Concretes are designed mostly for 28 days target. if this is to be targeted for say 56 or 90 Days, then it need to be engineered via experience and trials.
So, to design a concrete to yield at 90 days, one need to have experience in same or need to conduct trials to arrive at conclusion.
In such cases concrete designer is responsible to ensure concrete do achieve the strength at that age. Detection of the failure after such a long period will lead to a very high losses even in cases where construction is done in normal speed.