VOLUMETRIC BEHAVIOUR OF ASPHALT MIXTURES

Understanding the deformation behaviour of asphaltic mixtures in flexible pavement relies, to some extent, on the understanding of their volumetric behaviour. Also, for an accurate simulation of the deformation behaviour of asphaltic mixtures by constitutive models, this behaviour needs to be considered and taken into account. In this research, the volumetric behaviour of asphaltic mixtures under uniaxial and triaixal creep tests has been investigated. Two types of asphaltic mixtures used in the UK pavements, namely a gap graded Hot Rolled Asphalt (HRA30/10) and a continuously graded Dense Bitumen Macadam (10 mm DBM), both made with the same 70/100 penetration grade bitumen, have been selected. The radial and axial strains of cylindrical specimens under various test conditions have been measured and the volumetric and shear strain have been calculated. The variation of the volumetric strain is found to increase linearly with the shear strain with the slope of the line dependent on the temperature and type of mixture and independent of the deviator and confining stress levels