MODELLING THE LINEAR VISCOELASTIC RHEOLOGICAL PROPERTIES OF BASE BITUMENS

Abstract

A laboratory work has been carried out on four different unaged pure bitumens to determine the properties of the 2S2P1D (combination of two springs, two parabolic elements and one dashpot) model. Two types of tests namely the oscillatory dynamic and creep tests, were conducted in order to obtain the rheological data by means of the dynamic shear rheometer (DSR). Then, a method based on inter-conversions function was proposed to model the creep behaviour of base bitumen. It was found that the model which consists of seven parameters simulates in an excellent way the linear visco-elastic properties of the bitumens over a wide range of temperature and frequencies. Furthermore, a simple approximation applied to the 2S2P1D model allows to model the creep data satisfactorily. The goodness of fit statistical analysis showed that the model had a good correlation compare to the measured dynamic modulus data.