ABSTRACT
Certification of shotcrete nozzlemen has become quite popular since the first ACI Nozzlemen certification was held in Las Vegas in Spring 200 I. As part of the certification process, the examiner must determine if cores extracted from a specified test panel containing several reinforcing bars show adequate encasement of the reinforcing steel. Unfortunately, there is a limited amount of information available on what quality of encasement is acceptable. This information is critical to orient the shotcrete industry, particularly the members of the ACI C660 Shotcrete Nozzleman Certification committee. This paper presents data describing the effect of reinforcement encapsulation quality on shotcrete performances. Shotcrete performance is evaluated in terms of (i) bond between reinforcing steel and shotcrete, (ii) flexural performance of shotcrete beams, (iii) protection offered by shotcrete against corrosion of reinforcement and (iv) effect of defects on freeze-thaw resistance. A discussion on acceptable limits and certification criteria is also presented.
