Explanation of what is GFRP

GFRP stands for Glass Fiber Reinforced Polymer. The terminology used to refer to polymer or plastic corrugated rods that have been reinforced with glass fibre. It represents an efficient and durable alternative to steel bars. Its most notable properties are non-corrosion, tensile strength and low weight.

Fiber Reinforced polymer (FRP) is a composite material of a polymer matrix reinforced with fibers. The fibers used in FRP can be made of various materials, such as Basalt (BFRP), Carbon (CFRP), and Glass (GFRP). The polymer is usually epoxy, vinyl ester, or polyester thermosetting plastic.

No, GFRP rebar technology has actually been around since 1950s.

Fiber reinforcement bars are manufactured from glass fibre reinforced polymer which is highly durable and long-lasting and a much better alternative than your standard steel reinforcement bars. GFRP rebar is commonly used and installed in substations and for other electrical installations due to its non-conductive feature. Moreover, GFRP rebar is also non-corrosive which means you’ll save time and money in replacements in the years to come.

Products made of glass fibre reinforced polymer have a high durability and can withstand many years without compromising their structure. Polymers age very slowly, In addition, external influences such as humidity, heat or UV rays hardly deteriorate their properties and they are extremely resistant in aggressive environments.

GFRP is made by glass fiber that is 100% recyclable and the resin that can be degrade by UV if exposed, however when it is in concrete the material can be crushed with concrete without the need to remove it after +100 years and it can be part of the next recycled concrete which makes the concrete stronger.

One of the largest contributors to our failing infrastructure is corrosion of reinforcement in concrete. This results in shortened lifespans for concrete, higher repair costs, and can present safety issues. GFRP rebar is a completely non-metallic material that removes rust from the equation. With nothing to corrode, GFRP rebar offers a longer lasting solution that is price competitive with steel. It is also electro and magnetically inert, making it ideal for sensitive areas.

Yes, fiberglass costs less than plain steel. Aside from material savings, there are significant labor savings to be realized during the installation. Fiberglass rebar is about 75% lighter than steel rebar, so it costs less to ship. When installing this option, it is easier to handle and cut. There is no need for waterproofing additives, no allowances required for corrosion diameter reduction, and no need for extra concrete protection. Furthermore, there is no need for touch-ups of the surface coating or cathodic protection. This means GFRP reduces installation time and labor costs.

Issues related to production technology

Pultrusion is a production process based on the corrugation of polymeric materials or plastic materials. The result is reinforced plastic profiles, known as pultruded or pultruded profiles. In addition, thermoplastic pultrusion allows the profiles to be reinforced with other polymer resins, improving their flame-retardant properties or their strength.

Properties

Materials derived from glass fibre reinforced polymer production have a low weight and are extremely strong and resistant. It is a non-slip material (suitable for railings, cracks, gratings, sewers or drains), resistant to corrosion and does not propagate heat, electricity or fire. Structures made of GFRP have a low production and installation cost and are very durable, compared to other minerals and metals such as iron or steel.

With respect to fire, GFRP does not promote dispersion and is a good thermal insulator, compared to steel (the most commonly used metal for construction). It has good resistance to burning, which provides an effective barrier against heat, toxic gases and smoke. In addition, it can be covered with materials that provide extra protection, the most effective against fire being rock wool, cork agglomerate and calcium silicate.

Sections or cuts can be made in bars, rods, mesh or any material made of glass fibre reinforced polymer. Low speeds are recommended for optimum results and clean cuts.

No, GFRP rebar is orthotropic and non-ductile material, GFRP can be cut using steel saw, a band saw and or grinder with a diamond blade.

Tie GFRP rebar with stainless steel or nylon tie wire, you may use heavy-duty zip tie too. If corrosion or electromagnetic field is not a concern you may use uncoated wires too.

GFRP rebar cannot be bent after the curing cycle. All bends need to be fabricated in the GFRP manufacturing plant.

In contrast to steel, GFRP rebar cannot be welded, but efficient alternatives do exist. There is currently a lot of ongoing research on the bonding of composite materials by resin-bonding, riveting or bolting together.

GFRP rebar is both electrically and thermally non-conductive.

The change in the ambient temperature on the strength of composite reinforcement is practically unaffected. It can be used at temperatures from -70 to +110 degrees Celsius.

GFRP rebar that comply and meet with CSA, ASTM and ACI standards, which glass transition temperature of above 110 degree Celsius, can be in direct contact to heat of up to 110 degree Celsius without loosing the strength. GFRP at 400 degree Celsius will lose it tensile strength from 1400 MPa to about 650 MPa which is still higher than steel rebar at room temperature.

GFRP rebar have tested according to CSA & ACI standard at -40 degrees Celsius, and the effect was zero and in some case increase in performance.

At 1/4th the weight of steel, the weight of GFRP rebar is a big positive! Some ways in which this can work to your advantage:

  • Speed of placement. Lighter weight results in more productivity, which could cut your install time by over 50% depending on the complexity;
  • Safety. Carrying lighter loads can reduce injuries and result in less fatigue, and it poses less of a threat if dropped;
  • Shipping costs are likely to be a source of savings on some projects due to being able to ship more material on every truck.
The lighter weight will result beneficial in some applications.

GFRP is lighter than conventional steel and thus can, on occasion “float” when pouring certain concrete mixes of high slump.

GFRP rebar tends to be about double that of steel in tension. However, it does have a lower modulus of elasticity which can drive different design requirements.

GFRP has tested according to CSA, ASTM & ACI standards for durability criteria, they both retain +90% of ultimate tensile capacity after 2160 hours of direct exposure to an alkali solution with a pH level of 13 at 60 degrees Celsius, in compare to steel, GFRP rebar is much more resistant than the highest grade of stainless steel.

Comparison with steel

GFRP has superior properties to steel in a number of respects. Firstly GFRP never rusts. In addition, GFRP structures have far superior tensile properties, much better corrosion resistance and inherent electromagnetic neutrality. On the other hand, GFRP rebar is a more economical, durable and sustainable solution. As it has no metals in its composition it does not conduct electricity, making it an ideal choice for constructions or structures working with medium and high voltage lines.

GFRP is two times stronger, but more flexible than steel rebar and it behave linear elastic to failure, therefore there is no yield point to be determined however the material can take significantly higher load. Engineers must follow the Codes and Standards for GFRP rebar and not for Steel rebar. But in simple structures, it is often practiced to replace Steel rebar with GFRP rebar, which has a different diameter, but the same tensile strength.

Table of replacement of Steel rebar with GFRP rebar (diameter in mm).

Steel 7 8 10 12 14 16 18 20 22 25 26 22 25 26
GFRP 4.5 6 7 8 10 12 14 14 16 18 20 16 18 20

GFRP has a tensile strength of greater than 1000 MPa, in compare to steel (about 400 MPa), GFRP can take over 2x the tensile load of steel before failure.

GFRP has tensile modulus of greater than 55 GPa, in compare to steel (about 200 GPa), GFRP rebar is more flexible.

GFRP has tensile strain between 1.0% to 2.0%, steel has tensile strain about 15.0%, it means that GFRP-reinforced concrete is usually designed for concrete crushing failure while steel-reinforced concrete is typically designed for yield failure.

GFRP is much less than the cost of stainless steel. GFRP price is very competitive to black steel rebar but when you consider all the savings due to labor cost, corrosion protection additives, cover concrete and Transportation the cost could be lower than steel rebar.

Areas of use

All types of structures can be realised, from buildings, bridges, railway structures, dams, water channelling… The application of GFRP reinforcements covers all types of sectors, such as industrial, sanitary, agricultural and so on.

The performance of GFRP bars in two bridges more than a decade old are reviewed in the following report: Long-Term Durability of GFRP Internal Reinforcement in Concrete Structures Both bridges are located in the City of Rolla, Missouri, USA: Walker Bridge (built in 1999), which consists of GFRP-reinforced concrete box culverts; and Southview Bridge (built in 2004), which incorporates GFRP bars in the post-tensioned concrete deck.

Yes, moreover, the corrosion resistance of composite piles is substantially higher than that of steel reinforced concrete piles.

Yes, GFRP bars can be used as reinforcement in concrete subjected to seismic loading conditions. GFRP is capable of resisting reversal tension-compression cycles without failure. The large deformation, exhibited by GFRP material, allows the GFRP reinforced building to adequately dissipate the seismic energy. Currently more than 100 bridges and structures are reinforced with GFRP rebar in seismic regions. Although it has not been part of the code but there is no limit of why GFRP can not be used in seismic regions.

Design and installation

There are number of design guidelines available. Here are some well-known: International

  • ASTM D7205: "Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars";
  • ISO 10406: "Fibre-reinforced polymer (FRP) composite bars — Specification".
Canada
  • CAN/CSA-S806-10, “Design and Construction of Building Components with Fibre-Reinforced Polymers";
  • CAN/CSA-S6-06, "Canadian Highway Bridge Design Code";
  • CAN/CSA-S807-10 "Specification for fiber-reinforced polymers";
  • Design Manual No. 3, "Reinforcing Concrete Structures with Fiber Reinforced Polymers";
  • Design Manual No. 4, "FRP Rehabilitation of Reinforced Concrete Structures";
  • Design Manual No. 5, "Prestressing Concrete Structures with FRPs";
  • Design Guide, "Specifications for FRP Product Certification".
USA
  • ACI 440.1R (2015) "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars";
  • ACI 440.3R-04 (2004) "Guide for Test Methods for Fiber Reinforced Polymers (FRP) for Reinforcing and Strengthening Concrete Structures";
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar";
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete".
Europe
  • FIB Bulletin #10: "Bond of reinforcement in concrete";
  • FIB Bulletin #40: "FRP reinforcement in RC structures";
  • Report #STF 22 A 98741 "Eurocrete Modifications to NS3473 When Using FRP Reinforcement" Norway (1998);
  • AASHTO LRFD : "Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings". 1st Edition in 2009.

There are number of design guidelines available. Here are some well-known: International

  • ASTM D7205: "Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars";
  • ISO 10406: "Fibre-reinforced polymer (FRP) composite bars — Specification".
Canada
  • CAN/CSA-S806-10, “Design and Construction of Building Components with Fibre-Reinforced Polymers";
  • CAN/CSA-S6-06, "Canadian Highway Bridge Design Code";
  • CAN/CSA-S807-10 "Specification for fiber-reinforced polymers";
  • Design Manual No. 3, "Reinforcing Concrete Structures with Fiber Reinforced Polymers";
  • Design Manual No. 4, "FRP Rehabilitation of Reinforced Concrete Structures";
  • Design Manual No. 5, "Prestressing Concrete Structures with FRPs";
  • Design Guide, "Specifications for FRP Product Certification".
USA
  • ACI 440.1R (2015) "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars";
  • ACI 440.3R-04 (2004) "Guide for Test Methods for Fiber Reinforced Polymers (FRP) for Reinforcing and Strengthening Concrete Structures";
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar";
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete".
Europe
  • FIB Bulletin #10: "Bond of reinforcement in concrete";
  • FIB Bulletin #40: "FRP reinforcement in RC structures";
  • Report #STF 22 A 98741 "Eurocrete Modifications to NS3473 When Using FRP Reinforcement" Norway (1998);
  • AASHTO LRFD : "Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings". 1st Edition in 2009.

There are number of design guidelines available. Here are some well-known: International

  • ASTM D7205: "Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars";
  • ISO 10406: "Fibre-reinforced polymer (FRP) composite bars — Specification".
Canada
  • CAN/CSA-S806-10, “Design and Construction of Building Components with Fibre-Reinforced Polymers";
  • CAN/CSA-S6-06, "Canadian Highway Bridge Design Code";
  • CAN/CSA-S807-10 "Specification for fiber-reinforced polymers";
  • Design Manual No. 3, "Reinforcing Concrete Structures with Fiber Reinforced Polymers";
  • Design Manual No. 4, "FRP Rehabilitation of Reinforced Concrete Structures";
  • Design Manual No. 5, "Prestressing Concrete Structures with FRPs";
  • Design Guide, "Specifications for FRP Product Certification".
USA
  • ACI 440.1R (2015) "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars";
  • ACI 440.3R-04 (2004) "Guide for Test Methods for Fiber Reinforced Polymers (FRP) for Reinforcing and Strengthening Concrete Structures";
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar";
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete".
Europe
  • FIB Bulletin #10: "Bond of reinforcement in concrete";
  • FIB Bulletin #40: "FRP reinforcement in RC structures";
  • Report #STF 22 A 98741 "Eurocrete Modifications to NS3473 When Using FRP Reinforcement" Norway (1998);
  • AASHTO LRFD : "Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings". 1st Edition in 2009.

There are number of design guidelines available. Here are some well-known: International

  • ASTM D7205: "Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars";
  • ISO 10406: "Fibre-reinforced polymer (FRP) composite bars — Specification".
Canada
  • CAN/CSA-S806-10, “Design and Construction of Building Components with Fibre-Reinforced Polymers";
  • CAN/CSA-S6-06, "Canadian Highway Bridge Design Code";
  • CAN/CSA-S807-10 "Specification for fiber-reinforced polymers";
  • Design Manual No. 3, "Reinforcing Concrete Structures with Fiber Reinforced Polymers";
  • Design Manual No. 4, "FRP Rehabilitation of Reinforced Concrete Structures";
  • Design Manual No. 5, "Prestressing Concrete Structures with FRPs";
  • Design Guide, "Specifications for FRP Product Certification".
USA
  • ACI 440.1R (2015) "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars";
  • ACI 440.3R-04 (2004) "Guide for Test Methods for Fiber Reinforced Polymers (FRP) for Reinforcing and Strengthening Concrete Structures";
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar";
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete".
Europe
  • FIB Bulletin #10: "Bond of reinforcement in concrete";
  • FIB Bulletin #40: "FRP reinforcement in RC structures";
  • Report #STF 22 A 98741 "Eurocrete Modifications to NS3473 When Using FRP Reinforcement" Norway (1998);
  • AASHTO LRFD : "Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings". 1st Edition in 2009.

There are number of design guidelines available. Here are some well-known: International

  • ASTM D7205: "Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars";
  • ISO 10406: "Fibre-reinforced polymer (FRP) composite bars — Specification".
Canada
  • CAN/CSA-S806-10, “Design and Construction of Building Components with Fibre-Reinforced Polymers";
  • CAN/CSA-S6-06, "Canadian Highway Bridge Design Code";
  • CAN/CSA-S807-10 "Specification for fiber-reinforced polymers";
  • Design Manual No. 3, "Reinforcing Concrete Structures with Fiber Reinforced Polymers";
  • Design Manual No. 4, "FRP Rehabilitation of Reinforced Concrete Structures";
  • Design Manual No. 5, "Prestressing Concrete Structures with FRPs";
  • Design Guide, "Specifications for FRP Product Certification".
USA
  • ACI 440.1R (2015) "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars";
  • ACI 440.3R-04 (2004) "Guide for Test Methods for Fiber Reinforced Polymers (FRP) for Reinforcing and Strengthening Concrete Structures";
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar";
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete".
Europe
  • FIB Bulletin #10: "Bond of reinforcement in concrete";
  • FIB Bulletin #40: "FRP reinforcement in RC structures";
  • Report #STF 22 A 98741 "Eurocrete Modifications to NS3473 When Using FRP Reinforcement" Norway (1998);
  • AASHTO LRFD : "Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings". 1st Edition in 2009.

There are number of design guidelines available. Here are some well-known: International

  • ASTM D7205: "Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars";
  • ISO 10406: "Fibre-reinforced polymer (FRP) composite bars — Specification".
Canada
  • CAN/CSA-S806-10, “Design and Construction of Building Components with Fibre-Reinforced Polymers";
  • CAN/CSA-S6-06, "Canadian Highway Bridge Design Code";
  • CAN/CSA-S807-10 "Specification for fiber-reinforced polymers";
  • Design Manual No. 3, "Reinforcing Concrete Structures with Fiber Reinforced Polymers";
  • Design Manual No. 4, "FRP Rehabilitation of Reinforced Concrete Structures";
  • Design Manual No. 5, "Prestressing Concrete Structures with FRPs";
  • Design Guide, "Specifications for FRP Product Certification".
USA
  • ACI 440.1R (2015) "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars";
  • ACI 440.3R-04 (2004) "Guide for Test Methods for Fiber Reinforced Polymers (FRP) for Reinforcing and Strengthening Concrete Structures";
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar";
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete".
Europe
  • FIB Bulletin #10: "Bond of reinforcement in concrete";
  • FIB Bulletin #40: "FRP reinforcement in RC structures";
  • Report #STF 22 A 98741 "Eurocrete Modifications to NS3473 When Using FRP Reinforcement" Norway (1998);
  • AASHTO LRFD : "Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings". 1st Edition in 2009.

Storage

GFRP rebar is typically transported in coils of 100-200m for diameters up to 12mm, while diameters beyond 12mm are transported according to the vehicle length, usually 6m long bars (maybe longer, depends on the length of the truck or trailer). These transportation methods are designed to ensure easy handling and storage of the product during transit. However, it is important to handle and transport GFRP rebar with care to prevent damage or deformation. Proper packaging and securing of the product are essential to ensure that it arrives at its destination in good condition.

No, if it is more than 2 months. GFRP rebar is made from thermoset Matrix that can be degraded by UV radiation, due to cost competitiveness, GFRP rebar does not have a UV-inhibiting binders. Always cover the GFRP rebar from direct UV radiation with tarp if it is store outside.

Absolutely, GFRP rebar can be store under rain and snow with no problem since the material can not be corroded.

Ordering product

SMIN are your number #1 rated supplier of high-quality GFRP products. With years of experience, we truly go above and beyond for all our customers. Our GFRP products are available for domestic, industrial, and commercial customers.

We manufacture and supply GFRP rebars of diameters 3, 3.5, 4.5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 22, 25, 30, 32 and 34mm.

It’s really easy to place an order with us at SMIN. Simply order through the specific product page or go to our contact form and enquire about any of the products you are interested in. You can also contact us through our email address _______ and we will respond as quickly as possible.

Our GFRP rebar is acquired in a similar fashion to how you would buy your steel. We can take your bar list or drawings and convert it into a quote for you, and upon receipt of a purchase order we would begin fabrication. If requested, we can come up with our own bar list and will also help to optimize your project.

Depending on the size of your project, the lead time may vary. The average lead time on a standard project with some bends is ___ business days. We always keep a certain amount of ready products (especially the most popular diameters) in stock. You can always check availability. From orders that pull from stock, lead times tend to be about ____ business days to ship.

img