Developed heat-insulating dry mortar mixes for the finishing of aerated concrete walls

Abstract

The paper presents new compositions of lime heat-insulating dry building mixtures, designed specifically for the finishing of aerated concrete, characterised by the presence of a modifying additive based on aluminosilicates and calcium hydrosilicates, as well as highly porous filler – microspheres. The beneficial effect of a modifying additive based on a mixture of aluminosilicates and calcium hydrosilicates with high pozzolanic activity on the structure formation of lime finishing compounds has been established, and is manifest in a decrease in the content of free lime to 28·6%, an increase in plastic strength, and a 2·2 times  increase in the softening coefficient. It has been revealed that when using limestone heat-insulating dry construction mixtures of hollow glass microspheres and ash aluminosilicate microspheres, the crack resistance of the resulting coatings increases by reducing shrinkage deformations during the hardening process, increasing the ultimate tensile properties and cohesive strength of the finishing coating, and increasing water resistance by the formation of a composite structure with a closed porosity. Coatings based on the developed dry construction mixture are distinguished by low density and thermal conductivity and high vapour permeability, while possessing a sufficiently high crack resistance and weatherability.