[dexxxx_raw]

hello
my question can seem a little bit stupid  .however, i get that humidity represents the amount of water vapor contained in air.
 but i'm facing a problem in understanding how a cement powder could contain humidity. to be specefic is this humidty a water vapor or a liquid ? what is the chemical process during wich the h2o molecules are eliminated when this powder is heated ? and finally if this humidity is in form of water why doesn't react with cement ?

thanks.