W-6 is the lead product in this PU injection solution route for void filling, slab undersealing and leak sealing. In pavements, slabs, tunnels, basements and buried concrete, the problem is often not only water ingress. Hidden voids, pumping support layers, contact loss and local instability also need to be filled and stabilized. In these situations, a simple water-stop resin is often not enough.

W-6 is a two-component closed-cell polyurethane injection grout developed for controlled expansion, rapid filling and durable support recovery. It reacts quickly, expands into irregular cavities and forms a closed-cell body with low water uptake, frost resistance and dimensional stability. This makes it the preferred route when the project needs both filling efficiency and stable support performance after curing.

Why W-6 comes first

Controlled two-component reaction

W-6 uses a matched A/B system, allowing more controlled reaction behavior than one-part water-reactive products. This makes it more suitable for engineered undersealing, slab stabilization and support recovery work.

Closed-cell structure for durable filling

The cured body forms a closed-cell structure that helps reduce water uptake and improves long-term dimensional stability. This is especially valuable where the filled zone must continue to support service loads after injection.

Fast filling and return to service

W-6 offers adjustable gel time and a typical return-to-service window of 30 to 120 minutes, depending on temperature, load and project acceptance criteria.

High expansion for irregular voids

With a free-rise expansion ratio of 1–25×, W-6 can efficiently fill irregular cavities, contact gaps and under-slab voids that are difficult to reach with rigid filling materials.

Low-temperature and frost-resistant performance

The cured material has low water uptake, frost resistance of at least F200, and dimensional stability at both low and elevated service temperatures.

Microscopic structure analysis (SEM)

Typical applications

• Void filling behind slabs, pavements and industrial floors

• Slab undersealing and stabilization in roads, airport pavements and rigid panels

• Leak sealing and filling in basements, tunnels, manholes and buried structures

• Ground contact gap filling around utilities, retaining elements and structural interfaces

• Repair zones where rapid return to service is required

Typical application procedure

1. Prepare Components A and B according to the injection or placement plan.

2. Combine A+B in the correct ratio.

3. Use mechanical mixing until the material is uniform.

4. Place or inject the material into the prepared cavity or target zone.

5. Allow expansion and curing under controlled site conditions.

6. Finish the surface and confirm filling or support recovery.

   
   

Where the other two products fit

Hydrophilic Polyurethane Grout

Choose this route when the main problem is active flowing water and the priority is rapid water stop. It is water-reactive, gels quickly and is better suited to leak-cutting work than to support recovery or closed-cell filling.

AquaBond 40 NF Non-Foaming Structural PU Injection Grout

Choose this route when the project needs a denser, non-foaming structural injection body in wet cracks or water-bearing structures. It is better suited to waterproofing plus structural reinforcement where foaming is not desired.

Recommended product matrix

• W-6 Polyurethane Injection Grout (Two-Component, Closed-Cell) — lead product for void filling, slab undersealing and support stabilization

• Hydrophilic Polyurethane Grout — complementary route for active leak sealing and rapid water stop

• AquaBond 40 NF Non-Foaming Structural PU Injection Grout — complementary route for wet structural reinforcement and dense non-foaming injection

Technical support before quotation

• Structure type and repair location

• Void condition or slab support loss condition

• Need for undersealing, leak sealing or both

• Required reopening time

• Ambient and substrate temperature

• Injection equipment type

• Allowable lift or movement tolerance

Get a project-specific recommendation

If your project involves void filling, slab undersealing, support stabilization or rapid leak sealing, send us your project conditions and our team will recommend whether W-6 is the right PU route and when one of the two companion products should be used instead.