Composite Fiber from Rocks? Yes, as a Matter of Fact
- Ned Patton
- 11 minutes ago
- 8 min read
I have been seeing some interesting posts lately about the application of basalt fibers to all manner of composite material products and parts. I had not thought much about it until a recent post in Composites World (11/10/2025) talked about a new replacement for steel rebar made from basalt fibers. For those of you that aren’t rock people or that did not grow up in a part of the country where there were volcanoes, basalt is basically the rock that volcanoes spew all over the countryside when they erupt. I grew up in the Pacific Northwest, so I a quite familiar with basalt because that’s what we used to make driveways, and it is the crushed rock that everyone uses for all sorts of pavement materials.
As it turns out, Basalt fibers were originally developed in the US in 1923 by a Paul Dhe who was granted a patent for them (Wikipedia - https://en.wikipedia.org/wiki/Basalt_fiber). The idea didn’t get much traction until World War II when the militaries of the US, Europe, and the Soviet Union gained an interest in the use of these fibers for thermal protection. After the war, US companies (Owens Corning Fiberglass and Corning Glass Works which were two different companies at the time) shifted their focus back to glass for fibers while the Soviet Union continued to pursue the use of basalt fiber and perfected its manufacture. After the collapse of the Soviet Union in 1991, they started declassifying a number of things. It took until 1995 for the production of basalt fiber to be declassified and made available to the public. Since most of the basalt fiber production was centered in Ukraine, it took until Ukraine became independent of the USSR for their product to be sold on the open market. Of course by then most of the world had gotten used to glass fiber so there wasn’t much further research put into the development of high performance fibers made from this volcanic rock.
That is – until fairly recently. In a 2023 report on the market for basalt fibers, Grandview Research (https://www.grandviewresearch.com/industry-analysis/basalt-fiber-market) reports that from 2023 to 2030, basalt fiber composite demand will grow at a compound annual growth rate of 11.2% primarily due to the favorable properties of this fiber over glass.
So, how do you make basalt fiber, and what’s required? First you have to start with the right basalt, like the rocks pictured below.
To make basalt fiber, you have to start with a basalt that has the right mineral content, melt it down (2700 degrees F or 1500 C), and run the melt through a spinneret very much like the way they make glass fiber. Of course it’s a little more involved than this, but other than finding a quarry that has clean basalt with the right mix of magnesium and iron oxides with some other stuff sprinkled in the crystal structure of the rock (high alumina content is apparently good), and cleaning up the dirt from the crushed basalt, that’s about it. Quite unlike glass fiber manufacturing where the silica is first cleaned of all impurities before small amounts of other metal oxides are added to make the different grades of glass, basalt fiber manufacture is very straightforward, with zero harmful chemicals involved in its production. And if electricity is used to heat the furnace to 2700 degrees F, basalt fiber has basically a zero carbon footprint in its manufacture and does not produce any harmful or toxic effluents like most other composite fiber manufacturing processes do, including glass fiber.
And, interestingly enough, basalt fiber is stronger and less dense than glass fiber and has both a higher tensile modulus and higher strain to failure than glass fiber. It is also nearly impervious to chemical attack, can withstand higher temperatures because it melts at 1500 C versus glass which melts at around 800 C, and it is not only a better insulator than glass, it is also more fire resistant, most probably because of its very high melting temperature.
So what is this stuff used for? Well, that’s the article I saw in Composites World last week. Apparently, one of the larger precast concrete block manufacturers in the country announced a few weeks ago that they were going to introduce a basalt macro fiber short bar product to their precast utility infrastructure blocks. These blocks are used by utility companies to provide for underground utility infrastructure. The roughly square blocks are cast with all of the tubing runs required for the infrastructure installation, making them ready to just assemble in a ditch by hooking one block onto the next. This is apparently one of the newer means of installing the tubing necessary to provide utility infrastructure underground without having to run several different lines or pipes in one ditch.
The pic above is not the basalt fiber short bars that I saw in the Composites World article, but it is the best example of the highest tonnage use of basalt fiber today. Basalt fiber reinforcing bar is replacing glass fiber reinforcing bar because it is stronger than the glass fiber equivalent as well as being more resistant to corrosion with higher stiffness and higher elongation to failure. And it works as well as steel at about a quarter of the weight of steel. Basalt’s better resistance to corrosion and chemical attack than glass means that basalt rebar can be used in marine concrete pilings, bridge decks in areas where deicing chemicals are used, and in concrete structures in chemical plants where corrosive agents are common.
The article in Composites World that started me off on this subject was about an industrial agreement where one of the larger precast concrete infrastructure block manufacturers was beginning to eliminate their use of steel rebar and start using this short basalt fiber rod reinforcement in most if not all of their precast concrete blocks. The block manufacturer is Roman Stone, in business for over 100 years in the New York area (started in Brooklyn) that has now become one of the Nation’s premier engineered precast concrete infrastructure manufacturers. Their products are used by NYDOT (New York Department of Transportation), ConEdison, and the City of New York, as well as other cities and agencies in the New York metropolitan area. That makes them one of the largest in the country. And since they are in New York with its famously horrible winters and icy roads, this application of basalt fiber is going to be in high demand.
So, why haven’t we heard much about basalt fibers in the composites business? Aside from the fact that the Russians only declassified their process at the fall of the Soviet Union, and that the major manufacturing hub and all of the intellectual property was Ukrainian, there are a few other reasons. Since this stuff was behind the Iron Curtain until 1995, the global supply chain for it did not exist until around the turn of the millennium. All sorts of different composite fibers were already well entrenched in businesses, and a considerable amount of testing and manufacturing process control had been done with millions of dollars invested to make consistent products that could be used in regulated industries in the Western world. In other words, basalt fiber had not had its moment in the bright lights of getting a fiber approved for use in critical infrastructure like bridge decks, marine pilings, skyscraper framing (especially the higher floors where glass fiber composites have seen application), and other critical transportation and structural applications.
That is, however, changing, and changing rather rapidly. I only cited one study about the basalt fiber business outlook, but there are a few more that are even more positive. One from PR Newswire in Chicago (https://www.prnewswire.com/news-releases/global-basalt-fiber-market-forecast-report-2023-2028-use-of-basalt-fiber-in-composite-is-fastest-growing-segment-301991944.html) forecasted in 2023 that basalt fiber would have a CAGR of 12.5%, growing from a global market of $279M in 2023 to $503M in 2028. That is an astounding growth rate, which they attribute to the increasing demand across a “broad spectrum of global end-use industries”. They also attribute this increased demand to the chemical inertness, higher strength, and higher thermal resistance than other composite fibers, especially glass fibers. They also attribute this growth to the perception, correctly so, that basalt fiber has a very low carbon footprint compared to other high strength fibers.
The challenges of course are that the furnaces that make the stuff have to operate at very high temperatures, and the spinnerets that are used to make the fibers from the molten rock also need to be made from some very thermally resistant materials, which makes them more expensive and somewhat more difficult to make. These materials are considerably harder than typical metals used to make spinnerets, so drilling all of those tiny holes that the molten basalt is pressed through to make the fibers is far more difficult.
But, again, this is just an engineering and material science challenge, and since the demand appears to be strong, it will only be a matter of time before basalt fiber overtakes glass fiber in several markets, possibly even in the making of wind turbine blades and recreational boat hulls. At least with basalt you wouldn’t have to worry about the “osmotic blisters” that are the bane of most older sailboat and trawler owners’ existence.
That’s about it for this week’s post. As always, I hope everyone that reads these posts enjoys them as much as I enjoy writing them. And I hope people who are interested find something they can use in their lives or at least some ideas that they might be able to put into practice. At least I hope that these make people think a bit about sustainability and some of the major issues looming before us.
I will post this first on my website – www.nedpatton.com – and then on LinkedIn. And if anyone wants to provide comments to this, I welcome them with open arms. Comments, criticisms, etc. are all quite welcome. I really do want to engage in a conversation with all of you about composites because we can learn so much from each other as long as we share our own perspectives. And that is especially true of the companies and research institutions that I mention in these posts. The more we communicate the message the better we will be able to effect the changes in the industry that are needed.
My second book, which will be out sometime next year, is a roadmap to a circular and sustainable business model for the industry which I hope that at least at some level the industry will follow. Only time will tell. At least McFarland announced it in their Fall Catalog. And this time it is under a bit different category – Science and Technology. Maybe it will get noticed – as always that is just a crap shoot.
As I have said before, my publisher and my daughter have come to an agreement about the cover. So, I’ve included the approved cover at the end of this post. Let me know whether or not you like the cover. Hopefully people will like it enough and will be interested enough in composites sustainability that they will buy it. And of course I hope that they read it and get engaged. We need all the help we can get.
Last but not least, I still need to plug my first book. “The String and Glue of our World” pretty much covers the watershed in composites, starting with a brief history of composites, then introducing the Periodic Table and why Carbon is such an important and interesting element. The book was published and made available August of 2023 and is available both on Amazon and from McFarland Books – my publisher. However, the best place to get one is to go to my website and buy one. I will send you a signed copy for the same price you would get charged on Amazon for an unsigned one, except that I have to charge for shipping. Anyway, here’s the link to get your signed copy: https://www.nedpatton.com/product-page/the-string-and-glue-of-our-world-signed-copy. And as usual, here are pictures of the covers of both books.
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