Title:
Amount of Water Required for Complete Hydration of Portland Cement
Author(s):
Bryant Mather and William G. Hime
Publication:
Concrete International
Volume:
24
Issue:
6
Appears on pages(s):
56-58
Keywords:
DOI:
Date:
6/1/2002
Abstract:
There is a misconception, often stated, that it takes only the amount of water in a 0.2 w/c paste to hydrate all of its cement. This is based on the fact that only about 0.2 unit of water (by mass) chemically combines with cement during hydration. However, for a given volume of cement to hydrate completely, there must be an amount of original mixing water-filled space equal to 1.2 times the solid volume of the cement. This is because the hydration product has about 30% pore space that must be present, and water must be available to fill it. If the amount of original mixing water-filled space is less that that provided at a w/c of about 0.4, not all of the cement can hydrate, even though only half of the water will go into chemical combination.