WindCrete is a project ready to begin construction of ferrocement sparbuoys, for offshore wind turbines. While we’ve touched on, and even proposed such designs and the methodology to build them, this is the first real-world project I know of.
GICON is a German company proposing a ferrocement TLP (Tension Leg Platform) design for shallower installations (18m-500m depths)
As these technologies get more acceptance, and the construction costs level-out, I expect them to become more readily available.
As Basalt products become more readily available, reducing mass, increasing structural strength, and making for a more renewable product, and the potential of Geopolymer to reduce costs, as well. The future certainly is beginning to look more like Seasteading could start having results sooner.
(Note: Basalt rebar has ~30% of the mass of the equivalent steel, and as a direct replacement for steel reduces the environmental impact of mining, uses less energy to manufacture than smelting and is fairly universally available, as far as Planet Earth is concerned. In addition, since corrosion becomes a non-issue, the overall wall-thickness can be reduced, lowering both mass and costs even further. Certain potential Geopolymer formulas could reduce the cost of cement by as much as 65%, using generally available materials, as well.)