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2016FallShotcreteEMag

Goin’ Underground ACI Nozzleman Certification and Underground Robotics By Chris Zynda I have been in the shotcrete industry for over 50 years. It all started with shoveling sand behind a gunite (dry-mix) machine and then moving on to foreman, superintendent, and ultimately owner of a shotcrete contracting firm. I have been involved with wet-mix shotcrete for over 45 years. When we started with wet-mix, batch plants had no computers and the concrete mixture was never the same (except you could count on beer cans and large rock). Fortunately, the shotcrete industry has steadily evolved over the last 30 years with computergenerated concrete mixture designs and state-ofthe art batching equipment becoming the norm, rather than the exception. The tunnel and underground industry is one of the world’s largest users of shotcrete, both wet- and dry-mix processes. Figure 1 shows handnozzling with a dual-chamber dry-mix gun in an underground tunnel. Figure 2 shows hand-nozzling of an underground chamber and shaft with high reach lifts. (Note: No scaffolding required.) Shotcrete placement with robotic equipment has become commonplace for installing rock support, final tunnel linings, and repair in the underground industry. Figures 3 and 4 show Fig. 1 Fig. 2 Fig. 3 Fig. 4 40 Shotcrete • Fall 2016


2016FallShotcreteEMag
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