Hydraulic lime

Description

A type of Lime (Calcium oxide) that hardens by the chemical reaction with water. 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

chaux hydraulique (Fr.); cal hidráulica (Port.); hydraulic cement

Resources and Citations

• Christine Figueiredo, Alison Henry and Stafford Holmes " Hydraulic lime Production, Building Conservation Directory link

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 454

• 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

• Building Conservation Directory: website