Mass concrete is defined by
American Concrete Institute
The American Concrete Institute (ACI, formerly National Association of Cement Users or NACU) is a non-profit technical society and standards developing organization. ACI was founded in January 1905 during a convention in Indianapolis. The Institu ...
Committee 207 as "any volume of concrete with dimensions large enough to require that measures be taken to cope with the generation of heat from hydration of cement and attendant volume change to minimize cracking."
[ACI Committee 207–Mass and Thermally Controlled Concrete]
As interior temperature of mass concrete rises due to the process of
cement
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mi ...
hydration, the outer concrete may be cooling and contracting. If the temperature differs too much within the structure, the material can crack.
The main factors influencing temperature variation in the mass concrete structure are: the size of the structure, the ambient temperature, the initial temperature of the concrete at time of placement and curing program, the cement type, and the cement contents in the mix.
Mass concrete structures include massive mat foundations,
dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...
s, and other concrete structures with a width or depth exceeding three feet or one meter, ().
History
Historically, in Britain, mass concrete designated early concrete with no reinforcement cast in situ using shuttering. It was used mainly between 1850 and 1900 on a variety of buildings, mainly as a walling material or where mass was required for gravity such as in dams, reservoirs, retaining walls and maritime structures. In those days, the term was not officially defined and did not contain any connotation to large dimensions generating heat from hydration of cement, as these occurrences were not yet understood.
[Urquhart, Denis (2013). (huanhi]
"Historic Concrete in Scotland Part 1: History and Development"
Historic Scotland, National Conservation Centre, , p. 9
References
Concrete
Building materials
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