Wikipedia
Pykrete is a frozen composite material made of approximately 14 percent sawdust or some other form of wood pulp (such as paper) and 86 percent ice by weight (6 to 1 by weight). During World War II, Geoffrey Pyke proposed it as a candidate material for a huge, unsinkable aircraft carrier for the British Royal Navy. Pykrete has some interesting properties including its relatively slow melting rate (because of low thermal conductivity) and its vastly improved strength and toughness over ice; it is closer in form to concrete.
Pykrete is slightly more difficult to form than concrete, as it expands during the freezing process. However, it can be repaired and maintained using seawater. The mixture can be moulded into any shape and frozen, and it will be extremely tough and durable, as long as it is kept at or below freezing.
Usage examples of "pykrete".
He swung the chopper, and as he brought it down let go with a cry of pain, for the Pykrete had suffered little damage and his elbows had been badly jarred.
He then fired at the Pykrete, which was so strong that the bullet ricocheted, narrowly missing Portal.