What Is Glass Fiber Reinforced Concrete (GFRC)?
What Is Glass Fiber Reinforced Concrete (GFRC)?
Glass Fiber Reinforced Concrete (GFRC) is a type of concrete that is reinforced with glass fibers. It is also known as glassfiber reinforced concrete or GRC in British English. GFRC is primarily used in exterior building facade panels and as architectural precast concrete.
It is similar to materials such as fiber cement siding and cement boards. GFRC consists of high-strength, alkali-resistant glass fibers embedded in a concrete and ceramic matrix.
The fibers and matrix retain their individual properties while offering a combination of properties that can’t be achieved with either component alone.
The fibers provide reinforcement for the matrix and other useful functions in fiber-reinforced composite materials. Glass fibers can be incorporated into the matrix in either continuous or chopped lengths.
The original type of glass fibers had poor durability due to the alkalinity of cement reacting with its silica. In the 1970s, alkali-resistant glass fibers were developed by adding zirconia to the glass.
The higher the zirconia content, the better the resistance to alkali attack. AR glass fibers should have a zirconia content of more than 16% to meet international specifications.
What Is Glass Fiber Reinforced Concrete Used for?
Glass fiber reinforced concrete (GFRC) is a type of concrete that is reinforced with glass fibers.
There are many applications for glass-fibre-reinforced concrete (GFRC), including ornamental architectural accents, countertops, climbing walls, artificial rocks, fireplace surrounds, and columns.
These fibers are used to strengthen the concrete and provide added support.
Glass fibers were first used in Russia to reinforce cement and concrete, but they were eventually found to be susceptible to corrosion from the highly alkaline Portland cement matrix.
To address this issue, alkali resistant glass fibers were developed in the UK and other countries.
These fibers come in a variety of forms, including continuous rovings, chopped strand mats, cranette, wool, ropes, and woven fabric. Some glass fibers are even coated with epoxy resin to protect them from alkali attack.
To make GFRC, glass fibers are mixed with cement, water, and sometimes sand and lubricating admixtures such as polyethylene oxide or methyl cellulose. The resulting mix can be sprayed or cast into moulds, or it can be produced by extrusion or injection moulding.
In some processes, the fibers are chopped in situ and sprayed onto a mould along with a slurry of the right consistency.
This method is effective for producing shell roofs and sheets. Glass fibers can be added to the mix in quantities of up to 5% by weight.
The surface finish of GFRC panels can be varied using techniques such as sand blasting, acid etching, and polishing, and different colors can be achieved through the use of colored cements or pigments.
GFRC countertops can be finished using a range of decorative concrete techniques, including integral color, acid stain, and embedding decorative elements. Artificial rocks can be created using GFRC panels sprayed against molds made from real rock, and mounted on a structural steel framework. Fireplace surrounds can be made with GFRC, which can be molded into a variety of shapes and sizes.
Columns can be made with GFRC, which can be molded to replicate the look of stone, brick, or other materials. GFRC can also be used to create lightweight, non-load bearing walls, which can be molded into a variety of shapes and sizes.
Properties Of Glass-Fibre-Reinforced Concrete (GFRC)
The properties of glass-fibre-reinforced concrete (GFRC) panels are important to consider in their design.
To design glass-fibre-reinforced concrete (GFRC) panels, it is important to understand their basic properties under different types of forces, such as tensile, compressive, bending, and shear, as well as their behavior under secondary loading effects like creep, thermal response, and moisture movement.
GFRC panels have some differences compared to structural metal and fiber-reinforced composites. For instance, metals generally exhibit yielding and plastic deformation, while most fiber-reinforced composites are elastic in their tensile stress-strain characteristics.
However, fiber-reinforced composites can absorb high amounts of energy on a microscopic scale, similar to the yielding process in metals.
Composite laminates may experience gradual deterioration in properties under certain external loads, but they usually do not fail catastrophically. Damage development and growth mechanisms in metal and composite structures are also different.
Other notable characteristics of many fiber-reinforced composites include their non-corrosive behavior, high damping capacity, and low coefficients of thermal expansion.
GFRC architectural panels have a similar appearance to pre-cast concrete panels, but they are lighter in weight due to their reduced thickness.
Their lower weight reduces the loads on the building’s structural components, making the construction of the building frame more cost-effective.