Plain English Meaning
A lightweight, brittle concrete that breaks apart in a controlled way when an aircraft rolls over it, slowing the aircraft down without damaging it.
Full Definition
A specially engineered, low-strength cellular concrete designed to collapse predictably under the weight of an aircraft, used to construct Engineered Materials Arresting Systems (EMAS) installed at the end of a runway to safely decelerate an aircraft that overruns.
Context Anchor
You may see this term in runway safety discussions, airport planning material, or descriptions of an EMAS installed beyond a runway end.
Derivation
‘Crushable’ simply means able to be crushed. The phrase highlights that this is concrete deliberately made weak — the opposite of normal structural concrete — so that it gives way under the aircraft instead of resisting it.