rebar is included in concrete for the express purpose of HANDLING TENSION LOADS...As i said above, I'm a carpenter by trade, and I have, well, too much! experience with rebar...only, not as a basis for forging blades.
Concrete has incredible compressive strength, about equal to steel (though of course both materials have variables). What concrete lacks is tensile strength. Therefore, we place rebar in beams and such so that the steel can lend its tensile strength to the compressive strength of the concrete. In fact, most of the rebar is place near the BOTTOM of beams and girders, as this is where its tensile strength ismost useful.
So to say that rebar lacks tensile strength is a mistake...but other than its use in construction, i don't know what it's good for.