Forecasting Results of the Temperature and Moisture Content and Their Application to the Durability Calculation of External Cellular Concrete Walls

ABSTRACT

The results of numerical modeling of heat and moisture transfer processes in the outer walls of cellular autoclaved concrete and their application for calculating the durability are presented.

The calculations of the temperature and moisture content (drying) in non-stationary conditions for walls with external and internal polymercement plaster and without it are done. The boundary conditions for the calculation were taken from the actual data of meteorological observations. The initial humidity of the cellular concrete is 35 % by weight. The time step in the calculations is 3 hours. It is shown that the polymer-cement plaster from the outer and inner sides of the structure significantly increases the time of attaining to the required values of the cellular concrete moisture content. In the absence of plaster layers, the moisture content reaches values of about 5 % by weight in about three years of operation. The obtained results correspond to the available data of bench studies.

Two-dimensional non-stationary fields of temperature and moisture content of the corner connection of cellular autoclaved concrete walls have been calculated. The initial moisture content of cellular concrete is 5 % by weight. A way for durability calculating of external walls is proposed, with using the method of S. V. Alexandrovsky. The required parameters for durability calculation are determined with numerical modeling of the temperature and moisture content fields in non-stationary operating conditions of external walls. This makes it possible to shorten the time of investigations, since, unlike the original method, it is not necessary to carry out long-term field studies of the moisture content of materials.

Keywords: non-stationary heat and moisture transfer regime, moisture content by weight, drying of walls, numerical modeling, calculating the durability of walls.

For citation: Liashkevich U. Forecasting Results of the Temperature and Moisture Content and Their Application to the Durability Calculation of External Cellular Concrete Walls. Contemporary Issues of Concrete and Reinforced Concrete: Collected Research Papers. Minsk. Institute BelNIIS. Vol. 10. 2018. Pp. 185–199. https://doi.org/10.23746/2018-10-12 (in Russian)

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