AR Glass Fiber for GFRC Concrete

Alkali Resistant (AR) Glass Fiber is a critical component in Glass Fiber Reinforced Concrete (GFRC). Designed specifically for cement-based applications, AR glass fibers provide the tensile strength, crack resistance, and durability needed for high-performance concrete products including countertops, panels, and architectural elements.

Product Specifications

• Available lengths: 1/2" (13mm) and 3/4" (19mm)
• Alkali Resistant (AR) Glass Fibers
• Minimum 17% Zirconia content
• 18 micron filament diameter
• Approximately 200 filaments per strand
• High Young’s modulus for superior stiffness
• Small fiber diameter provides more individual fibers per pound
• Increases tensile strength (up to three times higher than steel by weight)

What is AR Glass Fiber?

AR glass fiber is specially formulated with zirconia to resist the highly alkaline environment of concrete. Unlike standard fiberglass, AR fibers will not degrade over time when embedded in cement, making them ideal for long-term structural and decorative applications.

Why Use AR Glass Fiber in Concrete?

• Increases tensile and flexural strength
• Reduces cracking and shrinkage
• Allows for thinner, lighter concrete sections
• Improves durability and longevity
• Essential for GFRC spray-up and premix applications

Common Applications

• Concrete countertops
• Architectural wall panels
• Furniture and decorative concrete
• Fireplace surrounds and cladding
• Lightweight precast elements

How Much AR Glass Fiber Should You Use?

Typical dosage rates vary depending on the application:

• Spray-Up GFRC: 3%–5% by weight of cement
• Premix GFRC: 2%–4% by weight of cement

Proper dispersion is critical. Fibers should be added at the end of the mixing cycle(once all other materials are thoroughly  blended).  Overmixing will cause the bundles to break apart and will make the mix very difficult and perhaps impossible to work with.

Tips for Best Results

• Use high-quality AR glass fiber with adequate zirconia content
• Combine with a quality polymer such as KongKrete for improved performance
• Use proper mixing techniques to prevent fiber balling
• Pair with optimized mix designs for maximum strength and workability

Why Choose Fishstone AR Glass Fiber?

At Fishstone, we supply AR glass fibers specifically selected for performance in GFRC systems. Our materials are trusted by professionals for consistency, strength, and ease of use in demanding applications.

Whether you're producing high-end countertops or large architectural panels, our AR glass fiber helps you achieve stronger, more reliable results.

Related Products & Resources

• KongKrete Acrylic Polymer
• Super Six Admix
• GFRC Guides & Tutorials

1.5lbs is the perfect size for your small projects and pre-measured to the exact amount of fiber to go into one of our Pre-blended bag mixes

Click Here for Data Sheet and further information