Porous magnesia compositions of a combined structure

Abstract

Porous magnesia compositions of a combined structure Olga MiryukRudny Industrial Institute, Republic of Kazakhstan E-mail: psm58@mail.ru Abstract. In this research were developed heat-insulating magnesia compositions with technogenic fillers. A comparative analysis of the structures formed by different methods shows the high porosity of the compositions using a foaming agent, polystyrene pellets. Here was shown the expediency of obtaining porous compositions based on mixed magnesia binders with the addition of wastes of enrichment of skarn-magnetite ores (up to 30 %). The efficiency of the heat-shielding properties of materials is ensured by the creation of a highly porous combined structure by optimizing the formulation of the molding masses and by rational combination of various techniques of porosity. Effect of porosity methods on magnesia compositions structure was investigated. The conditions for formation of combined structures due to combination of cellular, granular and fibrous porosity were determined. Combined structures of various compositions based on technogenic fillers are characterized by porosity of 75 -90%, density of 150 -400 kg/m 3 and coefficient of thermal conductivity of 0.04 -0.08 W/(m 0 C). Methods for preparing molding mixtures have been developed based on the primary contact of the components forming the matrix stability and providing a stable highly porous structure of the compositions.It is revealed that the magnesian compositions are distinguished by increased technology, ensuring the greatest strength of the porous materials.

Effect of additives on hydration and hardening of magnesia compositions

“…The range of the magnesia cement extends at the expense of compositions from the caustic magnesite and filler. Preference of ferriferous by-product additives in the magnesia cement is noted [7,10].…”

Porous aggregate development for lightweight concrete

“…To ensure energy-efficient construction, durable materials are required that combine high heat-shielding properties with structural stability. Numerous developments in recent years have been devoted to the development of porous concrete technology, which is represented by cellular concrete and lightweight concrete based on porous aggregates [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Aerated concrete compares favorably with an extensive raw material base, a variety of products, and economical operation.…”

“…Aerated concrete compares favorably with an extensive raw material base, a variety of products, and economical operation. However, low strength and tendency to shrinkage deformations limit the scope of cellular concrete [4,7,11]. Development of efficient lightweight concrete technology depends on the quality of porous aggregates.…”

“…Development of efficient lightweight concrete technology depends on the quality of porous aggregates. Relevant is a research aimed at reducing density and increasing strength of aggregates, reducing energy intensity of production [1,7,[10][11][12][13][14][15][16][17][18][19]. Porous aggregates with a density of 300 -900 kg/m 3 for heatinsulating and structural concrete have been developed [6,8,9].…”