Non-Linear Flow and its Temperature Dependence of Paving Straight Asphalt

Abstract

In order to investigate non-Newtonian flow of asphalt and its temperature dependence, viscosity and variation of specific volume with temperature were measured with a short tube type viscometer and dilatometer respectively.The results were as follows; 1) Calculated thermal expansion coefficient of free volume was quite similar to the difference of measured macroscopic expansion coefficient at the glass transition point. 2) The upper limit of the glass transition region, the width of its region and the standard temperature were -9°C, 22.5°C and 41°C respectively. 3) Extruding pressure to give the same rate of shear was in proportion with the ratio of the length to radius of short tubes. 4) The time-temperature superposition principle applied to the nonlinear flow and the experimental values of the shift factor aT0=(φ'T0/φ'T)σ checked well with the WLF equation. 5) Apparent flow curves checked with the de Waele-Ostwald's equation φ'=Kσn. The flow curve and the viscosity-rate of shear curve at arbitrary temperature were represented by the equations φaT0=(3+n) K0σn/4 and η(φ)={(3+n)K0/4}-1/nγ(1/n)-1aT01/n respectively. 6) Another shift factor was defined as bT=(σT/σT0)φ and the relation bT={η(T)/η(T0)}φ=aT01/n was observed. 7) Temperature susceptibility was expressed as equation dη(φ)/dT=(1/n){η(γ)/aT0}daT0/dT etc. 8) The apparent activation energy of flow observed at the stated values of rate of shear was represented by the equation ΔHa, φ=Rd ln bT/d(1/T) and the one at the stated values of shear stress coincided with the apparent activation energy for viscoelastic relaxation time.