$SILRES<sup>®</sup> BS 5350

SILRES® BS 5350 is a neat liquid siloxane used to impart water repellency to autoclaved aerated concrete AAC (also ALC) and to strongly reduce its capillary water absorption. It can be used for all produced densities above 150 kilograms per cubic meter.


Even though SILRES® BS 5350 is not water-based and contains no surfactants or solvents, as a so-called integral or in-mass hydrophobizing additive it is commonly used in the aqueous AAC slurry and disperses by the shear forces between liquids and solids in the mixer.

SILRES® BS 5350 can strongly reduce the water absorption of AAC (determined according to EN 772-11), but in contrast to other hydrophobizing additives at the same time has only neglectable influence on compressive strength and pore size distribution or thermal conductivity. No noteworthy influence on green strength has been observed in the recommended dosage range.

Furthermore, no negative effects on the adhesion strength of cementitious AAC thin bed adhesives have been observed.

SILRES® BS 5350 is used as a so-called integral or in-mass
hydrophobizing additive, which means that it is added to the water-based AAC slurry already at the slurry mixer. A common dosage level is 0.2 % by weight based on the overall solids in the AAC slurry.
Nevertheless, depending on the type of recipe and the produced density, orientating trials should preferably start at a dosage level between 0.1 and 0.15 % in order to ensure sufficient green strength.


Maximum temperature allowed during storage and
transportation: 50 °C.

The 'Best use before end' date of each batch is shown on the product label.

Storage beyond the date specified on the label does not necessarily mean that the product is no longer usable. In this case however, the properties required for the intended use must be checked for quality assurance reasons.

Sales and support

Wacker Chemical Corporation
3301 Sutton Road
Adrian, MI 49221-9397
United States
+1  888  922-5374 (Phone)

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