The main reason for the use of fiberglass reinforcement is the insufficient corrosion resistance of steel in an aggressive environment. The basis of the innovative reinforcement is a glass fiber of 10-15 microns, combining into a single structure using synthetic resins.
Fiberglass rebar is not oxidized and does not rust, not conduct electricity and is not limited in length. It is 9 times lighter than steel reinforcement, it has higher tensile strength. These advantages have been studied by Russian scientists since the mid-20th century. Today the composite is a demanded building material.
On the territory of Russia (that time the USSR) the development of non-metallic rebar began in the 1970s. The production centers were at that time in Moscow, Minsk and Kharkov. Research did not stop, but there were some constraining factors:
Gradually, glass fiber reinforced plastic was introduced into the production of power transmission line supports, baths in electrolysis shops, plates for storage facilities. Other directions developed: making structures from lightweight concrete, pouring foundations, producing beams and piles.
Striking examples of the use of composite rebar:
In civil construction, the use of composite rebar was inexpedient, since its cost exceeded metal analogs 3-4 times. But gradually the builders and engineers realized that the composite is better than the metal rebar, and the price went to the background, and as a result of the introduction of modern production technologies, the material became cheaper.
In the 2000s, the field of application of fiberglass rebar was significantly expanded and extended to the construction of civilian objects.
This was facilitated by 2 points:
1. Strength characteristics and chemical-mechanical properties of composite rebar have significantly improved.
2. The cost of non-metallic products has decreased, which is relevant for private construction (country cottages, cottages, residential houses in the city, etc.).
The only deterrent that passed from the 20th century to the beginning of the 21st century is the lack of regulatory documentation and standards, which prescribes the requirements for the use of fiberglass rebar in civil engineering. Since 2004, the complex research of innovative building material was carried out by the scientists of the number of national institutions.
The tests lasted several years, at the same time different technologies were used: rupture on special stands, soaking in alkaline environments, exposure to low and high temperatures, aging of samples. As a result, on January 1, 2014, GOST 31938-2012 «Composite polymer rebar for the reinforcement of concrete structures entered into force. General specifications. » This allowed the use of fiberglass rebar legally and everywhere.
Fiberglass rebar in construction in the US began to be used in the 60s of the last century, but only in 1983, the development moved to the state level. At this time, the first project of the US Department of Transportation «The use of composite technology in the design and construction of bridges» was released. Virtually the monopolist in the field of production of rebar made of fiberglass was the corporation Marshall-Vega Inc., then connected other market players.
At the end of the 20th century — at the beginning of the 21st century China became the leading consumer of composite rebar. Builders of the Celestial Empire today also use non-metallic rebar when working with a huge number of objects, from bridges to underground structures. In Europe, large facilities, in the construction of which the fiberglass rerebar was used, is a road bridge in Germany (1986), a winery in British Columbia (1998), and others.
Scientific research continues at the present time, since composite reebar is an interesting material with many advantages. Particular attention is paid to studying the factors that affect the deformation of concrete slabs with composite rebar. Such questions as the maximum moment of destruction of plates, the reasons of cracking of concrete products, the width of opening of cracks are analyzed. According to available data, composite materials are several times superior to metal analogues with the same technical and operational characteristics.