and extremely reactive (or expansive) soils.
The flooding events of 2010 and 2011 resulted in the existing granular pavement sustaining significant damage. The pavement underwent an extensive insitu foamed bitumen stabilisation rehabilitation in 2013-14 to improve the pavement’s stiffness and resistance to flooding.
Shortly after the pavement rehabilitation works, cracks began to appear in the pavement. These cracks continued to rapidly grow and multiply. The causes of the cracking are very complex; however, a key contributor is the effects of flood and drought cycles on the extremely reactive subgrades.
It was identified that waterproofing and repairing the cracked pavement surface was a priority to preserve the function of the road and prolong the pavement asset’s life. In 2020 the Toowoomba District commenced a maintenance project to:
- identify and evaluate the current pavement issues,
- develop, design and trial innovative pavement treatments, and
- select and construct pavement treatments considering competing priorities and limited funding.
Multiple pavement treatment types were developed which included the following innovations:
- Insitu stabilising existing foamed bitumen stabilised material using supplement materials and cementitious blend; and
- Using subgrade, granular, asphalt and spray sealing geosynthetics.
This presentation will highlight the innovative pavement treatments implemented on the Gore Hwy, and in doing so provide details on the constructability and current performance.
