Hydrophilic Rubber Waterstop (Water-Swelling Rubber Strip)
A functional joint-sealing material that expands on contact with water to form a dense, self-tightening seal across concrete joints. Designed for underground structures, tunnels, water tanks, and precast segments. Complies with GB/T 18173.3-2014.
PN Putty Type
Expansion ≥150% – 600%
Slow-Swell Grade Available


Product Types: PZ vs PN
We supply two distinct families to match your joint requirements:
| Feature | PZ (Product Type) | PN (Putty Type) |
|---|---|---|
| Appearance | Usually red, firm, rubber-elastic | Usually black, soft, tacky |
| Sealing Mechanism | Water swelling + rubber elasticity | Water swelling fills the gap |
| Tensile Strength | ≥3.0 – 3.5 MPa | Lower |
| Immersed Stability | Excellent (long-term immersion) | Fair |
| Typical Applications | Shield tunnel segments, precast joints, critical joints | Cast-in-place joints, water tanks, leak repair |
Technical Specifications (GB/T 18173.3-2014)
| Item | PZ (Product Type) Standard Range |
|---|---|
| Volume Expansion Ratio | ≥150% / 250% / 400% / 600% (by grade) |
| Hardness (Shore A) | 42 ± 7 (High-expansion models: 45 ± 10) |
| Tensile Strength | ≥3.0 – 3.5 MPa |
| Elongation at Break | ≥350% – 450% |
| Low-Temp Flexibility | -20°C × 2h, no cracks |
Quality Test Reports & Compliance
Below are the official Type Test Reports from the National Engineering Rubber Product Quality Inspection Center (CNAS & ilac-MRA Accredited). We display the cover pages for authenticity, and extract the key test data below.
PZ Type (Product) Test Data

- Volume Expansion: 479% (Req: ≥400%)
- Tensile Strength: 4.0 MPa (Req: ≥3.0 MPa)
- Elongation: 614% (Req: ≥350%)
- Low Temp (-20°C): No cracks
PN Type (Putty) Test Data

- Volume Expansion: 494% (Req: ≥220%)
- High Temp Flow: No flow at 80°C
- Low Temp (-20°C): No brittleness
Selection Guide & Restrictions
| Scenario | Recommendation |
|---|---|
| High water pressure, critical structures | Choose PZ (Product Type) |
| Cast-in-place joints, low pressure, cost-sensitive | Choose PN (Putty Type) |
| Large displacement (expansion/settlement joints) | ⚠️ Do not use. Must use EPDM Waterstop Bar. |
| Long construction period / humid site | Choose Slow-Swell Grade to avoid premature swelling |
Installation Key Points
1. Surface Prep
Concrete surface must be flat, dry, and free of loose debris.
2. Fixing
Nail-pin at 80–120 cm spacing, or use special adhesive to ensure a tight bond.
3. Splicing
No butt joints. Overlap ≥50 mm, bevel ends, and pin both sides.
4. Pouring
Prevent floating or displacement during concrete pouring. Avoid rain/snow.
Need a Grade Recommendation or Quote?
Send us your joint conditions (water pressure, joint type, expected movement). Our engineering team will recommend the exact PZ or PN model and provide a quotation.











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