Shotcrete, or sprayed concrete, was first used in 1907 and involves pneumatically projecting a concrete or mortar mixture at high velocity onto a surface. There are two main processes - dry process involves adding water at the nozzle, while wet process fully mixes all ingredients beforehand. Shotcrete provides advantages for constructing curved surfaces like domes and tunnels efficiently due to its ability to be sprayed onto irregular surfaces with little formwork needed. It allows for material placement in hard to access areas.