ASTM D 7234 : 2022

1.1This test method covers procedures for evaluating the pull-off strength of a coating on concrete. Pull-Off strength of coatings for other rigid substrates is described in Test Method D4541. The test determines the greatest perpendicular force (in tension) that a surface area can bear before a plug of material is detached. Failure will occur along the weakest plane within the system comprised of the loading fixture, glue, coating system, and substrate, and will be exposed by the fracture surface.

1.2This test method uses a class of apparatus known as portable pull-off adhesion testers.2 They are capable of applying a concentric load and counter load to a single surface so that coatings can be tested even though only one side is accessible. Measurements are limited by the strength of adhesion bonds between the loading fixture, coating system and the substrate or the cohesive strengths of the glue, coating layers, and substrate.

1.3This test method is suitable for both laboratory and field testing.

1.4Pull-off strength measurements depend upon both material and instrumental parameters. There are different instruments used that comply with this test method. The specific instrument used should be identified when reporting results. This test is destructive and spot repairs may be necessary.

1.5The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.