How to use Ardex k301

How to use Ardex k301

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ARDEX K301 is a Fast Setting Resurfacing and Levelling Compound for Concrete. ARDEX K301 is a grey powder consisting of special cements, graded aggregates and high quality synthetic resins. When mixed with water, a fluid mortar is produced which sets after approximately 1 hour and can normally be walked on after 2-3 hours at 20°C.

ARDEX K301 can be applied from 2mm to 20mm in a single application. The set and hardened ARDEX K301 is usually ready to receive light rubber wheeled traffic after 48
hours at 20°C.

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ARDEX K301 will smooth and level concrete surfaces such as balconies, patios, domestic driveways, garages, walkways and other concrete surfaces exposed to normal foot and rubber
wheeled traffic. ARDEX K301 can also be used for filling holes and resurfacing damaged floors, such as concrete or a bonded cement/sand screed (>30N/mm2 compressive and 1.5N/mm2 pull off), as well as pre-smoothing concrete floors prior to the application of a suitable damp proof membrane, such as ARDEX DPM 1C/1CR

All concrete surfaces should be mature i.e. at least 6 weeks old. The concrete surface must
be hard, sound, thoroughly cleaned, free of all oil, grease, curing compounds and other barriers to adhesion. The substrate can be dry or damp. ARDEX K 301 may be unsuitable for aged or frost damaged concrete subject to regular deflection from thermal cycling or mechanical loading.

Use a degreaser to remove oil, grease or similar contaminants and rinse well prior to mechanical preparation. All surfaces must be prepared as necessary to ensure good adhesion. The prepared surface must have the appearance of clean sound concrete with some exposed aggregate in the surface. There must
be no traces of any dirt, previous treatments or surface contamination.

Sufficient and thorough mechanical preparation is essential for commercial areas, especially those intended for exposure to regular or intensive rubber wheeled traffic, or heavy loading. Vacuum the prepared surface to remove all dust and debris, and ideally wash the surface using high pressure water jet equipment. All cracks in new and old concrete can be repaired to inhibit cracking in the ARDEX K301
with ARDEX EP 2000 (refer to the ARDEX EP 2000 datasheet). Any structural, movement or live joints must be carried through the ARDEX K 301 to the surface.

For internal applications prime the surface with ARDEX P 51 Primer diluted 1:1 on absorbent or 1:0.5 on non-absorbent substrates. Dilute with clean water, and apply with a brush or broom. Any ponding, puddles
or surface water must be removed with a broom so that excess primer is not incorporated in the mortar during application. Let the primer dry before ARDEX K 301 is applied For external applications prime with ARDEX P 51 Primer diluted 1:7 with clean water, and applied with a brush or broom. Ponding, puddles or surface primer must be removed with a broom so that excess water is not incorporated in the mortar during application.

Apply the ARDEX K 301 whilst the priming layer is still damp. In all areas subjected to regular rubber wheeled traffic or heavy loading, and on dense surfaces, ARDEX R3E Solvent Free Epoxy Primer should
be used to prime, sand blinding the surface with ARDEX Fine Aggregate while still wet. The surface must be allowed to cure and excess sand removed before applying ARDEX K301.

In a clean mixing container add the powder to the required amount of clean water whilst stirring thoroughly until a lump free mortar is produced. The mix proportions by volume are approximately 5 parts ARDEX K301 powder to 1 part clean water.

A 25kg bag requires 5¼ litres of water.

If gradient levelling has to be carried out, or a broomed finish required, the water content must be reduced. To pump the mortar, use continuous pumps with a capacity of 20-40 litres of mortar per minute.

Do not use excess water as this will reduce the strength of the set and hardened mortar. The use of an ARDEX mixing paddle with a 10mm chuck slow speed (600 -1000 r.p.m.) electric drill makes light work of mixing.

ARDEX K301 mortar should be applied within 30 minutes at 20°C. This time is extended at lower temperatures and reduced at higher temperatures.

Pour the mixed ARDEX K 301 onto the prepared and primed substrate. The mixed mortar will flow out and self-smooth during the first 10 minutes of its 30 minute working time. Spread the mortar using a steel trowel or float. For larger areas its recommended to use a gauging tool with thickness height adjustment to spread the mortar.

The applied ARDEX K301 surface can be left with a trowelled finish. Alternatively, to create a more non-slip finish, the water content should be reduced and then ‘broom finished’ once the initial set has occurred (approximately 40 minutes under normal conditions).

Once set, the freshly applied ARDEX K301 must be pro-tected from adverse climatic conditions e.g. rapid drying air flow, direct strong sunlight, frost, etc., or appropriate curing measures taken until hardened.

Apply at temperatures above 5°C.

If a second layer of ARDEX K301 is required, this should be applied after the first layer has fully hardened. The first layer should be machine sanded (paper 16 to 36), cleaned and primed with ARDEX P51 Primer diluted 1:1 with water for dry indoor use, and diluted 1:7 with water for external use or damp interior areas. The dilution rate of 1:7 should not be exceeded for external applications

ARDEX K 301 can be applied neat from 2mm to 20mm thick.
NOTE: The thickness of combined layers should not exceed 20mm.

Approximately 1.6kg ARDEX K301 powder/m2 /mm, i.e. approximately 3.0m2 at 5mm thickness per 25kg bag.

ARDEX K301 is packed in paper sacks incorporating a polyethylene liner – net weight 25kg.

ARDEX K301 must be stored in unopened packaging, clear of the ground in cool dry conditions and protected from excessive draught. If stored correctly, the shelf life is 12 months from the date of the packaging.

Note: For the latest technical or health and safety data on this product, consult the current technical or health and safety datasheet online at

ARDEX K 301 – Cementitious screed material of use internally and externally
EN 13813: CT-C30-F7-A22
Bulk density of powder approx. 1.37kg/litre
Weight of fresh mortar approx. 1.94kg/litre
Initial Set (Vicat) approx. 40 minutes
Final Set (Vicat) approx. 2 hours

Compressive Strength
After 7 days 20.0 N/mm2
After 28 days 30.0 N/mm2

Tensile Bending Strength
After 28 days 7.0 N/mm2

Overcoat time for industrial coatings
Thickness of ARDEX K301 Time
Up to 5mm – 2 days
Up to 10mm – 5 days
Up to 20mm – 7 days

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