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The study of the refractory concrete binding system based on phosphoric acid and aluminous cement
Pavlík, Tomáš ; Švec, Jiří (referee) ; Šiler, Pavel (advisor)
This thesis deals with refractory concrete binding system based on aluminous cement and phosphoric acid. The prepared refractory concretes were fired at 1 000 °C. Various effects on compressive strength of refractory concrete were studied. The influence of aluminous cement content and phosphoric acid content, the influence of various admixtures, the influence of plasticizers and the influence of time and method of sample storage were studied. Simultaneous thermogravimetry and differential thermal analysis of the basic unfired sample were performed. Finally, selected refractory concretes were fired at 110, 200, 400, 600, 800, 900, 1 000 and 1 100 °C. The compressive strength of these samples was measured and powder X ray diffraction analysis was performed. The compressive strength of refractory concretes under intermediate temperatures (800–1 100 °C) was most increased in samples with metakaolin and gray microsilica.
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Influence of multiple cyclic loading on the selected parameters of lightweight concrete
Alexa, Martin ; Misák, Petr (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with the observation of the values of selected parameters (especially the static modulus of elasticity) of light-weight concrete in compression before and after multiple cyclic loading. The deformation of test specimens during multiple cyclic loading were measured with resistive strain gauges. Test specimens (cylinders with a diameter of 150 mm and height of a 300 mm) were cyclically loaded and up to 4 500 loading cycles were performed. The aim of this thesis is assessment changes in the values of static modulus of elasticity depending on the number of loading cycles.
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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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Properties of Fiber Reinforced Plastics
Jastrzembská, Alena ; Petránek, Vít (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with the theoretical part of raw materials, production and properties of composite materials with fiber reinforcement and polymer matrix. It also gives a brief overview of selected prominent Czech and foreign producers of composite materials with polymer matrix and fiber reinforcement. The practical section deals with testing the durability of selected composite profiles immersion in aggressive environments and testing of compressive strength.
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The Use of the Ultrasonic Pulse Velocity Method for the In-situ Estimation of the Quality of Concrete
Sopúch, Martin ; Cikrle, Petr (referee) ; Kocáb, Dalibor (advisor)
The primary focus of this bachelor thesis is examination of concrete properties, principally with non-destructive methods. The ultrasonic apparatus Pundit PL-200 made by Proceq Company was used for the most of non-destructive examinations of the concrete. This paper is mainly focusing on determination of a modulus of elasticity. Measuring of the properties took place in the laboratory with use of probationary entities of 100 x 100 x 400 mm and in site on concrete block situated at BUT FCE campus. The probationary entities including twists from measured block were after non-destructive examining tested in the wring to secure more accurate results. The target of the research paper, firstly, was to attest options for determination of dynamic value. Secondly, with use of decreasing coefficient determine static values of elasticity modulus on the concrete that was built-in in a construction and, consequently, test practical usage possibilities of the modern apparatus Pundit PL-200.
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Diagnostics and assessment of the structure of bridge
Lehocký, Peter ; Komárková, Tereza (referee) ; Kocáb, Dalibor (advisor)
This diploma thesis focuses on diagnostics of bridge structures. First part of this diploma thesis will focus on theoretical knowledge about bridge structures and common diagnostic techniques suited for examining material priperties of samples taken from structure. Second part of this thesis will focus on practical use of experiments used in diagnostic branch. I will be doing visual observation of concrete structure followed by experiments on core samples. End of thesis will be evaluating structure from global perspective and will deliver specific sugestions for renovation.
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Study of the influence of feedstock composition and the values of the modulus of elasticity of concrete
Šafrata, Pavel ; Křížová, Klára (referee) ; Hela, Rudolf (advisor)
Modulus of elasticity is significantly reflected feature of concrete, besides the compressive strength in static design nowadays. Low modulus of elasticity can cause unacceptable deflections for subtle skeletal structures. It is at least irresposible to count with empirical formulas since there is a wide range of materials and additives in production of concrete. The aim of this thesis is to study the influence of large fraction aggregate on static and dynamic modulus of elasticity of concrete and recommendation for appropriate measures to produce concrete with high modulus of elasticity. The experimental part is further following up the influence of air content in concrete on the modulus of elasticity.
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Experimental determination of the relationship between NDT parameters and the compressive strength of concrete
Kozáček, Vojtěch ; Komárková, Tereza (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with non-destructive testing of concrete as well as with the relationship between determined parameters and the compressive strength of concrete. The thesis is mainly focused on the ultrasonic pulse velocity method and the rebound hammer test. The experimental part of the thesis describes non-destructive tests performed on concrete blocks. The compressive strength was tested on the drill cores taken from the concrete blocks. The aim of this thesis is to find regression models of the relationship between the compressive strength and non-destructive parameters, and the subsequent analysis of the results.
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The utilization of the pavement waste materials to roads
Furdaničová, Alice ; Šperka, Pavel (referee) ; Stehlík, Dušan (advisor)
The diploma thesis deals with the use of recycled asphalt with aggregate in a hydraulically bound mixtures. The mixture is determined in the base or sub-base course of the pavement. The theoretical part of the diploma thesis describes the base course of the pavement, the production of recyclates from construction demolition waste, the acquisition and processing of recycled asphalt, the road reuse and recycling. The thesis is enriched by a contribution from the implementation of recycled asphalt laying into the base course of the communication company SKANSKA a.s. and ČNES a.s. The next chapter describes detailed experiences with recycling abroad. The thesis also contains a description of laboratory tests, which are important for evaluating the properties of mixtures with recycled asphalt. The practical part verifies the suitability of the mixture of recycled asphalt and aggregate for the road surface by testing the transverse tensile strength, compressive strength and frost and water resistance. The mixtures used are found to be suitable for pavement base course.
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