Properties of capsules containing rejuvenators for their use in asphalt concrete

Rejuvenators are products designed to restore original properties to aged (oxidized) asphalt binders by restoring the original ratio of asphaltenes to maltenes. These products are used to retard the loss of surface fines and to reduce the formation of additional cracks; however, for a rejuvenator to be successful, it must penetrate the pavement surface. Besides, application of a rejuvenator will also reduce the skid resistance of the pavement, which may be significant for runways or other areas where high aircraft speeds are likely to occur. To solve this, in [1], these rejuvenators were encapsulated and mixed in asphalt concrete. The idea is that once the stress in the capsules reaches a certain threshold, the particles break and the rejuvenator is released. This research focuses on the properties of these capsules. Four different types of rejuvenators will be encapsulated and their effect on the properties of the capsules investigated. Besides, the release mechanisms of the capsules will be unravelled. Finally, the capsules will be mixed in a porous asphalt mixture, and their aspect examined under the microscope once the asphalt sample is broken under indirect tensile tests. (C) 2010 Elsevier Ltd. All rights reserved.