ABSTRACT
ABSTRACT: This paper describes a study of the rheological behaviour of ten fillers in three different bitumen types. The fillers were laboratory manufactured from clean single-sized aggregates and were grouped according to their broad petrologic type. Five of the fillers were produced from aggregates, which had calcium carbonate as the principal mineral, and five fillers were manufactured from aggregates that contained significant quantities of silica. The binders consisted of 40/60 and 10/20 penetration grade bitumens manufactured from a Venezuelan crude source and a synthetic polymer-modified resin. An extensive characterisation of the fillers was undertaken to account for particle size distribution, particle shape, bulk volume, surface area and surface energy. The bitumens where rheologically characterised using standard penetration and softening point tests and more complex creep compliance testing using a Dynamic Shear Rheometer. Additionally, the bitumens in the study were characterised for surface energy using a Sessile Drop technique allowing calculations of adhesion, W
nations. The creep compliance of the bitumen-filler mastics over a range of solid volume fractions (ϕ) was measured with the relative creep compliance being derived for each of the mastics using the ratio of the creep compliance of the pure bitumen to the creep compliance of the mastic. The maximum packing fraction (ϕ
simple two-point projection technique based on the reciprocal relative creep compliance. The intrinsic viscosity (from the Krieger & Dougherty rheological model) of each filler type was derived in each bitumen type and this in turn compared to the index properties obtained during the classification of the materials. In addition the product of intrinsic viscosity and maximum packing fraction in the Krieger-Dougherty equation, which describes the stiffening effects in the mastic outside of the bulk volume filling relation, ϕ/ϕ
free energy of the mastics provided.
