Published 2026-10-22 · last updated 2026-10-22 · Remarkable Group
Choose carbon for the highest tensile strength per kilogram and the lowest weight, fibreglass (AR glass) as a cost-effective, non-corrosive standard solution, basalt where heat resistance or chemical stability matter, and steel only where corrosion plays no role. All three composite alternatives do not rust; steel does, as soon as moisture and oxygen or chloride reach the metal.
Anyone specifying reinforcement for concrete or masonry can now choose between traditional steel and three non-corrosive composite materials: carbon, fibreglass and basalt. They solve the same problem (absorbing tensile forces that concrete or masonry cannot handle on its own), but differ strongly in strength, weight, price and where they are or are not suitable. This article puts the four side by side.
The values for carbon come from the technical data sheet of REBAR carbon (our own product); the rest is general material knowledge and gives typical values.
| Property | Carbon | Fibreglass (AR glass) | Basalt | Steel |
|---|---|---|---|---|
| Tensile strength | High: REBAR carbon ≥ 2,000 N/mm² | Medium, lower than carbon | Medium to high, comparable to fibreglass | Medium: structural steel is typically around 500-550 N/mm² |
| Weight / density | Very low: carbon fibre is typically around 1,600-1,800 kg/m³ | Low: fibreglass is typically around 2,500-2,600 kg/m³ | Low: basalt fibre is typically around 2,600-2,800 kg/m³ | High: steel is around 7,850 kg/m³, a factor of 3-5 heavier than the three composites |
| Corrosion | Non-corrosive, no metal | Non-corrosive, no metal | Non-corrosive, no metal | Susceptible to corrosion with moisture, oxygen and especially chloride (de-icing salt, seawater) or carbonation |
| Electrical / magnetic conductivity | Conducts electricity (carbon fibre is electrically conductive) | Does not conduct | Does not conduct | Conducts electricity and is magnetic |
| Alkali resistance | Alkali-resistant | Alkali-resistant (hence "AR": alkali-resistant) | Alkali-resistant | Not applicable (no alkali attack, but corrosion instead) |
| Typical applications | Highly loaded structures, bridges, tunnels, maritime construction, bed joint reinforcement (BRIKSY Carbon) | Floors, walls, bed joint reinforcement (BRIKSY AR-glas), general reinforcement meshes | Heat-exposed and chemically exposed applications, flexible reinforcement meshes | Standard load-bearing structures without corrosion risk |
| Price indication (relative) | High | Low to medium | Medium | Low |
Carbon has the highest tensile strength per kilogram of the four materials in this comparison and is the lightest. REBAR carbon, our carbon reinforcement bar, has a characteristic tensile strength of ≥ 2,000 N/mm², well above what structural steel achieves. That makes carbon the obvious choice where weight or transport plays a role (for example at a hard-to-reach location), where the highest strength per square millimetre is needed, or where an aggressive environment (chloride, seawater, de-icing salt) makes corrosion of steel unacceptable: bridges, tunnels and maritime structures.
Note: carbon conducts electricity. Near high voltage, with lightning protection, or where magnetic neutrality is required, carbon is not the right choice; fibreglass or basalt fits better there.
Remarkable products: REBAR carbon (reinforcement bar), GRID carbon (reinforcement grid), FLEX GRID carbon (flexible reinforcement mesh), BRIKSY Carbon (bed joint reinforcement for masonry).
AR glass (alkali-resistant fibreglass) is non-corrosive, electrically non-conductive and generally the most accessible in price of the three composite materials. That makes it a logical standard choice for reinforcement applications where carbon's extreme strength is not needed, but corrosion resistance is: floors, walls and bed joint reinforcement in masonry.
Remarkable products: GRID glass (reinforcement grid), FLEX GRID AR-glas (flexible reinforcement mesh), BRIKSY AR-glas (bed joint reinforcement for masonry).
Basalt, like fibreglass, is non-corrosive and electrically non-conductive. Basalt fibre is mentioned in general material literature mainly for its heat resistance and chemical stability, and is therefore interesting for projects with thermal loading or exposure to aggressive chemicals, alongside the ordinary reinforcement application.
Remarkable product: FLEX GRID basalt (flexible reinforcement mesh).
Steel remains the simplest and cheapest choice for many standard load-bearing structures, especially where corrosion plays no role (dry, shielded environments) and where the structural engineer wants to calculate with known, standardised steel grades. As soon as chloride, carbonation or a maritime or winter environment comes into play, extra concrete cover or a protective measure is needed to prevent corrosion; that is exactly the trade-off where carbon, fibreglass or basalt come into view as an alternative.
This comparison is intended to orient the material choice, not to produce a reinforcement design yourself. The structural engineer of the project decides which material, which quantity and which cover are needed, based on the applicable standards and the specific load. Processing (sawing, bending, fixing) differs per material; if in doubt, request the technical data sheet via the product page.
Not necessarily. Carbon is stronger per kilogram and does not rust, but steel is cheaper and the structural engineer has worked with it for decades. For a standard load-bearing structure without corrosion risk, steel often remains the obvious choice; carbon gains ground where corrosion, weight or concrete cover are the bottleneck.
Steel is a metal and corrodes electrochemically as soon as moisture and oxygen (or chloride, for example from de-icing salt or seawater) reach the metal. Fibreglass, basalt and carbon are not metals; they have no electrochemical corrosion process and therefore do not rust.
Not without coordinating with the structural engineer. Both are non-corrosive and electrically non-conductive, but they differ in strength, price range and in which products Remarkable offers them. Which of the two fits depends on the load and the budget of the project.
It can be in a few specific situations: near high voltage, with lightning protection, or where magnetic neutrality is required (for example in MRI rooms or certain laboratories). Fibreglass and basalt do not conduct electricity and are the more logical alternative in those cases.
Carbon (REBAR carbon, GRID carbon, FLEX GRID carbon, BRIKSY Carbon), AR fibreglass (GRID glass, FLEX GRID AR-glas, BRIKSY AR-glas) and basalt (FLEX GRID basalt). None of the products below are made of steel; steel appears in this article only as a comparison material.
Our specialists will gladly help you choose the right material.