On 29/09/2019 10:23, Tricky Dicky wrote:
Logic would suggest that if you have a DPM below the concrete then the only way out for the moisture is through the top surface. I believe curing time for concrete is 28 days.

I have not consulted this site in a while but checking it out may definitively answer your question;

http://pavingexpert.com/

Is the OP talking about 'drying' or 'curing'? If it dries out too
quickly it won't be able to cure properly; on the other hand nearly all
concrete is made with more than enough water to make it workable, and
the excess water will need to dry out eventually, depending on where it is.

With ordinary cement 28 days is the 'official' curing time, i.e. nearly
all strength is achieved by then.

--
Max Demian