Cement shelf life

[Biff]

Better still, give up the addiction to Ordinary Portland Cement and take up an enthusiasm for lime.

[Dave]

In article , The Natural Philosopher writes

This is not true, cement powder loses its reactivity and you will end up with a weak matrix, not critical as far as a post mix is concerned but could be critical elsewhere. Cement is at its most reactive just after its manufactured and gets slower and weaker from then on. Just because it has set doesn't mean its strong.

You obviously don't work with structural concrete or even slabs that need to have achieved a certain strength before loading. Concrete has initial set (surface hard) and final set (hard all the way through), you are right to say that these can be dependant on temp but you can achieve a false surface set if you have severe drying conditions. The rate of strength gain of concrete is a well understood area and are usually measured at 1, 3, 7, and 28 day intervals.

[Mike]

Hmm. I have some enthusiasm for lime but supporting posts whilst waiting for it to dry would test this enthusiasm well beyond it's limits :-)

[Andrew Gabriel]

In my experience, it just gets steadily more and more lumpy, as opposed to starting off as a fine running powder.