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.

Studies of Heat Insulation Concrete

“…The mixture is fed to the molding station and poured into the molds to the full extent. Products after stripping on a pallet are sent to the finished goods warehouse [10][11][12][13][14][15][16][17][18][19][20].…”

“…Further optimization of the properties of foam concrete was carried out through the use of dispersed wollastonite and diopside. The introduction of these additives makes it possible to improve the resistance of the foam in the mortar mixture of the foam concrete structure and to obtain a larger volume of air entrainment [5,8], while the average density of the foam concrete decreases (Table 1).…”

“…Due to the chemical affinity for cement stone minerals, diopside and wollastonite [6] provide a more durable contact layer between the additive and the cement stone. Wollastonite and diopside act as additional centers of crystallization, which as a result increases the stability of the foam in the mortar and allows to get a homogeneous structure of the foam concrete mixture and to prevent its shrinkage [7,9].…”

Multi-Span Composite Timber Beams with Rational Steel Reinforcements

“…Composite materials are distinguished by the absence of wood defects and the greater resistance to warping, curliness, and other defects inherent in solid wood products [4]. The creation of new composite products follows market differentiation and filling specific market niches [5][6][7][8]. For example, in Russia, for many years, comprehensive studies of glued wooden reinforced structures have been carried out; new types of them have been developed and implemented in industry [9,10].…”

Modeling of Aerated Cement Concrete Structure and Increasing its Crack Resistance

“…The use of disperse reinforcement is especially important for normal hardening foam concrete, since the problem of their fracture toughness largely limits the technology of monolithic construction [4,5].…”