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operator and should be able to fill any of the operates and maintains a clean gun and assists in positions if required. ensuring quality control. The gunman should be Nozzleman’s Duties—The nozzleman is a particularly attentive to the needs of the noz- key person in a shotcrete operation. He is respon- zleman to ensure that the mixture is properly sible for applying the shotcrete and bringing it prepared. The gunman generally oversees, con- to required line and grade in a workman-like trols, and coordinates the material mixing and manner. The nozzleman’s duties include coordi- delivery operation. nating the application with the foreman, finisher Pump Operator’s Duties (wet-mix)—The or rodman, and pump/gun operator. Before the pump operator regulates the pump to uniformly shotcrete is installed, the nozzleman should deliver the wet-mix shotcrete at the required rate. ensure that all areas to receive shotcrete are The pump operator is responsible for cleaning and clean, sound, and free of loose material and that maintaining the material hose and pump. The anchors, reinforcement, and ground wires are pump operator coordinates the delivery of the properly placed and spaced. shotcrete mix and monitors the water content by In the dry process, the nozzleman controls the observing or testing the slump of the mixture. The water content for hydration and ensures that the pump operator may change the delivery rate of operating air pressure is uniform and will provide the transit and ready mix trucks, including staging high velocity at impact for good consolidation. In the trucks at the pump. The pump operator is also the wet process, the nozzleman controls the air responsible for all the safety concerns of the pump that increases or decreases the velocity to ensure and delivery line. proper placement, which includes proper encase- Mixerman’s Duties—The mixerman’s duties ment of the reinforcement. include, where applicable, the proportioning and The nozzleman provides leadership and direc- mixing of the shotcrete mixture materials and tion for the shotcrete crew, which aids in the task maintaining and cleaning the mixing equipment. of shooting high-quality shotcrete. The nozzleman For field mixing, the mixerman is responsible for is usually an accomplished finisher or rodman and storage, care, and accessibility of the materials. gunman/pump operator. The mixerman makes sure that the mixture is free Wireman Duties—The wireman sets eleva- of contaminated materials and debris and that the tions and thicknesses for the shotcrete placement, aggregates have the proper moisture content. He which may include the top and face of the wall. ensures a constant flow of shotcrete materials but Grades set by the wiremen are the lines the noz- is also careful not to mix more material than can zleman and finishers will follow. The wireman be used within the specified time limits. The may use many devices for setting grades, such as mixerman supervises the laborers who are sup- piano wire, fiberglass-metal rods, plastic pipe, and plying and loading the mixer. so on. Hose Tender’s Duties—The hose tender’s Finisher/Rodman’s Duties—The finisher rods, duties include moving tools, equipment, hoses, or cuts, the freshly placed shotcrete surface, scaffolding, and materials. Hose tenders clean bringing it to line and grade before final finishing. work areas, remove rebound and overspray, and The finisher also locates and removes sand pockets, provide support for the shotcrete application. sags, and sloughs and guides the nozzleman to low Project Engineer, Project Manager, or spots that require filling with additional shotcrete. Superintendent’s Duties—On large or compli- Before the shotcrete is set, the finisher brooms cated projects, a project engineer, project man- and prepares the surface for final application. ager, or superintendent may be advisable. A Assistant Nozzleman’s Duties (blowpipe/air shotcrete contractor usually employs engineers, lance control)—The assistant nozzleman helps project managers, or superintendents who may the nozzleman by dragging the hose and per- not be assigned to a single project full time. The forming other duties as directed by the nozzleman. project engineer, project manager, or superinten- The assistant nozzleman relays signals between dent is responsible for the material selection, the gunman/pump operators and may also relieve mixture proportioning, preconstruction testing, the nozzleman for short rest periods. The assistant qualifications of the crew, equipment selection, nozzleman may operate the air lance, if one is project planning, scheduling, logistics, materials required, to keep the areas in advance of the handling, quality control, sampling and testing shotcrete free of rebound and overspray. The coordination, and troubleshooting technical assistant nozzleman may be a nozzleman trainee problems during construction. and place shotcrete under the direct supervision of a certified nozzleman. Crew Qualifications Gunman’s Duties (dry-mix)—The gunman General—The quality of a completed shot- provides a constant flow of properly mixed dry- crete application results from the combined skills mix material to the nozzleman. The gunman and knowledge of the shotcrete crew. The foreman Shotcrete • Summer 2013 29


2013SumShotcreteEMag
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