Basalt fibres in GRC/GFRC

Glass fibre reinforced concrete has long been the reference material for thin architectural panels, façade elements, and other cement-based products that need high tensile performance. But the recent literature shows growing interest in basalt fibres as a serious alternative for GRC/GFRC because they offer high tensile strength, good thermal stability, and strong chemical resistance while also being produced from abundant volcanic rock.

A practical way to think about basalt fibres is that they sit in a useful middle ground: stronger and often more heat-resistant than many polymer fibres, less vulnerable to alkali issues than ordinary glass fibres, and usually more affordable and scalable than carbon fibres. Reviews also note that basalt-fibre concrete often becomes less workable as fibre dosage rises, so mix design matters as much as the fibre itself.

Why fibres matter in GRC

GRC and GFRC are used because plain cement paste is brittle and weak in tension. Fibres bridge cracks, transfer stress after microcracking starts, and improve toughness, impact resistance, and post-crack behavior. In reviewed basalt-fibre studies, the overall pattern is consistent: the fibres can improve strength and ductility, but too much fibre reduces flowability and can offset the gains through poor dispersion and higher air content.

That balance is especially important for GRC, where thin-wall casting and uniform distribution are critical. In fibre cement products, a material that is theoretically stronger but difficult to place or consolidate can perform worse in real production than a slightly weaker but well-dispersed mix.

Basalt versus glass

For traditional GFRC, AR glass fibre is the benchmark, but basalt fibres are increasingly viewed as one of the most credible replacements or hybrid partners. The literature highlights an important distinction: glass fibres can perform well, but their alkali resistance is a long-standing limitation in cementitious environments, while basalt fibres are repeatedly described as more chemically stable in alkaline conditions

This does not mean basalt automatically wins in every mix. Some studies show basalt fibre mixes may still suffer from reduced workability, and the best dosage is often modest rather than high. The review evidence suggests an approximate optimum range around 0.5 to 1.5% by volume in many concrete systems, although the best proportion for GRC specifically depends on fibre length, matrix composition, and manufacturing method

Alternative fibres for GRC

If the goal is broader material selection, the scientific record points to several alternative fibres for GRC beyond basalt and glass. Polypropylene fibres are widely studied because they improve crack control, shrinkage resistance, impact response, and durability-related behavior, especially at low dosages. However, polypropylene has a lower modulus than mineral fibres, so it is usually better for crack mitigation than for high stiffness or structural load transfer.

Other alternatives include steel fibres, carbon fibres, and hybrid blends. Steel can improve toughness and post-crack carrying capacity but raises corrosion and workability concerns; carbon fibres offer excellent stiffness and strength but are expensive; hybrid systems can combine crack control from one fibre with stiffness or durability from another. In practice, this means the best fibre is not “the strongest” one, but the one that best matches the product’s exposure, load case, and manufacturing constraints.

What the studies show

Across the reviewed literature, basalt fibres tend to improve tensile, flexural, and fracture-related properties more reliably than compressive strength. That is exactly what you want in GRC products, where crack resistance and toughness are often more important than peak compressive capacity. Reviews also report better failure behavior, with basalt-reinforced mixes tending to fail less explosively and more ductilely than plain cement materials.

The same studies also warn that fibre dosage, length, and dispersion control everything. Longer fibres can bridge cracks more effectively, but they are harder to distribute evenly; higher volume fractions can improve bridging up to a point, but then reduce flow, trap air, and weaken the matrix. For manufacturers, this means the “best” basalt fibre mix is usually the one that maximizes uniformity, not the one that simply adds more fibre.

Mix design guidance

For GRC/GFRC development, the most defensible strategy is to start with a low-to-moderate basalt fibre dosage and then tune workability with the matrix, water-to-binder ratio, and admixtures rather than forcing the fibre content upward. The literature suggests that fibre length and dosage should be selected together, because the same percentage can behave very differently depending on geometry and dispersion.

A useful design rule is to treat fibres as a crack-management system rather than a strength shortcut. If the target is façade panels, cladding, or thin architectural elements, then abrasion resistance, toughness, and crack spacing are usually more valuable than a small increase in compressive strength. That is where basalt fibres and hybrid fibre systems can be especially attractive.

Best use cases

Basalt fibres are a strong candidate where GFRC needs better durability, thermal resistance, or long-term performance in harsh environments. They are also promising in applications where a manufacturer wants to reduce reliance on conventional glass fibres while keeping a mineral-fibre system with similar processing logic.

Polypropylene fibres are a better fit when shrinkage cracking, fire spalling mitigation, or low-cost microcrack control are the main goals. Steel and carbon fibres are more specialized choices for higher structural demand or premium performance targets. For many real-world products, a hybrid mix can be the most practical answer because it spreads performance across more than one fibre type.

Conclusion

The scientific literature supports basalt fibres as one of the most promising alternative fibres for GRC and GFRC, especially when the goal is improved crack resistance, ductility, and durability rather than pure compressive strength. The main engineering challenge is not whether basalt fibres work, but how to dose and disperse them without harming workability.

Should you still call it GRC? Or perhaps BRC and BFRC would be better in this case?

For architects, manufacturers, and researchers, the key message is simple: basalt fibres are not a drop-in miracle replacement for glass, but they are a highly credible next-generation option for durable, high-performance cement composites. In many cases, the best results will come from careful hybridization and mix optimization rather than from choosing a single fibre as a universal winner.

Resources

• Basalt Fibers Reinforced Concrete: Strength and Failure Modes – Buthainah Nawaf AL-Kharabsheh, Mohamed Moafak Arbili, Ali Majdi, Saleh M Alogla, A Hakamy, Jawad Ahmad, Ahmed Farouk Deifalla.[pmc.ncbi.nlm.nih]
• A review of the mechanical properties and durability of basalt fiber-reinforced concrete Yuanxun Zheng, Yu Zhang, Jingbo Zhuo, Yamin Zhang, Cong Wan[sciencedirect]
• Basalt fibre-reinforced concrete: review of fresh and mechanical properties – Naraindas Bheel.[link.springer]
• Dynamic behaviour of cement mortars reinforced with glass and basalt fibres – Luigi Fenu, Daniele Forni, Ezio Cadoni.[sciencedirect]
• Effect of the addition of polypropylene fiber on concrete properties: a review – Mujeebul Rahman Latifi Icon,Öznur Biricik Icon &Ali Mardani Aghabaglou[tandfonline]
• Review on the Durability of Polypropylene Fibre-Reinforced Concrete – Yanzhu Liu, Liang Wang, Ke Cao, Lei Sun.[onlinelibrary.wiley]
• Utilizing polypropylene fibers to improve physical and mechanical properties of concrete – Roohollah Bagherzadeh, Abdol-Hossein Sadeghi, Masoud Latifi.[journals.sagepub]
• Basalt Fibers: An environmentally acceptable and sustainable green material for polymer composites  – Praveenkumara Jagadeesh, Sanjay Mavinkere Rangappa, Suchart Siengchin.[sciencedirect]