General Processing Advice Moulding mortar (cement-bound) [A]
Preliminary treatment of the ground
Before BETEC moulding mortar is applied, the mineral ground should be freed of cement skin, dirt, grease, oil, dust, curing compound, paint residues, loose parts and other contaminants.
The ground should be roughened to such a degree that a good adhesion will be obtained. Roughening and removing cement skin of the mineral ground can be done by mechanical means such as spraying water under high pressure, grit blasting, dabbing, grinding or hacking (pneumatically, electrically, manually).
The mineral ground should be frost-free!
Pre-moistening of the ground
Highly absorbing grounds must be moistened with clean tap water until no more water is absorbed in ample time before the moulding mortar is applied. When applying the moulding mortar the ground should not be water-repellent (glistening wet); this will reduce adhesion. If the ground still shows too much water absorption, the adhesive surface will burn because of the low water-cement ratio.
There are various options for additional adhesive layers, dependent on the surface and field of application; refer to our technical staff concerning this.
BETEC moulding mortars can be mixed in a free-fall concrete mixer, forced mixer or in case of smaller amounts with a plaster mixer for electric drilling machines. For the correct water dosage we refer to the front of the packaging, the minimum and maximum water dosages are mentioned there. The water dosage must not be below the minimum need for water, the maximum dosage must not be exceeded.
Fill the mixer with 2/3 of the water dosage indicated, then add the BETEC moulding mortar.
First mix thoroughly, so that a mixture free of lumps is produced. Then gradually add the remaining 1/3 of the mixing water until the correct consistence is realised; do not add any more water than strictly necessary.
- Do not add water afterwards
- Always use clean tap water, or suited mixing fluids delivered by us
- The total mixing time amounts to a minimum of 3 minutes (approximately 3-5 minutes)
- The processing time amounts to approximately 50-70 minutes (high-early-strength mortars approximately 10 minutes) (20° C)
When applying moulding mortar it is always important to work from one side or angle, so that no air can be enclosed. Therefore see to it there are always enough vents. Furthermore, the moulding mortar should be poured in one continuous stream without interruptions; this will produce the best result. For special applications refer to our technical staff. In so far the construction to be grouted is not square, grouting must always take place from the longest side. Dependent upon the size of the grouting, a filling funnel can be used, so that the construction will be fully grouted because of the hydrostatic pressure.
When grouting large constructions, the use of fully automated mortar/conveyance pumps may be considered.
- Always use tight and non-porous molds
- The minimum processing temperature of BETEC moulding mortars is 5° C; refer to our technical staff for the application in temperatures of + 5° C to -5° C concerning measures that should be taken during the winter.
As BETEC moulding mortars are cement-bound materials, it is of the greatest importance that the mortar is cured. Because of the low water-cement ratio the mortar must be cured for 5 days at the minimum, in order to prevent premature desiccation and ensuing shrinkage. This can be done by wetting the mortar with clean tap water. Another option is covering the mortar with moist burlap covered with synthetic foil. Less time-consuming is the application of BETEC BETOFILM curing compound which must be applied in two layers.
Curing activities should be started as soon as possible, but at the latest after the mortar surface has started hardening.
Packaging and storage
BETEC mortars are delivered in packages of 20/25 kg; packaging consists of several layers of paper, with layers of perforated synthetic material in between. The packaging material is not water-tight and must be stored in a dry and frost-free place. In the original closed packaging the storage life of the mortar is 12 months.