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Development of a Binder Fracture Test to Determine Fracture Energy

Reynaldo Roque

出版	University of Florida, Department of Civil and Coastal Engineering, 2012
URL	http://books.google.com.hk/books?id=ke5_AQAACAAJ&hl=&source=gbs_api

註釋

It has been found that binder testing methods in current specifications do not accurately predict cracking performance at intermediate temperatures. Fracture energy has been determined to be strongly correlated to fracture resistance of asphalt mixture, so a new fracture test and interpretation system was developed based on finite element analysis (FEA) and prototype testing on a servo-hydraulic testing machine to consistently measure fracture energy of binder at intermediate temperature. For evaluation, the new test was applied to a range of binders, including unmodified binder, SBS-modified binder, rubber-modified binder, and hybrid binder from pressure aging vessel (PAV) residue or recovered from field test sections. Statistical analysis was conducted on test results, which showed that the new fracture test and interpretation system clearly differentiated binders by fracture energy values. Expected trends in fracture energy between binders were observed. It was also shown that, for the same binder, fracture energy is independent of loading rate evaluated in this study and test temperature from 0 to 15°C. Thus, fracture energy appeared to be a fundamental property of binder, which does not depend on test condition, and can be determined by tests performed at a single temperature and loading rate. The results also showed that different types of binder have different characteristic true stress-true strain curves, which can be used to identify binder type, modifier type, and relative content. Basic principles were proposed to identify the presence of modifier from true stress-true strain curves. A detailed testing protocol was recommended. The protocol helps assure the appropriate loading rate range so that the complete true stress-true strain curve can be identified for accurate determination of fracture energy.