Citation? Because I believe you are mistaken. Does a basalt rock have less tensile strength than a similarly-sized piece of concrete?
Your point based upon your assumption doesn’t accord with observed fact about ferrocement (steel has more elongation before failure than concrete as well, and yet you don’t see ferrocement structures failing due to “zero tensile strength in the steel until it is under strain”), and you have made no logical connection between your assumption and either cited or observed fact.
This illustrates a complete lack of understanding of the point actually being made. Basalt rebar is flexible. Your focus is in elongation. I get that. I believe you are incorrect about tensile strength, and you haven’t cited a source to back up your assumption.
My point, however; was not about elongation at all. Basalt rebar comes in coils under tension. When you uncoil it, it goes more or less straight but remains flexible. If you make a curve with it (like a sheer line) then it is under tension, not longitudinally, but horizontally. The sharper the curve, the more tension. If you don’t compensate for that, then you have internal structural members under tension in opposition to the embedding matrix of cement. You wouldn’t want flat steel plates forced onto a curved structure and then tack-welded into place without being shaped, either. Tension in the plate would work against the welds.
One way to eliminate that tension is pre-shape a thermo-plastic epoxy matrix of the ‘rebar’ using heat (JL’s suggestion in an older thread) and/or embedding the basalt fibers in a pre-shaped form before adding the epoxy matrix.
So the lesson here, amigo, is you appear to be so certain of your own opinions that you are not paying attention to the actual point made by other people, nor according them simple courtesy or benefit of the doubt when your own comprehension falls short.
It is an Internet forum, a certain amount of empty opinion is unavoidable. We don’t have to add to it unnecessarily.
This is simply not true. Corrosion can occur even when zincs are used, and it is not an insignificant expense or effort to maintain them, particularly on a larger vessel. Corrosion is greatly reduced when sacrificial anodes are used, but not absolutely eliminated. A steel hull will not last decades without zincs, it can corrode trough the hull in months or single-digit years.
Note: aluminum alloy is used as much as zinc now. I’ve done several dive jobs replacing these in the last year.
Because geopolymer is a relatively new material, is not as widely commercially available, and too many people assume that it is the same as Portland cement (including materials limitations), and that Portland cement’s positive attributes are outweighed by it’s drawbacks despite this opinion probably mostly being influenced by inexpert implementation as much as materials limitation.
But the main question was about basalt, not geopolymer. I brought geopoly into the conversation because it has better tensile strength and flexural modulus than OPC. And every few percent helps.
Note: I have no objections as to the viability of using basalt fibers rather than glass fibers in epoxy matrix for a fiberglass-like hull. Newer resins have increased UV resistance, better materials characteristics than the past, etc. But it will require significant expense and effort for maintenance haul-outs over time.