Advanced Materials Research Vol. 897

Abstract: The paper is devoted to development and research of decorative multi-component alkali activated cements with enhanced quality characteristics. The use of finely dispersed mineral additives and alkali metal salts allows to obtain multi-component cements with the lower content of OPC clinker. In chemical composition these decorative multi-component cements are similar to Roman cement. The developed multi-component cements have comparable or better performance properties compared to Roman cement and allow for to use them successfully in making plasters, mortars, etc. for restoration, finishing works and decoration of facades.

Abstract: The paper describes the mineralogical and petrographic examinations and testing of the mechanical properties of loess and the experimental adobe bricks. The tested material corresponds to a common loess, which was traditionally used in clay buildings in the region. Due both to its composition and mechanical properties it was found to be applicable as a rammed earth building material, and was later used for building a replica of a traditional Moravian folk house at the open-air museum in Strážnice, Czech Republic. The research is part of a cultural heritage documentation and preservation project.

Abstract: The territory of our country is very poor in natural resources of gypsum and the natural resource of anhydrite is missing completely. A considerable amount of gypsum is produced in the country as a secondary raw material originating during the desulphurization of flue gases in thermal power plants using limestone washing and in the chemical industry. This paper describes the different types of industrially generated gypsum, the production technology, and its potential use in the construction industry.

Abstract: The aim of the research was to find and test suitable plasticizing admixtures, which have result in reduction of high water coefficient, in order to improve final technological gypsum properties from waste sources of raw material.

Abstract: The purpose of research work has been to verify an influence of α-gypsum grinding on its final property. The production of α-gypsum was performed by pressureless method in salt solution with partial substitute still used dehydrating solution of sodium chloride and calcium chloride.

Abstract: Metakaolin, fly ashes and other secondary raw materials serves as suitable input in preparation of alkali-activated binders. This work deals with preparation of alkali-activated materials based on metakaoline and fly ash. Mixtures were prepared with a minimum of mixture water, ready for pressing. Prepared specimens were tested for tensile strength and pressure strength, resistance to high temperatures, frost resistance and resistance to water and salt.

Abstract: The paper deals with laboratory research and development of alkali activated system with thermal insulating properties where low density materials are used. The experiment is focused on strength and heat conductivity of prepared substances. In research five kinds of mixtures were prepared. The values of compressive strength and thermal conductivity of tested admixtures qualitatively correspond to commercially available building material. Results are foundations for next lightweight alkali activated system development and research focused on practical application in building industry.

Abstract: The article is focused on analysis of using geopolymers as matrixes to repair mortars designated for rehabilitation of reinforced concrete structures. Due to their specific properties, geopolymers show a high potential mainly for special applications. Rehabilitation of reinforced concrete structures exposed to extreme conditions is a field in which it is possible to effectively take advantage of geopolymers ́ exceptional properties.

Abstract: The paper focuses on the study of the formation mechanism of belite (dicalcium silicate) catalyzed with potassium ions in the form of chemically pure salt of potassium sulphate at various modes of firing in order to increase its reactivity. To verify the function of potassium sulphate as a substance enhancing the reactivity of C₂S, 3 material mixtures were tested; they contained 0, 1 and 2 % of K₂O recalculated per fired dicalcium silicate.

Abstract: This paper describes the failure analysis of a cold sleeve using modified adhesive layer of polymer Protegol. The tensile test was carried out to estimate material properties of the polymer and the two-parameter Mooney-Rivlin constitutive model was used. An axisymmetric FEM model with additional plane symmetry was developed for simulation of cold sleeve. Cohesive zone material failure modeling uses contact elements to model interface delamination. The bilinear behaviour of sleeve material with normal tractions and separation distances and material nonlinearities together with contact were considered. Commercial finite element software ANSYS was utilized to carry out the static nonlinear analysis.