What is a type of knot construction used to join two ends of webbing together and create a loop?

The type of knot construction used to join two ends of webbing together to create a loop is the bowline. The bowline knot creates a fixed loop at the end of a line, which remains secure and does not slip under load. It is particularly favored in rescue scenarios because it is easy to untie after being loaded, making it practical for situations where webbing needs to be quickly deployed and then reused.

The square knot, while it can join two pieces of rope, does not create a loop and can slip when loaded. The frost knot is primarily used for securing lines in fishing or similar activities but may not serve well in rescue operations that require reliability. The clove hitch is useful for securing a rope to a post or object but does not create a loop from two ends of webbing. Thus, the bowline is the appropriate choice for the purpose described in the question.