ABSTRACT
In Libya a large network of thousands of kilometers of highways and airfields was constructed during the last three decades. Unfortunately, many of these pavements have suffered from early distress in form of surface cracks appearing at pavement outer edges and along the white and yellow road markings. Preliminary diagnoses of these cracks indicated that they are non load-associated thermal cracks caused by the action of the severe environment. The basic purpose of this study was to investigate the problem of rapid hardening and aging of bituminous materials in hot arid regions. An experimental program has been carried out to follow up the process of hardening by monitoring the loss of volatile components and measuring the viscosity of the bitumen. Test samples were taken from selected sites where this phenomenon is experienced, to find out the effect of hardening due to aging and exposure to solar radiation at different depths from the surface and at different ages.
The Rheometer test was used to measure the viscosity of the bitumen binder. Two further tests for monitoring the hardening of the bitumen binder were carried out. These included a chemical analysis to measure the loss of volatile components of the binder using the Gas Chromatography technique, and the measurement of the apparent viscosity of the bitumen using the sliding plate viscometer. Finally, conclusions and recommendations drawn from this work are summarized.
