Bonding Course ZE

The perfect bonding between the concrete surface and the bonded screed.

DOSAGE

Mix Bonding Course ZE bag by bag of cement before use.
Fill a mixing vessel with approx. 6 l water, mix in a 25 kg bag of cement and 150 ml Bonding Course ZE and stir with an agitator until a pliable, pasty (yet not liquid) slurry is obtained.
The mixing time is 3 minutes.
This ensures proper blending of the ingredients with the cement and durable bonding.

For bonded screeds of quality CT-C40 concrete substrates of strength class C20/C25 are usually sufficient.
For higher strength classes (> CT-C50) and for fair-faced bonded screeds applied at layer thicknesses above 40 mm the substrate must comply with strength class C25/C30.
Surface tensile strength of concrete for bonded screeds
- without vehicle load ≥ 1.0 N/mm²
- with vehicle load ≥ 1.5 N/mm²
The surface of the concrete must be clean, absorptive, load-bearing, firm and without cracks.
Too soft and flaking layers and areas affecting the bond strength must be removed entirely by milling and/or shot peening.
- Any cracks in the substrate must then be durably closed and force-bonded with a suitable reaction resin and mechanical anchors in accordance with customary industry practices and standards.
Pre-wet the substrate the day before applying the bonding primer/composite screed.
On the day of application, the substrate must be wet (glossy), without puddles or wet spots.
Sprinkle quartz sand (grit size at least 0.8 – 1.2 mm!) generously over the areas treated with reaction resin.
Excessive, not firmly bonded sand must be entirely removed after the resin has cured and before wetting the surfaces or applying the bonding course.
A high-pressure cleaner must be used for precision cleaning.

Spread the mixed Bonding Course ZE on the prepared substrate and brush into the substrate with a hard brush (preferably with a rotating scouring machine).
Immediately cover the brushed-in Bonding Course ZE with Retanol® screed to prevent premature drying..
Then apply, compact and smooth the screed using the standard technique. Any dried (matt or light-coloured) bonding course is now unusable and must be removed mechanically down to the loadbearing substrate.
It must be made sure that the upper pore structure is stripped again to guarantee a sufficient bonding for a new application of bonding course.

DOSAGE & CEMENT QUANTITY

MIXING INSTRUCTIONS

Notes

For bonded screeds of quality CT-C40 concrete substrates of strength class C20/C25 are usually sufficient.
For higher strength classes (> CT-C50) and for fair-faced bonded screeds applied at layer thicknesses above 40 mm the substrate must comply with strength class C25/C30.
Surface tensile strength of concrete for bonded screeds
- without vehicle load ≥ 1.0 N/mm²
- with vehicle load ≥ 1.5 N/mm²
The surface of the concrete must be clean, absorptive, load-bearing, firm and without cracks.
Too soft and flaking layers and areas affecting the bond strength must be removed entirely by milling and/or shot peening.
- Any cracks in the substrate must then be durably closed and force-bonded with a suitable reaction resin and mechanical anchors in accordance with customary industry practices and standards.
Pre-wet the substrate the day before applying the bonding primer/composite screed.
On the day of application, the substrate must be wet (glossy), without puddles or wet spots.
Sprinkle quartz sand (grit size at least 0.8 – 1.2 mm!) generously over the areas treated with reaction resin.
Excessive, not firmly bonded sand must be entirely removed after the resin has cured and before wetting the surfaces or applying the bonding course.
A high-pressure cleaner must be used for precision cleaning.

Spread the mixed Bonding Course ZE on the prepared substrate and brush into the substrate with a hard brush (preferably with a rotating scouring machine).
Immediately cover the brushed-in Bonding Course ZE with Retanol® screed to prevent premature drying..
Then apply, compact and smooth the screed using the standard technique. Any dried (matt or light-coloured) bonding course is now unusable and must be removed mechanically down to the loadbearing substrate.
It must be made sure that the upper pore structure is stripped again to guarantee a sufficient bonding for a new application of bonding course.

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