This final report, in four volumes, of Strategic Highway Research Program (SHRP) Project A-002A describes intensive investigations of the chemical and physical properties of petroleum asphalts used in the construction of highway pavements. The emphasis in the chemical studies has been to measure and understand the various interactions among molecular species that contribute to a high molecular weight-like behavior that explains the rheological behavior of asphalt. In the measurement of physical properties primary emphasis was given to the characterization of rheological behavior, that is, viscoelastic behavior as a function of temperature and loading rate. The fracture (direct tension) behavior of asphalt cement was also investigated and limited studies were conducted on fatigue behavior and other miscellaneous physical properties. Correlation of chemical and physical properties to explain the nature of asphalt in terms of a self-consistent model has been another major effort, which in the main has been accomplished. The self-consistent description of petroleum asphalt has been used further to develop predictive capability for describing the anticipated performance of asphalts in roadways. The model and predictive capability constitute the major portion of volume 1 (ST 941577). The chemical studies and their implications constitute volume 2 (ST 940379). Physical property and field validation studies constitute volume 3 (ST 941188), and volume 4 (ST 941578) contains detailed descriptions of techniques, both established and newly developed, used throughout SHRP Project A-002A.
Samenvatting