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The Modulus of Elasticity of Air-Entrained and Non-Air-Entrained Concrete
Tichý, Aleš ; Misák, Petr (referee) ; Kocáb, Dalibor (advisor)
The bachelor thesis deals with the verification of the degree of influence of the air-entraining admixture on the modulus of elasticity of concrete. The experiment was carried out for these purposes. The values of static and dynamic modulus of elasticity were determined on drilled cores from concrete blocks of different mixtures. The magnitudes of dynamic modulus of elasticity were determined by using an ultrasonic pulse velocity method and a resonance method. The results are summarized in tabular and graphical form.
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The issue of determination of the static modulus of elasticity of concrete in structures
Halamová, Romana ; Misák, Petr (referee) ; Kocáb, Dalibor (advisor)
The thesis deals with the measurement of the elastic modulus of concrete in existing structures and possibilities of applicability of equations for the calculation of characteristic values of concrete compressive strength on the modulus of elasticity. The modulus of elasticity is determined by dynamic and static methods on specimens taken from the concrete blocks, whose composition varies by a water cement ratio and varying amounts of admixtures. In conclusion, the results of the measurements are compared and the characteristic values of the modulus of elasticity is determined.
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Comparison of dynamic modulus of elasticity repair materials exposed to thermal stress
Munduchová, Markéta ; Jakubík, Aleš (referee) ; Brožovský, Jiří (advisor)
Diploma thesis is composed of theoretical and practical part. In theoretical part there are findings related to structure changes of concrete exposed to high temperatures. Models used to simulate high temperature exposure of concrete are described in this thesis. Evaluation of internal structure damage is appropriate by using non-destructive methods, which determine dynamic modulus of elasticity in compression and tension. These methods includes ultrasonic impulse method and resonation method and therefore research was made of articles contains these methods. In experimental part of diploma thesis the test specimens was made from repair materials from UTHD and commercially produced repair materials. The test specimens were subjected to thermal load: 200, 400, 600, 800 °C. Damage of internal structure was examined by ultrasonic impulse method and resonation method.
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The Issue of testing shotcrete
Škapová, Pavla ; Hela,, Vlastimil (referee) ; Hubáček, Adam (advisor)
The master‘s thesis focuses on testing the shotcrete prepared in laboratory conditions. The main observed properties are compresive strenght of shotcrete and modulus of elasticity. The aim is assessment of methods for measuring those parameters. The calibrating correlations for strenght characteristics of shotcrete are given by obtaining the results of used methods. The shotcrete composition, amount and type of accelerating additive as well as economic aspect of using shotcrete is also assessed.
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Studying the behavior of concrete at high temperatures
Tillová, Jana ; Herka, Petr (referee) ; Bodnárová, Lenka (advisor)
This master‘s thesis is focused on the study of the behavior of cement concrete at high temperatures with a focus on monitoring the impact of aggregate and cement type. This work describes the processes in aggregates and cement matrix at high temperatures. The theoretical part describes the selestion of a suitable aggregate and cement for the surroundings with potential exposure to high temperatures. In the experimental part is given design of composition of a concrete with two types of aggregates and four cements. It has been suggested 8 recipes. Changes were observed densities, compressive strength and tensile strength in bending, calculate the velocity of propagation of waves with ultrasonic pulsed method. Also evaluated the appearance of the surface samples after thermal load – cracks on the surface and measure the maximum crack width.
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Influence of Air Entrainment and Curing on Development of Elastic Modulus of Concrete
Bartulíková, Radka ; Kucharczyková, Barbara (referee) ; Kocáb, Dalibor (advisor)
Master's thesis deals with influence of various factors on the concrete compressive strength and modulus of elasticity. This work concentrates mainly on the influence of early curing and air entrainment of concrete. One part of this work is the evaluation of laboratory measurement, which was carried out on cubes of standard and norm prisms. The development of elastic moduli was monitored in time to 730 days of age with respect to air entrainment and curing conditions. The second part of the experiment deals with a comparison of theoretical creep curves depending on the value of the modulus of elasticity based on different standards. Again, the air entrainment effect and influence of initial conditions are reflected.
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Testing early strength concrete by electronic tester
Holbová, Monika ; Kocáb, Dalibor (referee) ; Cikrle, Petr (advisor)
This project solves the creation of calibration relations for determining the compressive strength of early age concrete. It deals with news in the field of hardness methods. 36 samples were made for this experiment and tested by ultrasound and by impact hammer SilverSchmidt type L with Mushroom Plunger. The result is set of calibration relations for determining of compressive strength for different methods and their combinations.
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Detection of Failures and cavities in structures using radar
Tkadleček, Petr ; Anton, Ondřej (referee) ; Cikrle, Petr (advisor)
The bachelor‘s thesis describes non-destructive testing and methods, which are used in civil engineering. It is focused on the detection of failures and cavities in concrete structures. In the first part the methods are described and compared. The second part describes experimental measurements on concrete structures, which contain failures. The results are described and interpreted. The used methods are compared. It was evaluated, which of these methods is suitable for the detection of failures and cavities in structures.
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Comparison of elastic moduli of building materials
Ballon, Marek ; Hubáček, Adam (referee) ; Brožovský, Jiří (advisor)
The bachelor thesis deals with the detection of static and dynamic elastic moduli of building materials, their comparison and overview of the relationships between them. Describes methods for the determination of static modulus of elasticity in the press loading and dynamic modulus of elasticity obtained by non-destructive methods, including ultrasonic pulse method and resonance method.
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Comparison of selected parameters of tensile strength of concrete
Rozsypalová, Iva ; Žítt, Petr (referee) ; Daněk, Petr (advisor)
The thesis deals with a comparison of the selected strength tension properties of the hardened concrete and finding relationships between them. This is essentially a simple tensile strength, tensile flexural strength and tensile splitting strength. The text describe the testing procedures to determine the tensile strength of concrete. Furthermore, there are presented the results of testing on different types of concrete (plain concrete, lightweight concrete, steel-fiber concrete, polymer-fibre concrete and high strength concrete). The conclusion deals with the derivation of dependancy between concrete strengths and comparing the values obtained from the available relations with the results of the tests.
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