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Calibration of indirect methods for maesurement of properties of alkali activated concretes
Vrba, Pavel ; Kocáb, Dalibor (referee) ; Bílek, Vlastimil (advisor)
This work solves creation of calibration relations to determine cube compressive strength, dynamic and static elastic modulus of alkali-activated concrete by non-destructive methods. Alkali-activated concrete is spoken of as a new material used in civil engineering. It shows different properties than normal concrete based on Portland cement. That's why the modification of common calibration relation seems necessary. Fresh concrete was made in the concrete plan ŽPSV a.s., Uherský Ostroh in three mixtures and always in the number of 18 cubes and 3 prisms. The samples were tested by impact hammer Schmidt type L, type N, SilverSchmidt PC-N and by ultrasound in 6 time periods of three specimens. After that, the cube compressive strength was determined. Status of static elastic modulus was determined in a time period of 28 days. The results are calibration relations to determine the progress of compressive strength and modulus of elasticity for each method and their combination.
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Use of the ultrasonic pulse-echo method for diagnostics of structures
Juráň, David ; Kocáb, Dalibor (referee) ; Cikrle, Petr (advisor)
The bachelor thesis is dealing with the description non-destructive methods which are regularly used in practice. The emphasis is placed on ultrasonic pulse-echo method, the principle and possible application in diagnostic of reinforced concrete structures. In practical tasks was this method applied on different types of constructions for the purpose of determination the thickness. The measurement was taken with Pundit PL-200PE and Pundit 250 Array devices by Proceq company. The outputs from both devices were compared and evaluated to each other with regards to possible factors, that could deviate measured values from the real thickness of researched constructions.
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The Influence of Moisture of Lightweight Aggregate on the Concrete Properties
Pešek, Lukáš ; Lišovský, Martin (referee) ; Kocáb, Dalibor (advisor)
The bachelor thesis deals with the influence of moisture of lightweight aggregate on the concrete properties. In the experiment, test specimens from two different lightweight aggregate, and two different input moisture states of lightweight aggregate were tested. The tests were performed to determine the basic properties of lightweight concrete after 7, 28 and 90 days of maturing. Compressive strength, tensile splitting strength and depth of penetration of water under pressure were determined on cubic specimens. On the test prisms were performed tests to determine the flexural strength and dynamic modulus of elasticity. The results were processed and evaluated in tabular and graphical form to determine statistical data and formulate a conclusion.
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Evaluation of stone column defects using an ultrasonic method
Kršková, Šárka ; Kocáb, Dalibor (referee) ; Cikrle, Petr (advisor)
This Bachelor thesis deals with evaluation of structure defects in stone column using ultrasonic method. Content of this thesis is divided to theoretical and practical part. Aim of theoretical part is to explain process of evaluation of existing stone structures according to norm ČSN ISO 13822. This part also contains listings of method for stone testing and brief explanation of chosen types of rock used for stone structures. Practical part contains tests used on columns using ultrasonic method and laboratory tests of chosen samples. Evaluation of measuring using ultrasonic method is based on knowledge of this method and visual inspection of columns. In laboratory tests were compared results of chosen properties on examples of same type of rock. These examples had different shape, moisture and measurement.
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Aspects of building design focused on durability
Bučilová, Iveta ; Kocáb, Dalibor (referee) ; Vymazal, Tomáš (advisor)
The master´s thesis discusses the life of building structures in terms of selected causes of failures are listed and discussed in ISO 16204 - "Durability - Service life design of concrete structures". The selected causes of failures will be carbonation and frost resistance of concrete. These causes will be performed computational analyzes for few types of concrete, based on these anayzes will be possible to compare and analyze the requirements specified in standards ČSN EN 1990, ČSN EN 1992 and ČSN EN 206.
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Diagnostics of structures in the evaluation of faults and defects
Stehlík, Petr ; Kocáb, Dalibor (referee) ; Schmid, Pavel (advisor)
This bachelor's thesis deals with research into methods of measuring and evaluating faults and defects in structures. A part of this thesis is an analysis of the legal issues in regard to investigations of structural defects in buildings. This thesis also includes a practical study of a family house in Černopolní street, which was affected by masonry cracks. The study details the collection and processing of data and analysis of the possible causes of the failures.
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The Use of Non-Destructive and Destructive Testing Methods for the Determination of the Compressive Strength of Concrete
Fučík, Petr ; Cikrle, Petr (referee) ; Kocáb, Dalibor (advisor)
This thesis deals with the summary of hardness test methods, their principles and types of devices used for nondestructive measurement of hardness test, including the latest devices and their description. It describes the basic relationship between hardness and compressive strength as well as procedures for obtaining the compressive strength of concrete in the structure. It provides an overview of testing methods by two normative approaches of processing and evaluation. The experimental part deals with the measurement on concrete parts using devices OriginalSchmidt type N, SilverSchmidt type N and SilverSchmidt type L, testing concrete compressive strength on cores and development of regression curve of these values.
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Diagnostics of the bridge structure
Wünsche, Dominik ; Cikrle, Petr (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with the issue of bridge strustures, especially their diagnostics and evaluation. The work consists of two parts, theoretical and practical. The theoretical part deals with the basic description and division of bridge structures, brigde inspections and test methods, especially those that were used in the thesis during bridge inspections. The practical part includes a visual inspection of two bridges, their description, detection of faults and defects and their documentation. In the practical part, the basic maretial characteristics of concrete bridges were determined, the condition of structures was assessed and a proposal for the elimination of failures and defects was developed. In the end, the work deals with the evaluation of both bridges.
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Experimental study of reinforcement in light-weight concrete components
Lisztwan, Dominik ; Kocáb, Dalibor (referee) ; Vymazal, Tomáš (advisor)
This bachelor thesis describes the experimental comparison of behaviour of reinforced lightweight concrete panels. Panels are reinforced with traditional steel grid and basalt composite reinforcement. The comparison of results is based on set of data from static load tests. The results of load test are also compared to the results made with nonlinear numerical analysis by finite element method and also calculation by hand. A part of this thesis includes determination of physical and mechanical properties of used concrete.
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