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The new generation of high silica materials with high thermal resistance was created by leaching of chopped glass fibre. These materials with low thermal conductivity are inert to the majority of chemical reagents, resistant to organic and mineral acids, weak alkali, water and highpressure steam. High silica chopped strand mats are non-woven fabrics designed for using in a wide range of insulation and protection applications at temperature till 11000C. The technology and quality of leaching process of initial Si-Al-Na glass widely depends on quality of fibre surface characteristics, i.e., roughness of surface of glass filaments. The surface roughness of the fibre before leaching is a function of chemical durability, therefore it depend on content of Al2O3. The thermal conductivity (within 20…10000C) of chopped strand mats directly depends on the surface roughness. The morphology and compositional profiles of surface of glass fibre before and after leaching were investigated using AFM, SEM, X-ray microanalysis and X-ray powder diffractometer. The different defects for fibre with content of Al2O3 <2.5% and high roughness namely cracking and crystalline deposits of Na2SO4 on top and into pores of fiber after leaching have been identified. The presence of sodium ions on surface of fibre decreases the heat insulation properties of mats. The structure of glass filaments surface was investigated in order to clarify the influence of surface characteristics on thermal conductivity of high silica glass fibre non-woven fabrics.

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Clay of the deposit Liepa is used for the production of ceramic building and finishing bricks in the factory “Lode” in Latvia. In the present work different types of these clays were investigated and “quartz effect” was determined using quartz sand as a leaning material. The substitution of quartz sand with milled E-glass fibre from Valmiera Glass was investigated and the changes in the magnitude of the quartz inversion effect were analysed. Thermal expansion was the main method for the determination of possible formation of cracks during technological process. Powder of milled glass fibre in amount of 5–10 % affects such properties as water uptake, porosity and apparent density and provides the required material properties at a lower firing temperature.