Conseal CS231 - Low Expansion Sealing Gasket for Concrete Joints

Product Overview

Conseal CS231 is a low expansion butyl-based hydrophilic sealing gasket manufactured by Fosroc using a special mixing process. It is specifically designed for sealing non-moving joints in precast concrete structures and between in-situ pours and existing concrete. The product encapsulates hydrophilic materials into a butyl rubber base, creating a controlled moisture-activated seal that distinguishes it from traditional bentonite-based waterstops.

Key Features and Advantages

Design Philosophy

Conseal CS231 does not depend on moisture activation alone to work effectively. Its mechanical properties rely on the bond to each side of the joint rather than on product expansion itself. However, its controlled expansion in the presence of water increases seal effectiveness and accommodates small joint movements.

Key advantages include:

• No site welding required – simply butt and mould sections together
• Easy to handle – only requires priming the concrete face
• Surface tolerance – accommodates a moderate amount of surface irregularity
• Immediate sealing – provides compressible immediate effectiveness upon installation
• Chemical bonding – the heat of hydration assists with chemical bond formation to green concrete
• Highly elastic – possesses substantial elongation capabilities

Technical Specifications

Physical Properties

Material Composition

Conseal CS231 is manufactured through a special mixing process that:

• Encapsulates hydrophilic materials into a butyl rubber base
• Creates controlled moisture-activated expansion capability
• Produces a product with chemical bonding properties to concrete substrates

Application Areas

Conseal CS231 is ideal for sealing:

• Non-moving joints in precast concrete structures
• Joints between in-situ pours and existing concrete
• Manholes – as sealing strips
• Pipe penetrations – effective sealing application
• Box culverts – underground passages requiring reliable seals
• Non-moving construction joints where controlled expansion is required

Installation Instructions

Surface Preparation

1. Clean thoroughly – brush off all loose dust and dirt
2. Apply primer – use Fosroc Primer 24 to the area where Conseal CS231 will be fixed
3. Allow tacky state – wait approximately 15 minutes for primer to become tacky

Installation Process

1. Position gasket – firmly press Conseal CS231 onto the primed surface, ensuring alignment to engineer specifications
2. Apply pressure – use moderate hand pressure with the heel of the hand to ensure bonding
3. Remove backing – take off protective backing from the gasket
4. Join overlaps – knead together overlapped ends at joints to form a continuous strip
5. Prime second surface – apply Fosroc Primer 24 to the matching concrete surface
6. Final assembly – bring precast sections firmly together into the correct position once primer is tacky

Controlled Expansion Mechanism

Moisture Activation

The hydrophilic materials encapsulated within Conseal CS231 activate expansion when exposed to moisture. This controlled expansion:

• Compensates for moisture exposure – provides up to 10% expansion over 28 days
• Differs from bentonite products – will not soften or extrude from non-moving joints, unlike highly expansive hydrophilic waterstops that must be fully contained
• Enhances sealing – the expansion increases seal effectiveness while accommodating small joint movements
• Maintains material integrity – no material disintegration occurs during expansion

Supply Options

Conseal CS231 is supplied as trapezoidal profile strips in rolls:

Storage Requirements

• Shelf life – 12 months from manufacture date
• Storage conditions – original packaging in cool, dry conditions
• Temperature limit – not exceeding 25°C
• Note – storage above 25°C may reduce shelf life

Safety and Documentation

Safety Data Sheet (SDS) and Technical Data Sheet (TDS) are available from the Fosroc website. In case of emergency, contact any Poisons Information Centre (phone 13 11 26 within Australia) or a doctor for medical advice.

Comparison with Alternative Products

Conseal CS231 operates distinctly differently from bentonite-based highly expansive hydrophilic waterstops, which must be fully contained within non-movement construction joints to be effective. Conseal CS231's controlled expansion prevents extrusion from non-moving joints while still providing enhanced sealing performance.

References

• [1] Fosroc_Flamex_XT_TDS.pdf
• [2] Conseal_CS231_TDS.pdf