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Průša, David ; Žižková, Nikol (referee) ; Čermák, Jan (referee) ; Šuhajda, Karel (advisor)
In construction practice, microwave radiation is widely used for drying building materials, remediating damp masonry or sterilizing biotic pests that have invaded building structures. Another, albeit less frequent, use may be, for example, in accelerating the solidification of materials and components, where the time required to obtain the handling strength is reduced due to the effect of microwave radiation. The available scientific and technical literature indicates that some materials, such as brick elements, do not change their physical and mechanical properties when exposed to microwave radiation for moisture remediation, although this has not yet been sufficiently verified, and, in contrast, that there is a significant change in properties when microwave radiation is used to accelerate the setting of fresh mixtures, such as those containing a cementitious binder matrix. This thesis builds on many years of research in the area, complements and refines existing information, provides new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and compares them with reference values. It also provides an opportunity for further experiments that can build on this research. The experimental research was conducted on two independent sets of samples. The first experiment was carried out on a set of clay brick samples, using tests according to European standards, and focused on the effect of microwave radiation on compressive strength and water absorption. The experimental specimens were exposed to moisture followed by exposure to microwave radiation for drying and then compared with reference specimens. The data from these experiments suggest that microwave radiation can be used for the rehabilitation of brick elements and there is no significant change in the resulting mechanical properties with respect to the initial condition. The second experiment was carried out on a set of concrete mixtures, where the curing process was accelerated using microwave radiation, and the mechanical and physical properties obtained were compared with those of reference specimens. The data from this experiment suggest that microwave radiation can be used to accelerate the curing of concrete specimens, thereby obtaining the handling strength in a relatively short time, but a reduction in the resulting strength can be expected compared with reference specimens.
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Impact of injection on mechanical and physical characteristics of mortar
Fridrich, Pavel ; Myslín, Jiří (referee) ; Tomíček,, Oldřich (referee) ; Klečka,, Tomáš (referee) ; Tuza, Karel (advisor)
The increased moisture of the building materials causes the change of its mechanical and physical characteristic. In particular the high amount of loose water in construction shorten the lifetime of the building, is harmful to human beings due to biotic factors and increase the economic expenses of usage of the building. Apart from the costs of rehabilitation the loose water deteriorates the thermal insulative ability (thermal conductivity coefficient ) of perimeter masonry as well. The moisture gets into masonry not only through its deffects but also due to many different reasons. In order to improve the utility value of the buildings we have to deal with the rehabilitation of damp masonry with view to all possible causes. Only the properly working damp proofing ensures the protection against the water leaking from the subfoundation of the building. One of the direct techniques which have undergone rapid progress in last few years is the injection procedure. With use of experimental methods in my dissertation I deal with evaluation of two injection compounds used in Czech Republic and with its impact on the characteristics of the mortar. With the modern hollow bricks (system THERM) it is possible to create horizontal infusion into the lateral mortar grooves in future.
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Study of possibilities of optimalization of properties of alternative thermal insulating materials on natural base
Břicháček, Pavel ; Peterková, Jitka (referee) ; Zach, Jiří (advisor)
The presented work investigates the mechanisms of propagation of heat and moisture in the structure of heat-insulating materials based on natural fibers. The main aim of this work is the experimental verification of theoretical patterns, which are involved in the transport of heat and moisture in fibrous materials, especially the influence of fibers thickness and density of the fibrous materials. To widen outputs of the work were selected different kinds of natural fiber materials of vegetable and animal origin. The results of the work should help to optimize the production processes of natural insulation materials considering their optimal thermal properties. From the data collected are deduced general conclusions to better understanding the behavior of these materials.
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The thermal conductivity of non-standard materials for HVAC
Běťák, Karel ; Rubinová, Olga (referee) ; Uher, Pavel (advisor)
The thesis is focused on the determination of the thermal conductivity coefficient on the group of thermoplastics used for 3D printing (PLA, ABS, PETG). The thesis describes the materials used for 3D printing and the design of air conditioning for the grocery store. A stationary method was used for the solution. The heat flux passing through the sample was measured and the thermal conductivity coefficient was calculated. By the chosen method, we determined the coefficient is = 0,11-0,13 W/(m·K). Comparison with the available results of other methods and authors has shown that the resulting coefficient is lower. Based on the data, it is possible to compare the thermal properties of 3D printing materials.
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New Additional Industrial Insulation Systems for High Temperatures
Pániková, Juliana ; Kulísek, Karel (referee) ; Drochytka, Rostislav (advisor)
This bachelor´s thesis deals with the theoretical suggestion for external thermal insulation composite system with higher heat resistance. Here are briefly described appropriately selected materials with insulating properties and the most commonly used technology of prefabricated components. The practical part deals with theoretical calculations of heat transmission and suggestions for possible compositions including anchoring system and surface treatments.
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Development of thermal a acoustic insulations based on secondary raw sources from textil industry
Kosturová, Andrea ; Třísko, Pavel (referee) ; Zach, Jiří (advisor)
The objective of the presented diploma thesis is to evaluate the influence of modification on surface layer of products with their base structure from organical fibers and on the ability to resist increased humidity. Emphasis is puted on the description of humidity propagation in fiber materials ant he approximation of secondary waste from the textile industry as a potencional material for thermal insulation. The end of the theoretical part focuses on the types of possible surface treatment to prevent the ingress water into the structure of the material. The practical part verifies the selected type of modification of the surface layer of three materials choosen as test ensemble. After applying surface treatment, the effect of treatment on humidity sensitivity and water absorption was assessed. The determination of the thermal conductivity coefficient, the short-term absorption at partial immersion and the determination of the sorption humidity were made.
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Development of thermal a acoustic insulations based on secondary raw sources from textil industry
Kosturová, Andrea ; Třísko, Pavel (referee) ; Zach, Jiří (advisor)
The objective of the presented diploma thesis is to evaluate the influence of modification on surface layer of products with their base structure from organical fibers and on the ability to resist increased humidity. Emphasis is puted on the description of humidity propagation in fiber materials ant he approximation of secondary waste from the textile industry as a potencional material for thermal insulation. The end of the theoretical part focuses on the types of possible surface treatment to prevent the ingress water into the structure of the material. The practical part verifies the selected type of modification of the surface layer of three materials choosen as test ensemble. After applying surface treatment, the effect of treatment on humidity sensitivity and water absorption was assessed. The determination of the thermal conductivity coefficient, the short-term absorption at partial immersion and the determination of the sorption humidity were made.
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The thermal conductivity of non-standard materials for HVAC
Běťák, Karel ; Rubinová, Olga (referee) ; Uher, Pavel (advisor)
The thesis is focused on the determination of the thermal conductivity coefficient on the group of thermoplastics used for 3D printing (PLA, ABS, PETG). The thesis describes the materials used for 3D printing and the design of air conditioning for the grocery store. A stationary method was used for the solution. The heat flux passing through the sample was measured and the thermal conductivity coefficient was calculated. By the chosen method, we determined the coefficient is = 0,11-0,13 W/(m·K). Comparison with the available results of other methods and authors has shown that the resulting coefficient is lower. Based on the data, it is possible to compare the thermal properties of 3D printing materials.
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Impact of injection on mechanical and physical characteristics of mortar
Fridrich, Pavel ; Myslín, Jiří (referee) ; Tomíček,, Oldřich (referee) ; Klečka,, Tomáš (referee) ; Tuza, Karel (advisor)
The increased moisture of the building materials causes the change of its mechanical and physical characteristic. In particular the high amount of loose water in construction shorten the lifetime of the building, is harmful to human beings due to biotic factors and increase the economic expenses of usage of the building. Apart from the costs of rehabilitation the loose water deteriorates the thermal insulative ability (thermal conductivity coefficient ) of perimeter masonry as well. The moisture gets into masonry not only through its deffects but also due to many different reasons. In order to improve the utility value of the buildings we have to deal with the rehabilitation of damp masonry with view to all possible causes. Only the properly working damp proofing ensures the protection against the water leaking from the subfoundation of the building. One of the direct techniques which have undergone rapid progress in last few years is the injection procedure. With use of experimental methods in my dissertation I deal with evaluation of two injection compounds used in Czech Republic and with its impact on the characteristics of the mortar. With the modern hollow bricks (system THERM) it is possible to create horizontal infusion into the lateral mortar grooves in future.
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