Solid State Phenomena Vol. 296

Abstract: Contemporary demand after high-quality ceramics leads to the depletion of raw material deposits. The industry also produces waste secondary materials that cannot be used directly for the desired purposes. It is therefore necessary to find other uses for these materials. It is common practice in the ceramics industry to stockpile fine fractions of refractory clays prior to their firing in a shaft kiln. These fractions have the size of 35 mm and less and when stored in a mound are facing a risk of weathering. Finding a purpose for these unused materials will markedly slow down fresh clay mining and make the production more eco-friendly and cost-effective. This paper seeks a suitable technology of treating fine fractions of BC (Brezina Clay), sometimes called FBC (Fine Brezina Clay), prior to its being fired into grog. The stockpiles hold tens of thousands of tons of these fractions. The properties of the fired clay are determined by the length of time for which the material has been stockpiled, moisture content, of the clay, as well as the briquetting pressure before firing in a shaft kiln. FBC contains approx. 41 % of aluminium oxide. This amount is not high enough for certain applications. The aluminium oxide content can be increased by the addition of bauxite, corundum, mullite, kaolin, clays rich in Al₂O₃, or technical Al₂O₃. The experiment described in this paper tested how the addition of technical Al₂O₃ affects the pore structure of fired FBC, which is later used as a grog in both shaped and non-shaped refractory products. The influence of firing temperature on the material's mineralogy was examined as well

Abstract: Vacuum insulation panels (VIP) currently belong to a group of so-called super-insulating materials. These are special products with an extremely low equivalent value of the thermal conductivity coefficient. Despite this fact, the use of VIP in the construction industry is rather problematic. The main issue is the relatively complicated VIP integration into building structures, as well as the limited VIP durability. The issue of durability is also one of the main topics of VIP development and research in this field. The paper describes the possibilities of using CaO to increase the durability of vacuum insulation panels.

Abstract: The paper deals to create alkali activated composite based on the recipe of high-strength concrete. The paper includes the review of conditions for high-strength concrete proposing and preparation. Principles of design of high performance concrete based on Portland cement as a binder were described. The experiment was focused on the strength investigation of composites with different ratios of cement to slag, and also the effect of used activator on strength parameters was investigated.

Abstract: In the paper, the resistance of concrete to the erosive effect of water from a water jet was monitored. The tests were performed on concrete without the addition of fibres and on concrete with the addition of polypropylene fibres and steel fibres. The water flow hit the concrete surface at an angle of 90°. The water flow rate was 1.1 l/min and the water pressure was 80 MPa. After blasting the concrete with water jet, no cracks in the concrete were observed and the intended rugged surface relief was created. Steel fibres remained firmly anchored into the cement matrix.

Abstract: Up to now, questions related to the preparation of pure sulphate binders, ie anhydrite mortar, alpha gypsum and beta gypsum, have been monitored at laboratory and pilot plant level within the framework of the work carried out at BUT. However, beta gypsum cannot be considered a high-grade sulfate binder. Therefore, the subject of this article is the use of beta gypsum to develop a gypsum premix that can be classified as a mixed sulfate binder universally applicable to the preparation of dry mortar mixtures. [1,2]