Between Heat and Mass Transfer in Foam Concrete External Wall Covered with Plaster Mortar

Building wall structures made of foam concrete are becoming more and more popular due to their structural qualities and excellent thermal protection. The heat and moisture regime of wall structures made of foam concrete has a decisive effect on their strength and heat protection properties.
Purpose: The aim of this work is to clarify the heat and moisture transfer in foam concrete walls taking into account the influence of plaster layers deposited.
Methodology/approach: Numerical modeling is conducted for non-stationary heat and moisture transfer in a flat homogeneous wall composed of D400 aerated concrete with various exterior and interior plastering options for climatic conditions in Tomsk. Calculations show that the plaster mortar applied to the wall, results in a significant buildup of moisture, while the internal plaster mortar applied, has no discernible impact on the heat and moisture transfer of the wall structure.
Research findings: It is shown the influence of different plastering options on the position of the maximum moisture content in the wall made of foam concrete. The external walls coated with plaster mortar, including those performed after the first year of operation, demonstrate excessive moisture on the outer surface during the cold period due to the moisture condensation in the range of consistently low temperatures.

1. Grzyb K., Jasiński R. Full-Scale Studies of Stiffening Walls Made of Autoclaved Aerated Concrete. In: Proc. 7th Int. Conf. on Autoclaved Aerated Concrete. 2023; 6. (I. 2): 135–141. DOI: https://doi.org/10.1002/cepa.1973

2. Gorshkov A.S., Vatin N.I., Rymkevich P.P., Kydrevich O.O. Payback Period of Investments in Energy Saving. Magazine of Civil Engineering. 2018; 78 (2): 65–75. DOI: https://doi.org/10.18720/MCE.78.5

3. Min H., Zhang W., Gu X. Effects of Load Damage on Moisture Transport and Relative Humidity Response in Concrete. Construction and Building Materials. 2018; 169: 59–68.

4. Nizovtsev M.I., Terekhov V.I., Yakovlev V.V. Thermal Conductivity of Aerated Concrete with High Humidity. Izvestiya vysshikh uchebnykh zavedenii. Stroitel'stvo. 2004; (9): 36–38. (In Russian)

5. Vatin N.I., Glumov A.V., Gorshkov A.S. Influence of Physical-Technical and Geometrical Characteristics of Plaster Coatings on Moisture Regime of Homogeneous Foam Concrete Walls. Inzhenerno-stroitel'nyi zhurnal. 2011; (1): 28–33. (In Russian)

6. Krainov D.V., Sadykov R.A. Moisture Content Effect on Thermal Protection of Walling Structure. Vestnik MGSU. 2011; (3): 404–410. (In Russian)

7. Gagarin V.G., Zubarev K.P., Kozlov V.V. The Highest Moisture Area in Façade Heat-Insulation Composite Wall Systems with External Plastering. Vestnik of Tomsk State university of Architecture and Building. 2016; (1): 125–132. (In Russian)

8. Moyou A.Y., et al. Numerical Computation of Heat Transfer, Moisture Transport and Thermal Comfort Through Walls of Buildings Made of Concrete Material in the City of Douala, Cameroon: An ab Initio Investigation. Heliyon. 2024; 10 (I. 13): 34058.

9. Berger J., Gasparin S., Dutykh D. On the Solution of Coupled Heat and Moisture Transport in Porous Material. Transport Porous Media. 2018;121: 665–702.

10. Berger J., Dutykh D., Mende N. A New Model for Simulating Heat, Air and Moisture Transport in Porous Building Materials. International Journal of Heat and Mass Transfer. 2019; 134: 1041–1060.

11. Zhukov A.V., Tsvetkov N.A., Khutornoi A.N., Tolstykh A.V. Effect of Temperature Dependence of Sorption Isotherm and Coefficient of Moisture Conductivity on Moisture Transfer in an Foam Concrete Wall. Vestnik MGSU. 2018; 6 (117): 729–739. (In Russian)

12. Gagarin V.G., Zubarev K.P. Mathematical Simulation of Non-Stationary Humidity Regime of Fences based on Discrete-Continuum Approach. Vestnik MGSU. 2021; 15 (2): 244–256. DOI: https://doi.org/10.22227/1997-0935.2020.2.244-256. (In Russian)

13. Zubarev K.P., Gvozdkov A.N. Mathematical Simulation of Heat and Humidity Regime of Facade Thermal Insulation Composite Systems with External Plaster Layers in Stationary and non-Stationary Settings. In: Proc. 19th Int. Sci. Conf. ‘Indoor and Ambient Air Quality’. Volgograd, 2021. Рр. 19–25. (In Russian)

14. Zhukov A.V., Tsvetkov N.A., Khutornoi A.N., Kuznetsova A.A. Substantiation of Physico-Mathematical Model of Heat and Moisture Transfer in Aerated Concrete Extrenal Walls. In: Proc. 7th Int. Sci. Conf. ‘Investments, Construction, Real Estate as a Material Basis for Economy Modernization and Innovation’. Tomsk: TSUAB, 2017. Рр. 483–497. (In Russian)

15. Fokin K.F. Construction Heat Engineering of Enclosing Parts of Buildings. Moscow: AVOKPRESS. 2006. 250 р. (In Russian)