Hydration of Cement

             Anhydrous cement compound when mix with water and react with each other to form hydrated compounds of very low solubility .The hydration of cement can be visualized into following ways

• Through Solution
• Second Possibility

Through Solution:

            The mechanism of through solution is cement compound dissolve to produce super saturated solution from which different hydrated products get precipitated.

Second Possibility:

             In this ,when the water  attacks cement compounds in the solid state converting the compund during coarse of reaction between cement and water.

Structure of Hydrated Cement:

             To understand the behaviour of cement it is necessary to study the structure of hydrated,hidden cement base .

If concrete is consider as two phase materials namely

• Paste Phase
• Aggregate Phase

Water Requirement for Hydration:

             C2s are required about 21% of water by weight of cement and C3S requires 24% of water for chemical reaction with Portland compound.
              Generally ,23% of water chemically combines with cement and therefore is called Bound Water. A certain quantity of water is imbibed  within gel spores .This water is knowns as Gel water.It can be said that bound water and gel water are complementary to each other.
              Generally,15% of water by weight is required for the complete chemical reaction and for Gel formation.Here it is assumed that hydration is taking place in the sealed container where the moisture to and from the paste does n't takes place.