What is shockcrete?

Answer 1

The material you are likely referring to is called shotcrete, not shockcrete. Shock-crete is a flooring material and not used for Swimming Pools that I know of.

Shotcrete is sprayed onto surfaces (like pools) that contains a primer and a type of polyurethane topcoat that contains an aggregate that finishes off looking like concrete in most applications. it is used mainly to apply monolithic linings that have a good chemical resistance. it is often used in pools, tunnels, etc., much like gunite

i think its is concrete injected into the ground to firm up supports and the ground.