Description Ardex A35 MIX Rapid Screed is a blend incorporating standard Ardex A35 Cement and graded sand which has been specially formulated to produce ultra-rapid drying floor screeds for internal locations. With ‘RAPIDRY FORMULA’ Technology, Ardex A35 MIX can be walked on just 3 hours after application and ceramic and natural stone tiles can be installed after just 24 hours irrespective of thickness. Resilient floorcoverings such as carpet, vinyl and wood can be installed after 24 hours. Ardex A35 MIX achieves rapid strength and will pass a BRE Screed (ISCR) Test after just 6 hours. After a day, it will also exceed the acceptable minimum compressive and tensile bending strengths attained by ordinary cement screeds after 28 days. Ardex A35 MIX Rapid Screed is used to produce bonded, unbonded and floating screeds for internal locations. It can also be used for large repairs to existing cement/sand screeds. It is ideal for situations where early foot traffic and rapid hardening is required. Thickness: Ardex A35 MIX should be applied to the following thicknesses: Bonded screeds: 15mm – 40mm Unbonded screeds: 40mm Floating screeds: 75mm or 65mm in lightly loaded/domestic locations. When used for screed repairs, Ardex A35 MIX can be applied to the full thickness of the existing cement/sand screed. Substrate Preparation – Screeding: Bonded Screed: Ardex A35 MIX can be laid as a bonded screed by firstly applying an Ardex A35 MIX grouting slurry to a suitably prepared concrete base. The Ardex A35 MIX must then be placed and compacted on the base ‘fresh in fresh’ whilst the grouting slurry is still wet and workable. To prepare the grouting slurry, dilute Ardex P51 Concentrated Water Based Primer & Bonding Agent with an equal volume of water. Then add Ardex A35 MIX Powder with the diluted Ardex P51 to produce a grouting slurry of a creamy consistency. NOTE: The concrete surface must be prepared using suitable mechanised equipment to expose the coarse aggregate and be free from all barriers to adhesion. Unbonded Screed: For unbonded screeds, it is good practice to ensure that the concrete slab surface is reasonably true and flat prior to applying a proprietary damp proof/slip membrane. For uneven areas which require levelling or filling, consult the Ardex A46 datasheet for localised areas, and the Arditex NA datasheet for larger areas. Floating Screed: For floating screeds, place a suitable separating or damp proof membrane over the insulation before applying the screed mortar. NOTE: Where the concrete base is insufficiently dry (above 75% RH), direct to ground or ground supported without an effective damp proof membrane, or if the area is subject to rising damp, Ardex A35 MIX must be laid over an effective damp proof membrane. For unbonded and floating screeds, install a proprietary damp proof/slip membrane as recommended by BS 8204-1: 2003 A1: 2009 and BS 5385-3: 2014. For bonded screeds, firstly apply Ardex DPM 1 C/Ardex DPM 1 C R and allow to cure, and then apply Ardex R3 E Moisture Tolerant Epoxy Primer; fully sand blind whilst wet and allow to cure, sweep and vacuum clean before finally applying the Ardex A35 MIX bonding slurry. Alternatively, Ardex A38 MIX Pre-Blended Ultra Rapid Drying Cement for Internal & External Screeds may be applied direct to damp concrete using Ardex E100 Additive for Bonding/Slurry Grouts for the bonding slurry; for further technical information, please refer to the Ardex A38 MIX datasheet or contact Technical Services. Substrate Preparation – Screed Repairs: Repairs to dry internal screeds should be cut back vertically to sound screed material. The cut edges should then be treated with a bonding coat of Ardex A35 MIX powder mixed with Ardex P51 diluted with an equal volume of water, which is mixed to form a bonding coat of creamy consistency. Ardex A35 MIX should be compacted into the bonding coat while it is still wet and workable, i.e. fresh in fresh. Water Content: Add sufficient water to obtain a workable mix, up to a maximum of 2 litres per 25kg bag of Ardex A35 MIX. To achieve rapid drying and strength development, do not exceed the stated maximum water content. Mixing: Mix to a normal screed mortar consistency. When a sample of the mortar is squeezed in the hand, the sample should retain its shape and not crumble, and the hand should be left slightly moist. When a sample is compacted on the base, no film of water should form on the surface. Mixing should be performed using a pan, trough or other forced action type. Normal ‘free-fall’ mixers are not suitable for mixing semi-dry screed mortars. Use clean equipment and do not use other cements, lime or screed additives in the mix. Application: The working time of the mixed mortar is approximately 1 hour at 20°C, therefore mixing, placing, compaction and trowelling off must proceed without delay. The amount of mortar mixed and the area to be screeded should be limited so that trowelling off and finishing can be completed within this time. Where a new bay is laid against a set and hardened screed, it is recommended that day work joints are vertical and treated with the grouting slurry, as described under SUBSTRATE PREPARATION. Apply Ardex A35 MIX at temperatures above 5°C. Application over underfloor heating systems: When Ardex A35 MIX has been laid on a hot water floor system, 3 days should be allowed to elapse before heating the water up to a flow temperature of 25°C; this should then be maintained for a further 3 days. The maximum floor temperature should then be used and maintained for a further 4 days. Throughout this time, draughts across the screed must be avoided. The floor should then be allowed to cool down to room temperature (above 15°C) before laying floorcoverings. NOTE: Ardex A35 MIX screeds can be thermally loaded up to 65°C (water temperature). Drying Time: Ardex A35 MIX can be walked on just 3 hours after application and ceramic and natural stone tiles installed after just 24 hours, irrespective of screed thickness. Resilient floorcoverings can be installed after 24 hours. The screed will be fully dry after 24 hours. Surface Finish: Before fixing ceramic tiles and quarry tiles, the screed should be finished with a wood float. Prior to laying thin floorcoverings e.g. vinyl sheet, a very smooth surface may be obtained using any of the ARDEX Levelling Compounds which should be selected with the final floor finish in mind. Please see the relevant ARDEX datasheets for further information. NOTE: Screeds are not designed as wearing surfaces and the screed surface should be given adequate protection once dry against damage, wear and contamination during subsequent building operations. Protective coverings will also minimise any curling and lipping at joints in unbonded screeds. Coverage: Material requirement is approximately 1.85kg of Ardex A35 MIX per m² per millimetre of screed thickness i.e. approximately 0.5m² at 25mm thick or 0.9m² at 15mm thick per bag. Technical Data: Weight of fresh mortar: approx. 2kg/litre Working time at 20°C: approx. 60 minutes Walkability at 20°C: approx. 3 hours COMPRESSIVE STRENGTH (DIN 1164) After 1 day: 25.0 N/mm² After 3 days: 32.0 N/mm² After 28 days: 40.0 N/mm² TENSILE BENDING STRENGTH (DIN 1164) After 1 day: 5.0 N/mm² After 3 days: 6.0 N/mm² After 28 days: 7.0 N/mm² Product Datasheet Click here to view this product on the manufacturers website.
