APPLICATION OF THE COMPLEX MODULUS TESTS

THE RHEOLOGICAL BEHAVIOUR OF VARIOUS VISCOELASTIC BITUMINOUS MIXTURES AND THE STIFFNESS MODULUS VALUES NECESSARY FOR PAVEMENT DESIGN ARE EVALUATED AT THE LCPC BY MEANS OF THE COMPLEX MODULUS TEST. THE COMPLEX MODULUS IS A FUNCTION OF THE BITUMEN NATURE AND CONTENT, THE NATURE OF CHEMICAL ADDITIVES, THE GRADING CURVE, AND THE COMPACTION OF THE BITUMINOUS MIXTURES. THE MODULUS VALUES MEASURED FROM SAMPLES OF MATERIALS TAKEN FROM THE ROAD ARE WIDELY DISPERSED AND REFLECT THE DISPERSIONS IN COMPACTION DUE TO REAL CONDITIONS OF APPLICATION. THESE VALUES INCREASE WITH TIME AS THE BITUMEN HARDENS AND WITH THE TRAFFIC. THEY MUST BE TAKEN INTO ACCOUNT IN PAVEMENT DESIGN.