Hydrocell: Semi-Rigid Polyethylene Joint Filler

Overview

Hydrocell is a non-absorbent, semi-rigid, polyethylene joint filler material designed for use in forming expansion joints and supporting elastomeric sealants across diverse construction applications. It functions as a firm, consolidated joint filler and backing strip that provides continual structural support in demanding environments.

Physical Description and Composition

Hydrocell is manufactured as a semi-rigid, UV-resistant, cross-linked, closed-cell polyethylene sheet material. The product exhibits non-absorbent and rot-proof characteristics, making it ideal for applications involving exposure to moisture and organic degradation. As a polyethylene-based material, it delivers both durability and resilience in challenging conditions.

Key Physical Properties

Property	Specification
Form	Semi-rigid, closed-cell, polyethylene foam sheet
Density	110 kg ± 5 kg per m³
Water Absorption	Less than 2% after 28 days
Load Required to Compress 50%	420 kPa (MR610 / T1150)
Recovery	Greater than 90% (T1150)
Extrusion at 50% Compression	0.5 mm (MR610 / T1150)
Accelerated Weathering	Excellent / no degradation (Test MR610 / T1150)

Functional Characteristics

Bond Breaker Properties

Hydrocell functions as a bond breaker in joint sealing applications. As elastomeric sealants do not bond to Hydrocell, the additional need for separate bond breaker strips is eliminated. This characteristic is critical for allowing sealant to flex and move appropriately as joints expand and contract, ensuring proper three-sided bonding geometry.

Chemical Resistance

Hydrocell demonstrates excellent chemical resistance to a comprehensive range of substances when immersed for 7 days:

• Hydrochloric acid (10%): No reaction
• Caustic soda (10%): No reaction
• Acetone: No reaction
• Premium motor fuel: No reaction with slight swelling
• Diesel fuel: No reaction with slight swelling

Environmental Performance

• Heat Resistance: Suitable for applications up to 80°C
• UV Resistance: UV-resistant for outdoor and exposed applications
• Bacteriological Attack Resistance: Excellent
• Non-tainting: Suitable for use in potable water applications
• Bitumen Free: Does not contain bituminous materials

Standards Compliance

Hydrocell meets rigorous industry standards:

• AS 4020:2018: Complies at an exposure level of 15,000 mm² per litre, confirming suitability for use in drinking water applications (AWQC Report 320286)
• TfNSW Specification 3204: Meets performance requirements for preformed joint fillers for concrete road pavements and structures

Applications

Primary Uses

Hydrocell is used in forming expansion joints and is suitable for application in:

Water-Retaining and Water-Excluding Structures:

• Raw and potable water reservoirs
• Sewage treatment works
• Irrigation channels and culverts
• Basement structures and subways
• Retaining walls
• Deck slabs

Traffic and Infrastructure Applications:

• Concrete roads and bridges
• Heavy frequent traffic environments
• Floor joints subject to traffic loads
• Brickwork and blockwork construction

Load-Bearing Applications

Hydrocell is the recommended joint filler for applications subject to heavy loads instead of Expandafoam Open Cell. It is particularly suitable for:

• Water-retaining structures requiring semi-rigid backing
• Floor joints experiencing continuous movement and stress
• Applications involving traffic loading
• Environments demanding sustained structural support

Installation and Preparation

Joint Sealing Slots

When forming expansion joints with Hydrocell in in-situ concrete, joint sealing slots can be readily formed using the "Zip Top" technique:

1. Cut off a strip of Hydrocell to the required depth
2. Pin the strip back onto the main filler using small nails
3. Install the filler flush with the finished surface
4. Prior to sealing, pull the top strip easily from the joint to provide an uncontaminated sealing slot ready for preparation and sealing

Suspended Slabs

When installing Hydrocell in expansion joints between suspended slabs, partly projecting copper nails or daubs of adhesive may be used to help prevent displacement.

Pre-Installation Preparation

Prior to sealing, joints should be cleaned to remove any contaminants. The surface must be prepared to ensure proper sealant adhesion.

Supply and Specifications

Hydrocell is supplied in sheet sizes of 2.4 m long × 1.2 m wide and can be easily cut to required size with a sharp knife or fine saw.

Available Thicknesses

Sheet Thickness	Material Code
10 mm	FC701000-UNIT
15 mm	FC701010-UNIT
20 mm	FC701015-UNIT

Storage Requirements

Hydrocell should be stored in a clean area and not left exposed for long periods, especially in hot climates. Proper environmental management during storage is essential to maintain the product's integrity and shelf life.

Advantages Summary

• Non-absorbent and rot-proof
• Non-tainting for drinking water applications
• Resilient with excellent recovery properties
• Bitumen free for sustainable applications
• Heat resistant up to 80°C
• UV resistant for outdoor durability
• Readily compressible for flexible installation
• No need for separate bond breaker strips due to non-bonding properties with elastomeric sealants
• Excellent chemical resistance across diverse substances
• Complies with drinking water standards (AS 4020-2018)

Important Technical Considerations

As with all Fosroc products, users should consult the Technical Data Sheet (TDS) and Safety Data Sheet (SDS) carefully prior to use, as application and performance data may change from time to time. The product must be used in accordance with all guidelines and instructions to ensure proper performance and safety compliance.

References

• [1] Fosroc_Hydrocell_TDS.pdf
• [5] Fosroc_Hydrocor_Corkjoint _Type _3_TDS.pdf
• [7] Fosroc_Expandafoam_Closed_Cell_TDS.pdf
• [9] Fosroc_Expandafoam_Open_Cell_TDS.pdf
• [11] Fosroc_Expandafoam_TDS.pdf