About GRC
GRC stands for Glassfibre Reinforced Concrete. It is the generic term for a high-strength composite stone made up of cement mortar (a mixture of cement and sand-size aggregate plus additives) reinforced with bundled strands of special alkali-resistant glassfibre filaments.
Un-reinforced concrete is strong in compression but weak in tension. This is why reinforcement is added. Precast concrete is typically reinforced with steel, but precast concrete products are heavy because of their overall thickness.
With GRC, the glassfibre strands in the mortar (3-5% by weight depending on the process) greatly increase product strength while dramatically reducing product weight because of the much thinner but stronger wall sections. GRC products can be formed as thin as 6 mm (1/4 inch) so their weight is typically only 20-25% of the weight of traditional precast concrete products. This lightweight feature of GRC also makes it safer and easier to handle on site, and reduces loads on structures when installed.
The advantages and benefits of GRC
GRC combines the high strength of glassfibre with the rigidity of concrete. The resulting composite is a tough, rigid material that has a strength-to-weight ratio superior to most other commonly-used building products.
Other advantages and benefits of GRC include:
- Mouldable: GRC can be molded to accurately reproduce almost any small or large shape (e.g. curves, patterns, reliefs, etc),
- Colour: GRC products can be manufactured using different cements (e.g. white, off-white, or grey) that can be coloured with oxide pigments. Alternatively, products can be painted after curing.
- Impact resistant: GRC products are highly durable and impact resistant. They will not shatter upon impact, and any localized damage can usually be repaired.
- Weather-proof: GRC will not rust or rot, needs no painting, and because it contains no steel it will not corrode or expand. GRC does not suffer from traditional concrete cancers.
- Water Resistant: GRC is virtually impermeable to water thus making it ideal for products such as planters and water-features. Usually no additional waterproofing is required.
- Chemical Resistant: The high density and high cement content of GRC give it a higher chemical resistance than other cement-based materials.
- Fire Resistant: GRC does not burn or emit smoke when exposed to fire. This gives architects and designers greater flexibility in specifying components to satisfy fire performance requirements.
Environmentally friendly
The main constituents of GRC are based on the naturally occurring earth oxides that are used in the manufacture of cement and glassfibres. These are not generally regarded as pollutants.
The reduced weight of GRC compared to steel reinforced concrete products provides environmental benefits. An assessment carried out as part of a UK government-DETR/Concrete Industry Alliance ‘Partners in Technology’ project compared two precast concrete and GRC products that fulfil the same function. The results show that GRC has a lower environmental impact (around 40% less). The main reasons for the reduced environmental impact of GRC compared to traditional precast concrete are:
- Reduced cement usage per product
- Reduced transport costs
Free Downloads for detailed information about GRC
The features, advantages and benefits of GRC are explained in GRC in Action produced by the Glassfibre Reinforced Concrete Association in the United Kingdom (see www.grca.org.uk).