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Gem-Crete® TWM Plus
Traffic Waterproofing Membrane
Gem-Crete TWM PLUS is designed for waterproofing of light to medium traffic surfaces, including parking garages in new construction and restoration. It is also suitable for waste water tanks, secondary containment structures, tunnels, concrete slabs, balconies and patios. Gem-Crete TWM PLUS is breathable and is totally insensitive to substrate moisture, unlike polyurethane and epoxy membranes. It can be applied to completely water saturated concrete slab.
Composition and Materials
Gem-Crete TWM PLUS is a two component, flexible, breathable, cementitous liquid applied membrane.
Do not apply Gem-Crete TWM PLUS when the temperature is expected to be below 4°C (40°F) within 48 hours, or when rain is imminent. Follow Hot Weather concreting precautions when applying Gem-Crete TWM PLUS at temperatures exceeding 25°C (77°F) or under sunny and windy conditions.
Health and Safety
Gem-Crete TWM PLUS is non-toxic. Your skin might be sensitive to hydraulic cement, or the liquid additive. We recommend use of rubber gloves. Avoid contact with eyes and prolonged contact with skin. If contact occurs, flush immediately with water. Seek medical advice if irritation occurs. Harmful if digested. KEEP PRODUCT OUT OF REACH OF CHILDREN. FOR INDUSTRIAL USE ONLY. Consult MSDS for additional information.
Gem-Crete TWM PLUS is available in Industrial Grey and Light Grey colours. It can be coated with Gem-Coat WA ST to provide other colours. When Gem-Crete TWM PLUS Light Grey is used, we recommend application of a clear acrylic sealer Gem-Seal WA ST for cleanability.
Gem-Crete TWM PLUS Kit consists of a dry Component A, packed in 22.7 kg (50 lb.) bags. The liquid Component B of Industrial Grey, 7.20 L (1.92 U.S. gal.) and 6.92 L (1.81 U.S. gal.) of Light Grey, are packaged in plastic jugs.
Gem-Crete TWM PLUS kit, Industrial Grey, yields 15.4 litres (0.54 ft³) and covers approximately 9.6 m² @ minimum thickness of 1.6 mm (104 ft.² @ 60 mils) per kit, applied in two (2) coats – each coat approximately 0.8 mm (30 mils). The coverage of Light Grey material is 3% less when compared with the Industrial Grey. The actual coverage will depend on surface roughness, porosity and the thickness applied. The applicator must carry out a sample application to determine the actual coverage for the given substrate and application thickness.
Storage and Transportation
Gem-Crete TWM PLUS when stored on pallets in a dry, cool area, free from moisture and direct sunlight, has a shelf life of 12 months. The liquid Component B must not freeze. Packaged 40 kits per pallet.
|Flexibility (ASTM D522 Mod.) at 20ºC, non-reinforced||20%|
|Crack Spanning (Gemite ISO TP005) @ 20ºC, reinforced with NW Fabric||1.0 mm (40 mils)|
|Water Vapour Permeability, Engelfried-Klopfer Sd <3 m||Sd = 0.140 m|
|Salt Scaling Resistance, (ASTM C672)||Excellent|
|Hydraulic Impermeability TTP 1411
(negative side), 2 mm thickness
|Water head >38.4 m (>126 ft)|
Taber Abrador, ASTM D 4060 Mass 1000 g
|0.4 g per 1000 rotations|
|Chloride Salt Penetration Resistance Gemite Test Procedure||No chloride penetration|
Current Guide Specification and Application Instructions contain additional information specific to each application and must be followed. The applicator must, prior to bid, confirm the detailing, use of the Reinforcing Fabric NW, surface preparation, crack treatment and application procedures with Technical Service.
Remove all deteriorated and loose concrete, form release agents, oil, grease, laitance, dust, dirt and efflorescence by dry or wet sandblast, shotblast, or high pressure water (minimum 34.5 Mpa – 5,000 psi). In new balcony construction use industrial floor scrubbers to remove the surface laitance. Repair deeper areas using Gem-Plast Flex ST or MEADOW-CRETE® OV. Pre-fill all cracks with Cem-Kote Flex Plus. The proper surface preparation is essential for a successful waterproofing and concrete repair using Gem-Crete TWM PLUS. Contact Technical Service for detailed surface preparation instructions.
Thoroughly mix (by shaking) the liquid Component B prior to its use. Use standard paddle or helix screw type mortar mix, or heavy duty drill (400 – 600 rpm) with a mixing paddle. Pour approximately 80% of the liquid Component B into a clean mixer and gradually add the dry Component A, while mixing, until a smooth and lump free mix is obtained. Lumps will form if the dry material is added suddenly into the liquid. Add the remaining liquid, while mixing, to achieve the consistency required for a given application. A small amount of water can be added, if required, at higher ambient temperatures.
Trowel or brush apply Gem-Crete TWM PLUS to a minimum thickness of 1.6 mm (1/16″) in two (2) coats to a saturated surface dry (SSD) concrete. (The first coat 0.8 mm and the second also 0.8 mm thick). Gem-Crete TWM PLUS can also be spray applied using a Gemite Peristaltic Pump with a plastering spray nozzle. When using spraying, brush each coat to eliminate all “pinholes”. The second coat must be applied into “wet” first coat, as soon as possible, usually within 10 – 15 minutes, depending on temperature and relative humidity. The delayed application of the second coat could result in its de-bonding.
All moving cracks need to be treated using Cem-Kote Flex Plus and Reinforcing Fabric NW. Pre-fill any open cracks with Cem-Kote Flex Plus. Apply a thin coat of Cem-Kote Flex Plus, 15 cm (6″) wide, over the crack. Embed a strip of the Reinforcing Fabric NW, 10 cm (4″) wide, into the wet Cem-Kote Flex Plus. Let dry and apply a thin coat of Cem-Kote Flex Plus over the Reinforcing Fabric NW.
Reinforcing Fabric HD
In some instances, where a very high abrasion resistance and toughness are required, e.g. ramps, apply the Reinforcing Fabric HD to reinforce the layer of Gem-Crete TWM PLUS membrane. Apply first a thin layer of Gem-Crete TWM PLUS by brushing, or spraying. When spraying, brush each coat to eliminate all “pinholes”. Embed the Reinforcing Fabric HD into the first coat and follow with the second coat. The fabric must be fully covered and must not protrude through the surface. The minimum applied thickness of Gem-Crete TWM PLUS, including the Reinforcing Fabric HD, is 2.0 mm (80 mils).
Cure Gem-Crete TWM PLUS by air drying for a minimum of 2 days prior to opening the membrane to traffic. Longer curing times are required in cold, wet and humid conditions. Contact Technical Service for more detailed information. Protect fresh applications from rain, strong wind and intense sunlight for 12 hours. When working under tarps at freezing temperatures, avoid using propane heaters. Only electrical heaters should be used to prevent “carbonation” of Gem-Crete TWM PLUS.
In case of localized high wear or damage, the membrane is simply and easily repaired.
A limited twelve (12) month Material Replacement Warranty is available. For details contact Technical Service.
For advice on suitability of Gem-Crete TWM PLUS for a specific application, specification assistance and application advice, contact Technical Service at 1-800-563-3618.
Gemite Products, Inc.
1787 Drew Road,
Mississauga, ON L5S 1J5