Evaluation of the influence of finishing coatings on the change of the moisture regime of the gaz-concrete fencing construction

• Main Authors: Loganina Valentina I., Frolov Mikhail V., Skachkov Yuri P.
• Format: Article
• Language: English
• Published: Moscow State University of Civil Engineering (MGSU) 2018-12-01
• Series: Vestnik MGSU
• Subjects: aerated concrete fencing; finishing coating; humidity conditions; moisture condensation; contact zone
• Online Access: http://vestnikmgsu.ru/index.php/archive/article/download/4593

Introduction. Provides information about the moisture regime of the building structure of aerated concrete in the presence of finishing coatings. Plaster coatings based on dry construction mixtures Knauf Grunband, developed by the authors of lime compositions using hollow glass microspheres and ash aluminosilicate microspheres, cement-sand compositions were considered. Materials and methods. Aerated concrete blocks of various grades were used as the main material: D350, D400, D500, D600. Cement-slag plaster was adopted as an internal finishing layer for all variants. The outer surface of the wall is finished with Knauf Grunband dry construction mixtures, as well as developed lime compounds using hollow glass microspheres and ash aluminosilicate microspheres. The outside air temperature was determined, at which moisture condensation begins in the wall and on the border of the finishing layer - aerated concrete wall Results. When using Knauf Grunband plaster composition as finishing, the temperature of the onset of condensation drops to -9.0 °C. When using the developed DBM, obtained using hollow glass microspheres and ash aluminosilicate microspheres as fillers, the temperature of the onset of condensation decreases to -11.4 and -11.9 °С, respectively. Condensation at the border of the finishing coating - aerated concrete begins at a temperature of -2.4 °C, in a fencing structure of a gas concrete of the mark D400 with a plaster coating of a density of 1800 kg/m3 - at a temperature of -3.8 °C, and in aerated D400 grade with a plaster density of 1100 kg/m3 -at a temperature of -5.5 °C. Conclusions. The conducted studies prove that due to the use of heat-insulating DBM for finishing gas-concrete blocks of the D300-D600 grades, which allow to obtain coatings with a density of less than 800 kg/m3, the outdoor air temperature decreases, at which the moisture in the wall starts. Also, due to the use of the developed coatings, the external air temperature is significantly reduced, at which the finishing coating - aerated concrete begins at the border. This will minimize the amount of condensable moisture in the thickness of the enclosing structure and extend the service life of both the finishing coating and the wall as a whole.