Experimental Study on Deformation of Foamed Bitumen Bound Base Materials

Foamed bitumen bound base course materials were manufactured in the laboratory by mixing reclaimed asphalt pavement (RAP) with new crushed limestone and treated with foamed bitumen. Gyratory compacted specimens were also subjected to repeated loading under triaxial conditions which provided an approximate simulation of the traffic loadings experienced in actual pavements. A pilot-scale foamed bitumen stabilized pavement base course was also constructed. The Nottingham Pavement Test Facility was used to more realistically traffic the various trial pavement sections using a loaded wheel. It was found that the deformation resistance of foamed bitumen bound mixtures was dependant primarily on percentage of RAP in the mixes and penetration grade of bitumen generating the foam. The addition of small amounts of cement significantly enhances the deformation resistance of foamed mixes.