Hello Longliner45,
There is no need for experimental concrete in a submarine hull as the forces that appear in a submaine hull of thick walls are the same as in the walls of a submarine tunnel, the legs of a oilrig or the base of a concrete dam.
So reinforcing the concrete with something else than steel would not make any sense.
The reason why you use steelreinforcement in concrete is to give the concrete strenght against tension forces.
Steel and concrete have a very similar extension characteristic when temperature changes - this makes them ideal partners in a composite material.
Do not use other reinforcement materials in your concrete it is asking for problems...
Concrete engineering is a very simple sience with a couple of quite basic rules and very forseeable results if you stay within the rules.
This is why millions of constructions all over the world trust in reenforced concrete in aplications where live depends on it.
The new thing in a concrete submarine is applying the proven engineering of tunnels, oil rigs and dams, to submarines - basicly adding a motor, rudder, and tanks, to the structure to convert it into a submarine.
Do not leave the proven field of normal concrete - this is a dangerous way that can bring up catastrophic unexpected failure.
Kindest Regards,
W.Ellmer
