Main types of chopped fibers
GFRC Glass Fiber Reinforced Concrete: Glass fiber is made up from 200-400 individual filaments which are lightly bonded to make up a stand. These stands can be chopped into various lengths, or combined to make cloth mat or tape. Using the conventional mixing techniques for normal concrete it is not possible to mix more than about 2% (by volume) of fibers of a length of 25mm. The major appliance of glass fiber has been in reinforcing the cement or mortar matrices used in the production of thin-sheet products. The commonly used verities of glass fibers are e-glass used. In the reinforced of plastics & AR glass E-glass has inadequate resistance to alkalis present in Portland cement where AR-glass has improved alkali resistant characteristics. Sometimes polymers are also added in the mixes to improve some physical properties such as moisture movement.
Carbon Fibers: Carbon fibers from the most recent & probability the most spectacular addition to the range of fiber available for commercial use. Carbon fiber comes under the very high modulus of elasticity and flexural strength. These are expansive. Their strength & stiffness characteristics have been found to be superior even to those of steel. But they are more vulnerable to damage than even glass fiber, and hence are generally treated with resign coating.
chopped glass fibers alone cannot withstand the load and can easily fall under the load; However, when fiberglass is combined in concrete, because of the fact that the concrete prevents the fibers from moving under the load, each of the chopped fibers in the concrete can withstand a small amount of load on the concrete. The load applied to each of the fibers is transferred to the other fibers by the concrete matrix. Concrete also prevents fibers from damaging the environment. In fact, fiberglass can integrate with the concrete matrix and increase its performance against incoming loads. These fibers also increase the durability of concrete compared to base environments.
High strength: Due to the use of chopped glass fibers in concrete, their strength increases. This increase in strength results in hard and anti-cracking concrete.
Light weight: at constant strength, the weight of fiberglass concrete or GFRC is less than the weight of ordinary concrete; Therefore, the costs of transporting and placing this concrete in the mold are reduced.
Because fiber concretes are reinforced from the inside with a series of fine fibers, they can be cast in any format; Therefore, it is quite reasonable to use them in complex architectural forms.
Using chopped glass fibers, concrete is formed more easily and therefore the final surface of the concrete is smoothed better.
Concrete becomes more resistant to environmental effects such as corrosion and chemical attacks.
Less environmental pollution: One of the destructive effects of cement production is high pollution. This pollution is so great that 5 to 8% of the total volume of carbon dioxide in the atmosphere is caused by cement production. By adding glass fibers to concrete, an average of 1% of the cement used in concrete can be reduced. Since concrete is the most widely used material in the world after water, the same amount of 1% has a great effect.
The use of this type of fiber reduces the thickness of concrete. These concretes can be used to make prefabricated concrete panels. These panels do not need rebar to reinforce and in addition they are lighter in weight. These two points and the properties of GFRC concretes make it possible to use these panels in the construction of architectural elements outside the building and urban space.
In addition, the application of these fibers is also used in other industries and the manufacture of composite parts:
- Electrical industry
- automobile industry
- aerospace Industries
- military industries
- Artificial stones (decorative industry)
- Civil and construction materials such as gypsum and plaster materials
- Shipbuilding and power plant industries
History of Glass Fiber Concrete or GFRC
Glass fiber first made in Russia in the 1940s, inspired by composite materials such as thatch was made using chopped glass fibers. One of the problems observed in the prototypes was the base reaction that occurred during the hydration of the concrete. In that reaction, the hydrated cement reacts with the silica in the glass fibers, greatly reducing the performance of the concrete. In the 1970s, the problem was solved by adding zirconia (ZrO2) to the fiber composition, and glass fibers became commercially available for the first time.
Types of chopped glass fibers
The glass fibers themselves are divided into several types according to the percentage of each of their constituent elements.
AR-Glass: In cases where chopped fiberglass is used in conjunction with Portland cement, this type of fiber should be used; Because zirconia in this type of fiber prevents the reaction between Portland cement and glass fibers.
E-Glass: The most widely used type of glass fiber is type E. This product has chemical and electrical resistance and is used for general purposes.
R-Glass: In cases where higher resistance to corrosion is required, these fibers can be used.
S-Glass: A type of high-strength fiber that has the following properties: high strength, high hardness, high temperature resistance, corrosion resistance
C-Glass: This type of fiber can be used in environments with high corrosion.
ECR-Glass: This type of fiber can be used for applications that require high strength with electrical conductivity and high corrosion resistance.
Limits of Fiber Concrete or GFRC
The most important problem in GRC concretes is their reduced efficiency due to the reduction of water to cement ratio; Therefore, when mixing concrete, a suitable superplasticizer should be used to increase efficiency. If fiberglass is added to the concrete while mixing, it is possible for the fibers to become pellets. It should be noted that when mixing concrete, it should be mixed enough so that the glass fibers do not stick to each other. To prevent this problem, a special fan can be used. In such cases, the experts of Afzir Reinforcement Company suggest adding the fibers slowly and at regular intervals to the mixer.
- Heat resistant
- Impact resistance
- Increase tensile strength
- Resistance to fire and heat
- Increase the durability of concrete
- Reduce surface and hair cracks in concrete
- Increased abrasion resistance
- Reducing the water to cement ratio of concrete and thus reducing the shrinkage of concrete
This product can be used to reinforce concrete in the following cases:
- Concrete kerbs
- Floors and slabs of industrial sheds
- Sidewalks and streets
- Cement pipes
- Cover tunnels
- Prefabricated composite ceilings
- Concrete silos
- Deck of concrete stairs and walls
- 25 kg bags
- Colorless (Available in blue, red, green and yellow)
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Run by spray method
In GRC factories, by spraying, cement / sand slurry mortar and AR glass fibers chopped are sprayed into the mold and accumulated simultaneously. The amount of AR chopped fiberglass is about 5% by weight of mortar.
Execute by pre-stirring method
The whole pre-mixing process involves mixing cement, sand, water and AR glass fibers chopped inside the mixer before forming the mortar.
To produce a high quality mixture, it is necessary to stir in two steps. The first stage is designed to produce high quality slurry to achieve the required performance and uniform fiber composition. The second step involves adding fibers to the slurry. It is necessary to do both stages with the same equipment, but separate mixers must be used for each stage.
It is recommended to store alkaline resistant glass fiber chopped product in a cool and dry area. This product must be stored in company-specific packaging before use.
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Frequently Asked Questions
What is another name for GFRP glass fiber?
Also known as GFRC or GRC (Glass Fiber Reinforced Concrete).
Where is glass fiber concrete used?
Fiberglass or GRC concrete is often used in the construction of exterior facades of buildings or prefabricated architectural concretes.
What is the role of printed glass fibers in concrete?
Printed glass fibers are effective in better concrete cohesion and act like straw in old thatched buildings.
What is the main disadvantage of chopped glass fibers?
The most important disadvantage of GRC concretes is their reduced efficiency due to the reduction of water to cement ratio; Therefore, when mixing concrete, a suitable superplasticizer should be used to increase efficiency.