Shotcrete

Description

A concrete mixture that is sprayed at high velocity onto a surface. Shotcrete is also called Gunite from an early brand name. Shotcrete is composed of the same materials (Cement, Sand, Aggregate and Water) used for poured-in-place concrete. It can be applied by a wet-mix process in which the water is added prior to dispensing or by a dry-mix process in which the water is mixed in the nozzle during delivery. A patent for the first concrete sprayer was obtained in 1908 by Carl Akeley at the Field Museum of Natural History in Chicago. Shotcrete was used to apply thin layers to steel reinforced masonry sections, to coat building exteriors and to repair deteriorated stucco. Because it could be applied to vertical and overhead locations, it was also used to construct domes and shell roofs. The force produced as the concrete is propelled onto the surface negated any need for compacting the mixture. Cracking and debonding are seen in deteriorated shotcrete as well as corrosion of reinforcing bars.

Synonyms and Related Terms

betão projectado (Port.);

Brand names: Gunite

Resources and Citations

• Anne Sullivan, "Shotcrete", in Twentieth-Century Building Materials, T. Jester (ed.), McGraw-Hill: New York, 1995.

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998