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Research in the field of construction elements and design of concrete pavements
Grošek, Jiří ; Birnbaumová, Marie (referee) ; Vébr,, Ludvík (referee) ; Varaus, Michal (advisor)
The presented dissertation is focused on research in the field of dowels and design of concrete pavements using the finite element method. The theory part describes the history and the currently used techniques in the world and in the Czech Republic. The practice part of the dissertation contains a description of design methods, diagnostics of concrete pavements by using FWD and a description of laboratory tests on beams with inserted dowels. The results of measurements and modelling are verified on real operating conditions on testing fields. Based on the dissertation results, the amendment of the Czech standard ČSN 73 6123-1 regarding the position of dowels were proposed and approved. In addition, methodological guidelines of the Ministry of Transport regarding the measurements of the dowels and tie bars position and diagnostic by FWD was approved. The conclusion of the work summarizes and emphasizes the results of the dissertation.
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Asphalt recycled material to cold asphalt mixtures
Kotas, Vojtěch ; Varaus, Michal (referee) ; Stehlík, Dušan (advisor)
The thesis is focused on the use of R-material into cold asphalt mixtures, which is modern method using recyclate into subgrade of roads. Concretely, it deals with basic properties of R-material, such as grain size and compaction. It practically verifies and compares properties of cold asphalt mixtures with cement, asphalt emulsion or with combination of this two binders. As reference testing method was chosen test of tensile splitting strength.
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Properties of asphalt mixtures of SMA-type with RAP
Acuna Subia, Luis Carlos ; Hrbek, Kamil (referee) ; Varaus, Michal (advisor)
The aim of the diploma thesis is to verify and compare the properties of bituminous stone mastic asphalt, namely SMA 11S with modified PMB 45 / 80-55 asphalt binder or 50/70 road bitumen binder with rubber granulate. Comparison of properties is performed using functional tests. The thesis is divided into the theoretical and practical part. The theoretical part deals with the familiarization with the use of the SMA mixture, the selected concepts concerning recycling of non-leveled roads are described and described. Attention is paid especially to the recycling of roads in the Czech Republic with an emphasis on hot recycling on the incinerator, which allows increased dosing of Reclaimed Asphalt into asphalt mixtures. In the practical part, the results of the functional tests of the SMA 11S mixture, which have been taken from the test section, are processed and evaluated.
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Asphalt mixtures with the use of higher amount of RAP
Mucha, Bohumír ; Matoušek, David (referee) ; Varaus, Michal (advisor)
At the beginning of the Master’s thesis the asphalt mixture of the type asphalt concrete and its basic properties are described. The main point of this work is to compare the functional properties of asphalt mixtures with the addition of higher amount of RAP and various rejuvenators used in the experimental section. From individual samples of asphalt mixtures taken during the laying, the control tests were carried out and the process of permanent deformation with the wheel tracking test was monitored. After that, using functional tests the properties of asphalt mixtures with conventional modified and unmodified asphalt bitumen enriched with the addition of declaring similar properties were compared.
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Recycling of asphalt mixtures with standard amount of RAP
Staňková, Michaela ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
The diploma thesis deals with the design of an asphalt mixture for an abrasive layer with a standard R-material content (20 %) without the use of other softening additives, while the properties of the aged asphalt binder in the mixture were compensated by dosing "softer binder 70/100". Asphalt mixtures type ACO 11+ are designed to meet the requirements ČSN 73 6121: 2019. The aim of the work is to verify the expected properties of the asphalt mixture performed functional and empirical tests according to the standards for asphalt mixtures of the ČSN EN 12697 series.
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Influence of the temperature on the preparing of asphalt mixtures with higher amount of RAP
Škrobáček, Petr ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
This bachelor thesis is focused on the preparation of the reclaimed asphalt pavement for production of asphalt mixtures. In the thesis there is investigated the effect of the temperature of preparation the reclaimed asphalt pavement on the characteristic of the bitumen content. In the theoretical part there is described bitumen as such and reclaimed asphalt pavement. In the practical part there is described the preparation of the material for laboratory tests. The next step is the extraction and distillation of bitumen. These bitumens are tested according to depredescribed tests: ‘Determination of needle penetration (ČSN EN 1426)’, ‘The softening point (ČSN EN 1427)’ and ‘Dynamic shear rheometer’. In the last section of this bachelor thesis there is a comparison of the individual properties of the rendered bitumen of the asphalt mixtures of reclaimed asphalt pavement, with the aim of evaluating temperatures of preheating and degradation of the bitumen on the final characteristic of the asphalt mixtures witch higher quantity reclaimed asphalt pavement. The measured values of the temperature for preparation of reclaimed asphalt pavement shows that the temperature of the asphalt mixture before production has a significant effect on the characteristics of the bitumen, which is included in the reclaimed asphalt pavement. There is evident the difference between specimen of the asphalt mixture of reclaimed asphalt pavement and the reclaimed asphalt pavement. It is visible only from the bottom layer too.
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Recycling of asphalt mixtures with higher amount of RAP
Klimek, Matěj ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
The theoretical part of the diploma thesis recapitulates the existing literature in the field of recycling asphalt mixtures with a higher content of RAP (Reclaimed asphalt pavement). The practical part of the diploma thesis examines changes in the properties of asphalt mixtures with a higher content of RAP, due to changes in mixing time. Five mixtures have been proposed for this research. It is an asphalt mixture intended for the road abrasive layer (ACO 11+). Reference mixture "A" without RAP, with a standard mixing time of 25 seconds. Mixture "B" with 40% RAP, without rejuvenator, with an extended mixing time of 40 seconds. Mixture "C" with 40% RAP, with rejuvenator and standard mixing time. Mixture "D" with 40% RAP with rejuvenator and extended mixing time of 40 seconds. Mixture "E" with 40% RAP, with rejuvenator and extended mixing time of 55 seconds.
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