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Ballistic-Proof Concretes
Koutný, Ondřej ; Bílek,, Vlastimil (referee) ; Keršner, Zbyněk (referee) ; Ptáček, Petr (advisor)
Doctoral thesis „Ballistic-proof concretes“ deals with description, design and development of material based on ultra-high performance fibre reinforced cementitious composite with increased ballistic resistance i.e. increased resistance against high-strain rate dynamic loading induced by interaction of high-velocity moving objects. High mechanical properties, essential for such a material, are reached especially by maximal reduction of water-to-binder coefficient using high-range water reducing agents, high-strength aggregates and dense structure by precise selection and dosage of raw materials in the recipe. The main goal is to prepare a methodology for design of such a materials, observation of material behaviour on ballistic loading and quantitative description of material response for protective structures design. Properties of designed materials within this thesis are comparing with properties of commercially available and commonly used cementitious composites in order to create a concept for material limits in the field of ballistic protection. This concept enables to estimate ballistic protection of present or newly-designed materials and structures.
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Reactive powder concretes (RPC) with redispersible polymer powders
Ondrůšková, Nela ; Másilko, Jiří (referee) ; Šoukal, František (advisor)
The thesis entitled "Reactive Powder Concretes (RPC) with Redispersible Powder Polymers" deals with the description, design and development of a material with increased ballistic resistance, i.e. with increased resistance to high-speed dynamic stresses due to interaction with a projectile. The high mechanical properties of RPC are achieved mainly by reducing the water coefficient, using a large dose of superplasticizers and high strength aggregates to achieve the densest possible structure. The aim of this work is to investigate the effect of addition of redispersible powder polymer to RPC composite and to find the optimum type and amount of polymer to form a co-matrix, thus improving material properties such as flexural tensile strength and toughness. The preparation, procedure and processing of each formulation are described in each chapter, and the properties of these materials and observations of their behaviour under ballistic loading are described. Experimentally, the thesis focused on monitoring the effect of polymer type and amount, particularly on the change in bulk density and on compressive and flexural tensile strength. The results obtained for the different formulations were compared with each other and related to a reference. SEM analysis was performed to monitor the polymer film formation in the matrix. Based on the tests, two formulations with the best comprehensive properties were selected. These two formulations were subjected to DOP ballistic test.
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Ballistic-Proof Concretes
Koutný, Ondřej ; Bílek,, Vlastimil (referee) ; Keršner, Zbyněk (referee) ; Ptáček, Petr (advisor)
Doctoral thesis „Ballistic-proof concretes“ deals with description, design and development of material based on ultra-high performance fibre reinforced cementitious composite with increased ballistic resistance i.e. increased resistance against high-strain rate dynamic loading induced by interaction of high-velocity moving objects. High mechanical properties, essential for such a material, are reached especially by maximal reduction of water-to-binder coefficient using high-range water reducing agents, high-strength aggregates and dense structure by precise selection and dosage of raw materials in the recipe. The main goal is to prepare a methodology for design of such a materials, observation of material behaviour on ballistic loading and quantitative description of material response for protective structures design. Properties of designed materials within this thesis are comparing with properties of commercially available and commonly used cementitious composites in order to create a concept for material limits in the field of ballistic protection. This concept enables to estimate ballistic protection of present or newly-designed materials and structures.
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