Pasco Aquastop

For sealing non-moving construction joints in underground structures, basements, tunnels, and retaining walls, Pasco Aquastop provides a permanently active, swelling seal that prevents water migration under hydrostatic pressure. This hydrophilic polymer rubber waterstop is designed to replace conventional PVC waterbars in concrete joints, eliminating the need for seam welding and split forming.

How it works

Aquastop contains sodium bentonite, a clay structured with tightly packed, charged microscopic platelets. When water contacts the joint, molecules are attracted to these positive and negative charges, wedging between the platelets and causing them to swell. This controlled expansion forms an impermeable barrier. As hydrostatic pressure increases, the clay platelets compact to create a tighter, self-healing pressure seal that fills small voids and cracks in the concrete.

Numbers that matter

• 100% to 300% expansion: Swells on contact with water to fill joints and irregular concrete contours (expansion is subject to water quality, temperature, and storage conditions).
• >70m hydrostatic head resistance: Withstands extreme water pressures in deep underground stations, pits, and box culverts, remaining unaffected after 25 wet and dry cycles.
• 75mm minimum concrete cover: Requires fully confined installation with at least 75mm of concrete depth to the exterior wall surface to prevent damage from expansion forces.
• >450% elongation: Highly flexible polymer rubber base that contours around penetrations, pile caps, and irregular concrete surfaces without tearing.
• 19mm x 25mm profile: Supplied in lightweight 5-metre rolls for direct butt-end joining, creating a continuous waterstop without overlaps.

Where to use it

Aquastop is suitable for vertical and horizontal non-moving concrete construction joints, precast panels, and around penetrations, including:

• Single and multi-pipe penetrations: Installed around the outer diameter of pipes, sleeves, and block-out box constructions.
• Pile caps and grade beams: Wrapped around reinforcement bars, I-beams, and construction joints above the waterproofing layer.
• PVC waterbar transitions: Placed on the interior side of an existing PVC waterbar with a minimum 7.5cm direct-contact overlap.
• Irregular surfaces: Pressed directly into concrete cavities and minor depressions to eliminate gaps behind the waterbar.

Limitations

• Do not use as an expansion joint sealant.
• Standard Aquastop is designed for uncontaminated groundwater. If saltwater, organic contaminants, or severe groundwater chemicals are present, consult Pasco before installation.
• Do not pre-hydrate or submerge the waterstop in water. If the material becomes hydrated prior to concrete placement, it must be allowed to dry completely.
• Aquastop is not self-adhering and must be secured using Aquastop adhesive or mechanical fasteners.

Installation process

All concrete surfaces must be clean, structurally sound, and free of standing water, form release agents, curing compounds, and dirt. Brush-apply Aquastop adhesive along the concrete surface to the width of the waterbar (1 litre covers approximately 30 metres). Press the waterstop firmly into the adhesive while it is still tacky, typically within 10 to 15 minutes, then remove the release paper. If the adhesive dries before application, reapply. Ensure vertical sections are secured at the highest coil end, and butt-join all roll ends tightly together to maintain a continuous seal.