NATM SHOTCRETE AND SUPPORTS

This article reviews and compares dry-mix and wet-mix shotcretes, and describes the work of companies making or supplying shotcrete materials and accompanying tunnel supports. Almost all the companies considered come from the UK, Europe and USA, but one of them is South African. The main text of the article describes the companies' work and products, which are classified into: (1) chemical additives to shotcrete; (2) fibre additives to shotcrete; (3) machines for spraying concrete and shotcrete; (4) rockbolts; (5) arches. Five tables give the companies' names, addresses, and reference numbers for requesting further details. Manufacturers of shotcrete machines include the following: (1) Aliva AG of Switzerland, who manufacture dry-mix and wet-mix machines with a range of capacities useable with mechanised systems; (2) Master Builders Shotcrete Group in the USA, which makes both dry-mix and wet-mix units, together with mobile plants for feeding and mixing materials; (3) Putzmeister of Germany, which supplies shotcreting systems with continuous mixers, pumps, pipes, hoses, nozzles, additive dosage systems, and pressure control devices.