New RV concrete pad - how long until I can park on it?

We built our stick home about 18 years ago and had a similar problem. As I recall, the concrete guy told me I could get on it after 3 or 4 days with a light car, but not to allow trucks (or my 5th wheel) on it for about 2 weeks. This was probably overkill, but I had many thousands invested in the concrete and didn't want to test it out to see if he was wrong.