hydrophilic waterstop
Hydrophilic waterstop – water swelling rubber strip for concrete joints. Expands on contact with water, self-seals gaps. Ideal for tunnels, basements, dams.
Hydrophilic Waterstop – Water Swelling Strip for Concrete Joint Sealing
Our hydrophilic waterstop (also known as water swelling strip, water swelling rubber strip, or hydro-expansive waterstop) is a high-performance sealing material that expands upon contact with water, automatically filling gaps and preventing water leakage. Ideal for construction joints, pipe penetrations, and repair works in tunnels, basements, dams, and underground structures.
What is a Hydrophilic Waterstop?
A hydrophilic waterstop is a rubber strip containing hydrophilic (water-loving) additives or bentonite. When exposed to water, it swells to several times its original volume, creating a tight, self-sealing barrier against water ingress. Unlike conventional waterstops that rely on mechanical anchorage, hydrophilic waterstops provide active sealing even in imperfectly compacted concrete or irregular joints.
Our products are available in two main types: bentonite waterstop (clay-based) and synthetic hydrophilic rubber waterstop (polymer-based). Both offer excellent swelling performance and long-term durability.
Key Features
- High swelling ratio – Expands up to 300-500% of original volume when wet.
- Self-sealing – Automatically fills voids, cracks, and imperfect concrete surfaces.
- Easy installation – Can be nailed, glued, or embedded into green concrete.
- Chemical resistance – Resists dilute acids, alkalis, and sewage.
- Wide temperature range – Suitable for -20°C to +80°C environments.
- Compliant standards – Meets GB/T 18173.3, DIN 7865, and ASTM requirements.
Types of Hydrophilic Waterstops We Supply
- Bentonite Hydrophilic Waterstop – Natural clay-based; economical and widely used for underground structures.
- Synthetic Rubber Hydrophilic Waterstop – Polymer-based; higher swelling pressure and better durability.
- Profile Shapes – Available in round, strip, L-shape, and custom cross-sections.
- Adhesive-backed Water Swelling Strip – Self-adhesive version for quick retrofit applications.
Technical Specifications (Typical)
| Parameter | Value |
|---|---|
| Base material | Natural rubber / EPDM + hydrophilic polymer or bentonite |
| Swelling ratio (24h in water, %) | ≥ 300 (up to 500 on request) |
| Tensile strength (MPa) | ≥ 3.0 |
| Ultimate elongation (%) | ≥ 400 |
| Hardness (Shore A) | 45 ± 5 |
| Working temperature (°C) | -20 to +80 |
| Water pressure resistance (MPa) | ≤ 0.6 |
| Standards | GB/T 18173.3, DIN 7865 |
Applications
Our hydrophilic waterstops are widely used in:
- Tunnels & subways – Construction joints, segment joints.
- Basements & underground parking – Wall and floor construction joints.
- Dams & reservoirs – Cold joints, repair joints.
- Swimming pools & water tanks – Joints and pipe penetrations.
- Pipe penetrations through concrete – Sealing around pipes.
- Precast concrete segments – Joint sealing in segmental linings.
- Repair works – Retrofitting leaking joints.
Installation Guide
- Surface preparation: Clean the joint surface, remove laitance, dust, and oil. The concrete surface should be damp but not standing water.
- Positioning: Place the hydrophilic waterstop along the center of the construction joint. For embedded installation, press it into fresh concrete.
- Fixing: Use nails, staples, or adhesive to secure the strip. For vertical joints, use mechanical fasteners every 200-300 mm.
- Splicing: Overlap ends by at least 50 mm. For butt joints, use a small piece of the same material as a patch.
- Prevention of premature swelling: Keep the waterstop dry before concrete pouring. If rain is expected, cover with plastic sheeting.
- Concrete pouring: Pour concrete carefully to avoid displacing the strip. Ensure concrete fully contacts the strip.
Frequently Asked Questions (FAQ)
Q: How does a hydrophilic waterstop work?
A: It contains hydrophilic polymers or bentonite that absorb water and swell, creating a compressive seal against the concrete. The swelling pressure fills any gaps or imperfections, preventing water passage.
Q: What is the swelling ratio of your water swelling strip?
A: Our standard hydrophilic waterstop swells to ≥300% of its original volume within 24 hours. High-swelling versions (up to 500%) are available upon request.
Q: Can hydrophilic waterstop be used for moving joints?
A: No, hydrophilic waterstops are designed for non-moving or limited-movement joints (construction joints, cold joints). For expansion joints with significant movement, use center-bulb rubber or PVC waterstops.
Q: What is the difference between bentonite and synthetic hydrophilic waterstop?
A: Bentonite waterstop is clay-based, economical, and suitable for most underground applications. Synthetic hydrophilic rubber waterstop offers higher swelling pressure, better elasticity, and longer service life, but is more expensive.
Q: How to prevent premature swelling during installation?
A: Store the product in a dry place. During installation, avoid contact with water. If rain is forecast, cover the installed waterstop with plastic sheeting. Once concrete is poured, the waterstop will activate from the moisture in the concrete.
Q: Do you offer custom sizes and shapes?
A: Yes, we can produce custom cross-sections (L-shape, T-shape, round, etc.) and lengths. Send your drawing for a quotation.
Why Choose Guchen Hydrophilic Waterstops?
As a professional hydrophilic waterstop manufacturer and supplier with over 15 years of experience, we offer:
- Premium materials – virgin rubber + high-grade hydrophilic polymer or bentonite.
- Strict quality control – each batch tested for swelling ratio, tensile strength, and elongation.
- Compliance with GB/T 18173.3 and DIN 7865.
- Factory direct prices with fast worldwide delivery.
- Technical support and installation guidance.
📞 Get a hydrophilic waterstop quote – Send your application, size, and quantity requirements. We will reply within 24 hours.