Shotcrete is a placement method for concrete. If the sand can be used for concrete, it should be acceptable for shotcrete placement. To some extent, the type of shotcrete equipment may make a difference. If shooting wet-mix shotcrete, the concrete mixture must be able to be pumped. For pumpability, we do recommend a smooth gradation of the fine aggregate. If shooting dry-mix shotcrete, the sand gradation has much less effect, and you should be able to shoot most any sand in your concrete mixture.