Mechanics-Based Asphalt Binder Test Method for Low Temperature Performance Prediction
[ NCHRP 20-30 (NCHRP-IDEA) ]
Project Data
Staff Responsibility:
Dr. Inam Jawed
This project developed a test method based on fracture mechanics, for predicting low temperature performance of asphalt binders. A low-temperature yield test was developed and validated using asphalt binders modified with commercial polymer modifiers. A simple and accurate low-temperature fracture toughness test for asphalt binders was also developed. The test measures fracture toughness and fracture energy values on three-point bend specimens with aluminum inserts. The use of inserts significantly reduced the sample amount requirement (less than 3 grams) and showed an improvement over the current SHRP procedures. The effect of sample width on fracture toughness was investigated to ascertain the plane strain condition. A survey of Highways 118 and 17 test sections data on pavement cracking for use in establishing tests and asphalt binder performance in the field was conducted and fracture tests on unaged binders and aged binders from these highways were performed. Results to-date indicate a significant improvement of the IDEA test over SHRP tests for fracture and cracking predictions. The final report is available from the National Technical Information Service (NTIS # PB2004-103344).
