|
|
The Study of Aditives and Admixture Influence on High-Performance Concrete Properties
Šiler, Pavel ; Bílek, Vlastimil (referee) ; Brandštetr, Jiří (referee) ; Havlica, Jaromír (advisor)
The aim of this work was to develop the method for the determination of the superperplasticizers (SP) content in the water solution. The method developed was then applied to study the SP adsorption on the individual components used for high-performance concrete and the influence of the temperature and pH values over this adsorption. Furthermore the influence of the water to binder ratio, SP, finely grounded granulated blast furnace slag, fly ash, silica fume, finely ground silica sand and bauxite on the hydration process was studied by means of isoperibolic, isothermal and solution calorimetry. The compressive and flexural strength of most samples used in calorimetric experiments was also determined.
|
|
|
The influence of aggregate on the properties of high performance concrete.
Bezděk, Ondřej ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
This bachelor thesis is focused on the influence of aggregates on the mechanical properties of high-performance concrete. The flexural strenght and the compressive strenght were observed after 1, 7 and 28 days. The process of hydratation was monitored using isoperibolic calorimetry. Laser particle size analysis of aggregates was also performed. As materials were used: Portland cement CEM I 42,5 R-Sc Mokrá, finelly ground silica sand, calcinated bauxite, fine test sand ČSN EN 196-1, medium test sand ČSN EN 196-1, rough test sand ČSN EN 196-1 and polycarboxylate superplasticizer Glenium Ace 40.
|
|
|
High performace cement composites with increased abrasion resistance
Baranov, Dmitry ; Šuleková, Nikola (referee) ; Novotný, Radoslav (advisor)
The bachelor thesis deals with the effect of addition of potassium hydroxide solutions of different concentrations to HPC composites. The study focused mainly on parameters important for the abrasion of the composite such as surface hardness, which was measured in two ways. The first is by using of a manual hardness tester, the second is by a notching method through a drill with a tungsten carbide crown. The samples with the highest concentration of potassium hydroxide had the best results. It was assumed that the cause could be a very thin (400 1000 nm) dense layer on the surface with a predominant content of sulfur and potassium compounds, which was shown on an electron microscope. In addition to the hardness of the surface, other mechanical properties important for cements were monitored. Samples with different KOH concentration were tested for compressive and flexural strength.
|
|
|
Reactive powder concretes (RPC) with polymer latexes
Petrů, Ludmila ; Koplík, Jan (referee) ; Šoukal, František (advisor)
This thesis deals with the effect of polymeric latexes on the properties of concrete based on reactive powders. Three types of commercial latexes were used for the preparation of the samples, namely Revacryl, Duvilax and Plextol. Revacryl AE 2091 is an aqueous dispersion of styrene-acrylate copolymer with a high content of solids. Duvilax BD-20 is a homopolymer polyvinyl acetate dispersion that does not contain fillers with plasticizers. Plextol X 4002 is an aqueous, self-setting acrylic emulsion with a high content of solids. These latexes were added to the samples at concentrations of 0,20; 0,40; 0,60; 1,20 and 2,50 %. To determine the effect of latex on processability, the flow rate of the fresh mixture was measured. The main objective was to determine the ballistic resistance of modified concretes based on reactive powders. The DOP test was used for the determination. Furthermore, the change in mechanical properties was determined by adding a polymer to concrete based on reactive powders. The improvement in properties is expected to be due to the formation of a polymer film and a polymer-cement co-matrix. To demonstrate the film formation, the microstructure of the samples was observed by a raster electron microscope.
|
|
|
The Study of Aditives and Admixture Influence on High-Performance Concrete Properties
Šiler, Pavel ; Bílek, Vlastimil (referee) ; Brandštetr, Jiří (referee) ; Havlica, Jaromír (advisor)
The aim of this work was to develop the method for the determination of the superperplasticizers (SP) content in the water solution. The method developed was then applied to study the SP adsorption on the individual components used for high-performance concrete and the influence of the temperature and pH values over this adsorption. Furthermore the influence of the water to binder ratio, SP, finely grounded granulated blast furnace slag, fly ash, silica fume, finely ground silica sand and bauxite on the hydration process was studied by means of isoperibolic, isothermal and solution calorimetry. The compressive and flexural strength of most samples used in calorimetric experiments was also determined.
|
|
|
The influence of aggregate on the properties of high performance concrete.
Bezděk, Ondřej ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
This bachelor thesis is focused on the influence of aggregates on the mechanical properties of high-performance concrete. The flexural strenght and the compressive strenght were observed after 1, 7 and 28 days. The process of hydratation was monitored using isoperibolic calorimetry. Laser particle size analysis of aggregates was also performed. As materials were used: Portland cement CEM I 42,5 R-Sc Mokrá, finelly ground silica sand, calcinated bauxite, fine test sand ČSN EN 196-1, medium test sand ČSN EN 196-1, rough test sand ČSN EN 196-1 and polycarboxylate superplasticizer Glenium Ace 40.
|
guest ::
