The term “Green Concrete” refers to a freshly poured concrete mix that has begun to set, but has not yet fully cured.
The general industry recommendation is that it be allowed a minimum 30 day cure period before applying any resinous coating system. However, this is really a guideline, the actual wait period can be much longer, depending on the composition of the concrete mix, relative humidity, temperature and other conditions.
Don’t be rushed into making a decision to coat your concrete surface without knowing that it has cured sufficiently to maintain a strong bond.
New concrete can look dry well before it is ready to be coated. As a result of the concrete mix, site conditions, different areas of the slab may have varying levels of moisture. Therefore, proper testing of several areas for moisture/moisture vapour is the only valid way to tell if the slab is ready for coating.
I recommend you make sure that the company that wants your business provides this information. An industry expert will do this as a matter of course. Choose a company well experienced on this subject.