The roof should be covered or protected with some membrane or chemical topside to prevent water intrusion into the otherwise-base and exposed concrete. It is sloped, and if so, by how much? Water (rain) or snow loads as well? And have you verified there are no "ponds" or continuous wetted areas that do not drain?
shonuff....the acceptability of moisture in concrete depends on the application. For example, if you are considering applying a surface treatment to the concrete or if you are applying an adhesive to attach something to the concrete (flooring, roofing, etc.), the moisture content should be as low as possible and the pH should be allowed to reach a relatively low level as well. The moisture content in such applications should be in the range of 5 to 8 percent or even less. The pH should be in the 10 range for coating or latex adhesive application.
Otherwise, the moisture content in concrete is somewhat irrelevant and it is ok for it to be high as this allows better durability and strength in the concrete.
