Volume 39, Issue 2 (March 2011)
A New Laboratory Evaluation Method for the Adhesive Performance of Crack Sealants
Crack sealing is a practice used for routine and preventive maintenance as part of a pavement’s preservation strategy. However, crack sealant failures are common in Texas, particularly within the first 3 years of application (or service life). The major causes of sealant failures can be classified under two categories: Adhesion failure and cohesion failure. Although both failures can lead to a significant reduction in the service life of a pavement structure, adhesive failure is in most cases the dominant failure type. Several laboratory tests such as rotational viscosity, penetration, softening point, ductility, and bond tests are currently used to evaluate the properties of crack sealants. Among these tests, the bond test is specifically used to evaluate the adhesive failure of crack sealants and the procedure of the bond test is well documented in ASTM D5329-07. However, the bond test often takes several days to complete, and the pass/fail criterion is determined through visual observation, which is a very subjective process. Furthermore, the correlation between the bond test and adhesive failure performance of crack sealants in the field was found to be either weak or non-existent. In an attempt to minimize these problems, a simple, fast, and adhesive performance-related laboratory test method is developed in this paper to ensure the proper selection of a sealant for a given project.