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2016SummerShotcreteEMag

Pool & Recreational Shotcrete Corner Fig. 4: Experienced ACI Certified Nozzleman shooting a beam—no cuttings will be reused in the structure. Also, note the blue tarp providing protection from overspray 4. Shotcrete nozzleman should have a minimum of 3 years of experience and hold a current ACI nozzleman certification in the process being used. 5. Listing of the type of equipment: dry-mix gun, wet-mix pump, and air compressor size (minimum 250 cfm compressor for wet-mix and 500 cfm for dry-mix). 6. Concrete mixture design: minimum 4000 psi (28 MPa). During Construction 7. Proper setup of grades (including set wires for floor, walls, beam, and lights). 8. Prepare templates for radius sections (no steel stakes allowed in soil that may contact reinforcement). 9. Shooting sequence (cast or shoot floor FIRST). 10. NO rebound, cuttings, or spoils to be incorporated in fresh concrete sections. 11. All joints must prepped in the first 30 minutes. 12. Air lance used for shotcrete application. 13. Predampen subgrade or substrate before shooting. 14. Consider the shooting sequence for attached spa or wading pool. 15. Production rate (how many days for shotcrete placement). 16. Proper disposal of rebound removed from pool during shooting. 17. Proper curing. 18. Shotcrete materials, testing, and placement should meet the guidelines of ACI 506R-16, “Guide to Shotcrete.” Fig. 5: ACI-certified nozzleman shooting walls with air-lance (blow pipe) tender cleaning the floor/wall joint before shotcreting so no rebound is used in the structure. Also, note the floor was completed first. The reinforcement at the bottom of the wall is for a bench that will be shot after the wall is complete. The contractor will need to clean all rebound and cuttings out from the bench area before shooting it Fig. 6: When checking reinforcement, make sure the bars have proper clearance and cover. Reinforcing bars should be separated to meet the requirements of the project specifications and applicable local building codes. Stagger laps when possible to avoid bundling bars at contact laps, as seen at the top of the reinforcement in this image. Non-contact lap splices are preferred in shotcrete applications. Preconstruction shotcrete test panels may be required for contact laps that exceed No. 4 (No. 13M) reinforcement Fig. 7: Plumbing is a major component of most pools. Often, the plumbing components need to be placed in a way to allow for proper shotcrete placement. Enough room needs to be provided in the design for the plumbing, skimmer, lights, and reinforcing steel; pools take a lot of pre-planning with a qualified contractor and experienced crews Shotcrete • Summer 2016 27


2016SummerShotcreteEMag
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