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Manhole and pipe rehabilitation
Strong-Seal · Cementitious grout
Grout 250 Void and Leak Stabilization
A lightweight, volume-stable portland cement grout for filling voids behind manholes and other structures and filling abandoned lines, to stop leaks and prevent settling.
yield per bag
1.91 ft³
lightweight wet unit weight
70 lb/ft³
shrinkage at 28 days (ASTM C596)
0%
Fill the void, stop the settling
Pump it behind the wall. Voids behind a structure let water in and let the ground settle. Grout 250 is a volume-stable portland cement grout with lightweight aggregate that fills those voids, or an abandoned line, as a flowable fill.
1.91 ft³
Yield per bag
Lightweight aggregate. About twice the yield of Grout 1,000 per bag.
250+ psi
At 28 days
Structural or flowable fill for voids and abandoned lines.
GROUT250 60 lb bag · 40 per pallet
Fine soils
Formulated for sand
Made for fine, sandy soils or soils with low porosity.
0%
Drying shrinkage
Volume-stable, with 0% drying shrinkage at 28 days.
Pick the grout by the job
All three are volume-stable, Type I/II portland cement based grouts with 0% drying shrinkage. They differ in strength, weight and what they’re for. Grout 250 and Grout 1,000 are formulated for fine, sandy or low-porosity soils.
| Strong-Seal® grout | Strength at 28 days | Use it for | Weight and yield |
|---|---|---|---|
| Grout 250 This page | Over 250 psi | Filling voids behind structures and abandoned lines, with the most yield per bag | 70 ± 5 lb/ft³ 1.91 ft³ per bag |
| Grout 1,000 | Over 1,000 psi | Filling voids and abandoned lines where you need more strength | 105 ± 5 lb/ft³ 0.91 ft³ per bag |
| Grout 12,000 | Over 12,000 psi | Rebuilding corrugated metal culvert inverts, 24″ and larger, before Storm Seal® | 140 ± 5 lb/ft³ 0.55 ft³ per bag |
Five steps to fill a void
1
Find the leaks
Identify infiltration, especially at service lines, intersections, lifting holes and joints. Soak the soil outside to confirm leaks if needed.
2
Seal the face
Seal minor cracks with Strong-Plug®. Fill large voids, cracks and gaps around incoming lines with Strong-Seal QSR so grout can’t escape.
3
Drill and set packers
Drill holes through the wall in the recommended pattern. Set a grout packer in each hole until snug.
4
Flush with water
Pump water through each packer until it comes out another hole, then plug that hole. Stop if pressure rises more than 10 psi.
5
Pump the grout
Pump grout the same way, stopping if pressure rises more than 10 psi. Remove packers 3 hours later and fill the holes with a rapid-setting patch.
Abandoned lines: build a concrete bulkhead with inlet and outlet risers at each manhole. Pump through a flow-through packer in the inlet riser until grout comes out the outlet riser. Remove the risers 3 hours later.
Before you grout
Seal the face of the structure first, so the grout fills the void instead of leaking back out.
Seal minor cracks
Strong-Plug®
Sets in under a minute and hardens on contact with water. Seal minor cracks before you pump.
See Strong-Plug ›
Fill large voids and gaps
Strong-Seal QSR
Fast-setting mortar for benches, inverts and voids. Final set in 15 to 30 minutes.
See QSR ›
Meet Fernco Infrastructure
An overview of our manhole rehabilitation and trenchless pipe repair solutions.
Technical data
Specifications
| Part number | GROUT250 |
|---|---|
| Packaging | 60 lb bag, 40 bags per pallet |
| Compressive strength (ASTM C109) | Over 250 psi at 28 days |
| Drying shrinkage (ASTM C596) | 0% at 28 days, 90% RH |
| Wet unit weight (ASTM C138) | 70 ± 5 lb/ft³ |
| Yield per bag | 1.91 ft³ |
|---|---|
| Made with | Type I/II portland cement, pozzolans, lightweight aggregate and performance admixtures |
| Water | 4.0 gallons per bag |
| Equipment | SprayMate® 35C, SprayMate® 35D or MiniMate II, with grout packers and a nozzle with a control valve and pressure gauge |
| Typical structures | Voids behind manholes, tanks and containment, tunnels and pipelines, wastewater facilities; abandoned lines |
FAQ
Common questions
Grout 250 or Grout 1,000?
Both fill voids and abandoned lines. Grout 250 is lighter and yields more per bag. Grout 1,000 is heavier and reaches over 1,000 psi.
Can it fill an abandoned pipe?
Yes. Bulkhead each end with inlet and outlet risers, and pump through the inlet until grout comes out the outlet.
Does it need curing?
No curing steps are needed.
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.
How is it tested on the job?
Cast four 2″ cube samples each day, or for every pallet used, whichever comes first. Package, label and return them to the manufacturer for compressive strength testing per ASTM C109, following the owner’s or manufacturer’s directions.
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-Seal Grout 250 sell sheet with full specifications and application steps, plus the Fernco Infrastructure, Plumbing and WaterWorks catalogs.
Got questions?
Filling voids or abandoning a line? Our infrastructure team can help. Reach out, or find your Fernco rep.