THERMODYNAMIC BEHAVIOR AND PHYSICOCHEMICAL ANALYSIS OF EIGHT SHRP BITUMENS

In order to determine criteria for the characterization of bitumens from physical data and to analyze their thermodynamic behavior during thermal cycles, a homogeneous series of eight bitumens provided by the National Research Council as part of the Strategic Highway Research Program was studied. Thermodynamic properties (e.g., transformation temperatures, crystallized fractions, enthalpy changes, expansion and compressibility coefficients, pressure-temperature state diagrams) were studied using four complementary methods of analysis: differential scanning calorimetry, thermomicroscopy, thermobarometry, and thermodilatomicroscopy. The chemical compositions were defined by gel permeation chromatography, high-performance liquid chromatography, and synchronous excitation-emission ultraviolet fluorescence. Evidence of modification of physical properties, especially during thermal cycles, compared with the proportions of the different chemical components is shown and discussed.