Glassfibre Reinforced Concrete (GRC)

What is Glassfibre Reinforced Concrete?
GRC is a composite material consisting of a mortar and fine aggregate reinforced with alkali-resistant glass fibres. GRC is normally a relatively thin cross-section, typically 12mm thickness depending on the application, and as much the tests carried out to measure performance and ensure consistent quality differ from those of precast concrete. Whereas precast concrete is usually characterized by compression strength measured in cube units, the properties of GRC are measured by flexural strength testing of thin samples, where the performance by the fibre reinforcement is evident.

GRC presents architects and engineers with a material from which the most ambitious designs can be created. It can be moulded to form modern futuristic designs or to replicate traditional historic features. GRC can be painted, faced with fine aggregate, coloured or simply left with a natural white or grey, smooth or textured finish.

Architects Alan Dempsey and Alvin Huang have won a competition to design a temporary, freestanding pavilion that will be built in front of the Architectural Association school in London early next year. The competition celebrates the 1st anniversary of the AA’s Design Research Laboratory. It was open to all students and graduates of the London counties and called for designs that made innovative use of Fibre C, a glass fibre-reinforced concrete panelling material produced by Rieder.

The image above shows a stunning view of the Fibre C modules. This pavillion demonstrates the capabilities of GRC's constructability within a tight schedule and budget, simplicity and elegant form, effective use of material and as a continuous extension of furniture to roof structure.

Benefits of Glassfibre Reinforced Concrete:
- GRC products are lightweight, easy to handle and fast to erect
- GRC products reduce loadings on buildings leading to significant savings in superstructure
- GRC is excellent for reproduction and renovation
- GRC is environmentally friendly

Throughout the years, GRC has been a popular choice for modular building due to its strength and light weight. Often used for bathroom and shower pods, in Europe it is commonly found in all types of service and utility cubicles. GRC's ability to be moulded to complex shapes and contours and replicate fine detail means that it is the ideal choice for this type of work. Also being light in weight enables larger elements to be fitted without imposing significant additional loads on the existing structure.

The types of GRC:
Cast Premix - As the name suggests cast pre-mix is a process where the fibres are added to the concrete slurry during the mixing process. The mix is then poured or pumped into a mould using very similar methods to precast concrete.

Sprayed Premix - Although this method of manufacture uses pre blended fibres the mix is sprayed into open moulds. The spray can be directed to the vertical sides of the mould thus removing the need to manufacture complex and expensive closed moulds.

Simultaneous Spray - This method of production was the first to be developed and is the still the most widely used throughout the USA, Australia, Middle East, Europe and the Far East. When designing large scale GRC components such as cladding panels it remains the only practical method due to the significantly higher bending strengths attained.

Due to its durability and aesthetic appearance, companies are now beginning to develop GRC cladding systems consisting of a number of wall panels that interlock together using a purpose made system. The use of GRC as a cladding and façade material is rapidly increasing as it provides architects with a high quality finish ad contractors with a cost effective solution suitable for fast track installation.

Leading suppliers in the UK:
www.grcuk.com
www.fibretech.org
www.bcmgrc.com
www.grc-gbgroup.co.uk

Cladding system brochure:
http://www.bcmgrc.com/flipper/grc/cladding/index.html