METHOD FOR THE MANUFACTURE OF CONCRETE STRUCTURES HAVING HIGH IMPACT RESISTANCE AND FAVOURABLE DEFORMATION PROPERTIES BY MEANS OF CONCRETE SPRAYING

摘要

1470923 Spraying concrete B SANDELL and G LILJEGREN 31 July 1975 [2 Aug 1974] 31978/75 Heading B2F [Also in Division El] Concrete structures having high impact resistance and favourable deformation properties are manufactured by conveying a mixture of a binding agent such as cement, lime or gypsum and ballast such as sand in an air stream to a spraying nozzle 10 where water is added to the mixture through an annular passage 14 connected to a supply pipe 13 and particulate reinforcing material is added to the mixture in the nozzle either through an inlet 11 located downstream of the passage 14 or through an inlet 11' located upstream of the passage 14, and spraying the resulting mixture through the nozzle. The reinforcing material, which may be flat strips or threadshaped fibres of plastics material, glass or textile fibres or steel wire, is cut into suitable lengths by a cutter 16 which also acts as a fan and the reinforcing material is conveyed to the feed nozzle 11 or 11' through tubing 17, compressed air being introduced through a tube 19 so that the reinforcing material is sucked into the tubing 17 by ejector action. In the embodiment of Fig. 2 (not shown), pieces of reinforcing material are fed into a vibrating funnel-shaped container and allowed to impinge against an oblique plate so that they are aligned in a specific direction before passing into the tubing 17.