Elcometer 510 User Manual page 13

8 ASSESSING THE RESULTS (continued)
c) Glue failure: When no coating is present on the dolly it must be
recorded as a failure of the glue. This is normally due to incorrect
or insufficient mixing of the component parts of the adhesive,
incompatibility between the adhesive, the coating, the dolly, and /
or the test surface - see Section 5 - 'Securing the Dolly' on page
en-8 for more information.
Key
8.2 EXAMINING THE DOLLY (COATINGS ON CONCRETE)
When testing coatings on concrete it is common for the adhesive bond
between the coating and the concrete to exceed the strength of the
concrete itself. In this case concrete will be removed from the surface
and will be seen on the coating on the dolly face.
Observing the test area will give additional information about the type
of failure; adhesion and cohesion between different layers of the
coating.
Adhesive
Failure
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Dolly Face
c) Glue Failure
Dolly Face
Glue
Layer 3
Layer 2
Layer 1
Substrate
Partial Coating
Failure
Substrate
Coating
Failure
R
Concrete
Failure
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