In the late 1970s ACI Committee 201, Durability of Concrete, was finishing work on its "Guide to Durable Concrete" to update a 1962 report on the subject.
Today most concrete is consolidated by vibration. Vibration subjects the fresh concrete to very rapid impulses which temporarily liquefy the mixture and cause the concrete level to subside.
Shotcrete consists of the same basic ingredients as ordinary concrete; it is also feasible to use most of the same admixtures.
