Researching of the Water Resistance of Hydrophobized Tongue-and-Groove Gypsum Slabs

Tongue-and-groove slabs based on gypsum or modified gypsum binder, monolithic structure or with voids, porous or with the introduction of lightweight fillers, have established themselves as products that are indispensable for arranging premises inside a building. Researching of the properties of hydrophobized slabs allows you to expand the scope of products. The purpose of the research described in the article was to determine the possibility of using gypsum tongue-and-groove hydrophobized slabs in conditions of high humidity. Samples of slabs were tested for water resistance. The following characteristics were determined: water absorption, water adsorption by the outer surface of the slab, coefficient of strength reduction during moistening, contact angle of wetting, capillary absorption coefficient. A comprehensive research of hydrophobized tongue-and-groove gypsum slabs showed their increased water resistance in comparison with tongue-and-groove slabs of conventional composition. The humidity of the slabs upon admission to the laboratory was as follows: hydrophobized – 0.7%, ordinary – 4.5%. Water absorption after 2 hours for hydrophobized samples was 4.9%, for ordinary ones – 32.5%; after 24 hours, respectively: 14.2% and 33.3%. Hydrophobized boards have a significantly lower surface wettability (the contact angle is obtuse and is about 120°), while on ordinary slabs a drop of water does not hold, it is absorbed by the surface. The rate of capillary suction of water from hydrophobized plates is significantly lower than that of conventional plates. After a complex of field observations at the facilities, it is possible to draw up recommendations for the widespread use of hydrophobized tongue-and-groove plates in rooms with high humidity.

I.V. BESSONOV¹, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
A.D. ZHUKOV^1,2, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
E.A. GORBUNOVA^1,2, Engineer (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Research Institute of Building Physics of the Russian Academy of Architecture and Construction (21, Lokomotivniy Driveway, Moscow, 127238, Russian Federation)
² National Research Moscow State University of Civil Engineering (26, Yaroslavskoe Highway, Moscow, 129337, Russian Federation)

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