Aging of cements
Aging of cements is manifested by a decrease in their strength properties and a delay in the beginning and end of setting. The reason for aging is the hygroscopicity of cements, as a result, they combine with the moisture in the air, partially reacting prematurely. Higher class cements are more hygroscopic. Cementy, which have already partially aged, they are called weathered and can be easily identified by their lumps, that are formed in the cement. If the lumps do not rub easily between your fingers, (o means, that the degree of weathering is seriously advanced. Such cements cannot be used for load-bearing structures.
Cements properly stored, e.g. sealed in airtight containers, do not weathe. Therefore, cements stored in steel silos stay fresh longer, and when closed tightly, they do not age at all.