AB B20

Substrate type
Concrete surfaces and components, cement screed, compacted sand underlay, shuttering and formwork, insulation layers on sound surfaces, other substrates with adequate rigidity and bearing capacity.

Substrate preparation
The surface should be prepared adequately to the work to be performed. For repair, the surface should be dry, rough and strong enough, cleaned of dust, dirt, grease, remains of paint and other substances which may impair adhesion. Remove brittle and peeling layers. Rough smooth surfaces by scoring or graining. Before application, rub a small amount of concrete into the substrate, after prior moistening, to create a bonding layer (the so-called washing) and spread the concrete mortar immediately ("wet to wet") or treat it with ALPOL AG 702 primer. For elements made with formwork, shuttering or forms, these should be treated with special anti-adhesions products. Prior to making floors and bonded screeds, loose substrates should be reinforced with ALPOL AG 700 deep-penetrating primer and washed or painted with ALPOL AG 702 primer so as to reach the required adhesion.

Instructions for use
Mix the dry mix in an amount required to be used mechanically (with a cement mixer, mixing plant or concrete machine) or manually with the specified amount of clean and cool water to achieve a homogeneous mix and the required consistency. Mixing time 3–5 minutes. Spread the mix on the prepared substrate by pouring from the height not exceeding 1 m. Then, compact the concrete in a manner appropriate to the work, remove possible excess and smooth out the surface with a trowel or a skimmer blade. After levelling, the surface can be trowelled. Concrete works should be completed without interruptions within 1 hour, or within 30 minutes from mixture preparation while working at higher temperatures. While making the floor underlayment, pressure layers etc., the intervals between application of the subsequent mixture portions should not exceed 20 minutes. Use the concrete within 1 hour from mixing with water. If the concrete thickens in that period of time, stir it again without adding water. Add appropriate amount of water. Adding too much water will impair concrete strength and prolong its setting time, which may also lead to cracking. Foot traffic is allowed and the formwork can be disassembled after 48 hours after the work is finished.

Tools
Mixer or low-speed electric drill, basket mixer, notched trowel, putty knife.

Working conditions
Work in ambient and surface temperatures between +5°C and + 25°C. Do not add other substances to the concrete. Protect fresh concrete from precipitation and water and, for at least 7 days, protect it from excessive drying, sun and frost.

Storage
Store in original, unopened packages in dry place – shelf life 12 months from production date. Protect from moisture during transport and storage.

Notes
The specifications and instructions for use are given for the temperature of (20±2)°C and relative air humidity of (65±5)%. The workability may vary in different conditions. Becomes alkaline after mixing with water. Irritating to eyes, respiratory system and skin. Appropriate eye, respiratory and skin protection measures should be used. If the product gets into eyes, rinse immediately with plenty of water and seek medical advice. Keep away from children. Use water to remove fresh dirt or ALPOL AI 770 cleaner to remove hardened dirt. The manufacturer assumes no liability for damage resulting from improper or inappropriate use of the product.

General recommendations
When pouring the underlayment observe the rules related to expansion joints. Structural joints should be provided at the location of the building joints. Contraction joints should divide the floor into fields not exceeding 30 m2, of a side length up to 6 m. Isolation joints should be used to separate floor layer from other building components (walls, columns, stairs etc.). They are also used where the underlayment thickness is changed and at the contact point of various floors (e.g. entrance threshold), as well as to separate rectangular areas in rooms of complex geometry. Always follow good construction practices, observing health & safety standards and regulations.