
Stormwater rehabilitation
Strong-Seal · Cementitious groutGrout 12,000 Self-Consolidating Grout
A high-strength, self-consolidating grout that rebuilds the invert of a corrugated metal culvert to its original shape before it’s lined with Storm Seal®.
Rebuild the invert before you line
A culvert liner needs an even floor. When the invert of a corrugated metal culvert is scoured or washed out, Grout 12,000 flows in and levels it back to original dimensions, so Storm Seal® goes on evenly all the way around.
Over 6,000 psi in 24 hours.
Self-consolidating and volume-stable. It flows into the invert and levels with the bottom of the culvert.
GROUT12000 65 lb bag · 40 per palletOver 1,200 psi tensile at 28 days.
Formulated for stormwater applications and culverts 24″ and larger.
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 | 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 This page | 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 a rebuilt invert
- Divert and cleanDam, divert or bypass the flow. Jet out loose debris and remove loose or protruding brick, mortar, concrete or metal.
- Stop leaksStop active leaks with Strong-Plug®. Fill large voids and joints with a rapid-setting patch.
- MixUse 1.2 to 1.5 gallons of water per bag, water first. Keep it moving until you place it, because it can stiffen.
- PlaceStart at one end of the culvert and fill the invert until it’s level with the bottom. Where it’s scoured more than 2″ deep, add gravel up to 2″ from the bottom first. On steep grades, use a stiffer mix.
- Hold, then lineWait at least 1 hour, then apply Storm Seal®. Keep it damp, or use an ASTM C309 curing compound, until it’s lined.
Back in service: storm runoff after 4 hours. Stream flow after 8 hours.
Around the invert repair
Stop the leaks before you grout, then line the culvert with Storm Seal® once the invert is rebuilt.
Before, stop the leaksStrong-Plug®Sets in under a minute and hardens on contact with water. Once it sets, you can line right over it.See Strong-Plug ›
After, line the culvertStorm Seal®Spray-applied lining for culverts 24″ and larger. Hand sprayed or spun cast over the rebuilt invert.See Storm Seal ›
Meet Fernco Infrastructure
An overview of our manhole rehabilitation and trenchless pipe repair solutions.
Specifications
| Part number | GROUT12000 |
| Packaging | 65 lb bag, 40 bags per pallet |
| Compressive strength (ASTM C109) | Over 6,000 psi at 24 hours, 12,000 psi at 28 days |
| Tensile strength (ASTM C496) | Over 1,200 psi at 28 days |
| Flexural strength (ASTM C293) | Over 1,800 psi at 28 days |
| Drying shrinkage (ASTM C596) | 0% at 28 days, 90% RH |
| Wet unit weight (ASTM C138) | 140 ± 5 lb/ft³ |
| Yield per bag | 0.55 ft³, or 13.2 ft² at ½″ thick |
| Made with | Type I/II portland cement, pozzolans, masonry sand and performance admixtures |
| Water | 1.2 to 1.5 gallons per bag |
| Equipment | SprayMate® 35C, SprayMate® 35D or MiniMate II |
| Typical structures | Inverts of corrugated metal culverts 24″ and larger |
Common questions
How long before I can line it?
At least 1 hour before applying Storm Seal®. If more than 24 hours pass, check with us.
What if the invert is washed out deep?
Where it’s scoured more than 2″ deep, place gravel or other large aggregate up to 2″ from the bottom, then grout over it.
When can flow go back in?
Storm runoff after 4 hours. Stream flow after 8 hours.
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.
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 12,000 sell sheet with full specifications and application steps, plus the Fernco Infrastructure, Plumbing and WaterWorks catalogs.

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