What Makes an Adhesive "Structural"?
A structural adhesive is one designed to carry sustained loads in a structural assembly. Unlike general-purpose adhesives that primarily seal or bond non-load-bearing elements, structural epoxy adhesives must meet specific performance criteria for tensile strength, shear strength, creep resistance, and durability under environmental exposure.
Our structural adhesive range is specifically formulated for construction applications where the adhesive bond is a critical load path in the structural system.
Our Structural Adhesive Range
Steel Bonding Adhesive (XQ-JG)
Designed for bonding steel plates to concrete surfaces for flexural and shear strengthening.- Shear strength (steel-to-concrete): ≥ 14 MPa
- Tensile strength: ≥ 30 MPa
- Bond line thickness: 1-3mm
- Thixotropic (non-sag) for vertical and overhead application
CFRP Impregnation Resin (XQ-TJ)
A low-viscosity epoxy system for saturating carbon fiber fabric in wet lay-up applications.- Viscosity: 500-1,500 mPa·s (mixed)
- Tensile strength: ≥ 50 MPa
- Elongation at break: ≥ 2.5%
- Pot life at 25°C: 45 minutes
CFRP Plate Bonding Adhesive (XQ-PB)
Thixotropic paste adhesive for bonding pultruded CFRP plates to concrete or steel substrates.- Shear strength: ≥ 18 MPa
- Tensile strength: ≥ 35 MPa
- Bond line thickness: 1-5mm
- Non-sag on vertical surfaces
Metal Bonding Epoxy (XQ-MBA)
General-purpose structural epoxy for metal-to-metal and metal-to-concrete connections.- Shear strength (steel-to-steel): ≥ 20 MPa
- Temperature resistance: -40°C to +80°C
- Chemical resistance: Resistant to fuels, oils, and most solvents
Surface Preparation: The Most Critical Step
In our experience supporting over 1,000 structural bonding projects, the single most common cause of bond failure is inadequate surface preparation. The adhesive itself rarely fails — the interface does.
Concrete surface preparation:- Remove laitance, paint, coatings, and loose material by grinding or sandblasting
- Expose aggregate to create a rough, open-pored surface
- Clean with compressed air to remove dust
- Surface must be dry (moisture content below 4%)
- Apply primer if specified in the system datasheet
- Remove mill scale, rust, paint, and contamination
- Blast clean to SA 2.5 (near-white metal) standard
- Apply adhesive within 4 hours of blasting (before re-oxidation)
- Surface roughness Ra 50-75 μm is optimal for bond strength
- No preparation needed for fresh wet lay-up (bond is formed during cure)
- For secondary bonding to cured CFRP: light abrasion with 80-grit sandpaper, solvent wipe
Application Guidelines
Structural adhesives are typically applied using either cartridge guns (for small to medium areas) or bulk dispensing systems (for large projects). Key points:
- Mix components thoroughly according to the specified ratio (our products use 2:1 or 3:1 by volume)
- Apply within the pot life — do not extend by adding solvent
- Maintain minimum bond line thickness (usually 1mm) using spacer beads or shims
- Apply continuous pressure or clamping during cure to prevent void formation
- Do not load the bond until full cure is achieved (typically 7 days at 25°C for design strength)
Choosing Between Our Structural Adhesives
For steel plate bonding to concrete: Use XQ-JG (Steel Bonding Adhesive). It is specifically formulated for this application with the right rheology, bond strength, and cure characteristics.
For CFRP fabric application: Use XQ-TJ (Impregnation Resin). Its low viscosity ensures complete fiber saturation, and its elongation matches the carbon fiber system requirements.
For CFRP plate bonding: Use XQ-PB (Plate Bonding Adhesive). Its thixotropic nature allows application on vertical and overhead surfaces without sagging, and it maintains even bond line thickness.
For general metal connections: Use XQ-MBA (Metal Bonding Epoxy). It provides high shear strength across different metal combinations and resists harsh chemical environments.
Browse all structural adhesives or request technical data for your specific application.