The biggest differences between ordinary concrete and GRC relate primarily to the composition of the two composites, and consequently, their physical properties.
Traditional concrete consists mainly of gravel, binder – usually cement – and water with a small amount of the necessary additives or admixtures affecting its properties. In the case of GRC, it has the added glass fiber reinforcement.
At the most basic level, the difference between ordinary composite and GRC relates to the ratio of ingredients. First of all, the production of fiberbeton uses more cement – up to 50% of all minerals. The class of the cement used depends on the composite’s manufacturer, but it is usually 52.5 MPa, the highest possible increase in mechanical strength after 28 days, often exceeding 20 MPa. GRC also has much less water added – the mass ratio of water to the mass of cement in 1m3 of mixture is sometimes only 0.2, whereas in conventional concrete it reaches a value of 0.6 – 0.7. GRC also has added specialized plasticizers in place of water, as well as the above-mentioned glass fibers and a number of fillers (silica fume, etc.) in place of traditional aggregate. Interestingly, GRC does not usually use additives-enriched cement – any additional substances are metered manually, sometimes with an accuracy of a few grams per m3 of the mixture.
For obvious reasons, the differences in composition bring about the differences in the properties of the two composites. GRC is lighter, more resistant to bending, compression and tension, and is easier to maintain. Using special pigments, usually metal oxides, can give it a desired color. With the appropriate molds and casting techniques, GRC slabs can be freely formed and their surface shaped. Such “plasticity” of fiberbeton makes it – in contrast to traditional concrete – mostly used as an ornament or as the building blocks of individual interior design components, such as furniture, countertops, sinks, wall coverings and ceilings.
