Flexible, fibre-reinforced cementitious waterproofing for closed wastewater concrete exposed to microbiologically generated sulphuric acid.
Decision Summary
Core Uses
CEM-KOTE FLEX CR is used in digesters, sludge tanks, clarifiers, manholes, sewer systems, pumping stations, and lift stations. In these closed environments, hydrogen sulphide is converted by bacteria into sulphuric acid at the concrete surface, turning a waterproofing problem into a chemical durability problem.
For closed structures in the 20-50 PPM H2S range, Gemite specifies System #2: CEM-KOTE BARRIER COTE 100 at minimum 40 mils / 1 mm followed by CEM-KOTE FLEX CR at minimum 40 mils / 1 mm. The first layer establishes bond and vapor control; the second layer provides the flexible chemical-resistant protection.
The material combines waterproofing, breathability, crack resistance, freeze-thaw resistance, and chemical resistance for aggressive concrete service where rigid linings may be inappropriate or where a cementitious rehabilitation system is preferred.
Comparison Block
Technical Data Table
| Property | Value | Source / test |
|---|---|---|
| System type | Two-component, fibre-reinforced hydraulic cement material | Official product description |
| Coverage | 156 ft2 at 40 mils / 14.7 m2 at 1 mm per kit | One coat |
| Ultimate tensile strain | 20-25% non-reinforced; 25-30% reinforced | ASTM D412 Modified |
| Crack spanning | 0.5 mm non-reinforced; 1.6 mm reinforced | Gemite ISO TP 005 |
| Negative-side impermeability | Water head >130 ft / >39.8 m at 2 mm | TTP 1411 |
| VOC content | 0 g/L | Product data sheet |
Application / Specification Notes
Remove deteriorated concrete and contaminants by dry or wet sandblast or shotblast to achieve ICRI CSP #3 before applying the Barrier Cote / Flex CR system.
For System #2, specify 40 mils / 1 mm CEM-KOTE BARRIER COTE 100 followed by 40 mils / 1 mm CEM-KOTE FLEX CR.
Apply the second coat without disturbing the first. If wet-to-wet work is not practical, allow Barrier Cote to dry, then pressure wash before Flex CR.
System Compatibility / Related Product Notes
Required as the first coat in the Gemite System #2 sequence for closed H2S structures.
For H2S concentrations above 50 PPM or severe chemical containment, Gemite identifies an epoxy-based System #3.
May be embedded where additional tensile strength or crack treatment is required.
FAQ
When wastewater exposure adds chemical attack to the waterproofing requirement. It is not just keeping water out; it is protecting concrete from aggressive sewer conditions.
Barrier Cote can provide the high-bond first coat while Flex CR adds the flexible, chemical-resistant layer. The system should be selected according to the exposure and substrate condition.
No. Flex CR is suited to defined cementitious waterproofing and sewer-atmosphere conditions. Very severe chemical exposure may still require a dedicated resin lining.
Barrier Cote provides the high-bond first coat and initial barrier. Flex CR then adds the flexible, hydrogen-sulfide-resistant chemical protection layer required in the Gemite System #2 sequence.
For H2S concentrations above the Flex CR range or for very severe chemical containment, Gemite identifies epoxy-based protection such as GEM-COTE EP 100 as the higher-aggression system.
Send the substrate condition, exposure, traffic, crack profile, and coating sequence. Gemite can help confirm whether this product fits the project conditions.
Request Technical GuidanceOr contact us: office@gemite.tech · +40 232 273 031
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