If we do not have a concrete quality report from the lab but a field or physical quality of concrete is good?

Without Quality report, we can not ensure the concrete is good. We can perform NDT or core test to find the quality of concrete.

Dear Mr Mohammad,

If you have missed the concrete sampling or lab has lost the concrete sample then there is one option left with you. In that case client/ management can ask you to do rebound hammer test so as to assure the strength of concrete. Rebound hammer avg. reading can can show you the actual quality of concrete.

For more details check this link: https://theconstructor.org/concrete/procedure-for-rebound-hammer-test-on-concrete/9106/