What are the design considerations for shotcrete applications?

Shotcrete (pneumatically projected concrete) requires consideration of: (1) Wet vs dry process - wet more common, less rebound, better quality control, (2) Mix design for pumpability and adhesion with accelerators, (3) Layer thickness (25-75mm per pass) and curing between layers, (4) Rebound loss (10-30% for wet process), (5) Bond to substrate - surface preparation critical, (6) Reinforcement detailing - adequate cover, avoid shadow areas, (7) Quality control - cores, panel tests for strength and bond. Applications include tunnel linings, slope stabilization, repair work, and swimming pools.