Hydration & Curing
The essential element in all good communications is that the parties involved understand the vocabulary or language used by one another in expressing their ideas and thoughts. If an idea or thought is expressed that holds two different interpretations, then communication breaks down, or at the very least is confusing and perplexing to all parties. The National Plasterers Council addresses such an issue in Technical Bulletin #2, with regard to the often-misused terms of ‘hydration’ and ‘curing’.
In the NPC Technical Manual, 9th Edition, ‘hydration‘ is defined as….”the chemical reaction between hydraulic cement and water forming new compounds, most of which have strength producing properties.” The American Concrete Institute defines ‘hydration’ as the formation of compounds by combining water with hydraulic cement.1
The Portland Cement Association, in “Design and Control of Concrete Mixtures”, describe how hydraulic cement sets, or hardens, by reacting with water. During this reaction, called hydration, cement combines with water to form a stone-like mass.”3
‘Curing‘ is typically applied to cement and concrete trades to describe the actions taken to ensure that the maturation process or hydration process continues. Curing of plaster is defined in the NPC Technical Manual (Pg. 27) as the act or process by which the cementitious surface coating continues hydration. For the interior finishes of swimming pools, curing is done by immersing the cementitious coating in water as soon as possible after final set. The hydration of the cementitious compounds will continue underwater.”1