Effect of alumina-silica microsphere additives on properties of ceramic wall products

21st International Scientific Conference on Advanced in Civil Engineering "Construction - The Formation of Living Environment"

土木建筑工程

Bessonov, Igor^2 ; Larsen, Oksana^1 ; Alimov, Lev^1 ; Voronin, Viktor^1 ; Sapelin, Andrey^2 ; Komorova, Natalya^1

Moscow State University of Civil Engineering, Yaroslavskoye Shosse 26, Moscow

129337, Russia^1

Research Institute of Building Physics, Russian Academy of Architecture and Construction Sciences, Moscow

127238, Russia^2

关键词: Equivalent thermal;    Insulation performance;    Intergranular space;    Manufacturing technologies;    Mathematical experiments;    Optimal composition;    Pore-forming agents;    Vapor permeability;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/365/3/032011/pdf
DOI  :  10.1088/1757-899X/365/3/032011

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

Large size ceramic masonry products manufactured by forming and firing fusible clays are widely used. Their structure is presented with honeycomb porous walls which improve their thermal insulation performance. The movement of the thermal flow in this case is carried out by the maximum path from the inner to the outer surface. It leads to decrease the equivalent thermal insulation performance. The void ratio of this type of products is more than 50% and the density with voids is from 600 up to 800 kg/m3. Voids in ceramic hollow products are filled with masonry mortar and it leads to decrease their thermal properties. In this paper the research of modified raw clay by alumina-silica hollow microspheres as pore forming agent is presented. The optimal composition and manufacturing technology of the product was established by applying mathematical experiment planning method. The obtained composite included microspheres with bulk density of 360 kg/m3 as a filler and raw clay with a true specific gravity of 2500 kg/m3 as a binder. The technology of manufacturing consisted of mixing thoroughly dry powdered clay with hollow microspheres with addition of water until a homogeneous mass, forming in the mold at the required pressure, release from the mold and firing with appropriate temperatures. The structure factor of strength and the structure factor of thermal conductivity as criteria for optimization of the properties were chosen. Effect of moisture on the thermal conductivity, sorption, vapor permeability, water absorption and adsorption rate were investigated. It was found that the thermal conductivity decreases with the use of alumina-silica hollow microspheres for every percent of the moisture content, which is significantly less than the similar ceramic materials. The obtained material has contact structure with a partial filling of intergranular space and it is associated with the firing character of its production. The way of optimization the material structure is to improve the packing density of the microspheres by controlling their size distribution and providing a thin uniform dispensing of the clay mass over the entire volume of composite.