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New possibilities of using superabsorbent polymers in cement composites
Holubová, Petra ; Melichar, Jindřich (referee) ; Černý, Vít (advisor)
The work deals with the influence of superabsorbent polymers (SAP) on the structure and properties of cement composites. SAPs excel in their unique ability to hold large amounts of water. This property can be used in hydration processes for internal curing of concrete. Two types of mixtures were tested in cement paste, which were further modified by two types of SAP. SAPs were always used in two dosing modes (dry, in suspension). The samples were then stored for 28 days in a laboratory conditions, respectively. in an conditions with a temperature of 30 °C. Physical and mechanical properties, such as compressive strength, flexural tensile strength and bulk density, were determined. The addition of SAP to the mixture resulted in an increase in tensile strength of almost twofold. It can therefore be concluded that SAP helped with hydration processes.
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The rate of repeated capture and release of water by a mixed recyclate of disposable diapers and its individual components
Březinová, Štěpánka ; Ondreáš, František (referee) ; Jančář, Josef (advisor)
This bachelor’s thesis focuses on the recycling of disposable diapers. The waste from disposable diapers could be potentially used again and it is also a more ecological solution than incineration of this waste. The process of recycling separates individual parts of the diaper so they could be used again. In this bachelor’s thesis, the product of recycling is a recycled material that is composed of cellulose and sodium polyacrylate. Sodium polyacrylate is one of the superabsorbent polymers that have great absorptive qualities. The resulting recycled material has the same qualities as well. In the experimental part of this bachelor’s thesis, the recycled material is analyzed and the absorptive and desorptive qualities are compared with the qualities of sodium polyacrylate.
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The usability of secondary raw materials in the design of liquefied suspensions based on soil
Hrubý, Jakub ; Kulísek, Karel (referee) ; Černý, Vít (advisor)
The bachelor's thesis deals with the usability of secondary raw materials in the design of liquefied suspensions based on soils in the form of self-compacting grouts. The soil treated in this way can be used as a substitute for backfill material for excavations of engineering networks. The theoretical part deals with the classification and description of soils. Furthermore, the types of soil stabilization using lime, cement, including their liquefaction, are mentioned. A wide range of potentially suitable secondary raw materials and liquefaction mechanization is presented. In the practical part, the basic soil F6-Cl is selected on the basis of a set of available soils. The basic reference mixture consists of soil, lime, cement and liquefier. A proposal for the concept of experimental verification is presented. Part of the concept is the automated calculation of input raw materials. The effect of the action of the superabsorbent polymer and the accelerating additive is verified. Based on optimization selections, functional secondary raw materials are selected. The basic recipe with the optimal amount of accelerating ingredient achieves the best results. Recycled concrete and brick generally improve the resulting parameters. Bed ash achieves the highest strength with the lowest shrinkage.
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New possibilities of using superabsorbent polymers in cement composites
Holubová, Petra ; Melichar, Jindřich (referee) ; Černý, Vít (advisor)
The work deals with the influence of superabsorbent polymers (SAP) on the structure and properties of cement composites. SAPs excel in their unique ability to hold large amounts of water. This property can be used in hydration processes for internal curing of concrete. Two types of mixtures were tested in cement paste, which were further modified by two types of SAP. SAPs were always used in two dosing modes (dry, in suspension). The samples were then stored for 28 days in a laboratory conditions, respectively. in an conditions with a temperature of 30 °C. Physical and mechanical properties, such as compressive strength, flexural tensile strength and bulk density, were determined. The addition of SAP to the mixture resulted in an increase in tensile strength of almost twofold. It can therefore be concluded that SAP helped with hydration processes.
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|
|
The rate of repeated capture and release of water by a mixed recyclate of disposable diapers and its individual components
Březinová, Štěpánka ; Ondreáš, František (referee) ; Jančář, Josef (advisor)
This bachelor’s thesis focuses on the recycling of disposable diapers. The waste from disposable diapers could be potentially used again and it is also a more ecological solution than incineration of this waste. The process of recycling separates individual parts of the diaper so they could be used again. In this bachelor’s thesis, the product of recycling is a recycled material that is composed of cellulose and sodium polyacrylate. Sodium polyacrylate is one of the superabsorbent polymers that have great absorptive qualities. The resulting recycled material has the same qualities as well. In the experimental part of this bachelor’s thesis, the recycled material is analyzed and the absorptive and desorptive qualities are compared with the qualities of sodium polyacrylate.
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The usability of secondary raw materials in the design of liquefied suspensions based on soil
Hrubý, Jakub ; Kulísek, Karel (referee) ; Černý, Vít (advisor)
The bachelor's thesis deals with the usability of secondary raw materials in the design of liquefied suspensions based on soils in the form of self-compacting grouts. The soil treated in this way can be used as a substitute for backfill material for excavations of engineering networks. The theoretical part deals with the classification and description of soils. Furthermore, the types of soil stabilization using lime, cement, including their liquefaction, are mentioned. A wide range of potentially suitable secondary raw materials and liquefaction mechanization is presented. In the practical part, the basic soil F6-Cl is selected on the basis of a set of available soils. The basic reference mixture consists of soil, lime, cement and liquefier. A proposal for the concept of experimental verification is presented. Part of the concept is the automated calculation of input raw materials. The effect of the action of the superabsorbent polymer and the accelerating additive is verified. Based on optimization selections, functional secondary raw materials are selected. The basic recipe with the optimal amount of accelerating ingredient achieves the best results. Recycled concrete and brick generally improve the resulting parameters. Bed ash achieves the highest strength with the lowest shrinkage.
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