Monomix HD is a high strength, waterproof, shrinkage compensated, with good abrasion resistance for the structural repair, rendering and profiling of vertical, overhead and horizontal surfaces.

Monomix HD incorporates the most advanced cement chemistry. This results in a rapid hardening, high strength mortar with enhanced polymer properties. The thixotropic nature of the product enables easy trowel application for the structural repair of voids. The product can also be used for rendering and re-profiling of both vertical, horizontal and overhead surfaces.

Advantages of the Flexcrete Monomix HD

• Contains the latest cement chemistry, microsilica, fibre and styrene acrylic copolymer technology
• Enhanced polymer properties
• High bond strength
• Improved tensile and impact strength
• Excellent low sag properties
• Requires no substrate or inter-layer priming
• Part bags can be mixed
• Easily over coated with specialist masonry paints
• Requires only the addition of clean water.
• Dense matrix offers low permeability to water, even at 10 bar pressure, and very high diffusion resistance to acid gases and chloride ions.
• Resistant to sulphates to class DS-5/5m of BRE Special Digest 1.

Application

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 of STEEL REINFORCEMENT PROTECTOR 841 applied by brush.

Priming of Concrete

MONOMIX HD 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 HD should be mechanically mixed with 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 Flexcrete will not be responsible for failure due to incorrect mixing.

Placing

MONOMIX HD 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. For larger areas of repair, MONOMIX HD can be applied using wet or dry spray techniques. When wet spraying, use the higher level of water addition