Volume 2, Issue 1 (January 1974)
Glass Transition of Asphalts Under Pressure
A study was made of the glass transition phenomena on 28 different types of asphalts by means of a simple dilatometric procedure. The study was made over a range of pressures from 1 atm pressure up to approximately 2000 atm in some instances. A study of the pressure susceptibility of the asphalt glass transition temperature demonstrated that there is a linear relationship between the glass transition temperature and the pressure. The slope of this relationship was evaluated as the pressure sensitivity of the asphalt. Data are also presented on the viscosity of certain asphalts at temperatures of 10 to 60°C under 500 atm pressure. From plots of viscosity temperature data the viscosity at the glass transition temperature under 1 atm and 500 atm are compared. It was found for many of the asphalt studies that the viscosity at the glass transition was approximately 109 poises for estimates at both 1 and 500 atm absolute pressures.