Investiqation of Delamination on Ⅰ-65 in Indiana

摘要

This paper presents an investigation of delamination on the northbound driving lane of Ⅰ-65 near Brookston, IN, utilizing field pull-off tests to evaluate interface bonding strength. In addition, ultrasonic test, asphalt binder test, and mix property (mechanical and volumetric) tests [i.e., dynamic shear rheometer (DSR) test, asphalt binder extraction, binder content, sieve analysis, and mix specific gravities] were conducted to explore the cause(s) of delamination. The pull-off test results showed that the delaminated pavement had a weaker interface bond, which generated more top-down fatigue cracking. In addition, the delaminated pavement contained more aged asphalt binder and a higher percentage of air voids, which could have accelerated top-down fatigue cracking as well. In conclusion, the causes of delamination were a combination of weak interface bonding and asphalt mix durability of the surface course.