Advanced Materials Research Vol. 1124

Abstract: The paper describes use of hemp boon as a natural organic filler for building materials, especially concrete designed as heat - insulating filler material around the load-bearing structure of wooden buildings. In constructions, hemp has been used in the form of mats made of hemp fiber, with the addition of bonding bicomponent fibers and soda solution for protection against burning and rots. Mats are formed by pneumatic fleece, they are subsequently thermally treated and then cut to the desired dimensions. Calcium-hemp building material is a revolutionary construction and thermal insulating material which can be used for building the entire building, bricks or other insulation are not necessary. The trend is spreading across Europe from France, where the mixture of boon and lime was used in the 16^th and 17^th centuries for the construction of timber-framed houses. Although there are hundreds of buildings made from hempcrete in Europe, its use in our country develops very slowly. Concrete is a mixture of hemp boon, lime hydrate, cement and water. It is a recyclable material that offers high thermal and sound insulation. The biggest advantage is undoubtedly the speed of construction, namely hemp concrete hardens very quickly.

Abstract: This paper describes freeze-thaw resistance with sodium chloride solution of concrete mixtures based on alkali-activated fly ash. There are shown relationships between freeze-thaw resistance with sodium chloride solution and air content in fresh alkali-activated concrete and relationship between freeze-thaw resistance with sodium chloride solution and spacing factor of alkali-activated concrete. Also there is described relationship between air content in fresh mixture and compressive strength of alkali-activated concrete.

Abstract: Alkali-activated slag (AAS) binders have lower environmental impact due to its production process, but also have disadvantages as an increased shrinkage followed by formation of microcracks. The effect of polymer admixtures based on vinyl acetate, ethylene and acrylic acid ester, methyl metacrylate and different types of polyethylene glycol (PEG) and polypropylene glycol (PPG) on properties of alkali-activated slag concrete was studied. Admixtures used for mortars were tested to improve shrinkage, workability and compressive strength, flexural strength. The analysis also showed the effect of the admixtures on microstructure of the alkali-activated slag pastes and mortars.

Abstract: The research work was focussed on grinding processes of beta gypsum using Pulverisette 6 planetary mill in order to obtain best technological properties. Sulphur binders originate by burnout of calcium sulphate dihydrate at different temperatures. All types are classified in air mortars therefore they can solidify, harden and remain stable only on air. Laboratory processed beta gypsum prepared from Pregips calcium sulphate characterised with high purity and relatively low moisture from Precheza a.s. Přerov chemical works was selected as basic material. The microstructure was monitored using MIRA 3 scanning electron microscope.

Abstract: This paper is focused on the study of the parameters of developed composite materials with a polymer-cement matrix modified by raw materials from alternative resources. Test specimens were gradually exposed to extreme temperatures and subsequently cooled in a controlled manner under different conditions. Heat stress was applied up to 1,000°C. The effects of controlled gradual or shock water cooling were monitored on the basis of physical and mechanical properties. The by-products currently produced by the power and metallurgical industries were used as substitution components for matrix modification.

Abstract: The article presents results of the research focused on study of time development of composite material resistance to extreme exposition conditions. The tested materials were modified either in matrix respect (mixing binder) and aggregate item as well by alternative raw materials (lightweight aggregates). The emphasis was placed on evaluation of resistance at exposition in 28, 45 and 90-day extreme conditions ambient when the specimens were stored under standard conditions. Mortars were exposed in ambient with temperature up to 1000 °C and subsequently cooled under control in furnaces.

Abstract: In a world is of ever-increasing pressure on the use of fly ash in building materials. Despite these efforts the majority of produced energy by-products end up as reclamation material and only small part as high-quality materials. Technology of sintered artificial aggregate is fully based on the fly ashes and allows processing a high percentage of this raw material. The work is devoted to assessing the impact of fly ash character on the quality artificial aggregate. There were selected three fly ashes from high-temperature combustion technology and two from the FBC combustion. The results clearly show that the FBC ashes are not too useful for sintered aggregate technology. For fly ashes is determined primarily by their fineness and the amount of amorphous silica phase.

Abstract: Combustion of coal creates a high amount of by-products in heat power plants. The largest share occupies fly ash as solid mineral residuals. Global pressure grows currently for the use of energy by-products. Utilization as a raw material for production of artificial sintered aggregate is one of the ways to make optimal use of even low-quality fly ash. Environmental and economic reasons lead currently to trying to upgrade the technology, which will fully use of the principle of self-sintering process based on content of combustible substances.The amount of combustible substances is today increasing by coal as a primary and finite resource. There is also best way for utilization of industrial wastes that contain a suitable share of combustible substances for ensure the smooth running of sintering.The paper deals with laboratory verification of selected industrial wastes as a correction component in the sintered aggregate production technology. As an alternative raw materials were selected coal tailings, sludge from paper industry, sludge from waste water treatment plant and fly ash from municipal waste incineration plant. The aim of the study was to investigate the effect of corrective components to the quality of the resulting sintered aggregates.

Abstract: The paper describes the possibility of using textile fibers (natural and synthetic) for the production of thermal insulation materials in the form of mats using in construction. The paper deals mainly with soft thermal insulation mats and the factors that affect the thermal insulation properties of the insulating material in its manufacture and subsequent incorporation into the structure.

Abstract: Distribution function of relaxation time mathematically describes frequency dependence of the complex permittivity. Empirical function describing the complex permittivity in the frequency domain needs to be broken down to real and imaginary part, and thus separated. The permittivity is a function of the frequency of the electric field and describes behavior of technical dielectric in an alternating electric field. In this case the dielectric is a building material. The paper describes application of simulation models with variable distribution parameters and relaxation time.