Pull off adhesion test : choice and influence of the diameter of the dolly

[kinkin28]

Hello,

I am a french material engineer.

I want to carry out pull out tests on coatings applied on steel surface and concrete surface.

So my questions are :

- Do you know why the diameter of the dolly is different between concrete surface (50 mm) and steel surface (20 mm or < 20 mm)?

- Is there an influence of the diameter of the dolly on pull out test results ?

Thanks for your answers