The direct adhesion test is used to determine the adhesion strength of hot-poured asphalt crack sealant at the application temperature as specified in AASHTO MP 25 and PP 85.
The adhesion test is a test of fracture. The object of the test is to apply tensile forces to the interface between sealant and aluminum end pieces. Sealant is confined between two half-cylindrical aluminum end pieces. The applied force and displacement can be recorded as functions of time. Energy required to break the bond can be calculated by measuring the area under the load-displacement curve. This energy can be considered a measure of bonding. In addition, the maximum force to failure can be reported as adhesion strength.
This standard was formerly designated as provisional standard TP 89.
