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Manhole rehabilitation
Strong-Seal · Leak stop
Strong-Plug® Rapid-Acting Leak Stop Cement
A hydraulic cement that hardens on contact with water. Press it into an active leak in a manhole, tank or pipe and hold it until it sets.
final set
<1 min
psi compressive strength in 1 hour
1,000+
pull-out strength (ASTM C234)
14,000 lb
Stop the water first
Hold it in place, and it sets. Strong-Plug® is hand mixed and hand applied. Use it as a slurry, or press it in as a dry powder and let the leaking water harden it. Once it sets, Strong-Seal® products can go right over it.
2 ways
Slurry or dry powder
Mix to a slurry, or apply dry straight to the leak. No mixing needed for dry.
2,500+ psi
In 24 hours
Over 1,000 psi in 1 hour.
STRONG-PLUG 50 lb bucket
No loss
Sulfate resistant
No mass loss after 15 cycles at 2,000 ppm sulfate (ASTM C267).
100 cycles
Freeze/thaw tested
Passes ASTM C666 with no damage.
Five steps to a stopped leak
1
Clean
Pressure wash to a sound surface, 3,000 psi minimum. Remove loose brick, mortar and concrete.
2
Open the crack
Chip small cracks wider with a hammer and chisel so the slurry or dry pack can fill them.
3
Mix
For slurry, use 3 to 4 fluid ounces of water per pound, water first. Mix only what you can place in 1 minute. Dry powder needs no mixing.
4
Apply and hold
Press it firmly into the leak by hand or trowel. Hold it in place until it sets. With dry powder, the leaking water hardens it.
5
Plug weep holes
If you used weep holes to steer the water, plug them last the same way. No special curing needed.
Then line: once Strong-Plug® sets, Strong-Seal® products can be applied right over it.
After the leak stops
Strong-Plug® is the first step in a manhole rehab. Once the water is stopped, rebuild what’s damaged and line the structure.
Next, patch and rebuild
Strong-Seal QSR
Fast-setting mortar for benches, inverts and voids. Final set in 15 to 30 minutes.
See QSR ›
Then line the structure
Strong-Seal liners
Spray MS-2®A, MS-2®C or High Performance Mix over the repaired structure to stop infiltration and restore strength. Pick by how much corrosion you see.
See the liners ›
Meet Fernco Infrastructure
An overview of our manhole rehabilitation and trenchless pipe repair solutions.
Technical data
Specifications
| Part number | STRONG-PLUG |
|---|---|
| Packaging | 50 lb bucket |
| Final set | Under 1 minute |
| Compressive strength (ASTM C109) | Over 1,000 psi at 1 hour, 2,500 psi at 24 hours |
| Flexural strength (ASTM C293) | Over 1,200 psi at 28 days |
| Freeze/thaw (ASTM C666) | Pass, no damage, 100 cycles |
| Bond strength (ASTM C882) | Over 2,000 psi at 28 days |
| Sulfate resistance (ASTM C267) | No mass loss, 15 cycles at 2,000 ppm |
|---|---|
| Pull-out strength (ASTM C234) | 14,000 lb |
| Yield per bucket | 0.45 ft³, or 10.8 ft² at ½″ thick |
| Made with | Hydraulic cement, masonry sand and performance admixtures |
| Water | 3 to 4 fluid ounces per pound for slurry; none for dry application |
| Typical structures | Manholes, tanks and containment, tunnels and pipelines, wastewater facilities |
FAQ
Common questions
Slurry or dry?
Either. Slurry is mixed and pressed in by hand or trowel. Dry powder goes straight onto the leak and the infiltrating water hardens it. With either one, hold it in place until it sets.
How much do I mix?
Only what you can apply within 1 minute, mixed near the leak.
Can I line right over it?
Yes. No special curing is needed. Once it sets, Strong-Seal® products can be applied right over it.
What about big leaks?
Some leaks need weep holes to steer the water while you work. Plug those last. Severe infiltration may need pressure grouting.
What weather can I apply it in?
Don’t apply below 40°F, on frozen surfaces, or if the surface could freeze within 24 hours. Keep the material under 90°F and the mix water under 80°F. Chill with ice if you need to.
For distributors
Interested in carrying Fernco Infrastructure?
Fernco Infrastructure covers manhole, structure and pipe rehab with three product lines. Add them to your line card to serve municipal and contractor customers.
Documents
The Strong-Plug sell sheet with full specifications and application steps, plus the Fernco Infrastructure, Plumbing and WaterWorks catalogs.
Got questions?
Fighting active infiltration? Our infrastructure team can help. Reach out, or find your Fernco rep.