Brief history of shotcrete

The first Shot Concrete was used more than a hundred years ago and consisted of a coating, which was invented by the American naturist Carl Ethan Akeley (1864-1926), in 1907. His mortar-throwing machine was used to coat the metal skeletons of prehistoric animals, since with the traditional bending could not achieve the irregular shapes of the muscles of the dinosaurs. In 1907 he patented his equipment, known as the “cement-gun”. This system consisted of introducing the dry mix (cement and aggregates) through the impulsion pipe and the water in the nozzle.

 

The cement gun company commercially exploited the invention and christened it “Gunite” which actually meant a mortar applied pneumatically at high speed.

The procedure spread rapidly in Europe. In 1930 the term “Shotcrete” emerged, introduced by the “American Railway Engineering Association”, to describe the “Gunite” process, although it is currently used in the United States of America to generally describe mortars and thrown concretes. In 1954, the American Concrete Institute (ACI) officially defined shotcrete as “a mortar or concrete sprayed pneumatically at high speed against a surface.

More than a century after the invention of shotcrete, it remains one of the most important methods in concrete technology. Shotcrete has become an excellent choice for the concrete industry. The speed in the progress of the works and the versatility in its application make this method very attractive due to its advantages for the construction of tunnels, stabilization of slopes and support of structures without the need for formwork.

We could speak of cast concrete as a discipline in which various actors intervene: in the foreground the professionals who specify and design the projects, who are responsible for knowing the methodologies to be used in the different works; on another level no less important, those in charge of technological control, who are highly experienced professionals surrounded by trained personnel and knowledgeable about the standards and test methods applicable to the materials involved in the design of the mixtures. These human teams accompany the delivery of a product to a third phase, the placement, where we also find highly qualified personnel, the launchers, who in our environment have been trained in their specialty and transmit their knowledge from generation to generation. Ultimately, it is to them that we entrust all a technological development to establish a perfect interaction between the human being, the technology and the placement equipment. Only when everything is meshed and fully coordinated can concrete mixes be cast or sprayed with guaranteed success.

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