What is it about?

Our research focused on foamed bitumen stabilization, an environmentally sustainable technique for the construction and structural rehabilitation treatments of road pavements. This stabilization not only improves pavement performance and extends their lives but also reduces the materials' moisture susceptibility and improves pavement resilience to flooding. We undertook extensive laboratory experiments on a range of laboratory-prepared foamed bitumen stabilized (FBS) mixes, incorporating three granular base crushed rocks and two recycled material blends as host materials. A comprehensive testing procedure to assess and analyze the fatigue performance of FBS materials was produced. Most importantly, a new laboratory fatigue relationship to predict the performance of FBS materials was developed that will assist with the subsequent development of a performance-based in-service fatigue model for designing FBS flexible pavements.

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Why is it important?

Stabilization of existing pavements with foamed bitumen and a secondary binder permits the full utilization of existing pavements, up to 100%, which is a game-changer in terms of sustainability. This not only reduces the demand for non-renewable and finite natural aggregate resources but also lowers material transportation costs and reduces greenhouse gas emissions associated with pavement construction. These advantages together with improved pavement performance and resilience against the increasingly frequent occurrence of floods worldwide, make foamed bitumen stabilization an ideal choice for both pavement construction and rehabilitation treatments.


In recent years, there have been significant research and advances in the use of foamed bitumen stabilization for pavement construction and rehabilitation treatments of existing pavements. However, prior to our research, a performance relationship specifically developed for FBS materials was still lacking. Our paper marks a significant milestone by introducing a new laboratory fatigue relationship for FBS materials, derived from extensive laboratory experiments on a range of FBS mixes. While this paper contributes to a significant step forward allowing a better understanding of FBS materials behavior, we remain committed to applying these findings for the subsequent development of a performance-based in-service relationship for the thickness design of FBS flexible pavements.

Dr Negin Zhalehjoo
Australian Road Research Board

Read the Original

This page is a summary of: Laboratory Fatigue Characterization of Foamed Bitumen Stabilized Granular Base and Recycled Blends for Pavements, Geotechnical Testing Journal, September 2023, ASTM International,
DOI: 10.1520/gtj20230323.
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