Influence of Hydrated Lime on Linear Viscoelastic Properties of Bituminous Mixtures

An experimental campaign on the characterization of the tri-dimensional linear viscoelastic (3D LVE) behaviour of 2 bituminous mixtures was carried out. These 2 different mixtures were produced using the same aggregates and bitumen. As additives, two types of fillers, hydrated lime and limestone filler, were used. The goal was to evaluate the influence of hydrated lime on linear viscoelastic properties of bituminous mixtures. The linear viscoelastic behaviour of bituminous mixtures was studied using complex modulus tests (tension-compression test on cylindrical specimens) at different temperatures (from -25 to + 52 degrees C) and frequencies (from 0.003 to 10 Hz). Sinusoidal cyclic loadings of 50 mu m/m axial strain amplitude were applied. In addition to axial stress and axial strain, radial strains were also measured. The complex modulus E* and the complex Poisson's ratios nu* were then obtained and the three-dimensional (3D) LVE behaviour (with isotropy hypothesis) was then completely described. The Time-Temperature Superposition Principle (TTSP) was verified with good approximation. The same values of shift factor were obtained for uni-dimensional (1D) and tri-dimensional (3D) conditions. The 2S2P1D model (3D) developed by ENTPE team was used for modelling linear viscoelastic properties of the two mixtures. Effect of hydrated lime is discussed.