|
| |
|
|
The use of Electrical Properties of Composites with Modified Cement Matrix
Macháň, Ladislav ; Husák, Miroslav (referee) ; Sýkora, Jiří (referee) ; Šteffan, Pavel (advisor)
The dissertation thesis is focused on practical use of composite material with modified cement matrix. Especially the area of electrical behavior of composite materials in use has been examined, for strain sensing material. The experimental part solves the problematics of corrosion of carbon and metallic materials in alkaline environment of the cement matrix. The physical design of the sensor and its fabrication using functional composite cement material have been described here. The thesis has also discussed defining the influence of temperature change and humidity change on the change of electrical parameters of integrated sensors. An important part of the thesis is the area of evaluating a series of measurements of electrical parameters under dynamic loading. The thesis analyzes designed measurement method in detail, being suitable to determine electrical properties of cement composite materials including the construction of a monitoring system that enables practical application of sensors in complex structures.
|
|
|
Development of new types of composites for concrete rehabilitation with increased protection reinforcement
Taranza, Luboš ; Durica,, Tibor (referee) ; Dohnálek,, Pavel (referee) ; Bydžovský, Jiří (referee) ; Drochytka, Rostislav (advisor)
Around the world there is a great number of reinforced concrete structures, who´s life cycle, for which they were designed, is significantly shortened due to action of various aggressive environments, or due to defects created during the construction process. (i.e. insufficient steel reinforcement cover depth). One of the most common causes of problems in reinforced concrete structures is corrosion of steel reinforcement. It is necessary to repair structures degraded in this fashion and return them to their original state. We made a unique polymercement concrete repair system was developed with value added. Corrosion inhibitors, including the newly developed, are implemented into its polymercement matrix, which significantly limit the corrosive processes in all new materials. The principle of proposed solution is application of repair system on a corrosion damaged structure, and then the active substances in the repair material will penetrate into substrate concrete and protect corroded steel reinforcement. Another value added is the application of recycled raw materials into the proposed materials, which has indisputable environmental effect and simultaneously allows for improvement of some properties of the repair materials. Further was developed a new method for detecting corrosion inhibitors in concrete.
|
|
| |
|
|
Determination of inorganic corrosion inhibitors by ion chromatography
Kapiasová, Anna ; Kubíčková, Anna (advisor) ; Kozlík, Petr (referee)
Corrosion inhibitors are substances that prevent the internal surface of the cooling system from corrosion. Inorganic corrosion inhibitors contain inorganic anions that passivate the surface, thereby preventing the diffusion of oxygen into the system and protecting the surface from oxidation. This study is aimed at the development and validation of a method for the determination of inorganic corrosion inhibitors (specifically chlorides, nitrites, nitrates, hydrogen phosphates, sulfates and molybdates) by ion chromatography. The optimal separation of anions was achieved with a mobile phase consist of 3.3 mM sodium carbonate and 3.3 mM sodium bicarbonate (pH= 10.1) at 45 řC using the column Metrosep A Supp 7 (250 × 4.0 mm with particle size of 5 µm) (Metrohm, Switzerland). Under these conditions the analysis took 48 minutes. After validation, the method was used to determine corrosion inhibitors in real coolant samples. The peaks of the individual anions contained in the coolants were verified by spiking with standards of anions. The anion concentrations were determined from the areas of these peaks using the calibration curves. Key words ion chromatography, engine coolants, corrosion inhibitors, inorganic ions
|
|
|
Development of the electrophoretic method for determination of phosphates and borates in cooling mixtures
Listakhava, Iryna ; Křížek, Tomáš (advisor) ; Kubíčková, Anna (referee)
In this diploma thesis, a method of routine analysis of commercial coolants was developed, focused on the simultaneous determination of inorganic anions - phosphates and borates - as corrosion inhibitors in fresh mixtures and the markers of recycling quality. The method was developed for the instrumental technique of capillary zone electrophoresis with indirect detection at 254 nm. The following were optimized: background electrolyte (its composition, concentration, pH), measured samples (coolant dilution, suitable internal standard) and measurement conditions (capillary length, sample dosing). The influence of the sample matrix on the measurement results, the robustness of the calibration line (or the agreement of the response with the actual analyte concentration) and also the repeatability of the method were tested. Optimizations and tests resulted in a method based on a standard addition with the following parameters: background electrolyte of pH = 11.50 containing sodium chromate at 10 mmol l-1 concentration and CTAB at 1 mmol l-1 concentration; dilution of the coolant sample 20-50×, addition of internal standard MES at 0,1 mmol l-1 concentration, electrokinetic sample injection at -5 kV for 10 s, capillary length 50.0 cm, inner diameter 75 μm. The repeatability of the method expressed as a...
|
|
|
Electrophoretical determination of corrosion inhibitors in engine coolants
Smrž, Dominik ; Kubíčková, Anna (advisor) ; Coufal, Pavel (referee)
A determination of corrosion inhibitors in engine coolants represent a difficult analytical problem due to their different physicochemical properties. Nowadays a lot of instrument methods are needed to determine them. The aim of this work was the development of methods for their determination using only one instrumentation. Capillary zone electrophoreses was chosen as a suitable technique. Three electrophoretic methods for three groups of corrosion inhibitors were developed. Firstly, method for determination of inorganic anions was developed in range from 5 to 50 ppm with limit of detection around 1 ppm. Background electrolyte contains sodium chromate, CTAB and CHES solution. Analytes were detected indirectly at 450 nm. Another method was for determination of organic acids anions. They were determined in range from 5 to 500 ppm. Limit of detection for each analyte was around 1 ppm. Measurement was made with PDC a CTAC water solution. Indirect detection was used for this determination at 350 nm. Last developed method can be use for determination of aryltrizoles in range from 5 to 500 ppm. Limit of detection was around 1 ppm. As a background electrolyte was used sodium tetraborate solution. The developed methods were validated and their suitability for determination of corrosion inhibitors in real...
|
|
|
Development of new types of composites for concrete rehabilitation with increased protection reinforcement
Taranza, Luboš ; Durica,, Tibor (referee) ; Dohnálek,, Pavel (referee) ; Bydžovský, Jiří (referee) ; Drochytka, Rostislav (advisor)
Around the world there is a great number of reinforced concrete structures, who´s life cycle, for which they were designed, is significantly shortened due to action of various aggressive environments, or due to defects created during the construction process. (i.e. insufficient steel reinforcement cover depth). One of the most common causes of problems in reinforced concrete structures is corrosion of steel reinforcement. It is necessary to repair structures degraded in this fashion and return them to their original state. We made a unique polymercement concrete repair system was developed with value added. Corrosion inhibitors, including the newly developed, are implemented into its polymercement matrix, which significantly limit the corrosive processes in all new materials. The principle of proposed solution is application of repair system on a corrosion damaged structure, and then the active substances in the repair material will penetrate into substrate concrete and protect corroded steel reinforcement. Another value added is the application of recycled raw materials into the proposed materials, which has indisputable environmental effect and simultaneously allows for improvement of some properties of the repair materials. Further was developed a new method for detecting corrosion inhibitors in concrete.
|
|
|
The use of Electrical Properties of Composites with Modified Cement Matrix
Macháň, Ladislav ; Husák, Miroslav (referee) ; Sýkora, Jiří (referee) ; Šteffan, Pavel (advisor)
The dissertation thesis is focused on practical use of composite material with modified cement matrix. Especially the area of electrical behavior of composite materials in use has been examined, for strain sensing material. The experimental part solves the problematics of corrosion of carbon and metallic materials in alkaline environment of the cement matrix. The physical design of the sensor and its fabrication using functional composite cement material have been described here. The thesis has also discussed defining the influence of temperature change and humidity change on the change of electrical parameters of integrated sensors. An important part of the thesis is the area of evaluating a series of measurements of electrical parameters under dynamic loading. The thesis analyzes designed measurement method in detail, being suitable to determine electrical properties of cement composite materials including the construction of a monitoring system that enables practical application of sensors in complex structures.
|
|
| |
guest ::
