Glassfiber reinforced concrete (GRC)
Glassfiber reinforced concrete (GRC) is the unique composite material consisting of plasticized mix of concrete with glassfiber, which functions as reinforcing.
Basic material properties:
- The durability is exceeding durability of usual concrete and weight several times less the weight of concrete,
- its low weight is closely connected with unique possibilities of installation.
Reinforcing concrete with glassfiber not only improves strength properties of the concrete, but that is more important, raises performance properties of the products and structures, that means:
- resistance to temperature and humidity, to dynamic impacts, deterioration that in return allows to receive appreciable economic benefit by manufacturing and installation of GRC décor elements.
Glassfiber reinforced concrete possesses high figure of durability:
- At bending - the large shock strength, elasticity,
- Resistance to cracking,
- Frost resistance,
- Fire resistance,
- GRC possesses high resistance to chemicals, including city pollution and solutions of salts, and consequently it can be used as a material for facades refinishing,
- To all listed it has good acoustic characteristics,
- It also does not rot, corrode of rust, and does not burn.
By its purpose the glassfiber reinforced concrete can be divided into structural, waterproofing, decorative and special GRCs. On base of its purpose, it gives certain properties by connecting long-fiber and short-fiber elements of glass-fiber reinforcement and manufacturing techniques.
The GRC material gives to the architect such possibility of an embodiment of his plans with which any other material cannot compete on its plastic properties, a pliability, property to transfer and change the working surface, and also ease of work. Applying a basis of grey or white cements with an insignificant addition of inorganic dyes, and also sand and other filling materials, makes is possible to create wide scale of colors. The applied layer which is not exceeding thickness of 5-15 mm makes the minimum expenses for materials.
As considerable addition to facing panels can be decorative architectural semi-antique elements the can serve also at restoration and reconstruction of buildings. GRC is indispensable for framing a window or door openings, for cornices at building perimeters, manufacturing of porticoes, sunscreens, and for hardscaping constructions. GRC allows shaping a product of any profile; give a form and a surface finishing matching to a surrounding landscape.
There are two methods producing GRC products: a premix and air sprayed method
The word premix tells for itself. That is preliminary mixing of a cement-sandy mix with small chopped glassfiber, and following pouring it into in advance prepared form. This method is acceptable basically for the large-sized designs, not demanding for a special thin-wall design.
For manufacturing of architectural decoration products air spraying method more often is used; it allowing achieving an organic combination of durability and grace. Air spraying is performed by means of a special air compressor in which there are special knifes for cutting the glassfiber.
Forms are filled in two stages. The first stage is spreading of a superficial obverse layer by thickness of 1-1,5 mm, that consisting of cement-sand mixes without add-on of glassfiber. The second stage is applying of the basic strength layer – approximately 15–25 mm with automatic feeding of adjustable - dosed reinforcing glassfiber.