MECHANICAL BEHAVIOUR OF BITUMINOUS MIXTURES

THE AUTHORS USE A STATIC TRIAXIAL TEST TO STUDY THE INFLUENCE OF THE MIX-DESIGN PARAMETERS OF DIFFERENT MIXTURES ON THEIR MODULUS, ULTIMATE STRENGTH, COHESION AND INTERNAL FRICTION ANGLE; IT IS CONCLUDED THAT: (1) HIGH TEMPERATURES HAVE A LARGE INFLUENCE; (2) THE ANGLE OF INTERNAL FRICTION IS OF PARAMOUNT IMPORTANCE ABOVE THE LIMIT TEMPERATURE; (3) THE INCREASE IN FINES CONTENT UP TO 8% IS A FAVOURABLE FACTOR; (4) THE BINDER CONTENT SHOULD BE KEPT BELOW A CERTAIN LIMIT; (5) THE FINES/BITUMEN RATIO HAS A MARKED INFLUENCE ON THE ANGLE OF INTERNAL FRICTION; (6) DISCONTINUOUS FORMULAE APPEAR TO RESULT IN BETTER BEHAVIOUR THAN CONTINUOUS ONES; (7) THE VOIDS CONTENT OF THE MIXTURE IS VERY IMPORTANT AND THE TENDENCY SHOULD BE TOWARDS A 5% VALUE WITH FORMULAE LESS SENSITIVE TO POST-COMPACTION. CRITERIA ARE PUT FORWARD FOR THE SELECTION OF MIX-DESIGN FORMULAE. FOR THE COVERING ABSTRACT, SEE IRRD ABSTRACT NO 107043.