Improvement of Heat-Insulating Properties of Foam Concrete by Means of Mineral Additives

Abstract

Foam concrete solidifying in natural conditions significantly shrinks, which causes deterioration of the porous structure and thus the increase in the heat conductivity of the material. One of the solutions for this problem is application of mineral modifiers. As the mineral modifiers the authors used the production waste – mineral additives (wollastonite, diopside) at natural dispersive capacity, as well as milled down to 300 and 600 m2/kg of specific surface. The application of perlite microspheres in foam concrete was investigated. The thermal conductivity coefficient was defined by rapid method. The optimal composition of the mixture for manufacturing foam concrete products with mineral additives ensures the decrease in the heat conductivity coefficient by 41-43% compared to the reference composition. At complete replacement of fly-ash aggregate by perlite microspheres the thermal conductivity coefficient decreases down to 0.062 W/ (m×°С). The economic effect of application of the developed foam concrete with the additive of wollastonite and diopside compared with the foam concrete presented on the market is equal to 259 / 388 RUB/m2 of an erected structure at the density of D300/ D400 respectively. Thus, directed regulation of the porous structure of cellular concrete leads to significant improvement of stability of the foam concrete mixture, which makes the prerequisites to the decrease in the thermal conductivity of the material and positive technical and economical results.