Complex modulus and fatigue resistance of bituminous mixtures containing hydrated lime

Abstract

An ongoing study on influence of hydrated lime on mechanical properties of bituminous mixtures is carried out. In this paper we focus on Linear ViscoElastic (LVE) properties and fatigue behavior.Nine mixtures were produced with the same 35/50 penetration grade bitumen, three different bitumen contents (4.4%, 5.1%, 5.8%) and three different hydrated lime contents (0%, 1.25%, 2.5%). Hydrated lime replaces a part of limestone filler (the mass of removed filler for the same mass of added hydrated lime). LVE properties of mixtures (complex Young’s modulus) were determined using a tension/compression test developed at University of Lyon/ENTPE. In the same time, two points bending tests were used to evaluate fatigue resistance.Surface response methodology and ANOVA (ANalysis Of VAriance) were carried out on experimental data obtained for different responses in order to evaluate the influence of bitumen content and hydrated lime content on linear viscoelastic properties and fatigue resistance.Time-Temperature Superposition Principle (TTSP) was verified with good approximation using very close shift factors for all tested materials. The use of hydrated lime filler (instead of limestone filler) induces an increase of complex modulus. Its effect increases with hydrated lime content. Hydrated lime does not change fatigue resistance of mixtures.