Why and How to Certify Sprayed Concrete Nozzle Operators为什么和如何认证喷射混凝土喷嘴操作员.pdf

ITA, SAIMM, and SANCOT: ‘Shotcrete for Africa’ Conference 2nd/3rd March 2009 C. Larive WHY AND HOW TO CERTIFY SPRAYED CONCRETE NOZZLE OPERATORS? C. Larive CETU (Tunnels Study Centre) Ministry of Ecology, Energy, Sustainable Development and Town and Country Planning ABSTRACT The quality of sprayed concrete is highly dependent on the skill of the nozzle operators. No universal standards are available to certify their ability to spray concrete. So it is necessary to identify all the available certification programmes in order to check and, if necessary to improve, the expertise of nozzle operators. This paper describes a number of the independent certification prorgammes run by different organisations. Four main programmes are now available. Three others are being developed. Certification, added to all the necessary training, is the best way to raise the quality of sprayed concrete. ∗ 1. WHY CERTIFY SPRAYED CONCRETE NOZZLE OPERATORS ? Sprayed concrete is both very similar and very different from “ordinary” poured concrete: • similar, as it is made of the same materials and provides about the same mechanical properties and durability • but very different as it is much more flexible to use but also much more dependent on the skill of workers (which does not mean that qualifications are not also an issue for poured concrete). • Having said that, as it is in their best interests, we could expect companies to have “the right person in the right place”. But, how can we be sure of that? How do we minimise the risk of mis