Tuesday, 3 September 2024
In a step towards extending the life of pavement rehabilitation works, recent research has progressed refinements to the design of asphalt overlays to mitigate reflective cracking.
A new Austroads report details the findings of research into prediction procedures and ways to improve current practice to bolster the longevity and cost-effectiveness of pavement rehabilitation treatments.
When pavement rehabilitation treatments are applied to cracked or jointed pavement layers, the cracks can reflect through the treatment and reduce the long‑term performance of the pavement. The propagation of a crack from the existing pavement into and through an asphalt overlay is known as reflective cracking. Reflective cracking is mainly caused by traffic and environmental loadings.
“The results suggest there may be potential in hotter climates to reduce the current minimum 175 mm thickness of overlay cover,” said Ross Guppy, Manager of Austroads’ Transport Infrastructure Program.
“The findings also suggest that the current weighted mean annual pavement temperature (WMAPT) approach may not be appropriate for reflective cracking and that a different temperature characterisation may be needed when predicting reflective cracking.”
The report addresses the findings from a larger Austroads project on reflective cracking and investigates the Texas Transport Institute (TTI) prediction model.
The work focused on understanding the TTI methodology and its associated software, and assessing the feasibility of adopting it within the context of Australian and New Zealand design methods for flexible pavements.
The project concluded that to confidently change the recommended design approach in the Austroads Guides, comprehensive research on the in-service reflective cracking performance across a wide range of Australian and New Zealand climates is required.
Download Evaluation of a prediction procedure for pavement reflective cracking