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Effect of curing conditions on the properties of alkali activated slag
Rypák, Peter ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Combination of fine ground granulated slag with proper alkaline activator gives alkali-activated slag – a material with remarkable properties. Theoretical part of the thesis deals with summarizing basic informations about alkali-activated slag, its properties, production and utilization. It also follows research devoted to effects of curing of alkali activated slag and shrinkage-reducing admixtures on its properties. Objective of the experimental part is to determine the influence of curing conditions on the mechanical properties and microstructure of alkali-activated slag. These properties are also monitored in alkali-activated slag with carbon nanotubes and hydroxypropylmethylcellulose as an shrinkage-reducing admixtures.
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Utilization of by-pass cement kiln dust in alkali activated materials
Kiripolský, Tomáš ; Beranová, Denisa (referee) ; Kalina, Lukáš (advisor)
By-pass cement kiln dust (CKD) is a fine grained by-product of Portland clinker manufacturing. Its chemical composition is not suitable for the returning back into the feedstock and therefore has to be discharged. Such the increasing waste production contributes to lowering of the environmental impact of cement industry. The possible solution for the ecological processing of CKD is its incorporation into alkali activated blast furnace slag binders. Thanks to the high alkaline content, CKD serves as an effective accelerator for the latent hydraulic substance and at the same time solves the significant shrinkage of alkali activated materials which considerably limiting their practical applications. It was found out that the suitable amount of CKD (20 % replacement of slag) in combination with sodium carbonate increases the compressive strength development of about 10 % and reduces the drying shrinkage (11 % reduction). On the other hand this type of inorganic admixture accelerated the hydration process resulting in rapid loss of workability and shortening the initial setting time. The mechanism of action of CKD in alkali activated matrix has been investigated as well as its optimal dosage in the means of mechanical properties.
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Utilization of by-pass cement kiln dust in alkali activated materials
Kiripolský, Tomáš ; Beranová, Denisa (referee) ; Kalina, Lukáš (advisor)
By-pass cement kiln dust (CKD) is a fine grained by-product of Portland clinker manufacturing. Its chemical composition is not suitable for the returning back into the feedstock and therefore has to be discharged. Such the increasing waste production contributes to lowering of the environmental impact of cement industry. The possible solution for the ecological processing of CKD is its incorporation into alkali activated blast furnace slag binders. Thanks to the high alkaline content, CKD serves as an effective accelerator for the latent hydraulic substance and at the same time solves the significant shrinkage of alkali activated materials which considerably limiting their practical applications. It was found out that the suitable amount of CKD (20 % replacement of slag) in combination with sodium carbonate increases the compressive strength development of about 10 % and reduces the drying shrinkage (11 % reduction). On the other hand this type of inorganic admixture accelerated the hydration process resulting in rapid loss of workability and shortening the initial setting time. The mechanism of action of CKD in alkali activated matrix has been investigated as well as its optimal dosage in the means of mechanical properties.
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Effect of curing conditions on the properties of alkali activated slag
Rypák, Peter ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Combination of fine ground granulated slag with proper alkaline activator gives alkali-activated slag – a material with remarkable properties. Theoretical part of the thesis deals with summarizing basic informations about alkali-activated slag, its properties, production and utilization. It also follows research devoted to effects of curing of alkali activated slag and shrinkage-reducing admixtures on its properties. Objective of the experimental part is to determine the influence of curing conditions on the mechanical properties and microstructure of alkali-activated slag. These properties are also monitored in alkali-activated slag with carbon nanotubes and hydroxypropylmethylcellulose as an shrinkage-reducing admixtures.
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