Reinforcement with microconcrete
Introduction
glass-fiber reinforced concrete (GRC, from the English glass reinforced concrete, or also GFRC, glass-fiber reinforced concrete) or glass-reinforced concrete is a construction material composed of concrete reinforced with fiberglass.
Origin
Concrete is a material that does not resist tensile stress, so to be used in construction it must be reinforced with bars or steel mesh, thus constituting reinforced concrete. However, it is necessary to protect the bars against corrosion, since steel rusts slowly in contact with the environment. For this reason, the reinforced concrete pieces must have several centimeters of concrete on each side of the bars, which results in a high final thickness of the resulting pieces. GRC was first devised in Russia in the 1940s in an attempt to reduce the thickness of concrete pieces and make them suitable for use in façade enclosures. To do this, the steel reinforcement was replaced by strands of fiberglass, which do not require such protection, thus obtaining thinner panels (another theory, not documented, suggests, however, that the use of fiberglass arose in an attempt to save steel for the war industry during WWII).
Starting in the 1960s, fiberglass began to be used to replace asbestos, due to the latter's carcinogenic potential.[1] But until the 1990s, with the rise of prefabricated construction, this material did not begin to become popular.
There is an international association to regulate the use of this material, called GRCA (International Glassfibre Reinforced Concrete Association).[2].
Composition
GRC is a composite or composite material: glass fibers are projected onto a cement mortar base in several layers, creating a final material that combines the qualities of both.
Because the purpose of the GRC pieces is to create "face" panels, the "Mortar (construction)" mortar usually uses white concrete <!R1> (lighter than the generic one), and fine-grained sand; which is why it is also called “microconcrete”. In addition, different additives are usually used in the mixture to facilitate the removal of the mold, or to better control the evaporation of water and thus avoid cracking of the pieces. It also allows the use of colorants in the mixture.