Jiri Zach

Utilization of Lightweight Aggregate from Expanded Obsidian for Advanced Thermal Insulating Plasters Production

The thermal insulating of new and existing buildings is of a key influence in reduction of their energetic demand factor resulting in reduction of emissions of gases, carbon particles and dust which directly improves the environment. At development of light thermal insulation plasters with very low thermal conductivity the foam-plastic matters or light porous aggregates are frequently used at present. The foam-plastic materials do not appear as convenient ones in view of the environment and sustainable development as well. In the given case the thermal insulation plasters based on light cellular aggregates appear as more suitable. However a majority of light aggregates (for example expanded perlite) do not show a good ratio of insulation and mechanical properties. The paper describes a design and development of thermal insulation plasters based on expanded obsidian that can be used for thermal insulating of building constructions and for moisture sanitation. Considering the applied type of aggregates the materials show better ratio of thermal insulation and mechanical properties while in practice the plasters can be used as a full- value alternative for classical thermal insulation systems.

Study of Behaviour of Advanced Silicate Materials for Thermal and Moisture Rehabilitation of Buildings

The article describes the results of research work carried out in cooperation between the Faculty of Civil Engineering in Brno and the Faculty of Civil Engineering in Vienna concerning the development and study of the behaviour of heat-insulation plasters on a silicate basis, in particular in the area of the transfer of heat and moisture in their structures. The main objective was to determine the capillary activity of the thermal moisture behaviour of the developed materials which can be source material for the further part of the research solution addressing the simulation of the behaviour of these thermal-insulating plasters in real constructions.

Investigation of Thermal Insulation Materials Based on Easy Renewable Row Materials from Agriculture

Production of building materials is mostly energy consuming. In the sphere of insulation materials we mostly see rock wool based materials or foam-plastic materials whose production process is demanding from material aspect and raw materials aspect as well. At present the demand for thermal insulation materials has been growing globally. The thermal insulation materials form integral part of all constructions in civil engineering. The materials mainly fulfill the thermal insulating functions and also the sound-insulating one. The majority of thermal insulation materials are able to fulfill both of the functions simultaneously. The paper describes questions of thermal insulation materials development with good sound properties based on natural fibres that represent a quickly renewable source of raw materials coming from agriculture. The main advantage of the materials are mainly the local availability and simple renewability of the raw materials. In addition an easy recycling of the materials after their service life end in the building construction and last but not least also the connection of human friendly properties of organic materials with advanced product manufacture qualities of modern insulation materials.

Investigation of Anti-noise Absorptions Walls Development with Utilization of Waste from Agriculture

Along side with the fast infrastructure development such as highways, roads and railroad tracks there is increasing stress on protection against noise produced by these line sources. In general it seems to be the most efficient way to reduce noise by building anti-noise walls along line sources of traffic noise. Anti-noise walls absorb the noise and protect from distribution to surrounding environment. The paper describes possibilities of use of waste from production of technical hemp for production of anti-noise walls with high level of sound absorption. Advantages of these walls are not only good acoustic properties but also lower price and utilization of environmental friendly material. The used technical hemp is easily renewable material source; technical hemp can be substituted by another similar material typical for the particular area or more easily accessible.

Utilization of Non-Traditional Fibers for Light Weight Concrete Production

Along with energy savings for heating and cooling, the demand for thermal insulation materials is increasing and is an attempt to achieve good thermal insulation properties for some of the construction materials. In the field of porous and lightweight concrete, this is e.g. concrete for foundations, concrete for floor constructions or flat roofs. The problem with these concrete is a relatively rapid drop in mechanical properties in reducing bulk density, with using conventional silicate binders, especially in the area below 1000 kg/m3. The paper describes the possibility of using recycled organic fibers in combination with lightweight aggregates based on foam glass for the production of porous and lightweight concrete with a good ratio of mechanical and thermal insulation properties.

Properties of Lightweight Concretes Made of Aggregate from Recycled Glass

The paper describes the basic properties of newly developed lightweight cement concrete containing lightweight aggregate based on recycled glass. The basic properties of concrete were observed, i.e. bulk density in fresh and hardened state and compressive strength. Given the low bulk density of the concretes being designed, thermal conductivity is also observed in order to assess the options off improving thermal insulation properties in a structure where such concrete may be used. Thermal insulation properties are the primary parameter in the implementation of floor or ceiling structure composition.

Utilization of Alternative Insulation Materials for Thermal Insulating Ceramics Blocks Production

There has been a substantional increase of atributes for building constructions in area of thermal protection in last decade. This was shown as increasing of requirements for materials and components intended for building of cover constructions as well. In case of shaped bricks used for perimeter walls advanced production technologies were applied. These technologies consist of decreasing thermal conductivity coefficient for brick clinker, of decreasing inner ribs thickness and in last years this concerns the technology of filling inner cavities of shaped bricks with thermal insulating materials as well. This paper describes possibilities of using alternative raw material sources (natural fibres originated in agriculture, separate textile waste, ....) as integrated insulating layers in contemporary ceramic shaped bricks with high usable qualities.

Design Procedure Concerning Composition of Composites Containing Gypsum-Free Cement

Composites containing gypsum-free cement features quick strength rise at the age between 1 and 3 days. Such property predestine gypsum-free cement concrete for repair of building constructions that are to be put into service as soon as possible. Repair of concrete-cement pavements and surfaces of similar character belongs to one of field of gypsum-free cement concrete application. Materials of these constructions shall comply not only with required strength characteristics but also with needed durability. That is why resistance to alternate frost, thawing and chemical deicing substances is the principal property of GFC concrete surface. Properties of gypsum-free cement concrete – whether fresh or hardened – are mainly affected by following factors: properties of gypsum-free cement (fineness of grinding, quantity of admixtures controlling initial setting time, clinker chemical composition) as well as mineralogical and chemical composition of natural compact aggregates, and water-cement ratio. Factors listed above are to be taken into account also during design of gypsum-free cement concrete composition. This article deals with design procedure concerning composition of concrete containing gypsum-free cement considering its specificities.

Influence of Curing on Physico-mechanical Properties of High Performance Concrete

The use of high performance concrete requires also obtaining knowledge about factors influencing physico-mechanical properties of concrete. The paper describes knowledge on selected factors of different types of curing influencing physico-mechanical properties of concrete, these are namely compressive strength, density of hardened concrete and modulus of elasticity obtained by ultrasonic impulse method. Influence of curing was monitored on industrially produced concrete class C80/95. Samples of concrete were placed in 3 different curing environment – standardized curing (95%, t=20 -- 20C), laboratory environment (=30-35%, t=20-250C) and finally at climatological station in winter season (February till April) It was proofed that there is significant influence on all samples but in different rate.

Design of HPC Composition from Point of View of Hydration Heat Development

The start of the 21st century represented High Performance Concrete (HPC) as one of the best materials for infrastructure construction. From the point of view of the behavior of HPC during setting and hardening time, hydration is a very important course of hydration heat liberation. Through relatively high, binder content in HPC it is often the inner temperature of concreted construction that rises up to critical temperature. Then owing to the temperature dilatation and negative tension formation of cracks begin in the concrete structure. In build praxis it is possible to affect hydration heat liberation by selecting optimal type of binder and by utilization of suitable type of superplasticizing admixture. This paper describes possibilities of utilization of isoperibolic calorimeters for assessment of intensity of hydration heat development for cement pastes and possibilities of practical application of these measurements in building practice.