Application of MMLS3 in laboratory conditions for moisture damage classification of bitumen stabilised materials

Abstract

The Model Mobile Load Simulator (MMLS3) is a one-third scale accelerated pavement testing (APT) device. It is well engineered and widely used for simulating long-term pavement performance under in-service conditions. However, the current laboratory-testing protocol using MMLS3 is not defined for testing bitumen stabilised materials (BSMs), such as foamed bitumen and emulsion stabilised materials. The process associated with moisture ingress and damage in the BSMs layer is complex and can occur over a long time, under in-service conditions. It is believed that APT research into moisture damage of BSMs can provide invaluable insights into distress mechanisms in spite of accelerated damage compressed into a shorter time frame. This paper presents the results of an experiment using wet MMLS3 trafficking, aimed at providing measurable damage that can distinguish between resistance of different BSMs. The mix compositions investigated comprised aggregates blends with and without reclaimed asphalt pavement (RAP) and different binder types (bitumen emulsion and foamed bitumen) and addition of active filler (cement and lime). The findings show that the revised MMLS3 testing protocol, as developed for the BSMs investigation, can be used to distinguish between the mixtures of high resistance and high susceptibility to moisture damage.