Glass Fiber Reinforced Polymer (GFRP) is competing with steel for the position of the preferred method of reinforcement in concrete foundations. GFRP’s high tensile strength, low weight and natural resistance to corrosion reduce maintenance, streamline installation and improve both safety and long-term ROI. We asked three leading fiberglass rebar manufacturers who are all CFA members—GatorBar, Mateenbar and MST Rebar—to share their thoughts about the benefits, challenges and applications of GFRP.

Q1: HOW WOULD YOU EXPLAIN GFRP TO A CONTRACTOR WHO IS UNFAMILIAR WITH IT, AND WHAT ARE ITS PRIMARY MATERIAL PROPERTIES COMPARED TO TRADITIONAL STEEL REBAR?

MST Rebar: GFRP rebar serves the same fundamental purpose as traditional steel reinforcement—it provides tensile capacity—but it does so using a different material system. GFRP is a composite material made of high-strength glass fibers, which provide the tensile capacity, embedded within a durable resin matrix that gives the bar its shape and protects the fibers.

GatorBar: GFRP is a lightweight, non-rusting alternative to traditional steel rebar. It has very high tensile strength but a lower modulus of elasticity than steel, meaning it is less stiff and behaves differently under load. Because it does not corrode in harsh environments, it can significantly extend the service life of concrete structures. Its lighter weight also makes it easier to handle and install, though it must be designed and detailed specifically for its material properties.

Mateenbar: Fiberglass, or GFRP, rebar is lighter weight than steel, easy to cut and has a higher tensile strength than comparable steel products. GFRP reinforcing bars are manufactured using a pultrusion process where strands of glass fiber are pulled through a vinyl ester resin bath and then through a die to mold the glass and resin material into bars that cure to solid form. This precision manufacturing ensures consistent performance, which is critical for structural reliability.

Q2: WHAT ARE THE KEY PERFORMANCE DIFFERENCES BETWEEN GFRP AND STEEL REINFORCEMENT, AND HOW DO THOSE DIFFERENCES IMPACT REAL-WORLD APPLICATIONS?

MST Rebar: From a practical standpoint, one of the most noticeable differences for contractors is weight—GFRP rebar is approximately 75% lighter than steel, making it easier to transport, handle and install on site.

Mateenbar: Unlike steel reinforcing bars, GFRP reinforcing bars do not exhibit any yielding under load. GFRP reinforcing bars have a higher tensile strength but a lower tensile modulus. Additionally, they are lighter in weight, and the materials are non-ferrous, so there is no corrosion. As with any construction material it is critical to always require GFRP that meets or exceeds the relevant ASTM standards and specifications.

GatorBar: GFRP features two times the tensile strength and is four times lighter than steel. It is rust-free, corrosion-free and longer lasting than traditional rebar. Its lightweight nature can reduce installation costs by 35 to 45% based on field studies measuring labor savings. The lighter weight also improves transportation efficiency, one truckload of GFRP #3 is equivalent to about seven truckloads of steel.

Q3: IN WHAT TYPES OF RESIDENTIAL FOUNDATION APPLICATIONS DOES GFRP PROVIDE THE MOST VALUE, AND WHERE MIGHT IT NOT BE THE BEST FIT?

Mateenbar: GFRP is perfect for projects like foundations, driveways, pool decks, patios, sidewalks and more. In addition, it is ideal for light industrial projects like single-story buildings and residential foundations. Its lightweight design simplifies handling while delivering high tensile strength, making it the ideal solution for residential projects, light industrial applications and masonry reinforcement.

GatorBar: GFRP provides the most value in residential applications such as slabs-on-grade, driveways, patios, basement floors, footings, stem walls and ICF walls. Its corrosion resistance makes it especially beneficial in wet, coastal or chemically aggressive environments where steel reinforcement can deteriorate. However, GFRP may not be the best fit in applications requiring ductility or certain fire-rated structural performance unless specifically engineered, since it does not yield like steel and behaves differently under load.

Q4: WHAT DESIGN, INSTALLATION OR INSPECTION CONSIDERATIONS SHOULD CONTRACTORS BE AWARE OF WHEN WORKING WITH GFRP COMPARED TO TRADITIONAL REBAR?

Mateenbar: Since the resin used in the bars cures during the manufacturing process, GFRP bars are not able to be bent in the field. Put another way, any bent shapes need to be formed in the bar in the manufacturing facility (like steel, prior to delivery at the job site in most markets). Because of this process the bends are exact, which we see as an advantage. The bars are formed around the necessary pins and cured in place meaning tolerances, shape and dimensions are exact and more importantly the same time after time. Concrete construction follows the building codes, of course, and ICC-ES equivalency evaluations reports exist for easy conversion of foundations to GFRP reinforced concrete; ours is ICC EER-5548.

MST Rebar: Contractors should be aware that GFRP reinforcement is not always a direct one-to-one replacement for steel in structural applications. Designs using GFRP follow codes such as ACI 440.11, which may result in different bar spacing or placement compared to steel designs under ACI 318. To simplify this process, pre-engineered solutions—such as ICC-ES evaluation reports (e.g., EER-4664)—are available to provide standardized reinforcement layouts for residential foundations without requiring project-specific engineering.

Q5: WHAT IS THE BIGGEST CHALLENGE FACING THE CONCRETE INDUSTRY MOVING AWAY FROM STEEL TO GFRP?

GatorBar: The biggest challenge facing the concrete industry in moving from steel to GFRP is industry familiarity and design comfort with steel versus limited experience with FRP properties. Engineers are highly accustomed to steel’s behavior, while GFRP’s lower modulus of elasticity and elastic‑to‑failure behavior are often misunderstood as disadvantages. Because GFRP does not yield like steel and behaves differently in crack control and stress distribution, it requires adjusted design approaches and education. Overcoming this knowledge gap and changing long‑established specifications is the primary barrier to widespread adoption.

MST Rebar: The primary challenge is education and familiarity. While GFRP reinforcement has been extensively tested and used in real-world applications, many engineers, contractors and inspectors are still more familiar with traditional steel reinforcement. Expanding the use of GFRP requires increased familiarity among engineers for design and specification, awareness among contractors of installation practices and comfort among inspectors with code acceptance and compliance.

For more industry insights, educational materials and project support, visit the CFA website at cfaconcretepros.com or scan the QR code.

Please note that no information provided herein should be interpreted as a warranty or guarantee, whether expressed or implied. This includes, but is not limited to, any implied warranty of fitness for a particular purpose.

ABOUT THE COMPANIES

GatorBar is a 100% USA-made GFRP manufactured by Neuvokas Corporation as an alternative to steel reinforcement. It is lightweight, corrosion-resistant, high-strength and ICC-certified (ESR- 526), designed to extend concrete service life while improving installation efficiency. Learn more about them by visiting gatorbar.com or by scanning the QR code.

Mateenbar leads innovation in fiberglass rebar, producing products like Greenbar2X for residential and light industrial projects and Mateenbar60 for larger infrastructure. With a long history in manufacturing and a focus on sustainability, Mateenbar supports the industry with technical guidance and nationwide distribution. Visit their website at mateenbar.com or by scanning the QR code.

MST Rebar is known for its engineered solutions and expertise in composite reinforcement, providing durable GFRP bars that meet modern performance and compliance standards. Their commitment to quality helps contractors succeed with reduced corrosion risk and maintenance needs. Visit their website at mstbar.com or by scanning the QR code.