Hydrocor Corkjoint Type 3: Technical Details, Specifications, and Features

Product Overview

Hydrocor Corkjoint Type 3 is a self-expanding joint filler manufactured by Fosroc, designed for use in various construction applications. It is made from cork granules bound together with insoluble synthetic resin, creating a semi-rigid, compressible backing material that expands when exposed to moisture.

Composition and Material Properties

The product consists of cork granules as the primary raw material component, held together with synthetic resin binding. This combination creates a resin-bonded cork sheet form that provides both structural support and resilience in joint applications.

Physical Form

• Form: Compressible sheet, resin bonded cork
• Appearance: Solid, compressed cork sheet material
• Supply Format: Available in standard and custom sizes for different applications

Performance Specifications

Expansion Characteristics

Hydrocor Corkjoint Type 3 exhibits controlled expansion when exposed to moisture:

• Water Expansion (Boiling): Minimum 40% expansion in boiling water over a one-hour test period
• Self-Expanding Property: Expands to fill joints and accommodate movement

Compression and Recovery Properties

• Load Required to Compress to 50%: 1.3 to 1.5 MPa
• Recovery After 50% Compression: Greater than 90% with less than 6mm deviation under test conditions
• Extrusion at 50% Compression: Less than 1mm in use, demonstrating excellent extrusion resistance under pressure

Durability Characteristics

• Resilient: Recovers well after compression and maintains functionality
• Waterproof: Provides moisture barrier characteristics
• Lightweight and Easy to Handle: Facilitates installation and handling on construction sites

Key Advantages

Hydrocor Corkjoint Type 3 offers several significant benefits for joint sealing applications:

• Supports Sealants Subject to Hydrostatic Pressure: Provides necessary backing for elastomeric sealants in water-retaining structures
• Minimal Extrusion Under Pressure: Maintains integrity and prevents material loss during compression
• Expands to Fill Joints: Self-expanding nature ensures complete joint filling
• Resilient and Waterproof: Maintains performance properties over time
• Light Weight: Easier to transport and install compared to alternative materials

Application Areas and Uses

Water Retaining Structures

Hydrocor Corkjoint Type 3 provides backing to joint sealing systems in:

• Dams
• Reservoirs
• Culverts
• Canals
• Sea walls
• Water treatment structures
• Water storage structures

Water Excluding Structures

Suitable for filling expansion joints in:

• Basements
• Subways
• Site slabs

Traffic Areas

• Internal Traffic Areas: Supports joint sealants subject to pedestrian or wheeled traffic
• External Traffic Areas: Provides support for traffic-bearing joint systems
• Roads, Bridges and Carparks: Used in both expansion and static joints

Installation and Application Instructions

Pre-Installation Preparation

• Protective Wrapping: Hydrocor Corkjoint Type 3 is supplied with waterproof wrapping that must NOT be removed until immediately prior to fixing
• Storage: Should be stored in original packaging in cool, dry conditions

Fixing Procedure

1. Bonding Method: Fixed in place by bonding to concrete using construction adhesive after shutter removal
2. Concrete Placement: The next section of concrete is then poured directly against the Hydrocor Corkjoint Type 3 with minimal delays
3. Sealing Slot Formation: After initial concrete cure, the top section is removed using either a power grinder or saw to form a sealing slot of required dimensions

Alternative Installation Method

To avoid cutting or grinding steps, the product may be:

• Initially placed below the concrete surface at the required sealing slot depth
• Covered with a removable section (timber or polystyrene foam) reaching the concrete surface
• Easily removed once concrete has cured

Bond Breaker Application

Fosroc Bond Breaker Tape must be applied over the Hydrocor Corkjoint Type 3 prior to application of joint sealant to ensure proper three-sided adhesion of the sealant.

Product Supply Options

Standard Sizes

Dimension	Product Code
100mm x 10mm x 1.5m	FC750000-UNIT
125mm x 10mm x 1.5m	FC750002-UNIT
150mm x 12mm x 1.5m	FC750003-UNIT

Custom Sizes (Made to Order)

• Width Range: 50mm to 635mm in depth
• Thickness Options: 10mm, 12mm, 15mm, 16mm, 20mm, 25mm, and 30mm
• Length Options: 930mm, 1200mm, 1500mm, and 1800mm
• Product Code: FC7CSPEC-UNIT

Limitations and Considerations

Staining Potential

Hydrocor Corkjoint Type 3 may cause staining of surrounding concrete in damp conditions, particularly on:

• Light-colored concrete surfaces
• Exposed aggregate finishes produced by high-pressure hosing

Note: Staining typically disappears after 6–8 weeks of normal weathering.

Alternative Solution

Fosroc Hydrocell, a non-staining polyethylene foam filler, may be more suitable for applications where concrete staining is a concern.

Traffic Load Considerations

For internal or external traffic areas with high traffic loads, it is recommended to recess the joint sealant approximately 2mm below the surface to avoid direct abrasion from potential expansion of the filler.

Storage Requirements

• Original Packaging: Must be stored in original packaging
• Conditions: Keep in cool, dry conditions
• Environmental Factors: Shelf life may be reduced in high humidity locations

Design and Compliance

Joint Sealing System

Hydrocor Corkjoint Type 3 forms part of a complete joint sealing system when combined with a suitable joint sealant, providing semi-rigid backing that supports elastomeric sealants subject to hydrostatic pressure and movement.

Static and Expansion Joints

The product is designed to fill both:

• Static joints: Non-moving joint types in structures
• Expansion joints: Movement-accommodation joint types in various building applications

Documentation and Safety Information

A Safety Data Sheet (SDS) is available from the Fosroc website and must be read carefully prior to use, as application and performance data may change over time. The Technical Data Sheet provides essential information for safe and effective product use and application.

References

• [1] Fosroc_Hydrocor_Corkjoint_Type_3_TDS.pdf
• [3] Fosroc_Hydrocor_Corkjoint_Type_106_TDS.pdf