Normally the contact element is a bond element between steel bar and concrete and during pull out simulation this must be the bond resisting pull out.

Have you taken the same element for both?

So, either you can chose contact element or you can simply glue them ( concrete and steel bar) that may work for your purpose.

No sir ;

For the concrete element SOLID65, and for the steel LINK8,

Can you sir tell me how I integrate the bond length between steel and concrete.

check this video on youtube it might help you

https://www.youtube.com/watch?v=5W4dgjj3dOw

Thank you Zeinah Mohamad Elnassar;

I check it, the problem is that my SOLID concrete has a cylindrical geometry so the coincident nodes between the cylinder and the link are insufficient because the length of the bar is not identical to the cylinder.