Page 44

2016FallShotcreteEMag

Goin’ Underground using the CP-60(15), “Craftsman Workbook for ACI Certification of Shotcrete Nozzleman,” as the key reference for the program. ACI CP-60 has all the information needed to become familiar with topics such as water-cement ratio (w/c) and importance of aggregate gradations. I have mentioned only two topics from this workbook. Do you know how your crews would answer these two questions? Figures 6 and 7 show both vertical and overhead performance panels being placed for the ACI Nozzleman Certification Program. Shotcrete for producing tunnel final linings is a fairly new application. Due to the availability and use of chemical admixtures, equipment, closely controlled concrete mixtures, and placing and finishing techniques, shotcrete is routinely used for structural reinforced retaining walls and heavily reinforced overhead sections (Fig. 8 and 9). In summary, underground shotcrete is a huge market around the globe. Advances in shotcrete technology have improved materials and placement equipment, including “robotic equipment.” However, although robotic equipment helps eliminate the physical and safety demands of hand-nozzling, successfully placing quality shotcrete underground is still highly dependent on the knowledge and skill of the nozzleman. The best way for a specifier or contractor to confirm a nozzleman’s knowledge of the basics of shotcrete is to require them to hold a current ACI Shotcrete Nozzleman certification in the process and orientation to be used on the project. ASA’s website (www.shotcrete.org/education/ index.htm) has an excellent compilation of nozzleman certification resources from both ASA and ACI. Chris Zynda is a Past President of the American Shotcrete Association, current President of the Shotcrete Concrete Contractors Association, General Manager with JJ Albanese Concrete—Shotcrete Operations, and an ACI-approved Examiner for Shotcrete Nozzleman Certification. He is a member of ACI Committees 506, Shotcreting, and C660, Shotcrete Nozzleman Certification, and ASTM Committee C09, Concrete and Concrete Aggregates. Zynda is also an approved Underground Examiner with California Transportation Agency. Fig. 7 Fig. 8 Fig. 9 42 Shotcrete • Fall 2016


2016FallShotcreteEMag
To see the actual publication please follow the link above