What is glass fiber reinforced concrete
Glass fiber reinforced concrete is a type of fiber-reinforced concrete, it is also known as GFRC or GRC. glass fiber contains a chopped form of glass. GFRC matrix contains cement, sand, water, admixtures, and randomly dispersed glass fibers. It used mainly in the exterior of the building as facade panels.
History
The GFRC was first used in Russia (the 1940s) but the corrosion in the glass was the disadvantage to use this material. After that, British scientists used alkali-resistant glass fiber (the 1970s) and it was successful. since then, GFRC becomes a versatile material.
In the present period, the use of GRC is increasing in construction industries. market valuation for the global glass fiber reinforced concrete was estimated to reach 3.35 billion US dollars by the end of 2023.
Glass fiber
Glass fibers are produced in three basic forms, such as roving, strands, woven, or chopped strands mats.
The concrete has a high alkaline environment, The use of glass in concrete makes the corrosion in the glass and loss of tensile strength in GFRC. With the use of alkali-resistant glass, this problem has fixed.
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| Fiberglass |
The commonly used glass fibers are E-fibers and AR-fibers. E-fibers can not resist the high alkaline environment of concrete. however, AR-fibers can resist highly alkaline concrete. AR-fibers contain a minimum of 16 % of zirconium dioxide.
Glass fibers are made from 2000 to 4000 different filaments which are lightly bonded and make the strand. These strands further chopped or combined to make cloth or tape.
Glass fiber reinforced concrete
GFRC is very light in weight and has high compressive and tensile strength as compared to conventional concrete.
GFRC is a versatile material for the construction industries. This material mostly used for the non-structural purpose, it's lightweight and high strength properties make this material more efficient in facade cladding.
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| Glass facade |
If the number of fibers is increased in the GFRC results in high tensile strength and if the polymer content in GFRC is high makes a concrete crack resistant and flexible.
In the past 30 years, the use of glass fiber reinforced concrete has become popular especially in the making of architectural facade cladding.
In facade cladding, concrete containing glass fibers is used. The function of the glass fiber is to provide reinforcement for the concrete, as concrete is weak in tension, and glass fibers have high tensile strength.
With the change in the properties of glass, fibers can lead to change the properties of this composite GFRC. As the properties of GFRC depend on the fiber's length, size, manufacturing process, application techniques, curing condition, etc.
Production
There are two techniques for the production of GFRC. spray-up and premix.
Spray-up
The process for application is similar to that shotcrete. The concrete is sprayed in the fluid concrete form. The length of the fibers (25-40 mm) are large in this fluid concrete mix, which can reduce workability. The amount of fibers in this technique is around 5% by weight. This technique is highly costly.
First, the concrete mortar is created and separated from the fibers, concrete mortar and fibers are mixed at the jet of the spray gun and then applied. larger fiber length and high fiber load give a higher strength to the concrete.
Premix
In this technique, The length of the fibers (12 mm) is cut and the amount of the fibers is also reduced (3.5 % by weight) which gives lower strength to the concrete mix as compare to the spray-up technique.
Premix is less costly as compare to the spray-up technique.
The production techniques require to check some of the parameters before finalized the GFC according to some standard codes.
GRC is tested for parameters like density, workability, compressive and tensile strength, tolerance, surface finish, creep, etc.
Mechanical and physical properties
The compressive strength of GFRC is increased with the controlled volume of fibers. an excessive amount of fibers results in a decrease in workability and compressive strength.
There is no significant influence on the modulus of elasticity of concrete with glass fibers.
The fibers reduce the micro-crack in fresh concrete and increase the flexural strength as compared to the traditional concrete.
Curing of GFRC for the long term should be avoided, due to the polymer used in the concrete mix. The fibers have a very high surface area that could make the drying and loss of strength in the concrete.
The improper curing in this concrete could make some undesired effects. The curing must be done according to the guidelines to make sure the concrete with glass fibers can have adequate strength.
Alkali-resistant glass fibers are very useful to prevent the drying shrinkage and creep strain of concrete.
Advantages
The advantages of using this material are as follows.
- Easy to transport and install.
- Lightweight and durable as compared to traditional concrete.
- GFRC could be cast in any desired shape.
- unlikely to burn.
- used to make thin and strong concrete.
- Environment-friendly.
- High tensile strength compared to normal concrete.
- Attractive and better appearance.
Disadvantages
This product has the following disadvantages.
- During the mixing, the glass may break due to abrasion and impact forces created by the aggregate in the concrete mixer.
- High cost.
- Drying out fast.
Application
The application of this material is broader due to its ease of transportation and installation.
This material is used in many aspects due to its favorable properties.
The properties of this material ( fiber length, mix design, manufacturing, and applying techniques) changes according to use.
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| Glass fiber reinforced concrete ImageCredit - https://tmrblog.com/ |
Use in ornamental concrete works like statues, domes, fountains, artificial rocks, railing, etc.
To make water-resistant concrete.
To make 3D concrete elements.
Building renovation.
Its water-resistance properties make the use of this material in water and drainage works.
Bridge and tunnel lining panels.
Conclusion
From the above presentation, it is clear that using GFRC for non-structural purposes is very much efficient. The compressive strength can be improved up to a certain limit with the controlled amount of fibers. The tensile strength can be increased.
This decorative material is in the focus of engineers and architects due to its special properties and mass color availability.
Construction industries always demand such material that has multiple uses.
For further discussion, comment below.
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