Abstract
Petroleum asphalt is a so-called viscoelastic material. In this paper, the dynamic properties of some kinds of straight asphalts, which are residual materials obtained in a vacuum distillation process of crude oil, have been investigated by means of a method which has been effective in studying the linear viscoelasticity of many kinds of amorphous polymers. Furthermore, the viscoelasticity of straight asphalt with crystal paraffin or some kinds of stearates has been also examind.
The results obtained are as follows:
(1) Straight asphalt is a thermorheologically simple material, the temperature dependence of the shift factor aT reduced to the standard temperature Ts obeys the WLF's equation and this material has a glass transition point Tg and the difference between Ts and Tg is about 50°C.
(2) The dynamic viscoelasticity of asphalt with crystal paraffin varies rapidly at temperature where the crystallization or melting of the paraffin occurs.
(3) The dynamic viscoelasticity of asphalt with Al-stearate does not differ so much from that of one without it, but that of the asphalt with Ca-stearate or Na-stearate clearly differs from that of one without them. Namely, that dynamic viscosities of these materials vary remarkably depending upon frequencies.
