RESISTANCE OF MORTARS WITH GYPSUM, LIME AND COMPOSITE BINDERS AGAINST MOLDS

Resistance of three mortars (the lime mortar, the gypsum mortar and the mortar with the composite binder) against molds was evaluated. Mortars were also compared according to their pH, bulk density, strength and porosity. Experiments showed that the lime mortar has the best resistance against molds and the lowest bending and compressive strength. The mortar with the composite binder has better mold resistance and higher bending and compressive strength than the gypsum mortar

EXPERIMENTAL AND NUMERICAL INVESTIGATION OF CEMENT PASTE MICROSTRUCTURE AND ITS HYDRATION UNDER SHORT-TERM EXPOSURE TO ACETONE

The solvent exchange methods are commonly used in order to arrest cement hydration reaction. This paper presents preliminary results of experimental investigation of cement paste microstructure under short-term (24 hours) exposure to acetone as a solvent in order to estimate the influence of solvent soaking time. The methodology to determine the effect of soaking time based on numerical prediction is also presented and described. The immersion of cement samples with the cross-section of 10×10 mm in acetone for 24 hours at the sample age of 15 hours does not enable to fully stop the hydration reaction, however, it can slow down the hydration reaction significantly. According to the comparison of several measured data (nanoindentation, scanning electron microscopy, observation made by optical microscope, mercury intrusion porosimetry) at the sample age of 1 month with the numerical simulation, the equivalent sample age is determined as approximately equal to 69 hours

Experimental analysis of micro-cracks on the change of moisture transport properties of AAC

In this paper, series of experiment measurements is carried out in order to study effect of freeze/thaw loading on the change of moisture transport properties of autoclaved aerated concrete. The samples were subjected to 15, 30 and 45 freeze/thaw cycles and subsequently basic physical properties, pore size distribution and water vapor and liquid water transport properties were investigated. The results showed significant changes in material properties of the material. The results of this research can be further implemented into computational models in order to bring the simulation results closer to the reality

Body composition parameters in dependence on the metabolism degree in patients with COPD

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Student: Magdaléna Doleželová Supervisor of master thesis: PharmDr. Miroslav Kovařík, Ph.D. Title of master thesis: Body composition parameters in dependence on the metabolism degrese in patiens with COPD Chronic Obstructive Pulmonary Disease (COPD) is a very serious illness characterized by incompletely reversible airflow obstruction and lung emphysema. Contributes to its overall severity are extrapulmonary manifestations, especially cachexia and loss of lean tissue mass. Chronic inflammation of the respiratory airways and increased respiratory effort cause the hypermetabolic state to some patients with COPD. This thesis investigates the impact of increased metabolism on body composition in patients with COPD. Our study included 50 COPD patients (38 men, 12 women) who were examined by bioelectrical impedance. In this study, we compared the parameters of body composition of men with resting energy expenditure REE > 130% (hereinafter Men over 130%) (n = 9) and the group of men with REE < 130 % (hereinafter Men below 130 %) (n = 29). In the group of Men over 130 % we found a lower average value of body weight by 18 % compared to Men below 130 %. Total body and intracellular water were 12 %..

Body composition parameters in dependence on the metabolism degree in patients with COPD

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Student: Magdaléna Doleželová Supervisor of master thesis: PharmDr. Miroslav Kovařík, Ph.D. Title of master thesis: Body composition parameters in dependence on the metabolism degrese in patiens with COPD Chronic Obstructive Pulmonary Disease (COPD) is a very serious illness characterized by incompletely reversible airflow obstruction and lung emphysema. Contributes to its overall severity are extrapulmonary manifestations, especially cachexia and loss of lean tissue mass. Chronic inflammation of the respiratory airways and increased respiratory effort cause the hypermetabolic state to some patients with COPD. This thesis investigates the impact of increased metabolism on body composition in patients with COPD. Our study included 50 COPD patients (38 men, 12 women) who were examined by bioelectrical impedance. In this study, we compared the parameters of body composition of men with resting energy expenditure REE > 130% (hereinafter Men over 130%) (n = 9) and the group of men with REE < 130 % (hereinafter Men below 130 %) (n = 29). In the group of Men over 130 % we found a lower average value of body weight by 18 % compared to Men below 130 %. Total body and intracellular water were 12 %..

The hygrothermal performance of concrete with coarse aggregates made of recycled concrete pavements

This paper deals with an investigation of the hygrothermal performance of concretes containing various amounts of recycled aggregates originating from crushed concrete pavements. The performance, which was obtained using computational modelling of coupled heat and moisture transport, is predicted on stand-alone samples as well as on built in samples in a real construction exposed to weather data of Ostrava, Czech Republic. The results revealed that the influence of recycled aggregates as substitution for natural stone does not negatively affect the hygrothermal performance of the concrete. The highest difference found was less than 1°C and 12% of RH in the case of stand-alone samples and only 2.2% of RH when built in. Therefore, the application of crushed concrete pavements as aggregates in concrete composition can be highly recommended as it brings other benefits such as economical and environmental

The hygrothermal performance of concrete with coarse aggregates made of recycled concrete pavements

This paper deals with an investigation of the hygrothermal performance of concretes containing various amounts of recycled aggregates originating from crushed concrete pavements. The performance, which was obtained using computational modelling of coupled heat and moisture transport, is predicted on stand-alone samples as well as on built in samples in a real construction exposed to weather data of Ostrava, Czech Republic. The results revealed that the influence of recycled aggregates as substitution for natural stone does not negatively affect the hygrothermal performance of the concrete. The highest difference found was less than 1°C and 12% of RH in the case of stand-alone samples and only 2.2% of RH when built in. Therefore, the application of crushed concrete pavements as aggregates in concrete composition can be highly recommended as it brings other benefits such as economical and environmental

Basic Physical, Mechanical, Thermal and Hygric Properties of Concrete with Coarse Aggregates Fabricated from Recycled Concrete Pavements

Concrete production unfavourably affects the environment due to high energy demands of cement production and consumption of limited natural resources. Therefore, waste utilization in fabrication of cementitious material is beneficial and legitimate. Significant reduction of environmental impact can be secured by utilization of various types of wastes or byproducts used for a partial substitution of cement binder or aggregates. However, the use of waste materials usually leads to deterioration of material properties of the designed composites. Therefore, it is very important to thoroughly investigate important materials properties to verify performance and practical usability of the newly designed materials. In this paper, three types of concrete mixes were designed. The reference concrete involved fine and coarse natural riverbed aggregates and two other mixes were designed using both, natural and recycled aggregates represented by crushed concrete paving cobbles. Concretes were tested in terms of basic physical properties (bulk density), mechanical properties (compressive strength), thermal properties (thermal conductivity, specific heat capacity, thermal diffusivity), and hygric properties (water vapour diffusion resistance factor, water vapour sorption at 97% RH, water absorption coefficient, moisture diffusivity) and experimentally determined data were compared and discussed. It was observed that materials properties of concretes with recycled aggregates are comparable with those of the reference concrete which is a promising fact from the environmental point of view

Basic Physical, Mechanical, Thermal and Hygric Properties of Concrete with Coarse Aggregates Fabricated from Recycled Concrete Pavements

Concrete production unfavourably affects the environment due to high energy demands of cement production and consumption of limited natural resources. Therefore, waste utilization in fabrication of cementitious material is beneficial and legitimate. Significant reduction of environmental impact can be secured by utilization of various types of wastes or byproducts used for a partial substitution of cement binder or aggregates. However, the use of waste materials usually leads to deterioration of material properties of the designed composites. Therefore, it is very important to thoroughly investigate important materials properties to verify performance and practical usability of the newly designed materials. In this paper, three types of concrete mixes were designed. The reference concrete involved fine and coarse natural riverbed aggregates and two other mixes were designed using both, natural and recycled aggregates represented by crushed concrete paving cobbles. Concretes were tested in terms of basic physical properties (bulk density), mechanical properties (compressive strength), thermal properties (thermal conductivity, specific heat capacity, thermal diffusivity), and hygric properties (water vapour diffusion resistance factor, water vapour sorption at 97% RH, water absorption coefficient, moisture diffusivity) and experimentally determined data were compared and discussed. It was observed that materials properties of concretes with recycled aggregates are comparable with those of the reference concrete which is a promising fact from the environmental point of view