1) Anhydrous cement does not bind fine and coarse agreegate. It aquares adhesion property only when mixed with water. The chemical reaction that take place between cement and water is referred as hydration of cement.

2) The chemistry of concrete is essentially the chemistry of the reaction between cement and water. On account of hydration certain product are formed. These product are important because they have cementing and adhesive value.

3) The quality, quantity and continuity, stability and the rate of formation of the hydration product are important.

4) Anhydrous cement compounds when mixed with water react with each other to form hydrated compounds of very low stability.

5) The hydration of cement can be visualized in two way.

$\quad$ A) The first is “through solution” mechanism.in this the cement compound dissolved to produced a super saturated solution from which different hydrated product get precipitation.

$\quad$ B) The second possibility is that water attack cement compound in the solid state converting the compound into hydrated product starting from the surface and preceding to the interior of the compound with time.