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Development of structural concrete with power plant ash
Ťažký, Martin ; Sokol, Pavel (referee) ; Hela, Rudolf (advisor)
Worldwide production of concrete is increasing, what has a negative environmental load of cement production. That is due to effort in building construction, also concrete production, greater use of the secondary raw materials. Fly ash is the most commonly used secondary raw material. His used has a very good impact on the economy and ecology of production and positively affects on the properties of concrete in both the fresh and hardened state. The aim of this bachelor's thesis was to improve its use in concrete, using a minimum void fraction of dry mix cement-fly ash.
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High-grade concrete using nanoparticles
Labaj, Martin ; Bodnárová, Lenka (referee) ; Hela, Rudolf (advisor)
The aim of this paper is to summarize and assess the possibility of using nanoparticles as additives in high performance concrete. These particles have the ability to improve the mechanical and physical properties of cement composites or even gave them brand new ones. Industrial use, however, is hampered by several obstacles. In particular, it is the task of effective incorporation of nanoparticles into the matrix, the health and environmental risks and, last but not least, the financial costs. The experimental part of the work deals with the first-mentioned problem, namely with dispersing carbon nanotubes in aqueous solution and their subsequent integration into the structure of cement mortar.
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SCC with secondary raw materials
Ťažká, Lucia ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
Bachelor thesis is focused on the possibility of using secondary raw materials and their application to the production of SCC. Large part deals with impurities of type I and its application results mainly from abroad. Furthermore, this work examines the impact of different types of impurities on the resulting concrete durability in various aggressive environments. The practical part is focused on the use of chemically non-reactive additives of type I instead of the commonly used additives of type II which are used to replace part of cement and the resulting design and manufacture of low-strength SCC using appropriate additives.
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Cement composite materials with polypropylene fibers
Preisner, Martin ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with summarizing the possible effects of the addition of polypropylene fibers, especially low temperature plasma treated on the properties of cement composites and concrete. They are given basic information and distribution of polypropylene fibers. It describes the finish polypropylene fiber low-temperature plasma. The experimental part focuses on the effect of dispersion of polypropylene fibers treated plasma in the cement matrix.
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High volume fly ash concrete
Kučera, Jakub ; Sokol, Pavel (referee) ; Hela, Rudolf (advisor)
Bachelor thesis consist of two parts. The aim of teoretical part is to explore possibilities of usage and properties of high volume fly ash concrete with 40 – 70 % cement replacement. To make an overview of development of strength, durability in various environments, reduction of heat evolution etc. The aim of the experimental part is to compare properties of various class concretes with various amount of fly ash.
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Special surface finish architectural concrete
Gajdoš, Jan ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
The aim of this work is to describe modern methods of finishing concrete with architectural division of the surfaces created in fresh and hardened state. In this work describes the various influences and their effects on the resulting surface such as concrete composition, method of storage or production and compaction of concrete. In the practical part of the thesis focuses on the technology of graphic concrete and its application to vertical monolithic wall.
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Study of the effect of concrete composition on the abrasion surfaces
Hoško, Marek ; Reiterman, Pavel (referee) ; Hela, Rudolf (advisor)
This work deals with summarizing knowledge on issues related to the loss of skid resistance properties of roads, which is caused by surface abrasion. Then indicates the relation between types of aggregates and paste volume to abrasion, impact compressive strength, aeration rate and different types of finishes. In the practical part were designed recipe CB II with different types of coarse aggregate. Samples were tested for abrasion method according to Böhm according to CSN 73 1324 Determination of abrasion of concrete.
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Properties of cementitious composites with plasma treated polymer fibers
Počekajlo, Václav ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
Modification of polymer fiber low temperature plasma is one of the ways to enhance the properties of modified fibers as follows. This work aims to evaluate the effect of plasma treated polypropylene fibers on the rheological properties of cement composites. The theoretical part describes the treatment and the effect of plasma treatment on polymer fibers. The influence of polypropylene fibers treated by low-temperature plasma on the workability of concrete. The practical part is described and evaluated experimental verification of the influence of the addition of commercially available fibers and fibers treated plasma on the rheological properties of fresh cement composite.
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Effect of fly ash on the durability of concrete
Vašek, Tomáš ; Kulísek, Karel (referee) ; Hela, Rudolf (advisor)
Bachelor thesis consists of two parts, theoretical and practical. In the theoretical section provides basic information on the manufacture of fly ash, development and principle of High Volume Fly Ash Concrete and view on this type of concrete in the Czech Republic. Listed below are the world´s knowledge of conduct of durability and potential problems that can act on them. The theoretical part ends with summary of the utilization of fly ash in various areas of construction industry. In the practical part compares the characteristics of each recipe containing fly ash with recipe containing only Portland cement. Finally, is evaluation of results of practical part and influence on the durability of fly ash concrete.
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