Sewers & Manholes

Concrete sewers and manholes are exposed to sulfuric acid attack by Microbiologically Induced Corrosion (MIC) – conversion (oxidation) of hydrogen sulfide to sulfuric acid, that causes severe concrete deterioration (mainly above the liquid levels).

Gemite’s Cem-Kote chemically resistant waterproofing systems will stand-up to the very aggressive chemical attack by MIC formed sulfuric acid and can be applied at even 100% high RH and on saturated concrete surfaces, since it is insensitive to moisture, unlike epoxies or polyurethanes.

Surface Preparation

Clean the new concrete surface using 34 MPa (5,000 psi) pressure water to obtain minimum CSP #3 per ICRI (International Concrete Repair Institute).

In restoration projects 48 MPa (7,000 psi) pressure water, or sandblasting may be required, depending on contamination, strength and depth of concrete deterioration.

Always consult suitable method of surface preparation for specific project with Gemite’s Technical Service.

Corrosion Protection – Fibre-Prime

Clean reinforcing steel using mechanical abrasion, but “white metal” surface is NOT required.

Fibre-Prime, polymer modified cementitious rustproofing, with migrating corrosion protection technology, is applied in 2 coats over exposed rebar surface to protect partially “buried” steel from future rusting.

Active Leaks

In underground (negative side) waterproofing such as sewers, it is essential that any “active” water leakage is stopped using Fibre-Patch WP (or injection systems), to allow application and cure time for the waterproofing coatings.

Sewers – New Construction (System # 2)

1st coat  =    Cem-Kote Barrier Cote 100      1 mm (40 mils) thick

Vapor retarder providing exceptional bond.

  •      Air cured for 1-2 days minimum
  •     Clean using 34 MPs (5,000) psi pressure water, before applying Cem-Kote Flex CR

2nd coat  =   Cem-Kote Flex CR           1 mm (40 mils) thick

Waterproofing + protection against MIC produced sulfuric acid

Flexible, polymer modified calcium aluminate cement coating with high resistance to acids and superior chemical protection in sewer and manhole environments.

Cem-Kote System is very easy to apply and provides a long-lasting protection and smooth surface that prevents any build up on the walls of sanitary sewers, which may impede and reduce the flow.

Sewers – Restoration

Gemite offers cementitious or geopolymer systems for repair and relining of sewers, tunnels, pipes, manholes, wet wells and other similar structures that suffer from corrosion, water leakage (ingress or egress) or structurally compromised.

Gemite Systems are applied using pumps and spray equipment, or spin-casting equipment that assures a precise and controlled installation that results in durable monolithic structure highly resistant to acids.

In restoration projects the concrete surface is seriously contaminated and may be deteriorated (eroded) to varying depth.

Relining

  1. Clean and reprofile concrete surface using high-pressure water 34-48 MPa (5-7,000 psi) to obtain minimum CSP #3 per ICRI (International Concrete Repair Institute) or sandblasting, depending on contamination and deterioration.
  2. Reprofile eroded surface using Gem-Cote TC
  3. Cem-Kote Barrier Cote 100 – applied by spraying or brushing at min. 1 mm (40 mils) thickness
  4. Air-cure for minimum 1-2 days
  5. Clean with 34 MPs (5,000) psi pressure water
  6. Cem-Kote Flex CR applied by spraying or brushing at min. 1 mm (40 mils) thickness
  7. Curing – 3-day air cure is sufficient prior to exposure to water

Thicker (Structural) Repairs

Requiring repair and reprofiling from  6 mm and higher (½” to several inches), depending on surface deterioration and structural requirements.

Surface Preparation

Clean the concrete surface using 34-48 MPa (5-7,000 psi) pressure water or sandblasting  to obtain minimum CSP #3 per ICRI (International Concrete Repair Institute).

Corrosion Protection – Fibre-Prime

Clean reinforcing steel using mechanical abrasion, but “white metal” surface is NOT required.

Fibre-Prime, polymer modified cementitious rustproofing, with migrating corrosion protection technology, is applied in 2 coats over exposed rebar surface to protect partially “buried” steel from future rusting.

Spray-Cast Sewer Liner – up to 15 cm (6”) in one application

Spray/Cast Applied Fully structural lining that provides permanent protection against acid formed by MIC microbiological conversion of H2S and attack by other chemicals for relining of storm or sanitary sewer pipes.

Spray-Cast Sewer Liner is easily and quickly applied to deteriorated concrete surfaces using wet shotcrete pump, making it a perfect solution for non-round sewer profile  It has a very low rebound, stops water infiltration and provides long-lasting crack resistance and performance.

Manholes – Restoration

Key problem for manholes is the water infiltration through joints and cracks. The increase in inflow overloads the wastewater treatment system and increases the cost of the treatment.

The water inflow may result in discharge of untreated water that causes an environmental hazard.

Many problems are related to chemical deterioration due to exposure to H2S as a result of MIC (Microbiologically Induced Corrosion).

Surface Preparation

Clean the concrete surface using 34-48 MPa (5-7,000 psi) pressure water or sandblasting  to obtain minimum CSP #3 per ICRI (International Concrete Repair Institute).

Corrosion Protection – Fibre-Prime

Clean reinforcing steel using mechanical abrasion, but “white metal” surface is NOT required.

Fibre-Prime, polymer modified cementitious rustproofing, with migrating corrosion protection technology, is applied in 2 coats over exposed rebar surface to protect partially “buried” steel from future rusting.

Cem-Kote Barrier Cote 100

Cem-Kote Barrier Cote 100 delivers superior bond, even to contaminated concrete & provides super tough surface with high abrasion resistance and is insensitive to moisture in the concrete and high relative humidity allowing application under conditions under which is impossible to apply polymer coatings.

Cem-Kote Flex CR – Chemically Resistant Waterproofing Liner (System #2)

Technological breakthrough for the municipal wastewater & manholes – Flexible, calcium aluminate cement polymer modified waterproofing coating, resistant to sulfuric acid, generated by MIC (Microbiologically Induced Corrosion) – micro-biological oxidation of hydrogen sulfide.

Cem-Kote Flex CR maintains a higher pH, making it more resistant to MIC, and provides long-lasting performance liner for moderate H2S exposure, such as manholes.

Spray-Cast Sewer Liner- up to 15 cm (6”) in one application

Spray/Cast Applied Fully structural lining that provides permanent protection against acid formed by MIC microbiological conversion of H2S and attack by other chemicals for relining of storm or sanitary sewer pipes.

Spray-Cast Sewer Liner is easily and quickly applied to deteriorated concrete surfaces using wet shotcrete pump, making it a perfect solution for non-round sewer profile  It has a very low rebound, stops water infiltration and provides long-lasting crack resistance and performance.

Gem-Cote EP 100 – >50 ppm H2S Exposure

Superior performance, highly chemically resistant 100% epoxy coating for above 50 ppm H2S exposures.

Cem-Kote Barrier Coat 100 vapor retarder must be used as a base coat to reduce moisture levels to allow application of the epoxy.