Flexcrete Monomix HD is a single component, standard density cementitious mortar which is polymer modified and fibre reinforced. The product’s thixotropic nature enables easy, high build hand and trowel application for the structural repair of voids and the rendering and re-profiling of vertical, horizontal and overhead surfaces. It can also be applied using spray techniques in large areas.

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• Features & Benefits
• Preparation
• Mixing
• Application & Curing
• Application Top Tips
• Technical Data

Features & Benefits

• Incorporates the latest cement chemistry, microsilica, fibre and styrene acrylic copolymer technology
• Simply mixed with clean water, part bags can be mixed
• Generally requires no substrate or inter-layer priming
• Easy to achieve a high quality trowel finish
• Single layer build up to 80mm (vertical or overhead)
• Suitable for application by dry or wet spray techniques
• Excellent low sag properties
• Bond strength exceeds tensile strength of concrete, ensuring monolithic performance
• Dense matrix with low permeability to water
• High diffusion resistance to acid gases & chloride ions
• Resistant to sulphates to class DS-5M of BRE Special Digest 1
• High impact resistance, suited for floor or deck repairs
• Easily overcoated with specialist membranes to provide further protection and aesthetic quality
• UKCA & CE marked in accordance with EN 1504-3
• Highways Standard Series 5700 (Concrete Repairs) and CS 462 (Repair & Management of Deteriorated Concrete Structures)
• LU Standard 1-085 ‘Fire Safety Performance of Materials’

Preparation

Mechanically remove all damaged concrete or failed repairs back to a sound core. Except in new construction, expose the full circumference of the steel reinforcement 25mm behind the bars and 50mm beyond visible corrosion.

On cutting back, feather edges must be avoided. Step the perimeter of the repair to a depth of 10mm preferably using a power chisel or by saw or disc cutting.

The areas to be repaired must be free from all unsound material including laitance dust, oil, grease, corrosion byproducts and organic growth.

Smooth surfaces should be roughened and reinforcement cleaned to bright steel using wet grit blasting techniques or equivalent approved methods. Power tools such as a needle gun, angle grinder or wire brush may be used on concrete which is not chloride contaminated.

• The compressive strength of the parent concrete should be minimum 20 MPa.

The prepared substrate should be thoroughly soaked with clean water until uniformly saturated without any standing water.

Treatment of Steel Reinforcement:

Treat exposed steel reinforcement with 2 x 1mm coats Flexcrete Steel Reinforcement Protector 841 applied by brush.

Priming of concrete:

Monomix does not generally require a primer. Highly porous substrates may be primed with a polymer admixture 850 slurry coat. The slurry coat should also be used when treating larger areas of waterproof concrete.

Mixing

Monomix should be mechanically mixed using a forced action pan mixer or in a clean drum using a slow speed drill and paddle. A normal concrete mixer is not suitable.

For normal applications, use between 2.3-2.7 litres of clean water per 25kg bag. For part bags, this equates to 7-8 volumes of powder to 1 volume of water. Typically, for high build applications use 2.5 litres of clean water per bag and mix for 2-3 minutes. Mix to entrain as little air as possible. Use without delay.

• Note - These instructions must be adhered to as we will not be responsible for failure due to incorrect mixing

Placing & Curing

Monomix can be applied by float or trowel in single layers up to 80mm. Shuttering may be required to allow for compaction if working to reveals. Care must be taken to ensure that an initial thickness of mortar, typically 5-10mm, is well placed and adhered before building up to larger depths.

For multi-layer applications, it is important to ensure that previous layers are well keyed and stable but not fully set (typically 2-6 hours) prior to the application of subsequent layers. No inter-layer priming is required. Final profiling is achieved with a steel float.

Curing:

When curing, normal concreting procedures must be adhered to. Protect from strong sunlight and drying winds with Cure-Seal WB, polythene sheeting, damp hessian or similar.

Application Top Tips

1. For multi-layer application, use the fingers of a gloved hand to stipple the surface of the first layer
2. Do not wet out or prime between layers
3. If the mortar thickens, remix but do not add extra water
4. Do not over trowel. If the mortar begins to slump, allow to stabilise and refinish
5. When finishing, trowel from centre out towards the perimeter working into the edges of the repair
6. For areas subject to vehicular traffic use Monomix HD
7. For large areas of repair consider using Monomix WS applied with wet spray techniques
8. Cold Weather Working - ≥ 3°C on a rising thermometer, ≥ 5°C on a falling thermometer
9. Hot Weather Working - Store material in cool conditions to maximise working life. Shade applied material from strong sunlight. Spray-apply a second mist coat of Cure-Seal WB. If possible, avoid extreme temperatures by working at night
10. Do not use Monomix when the temperature is below 5°C and falling. Not suitable for use on trafficked areas

Technical Data