Long delayed Planning consent means that my 10 bags of 25kg have sat in my garage for nearly two years. At last ready to erect the posts - but will the mix still be any good? Clearly the gravel and sand are fine but will the cement have lost its effectiveness? Presumably I could add and mix fresh dry cement in each bag to ensure that it works, but no idea how much.
If they are bone dry they may be ok but its very unlikely that they ahve sat for 2 years and not soaked up some moisture. We would not chance it in post holes as, if its no good it could be much more expensive to put it right.