Hydraulic cement

Description

A calcium-containing cement that reacts with water to harden, even without drying. Hydraulic cements composed of lime and volcanic ash (pozzolana) were first used in ancient Greece and Rome. The mixture must contain at least 12% of a silicate/aluminate component such as Clay, Calcium silicate (portland cement), calcium-aluminate, magnesium oxychloride, Pozzolana, Slag, barium silicate/barium aluminate, brick dust, volcanic ash, Pumice, etc. These may be present as original components in the burnt limestone or as additives. In water, the lime mixture hardens to a water resistant solid due to complex exothermic chemical changes involving the hydration of calcium silicates and aluminates.

Examples are: Roman cement, and Portland cement.

Synonyms and Related Terms

ciment hydraulique (Fr.); cimento hidráulico (Port.); water cement; water lime; Roman cement; portland cement; Rosendale cement; slate cement; hydraulic lime; pozzolana

Risks

• Reaction with water may be exothermic

Resources and Citations

• J.H.Wills, "Inorganic Adhesives and Cements" in Handbook of Adhesives, I.Skeist (ed.), Van Nostrand Reinhold, New York, 1977. p.117-138.

• John Ashurst "The Technology and Use of Hydraulic Lime" Building Conservation Directory 1997: Link -(contains specifications and characteristics of different mixture compositions)

• R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966

• Thomas Gregory, The Condensed Chemical Dictionary, Reinhold Publishing, New York, 3rd ed., 1942

• Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985

• Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996