ASTM D7234-21 Standard Test Method for Pull-Off Adhesion Strength of Coatings on Concrete UsingPortable Pull-Off Adhesion Testers

Designation: D7234-21 Standard Test Method for Pull-Off Adhesion Strength of Coatings on Concrete UsingPortable Pull-Off Adhesion Testers1 1. Scope 1.1 This test method covers procedures for evaluating thepull-off adhesion strength of a coating on concrete.The testdetermines the greatest perpendicular force (in tension) that asurface area can bear before a plug of material is detached.Failure will occur along the weakest plane within the systemcomprised of the loading fixture,glue，coating system,andsubstrate，and will be exposed by the fracture surface. 1.2 This test method uses a class of apparatus known asportable pull-off adhesion testers.3They are capable of apply-ing a concentric load and counler load to a single surface sothat coatings can be tested even though only one side isaccessible. Measurements are limited by the strength of adhe-sion boncls between the loading fixture,coating system and thesubstrate or the cohesive strengths of the glue, coating layers.and substrate. 1.3 This test method is suitable for both laboratory and fieldtesting. 1.4 Pull-off adhesion strength measurements depend uponboth material and instrumental parameters.There are differentinstruments used that comply with this tcst method. Thespecific instrument used should be identified when reportingresults. This test is destructive and spot repairs may benecessary. 1.5 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly. l.6 This standard does nor puarport to address all of thescafety concernas.if ary. as.sociated with irs use. It is there spowsibility of the user of this sfandard to establisha appro-priete safevy,eara,and environPenial practices and deter-nsine rhe applicabiliry of reguiatory linuitations prior to use. D7234-21 Standard Test Method for Pull-Off Adhesion Strength of Coatings on Concrete UsingPortable Pull-Off Adhesion Testers