CONTRIBUTING TO A SOUND INDUSTRY

This article describes some of the many types of specialist manufacturing equipment and chemical products for shotcreting of tunnels, and lists some of the many companies prepared to provide services and advice. Shotcrete is concrete that has been sprayed on to surfaces with any orientation. It becomes compact while, at the same time, forming a rigid support for the material to which it adheres. Both wet and dry shotcreting methods are used, and each of them has its characteristic problems and types of equipment. Robot technology, applied to shotcrete placement, has solved many of the challenges posed by rapid tunnel excavation through unstable ground. Ingersoll Rand of the USA makes a range of shotcrete robots, and Shotcrete Technologies of the USA makes the Shot-Tech robotic arm. Master Builders Technologies Delvocrete hydration control technique points the way to much better flexibility and quality in the use of wet-mix shotcrete. New materials on the market, for use with shotcrete, include: plasticisers, accelerators, resins, spray-applied concrete mixtures, additives, concrete coatings, and steel fibres and other fibres. The author concludes that shotcrete is likely to become a primary support tool for tunnelling.