Full-Scale Accelerated Pavement Testing and Fatigue Damage Evaluation of Foamed Bitumen-Stabilised Crushed Rock and Recycled Materials

Foamed Bitumen-Stabilised (FBS) materials are used for in situ rehabilitation or strengthening treatment of unbound granular pavements but can also be manufactured ex situ for new pavement construction. This study examined the field performance, tested using full-scale accelerated pavement testing, of foamed bitumen-stabilised materials incorporating high concentrations of recycled pavement materials. The Australian Accelerated Loading Facility (ALF) was used to evaluate a 100% crushed rock FBS mix (control mix) and two recycled material blends (a 50% reclaimed asphalt pavement and 80% previously cemented material) all stabilised with 3% bitumen and 2% hydrated lime. The accelerated loading accumulated over 3.6 million ALF loading passes at 40 and 60 kN, with continuous monitoring of the pavement stiffness and surface condition. The effect of traffic on the FBS material fatigue damage was analysed by the ratio of modulus between the trafficked and untrafficked areas. Data showed that the incorporation of 50% RAP increased fatigue performance without a detrimental effect on rut resistance. The average field fatigue performance of the previously cement-stabilised mix was similar to that of 100% crushed rock. However, performance variability should be considered for a risk-based approach and high stress applications.