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476660-00070-1 Report Abstract

Quantitative Characterization of Microstructure of Asphalt Mixtures

Amit Bhasin, Swapneel Badgekar and Anoosha Izadi, University of Texas at Austin, October 2010, 56 pp. (476660-00070-1)

The microstructure of the fine aggregate matrix has a significant influence on the mechanical properties and evolution of damage in an asphalt mixture. However, very little work has been done to define and quantitatively characterize the microstructure of the asphalt mastic within the asphalt mixture. The main objective of this study was to quantitatively characterize the three dimensional microstructure of the asphalt binder within the fine aggregate matrix of an asphalt mixture and compare the influence of binder content, coarse aggregate gradation, and fine aggregate gradation on this microstructure. Results indicate that gradation of the fine aggregate has the most influence of the degree of anisotropy whereas gradation of the coarse aggregate has the most influence on the direction anisotropy of the asphalt mastic within the fine aggregate matrix. Addition of asphalt binder or adjustments to the fine aggregate gradation also resulted in a more uniform distribution of the asphalt mastic within the fine aggregate matrix.

Keywords: Asphalt Mixtures, Fatigue Cracking, Microstructure, X-Ray CT

ENTIRE REPORT (Adobe Acrobat File – 5 MB)