Simpson Strong Tie FX-225 Non-Shrink Underwater Grout is a flowable, high-strength cementitious grout specifically engineered for underwater applications where dewatering or cofferdams are impractical or cost-prohibitive. Formulated with specialized anti-washout admixtures, corrosion inhibitors, and polymers, this non-metallic grout maintains its integrity and strength even when placed directly in saltwater or freshwater environments. With its ability to achieve 7,000 psi compressive strength in 28 days, FX-225 provides reliable structural performance for marine infrastructure repairs, pile jacket installations, and underwater concrete restoration projects.
This grout’s unique formulation allows for pump or tremie placement underwater while preventing segregation and washout that typically compromises conventional repair materials. Its shrinkage-compensated design ensures dimensional stability and excellent bond strength to existing concrete and steel substrates. Ready to use with simple water addition, FX-225 eliminates the complexity and expense of traditional underwater repair methods while delivering consistent, long-term performance in the harshest marine environments.
✨ Looking for a different cement grout?
We’re here to answer all of your questions about cement grout, or any of the other products we carry.
Key Features of Simpson Strong Tie FX-225
Flowable and Pumpable Design
Self-leveling consistency ideal for tremie or pump placement through annular spaces and confined areas underwater.
Anti-Washout Technology
Specialized admixtures prevent material loss and segregation when placed in moving or turbulent water conditions.
No Dewatering Required
Eliminates the need for expensive cofferdams or dewatering systems, reducing project costs and complexity.
Shrinkage Compensated
Engineered to exhibit positive expansion during cure, ensuring tight contact with existing substrates and preventing voids.
Superior Bond Strength
Achieves 3,000 psi bond strength to existing concrete and steel surfaces for reliable structural connections.
Corrosion Protection
Contains corrosion inhibitors to protect embedded steel reinforcement and extend service life.
Marine Environment Rated
Formulated specifically for saltwater applications with excellent resistance to chloride attack and freeze-thaw cycles.
Extended Aggregate Option
Can be extended with up to 30 pounds of 3/8-inch pea gravel per bag for larger volume applications.
Recommended Applications for Simpson Strong Tie FX-225
Simpson Strong Tie FX-225 is engineered for marine construction professionals and underwater repair specialists who need reliable structural grout placement without the logistical challenges of dewatering. Its anti-washout properties and high early strength make it particularly suitable for critical infrastructure repairs where traditional above-water methods are not feasible.
Ideal Applications Include:
-
- Concrete repairs in marine structures and waterfront facilities
- FX-70 pile jacket installations and repairs in harbors and docks
- Underwater grouting of bridge piers and foundation elements
- Seawall repair and restoration without dewatering requirements
- Structural underwater concrete patching and void filling
- Marine foundation reinforcement and anchoring systems
- Tidal zone repairs where continuous submersion occurs
- Emergency underwater structural repairs requiring immediate strength
Technical Specifications – FX-225
Non-shrink underwater grout with comprehensive performance data for marine structures and underwater applications.
7,000 PSI Ultimate Strength
30 min Working Time
Underwater Application
Non-Shrink Formula
Flowable & Pumpable
No Dewatering Required
Anti-Washout Formula
Saltwater Compatible
Excellent Freeze-Thaw Resistance
Bonds Well to Concrete
Frequently Asked Questions
What water temperatures can FX-225 be applied in?
FX-225 should only be applied in water temperatures between 40°F (4°C) and 90°F (32°C) for optimal performance and curing.
How long is the working time for underwater placement?
The grout maintains a 30-minute working time at 75°F, allowing sufficient time for proper placement through pumping or tremie methods.
What thickness limitations apply to underwater applications?
For underwater applications, FX-225 can be placed from a minimum of 1 inch to a maximum of 8 inches thick when used neat, or up to 24 inches when extended with pea gravel.
Can FX-225 be used above water as well?
Yes, FX-225 is suitable for both above-water and underwater applications, with specific surface preparation requirements for each condition.
What surface preparation is required for underwater use?
Surfaces must be cleaned of loose rust, marine growth, oil, and contaminants using high-pressure water blasting to achieve ICRI CSP 6-9 profile.
How should the grout be mixed for underwater placement?
Mix with 90% of the total water first, slowly add the entire bag contents while mixing, then adjust with remaining water to achieve proper consistency. Mix for approximately 3 minutes without re-tempering.
What certifications are required for underwater installation?
Underwater placement should only be performed by certified professional divers with experience in underwater construction methods.
Need Help Choosing the Right Cement Grout?
We’re here to answer all of your questions about cement grout solutions, product compatibility, and application techniques. Get expert guidance for your specific project needs.
Professional Grade Products
Quality Customer Service
Technical Support
