Quantifying structural behaviour of foam bitumen stabilised (FBS) pavements

摘要

Foamed bitumen stabilised (FBS) pavement is becoming more widely used around the world, yet comprehension of its properties within a pavement configuration is not well understood. The performance of FBS pavements in New Zealand using falling weight deflectometer (FWD) data has been reviewed to enable rationalisation of modelling techniques. FWD derived parameters and models for FBS are compared to international guidelines, as well as currently recommended design parameters and models in use internationally. Interpretation of FWD derived data strongly indicates that moduli of FBS (and cement treated) layers are primarily dependent on the stiffness of supporting layers (subbase and subgrade). Consequently, alternative models which quantify characteristic FBS moduli based on supporting layer stiffness and standard central deflection have been determined.An assessment of FWD recorded surface temperatures (at the time of testing) versus FBS moduli indicates that in-service pavements constructed in accordance with New Zealand customary practices exhibit significant temperature sensitivity (as would be expected owing to the inclusion of bitumen in the FBS layer). Subsequently, appropriate correction factors for standardising moduli to a reference temperature have been evaluated.