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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comportamiento mecánico de las mezclas tipo SMA (Stone Mastic Asphalt)

Paredes Matta, Elizabeth Victoria Adela January 2010 (has links)
El Stone Mastic Asphalt, SMA, diseño de origen alemán desarrollado en los años 60 ha permitido dar solución a los problemas de tránsitos pesados y climas fríos, de las carreteras en Europa, EE.UU. y Canadá y recientemente en Brasil y Argentina. El concepto de diseño SMA se basa en una estructura granular donde predomina el contacto piedra-piedra el mismo que le provee de alta resistencia cortante, baja deformación permanente o “rutting” y considera un buen porcentaje de ligante que le confiere una excelente durabilidad.
2

Low Temperature Performance of Wax Modified Mastic Asphalt

Butt, Ali Azhar January 2009 (has links)
The current interest in energy saving asphalt production techniques is great and several new processes have been developed to reduce the mixing and compaction temperatures for hot mix asphalt. In particular, mastic asphalt products (Gussasphalt) require high working temperatures, and harder requirements concerning bitumen fumes and carbon dioxide emissions have been introduced for such products. Consequently, the need of a new means of producing and placing mastic asphalt at lower temperatures is particularly large. One way of reducing asphalt mixture temperature is by using special flow improving additives like wax. This technique has successively been tried in several studies for polymer modified mastic asphalt used for bridge decks and parking areas in Sweden. However, there still are uncertainties about possible negative impact on crack susceptibility at lower temperatures due to the addition of wax. In this study, 4% montan wax (Asphaltan A) was used for one particular polymer modified mastic asphalt product. Type and amount of wax additive was selected based on results from earlier studies. The impact on binder, binder/filler mixtures and mastic asphalt from production was tested in the laboratory, focusing on low temperature performance. The bending beam rheometer (BBR) was used for determining low temperature creep compliance and the tensile stress restrained specimen test (TSRST) for determining fracture temperatures. Binder properties were determined using dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy and conventional tests (softening point, penetration, elastic recovery, Fraass breaking point, viscosity and storage stability). Aging was performed using the rolling thin film oven test (RTFOT) at 200°C. As expected, the addition of wax to the polymer modified binder showed a viscosity reduction at higher temperatures, corresponding to a similar positive effect of more than 10°C on production and laying temperature for the mastic asphalt. DMA and BBR results showed some increase in stiffness and a more elastic response of the wax modified binder at medium and low temperatures. The TSRST fracture temperature was 5 °C higher for the mastic asphalt containing 4% wax, indicating however no dramatic negative impact on crack susceptibility.
3

Modeling static creep with stress reversals of mastic asphalt.

Tigabu, Romel January 2011 (has links)
This thesis studies the strain response of mastic asphalt to arbitrary tension, arbitrary compression, alternating tension/compression, loading, zigzag loading and sinusoidal loading. In order to model the strain response to different loading histories, the scissors model is employed. Matlab modules are developed that are able to predict strain response not only for creep loading but also for other types of non constant stress loading such as zigzag loading and sinusoidal loading. In addition, another phenomological model, i.e. the viscoelastoplastic continuum damage model, is summarized and discussed in detail with respect to its applicability for the available data set.
4

Determination of thermal conductivity for mastic asphalt by combining previously performed laboratory work and TASEF / Bestämning av termisk konduktivitet för gjutasfalt genom kombination av tidigare utfört laborationsarbete och TASEF

Kruse Lindgren, Martin January 2021 (has links)
Mastic asphalt is a material which in Sweden mainly is used as coating for bridges, parking decks, courtyards and terraces. Mastic asphalt is a material built-up by a combination of bitumen (a type of binder), well-graded aggregate (consists of both coarse and fine ballast), filler, sand and sometimes also fine graded macadam. Mastic asphalt is described as a material which in Sweden have potential to expand further.  At the same time, it is becoming increasingly popular to construct buildings with solid timber frames. In 2019, the Swedish market for forestry and algaculture was analyzed, after which cross-laminated timber proved to be the construction-material that increases most in popularity. In constructions, mastic asphalt and timber may be combined. In Växjö Sweden for example, a parking deck called Limnologen is constructed with both timber frames and mastic asphalt as pavement. Another example were mastic asphalt and timber have been combined is an enormous car park built in Studen, Switzerland, which have 2142 parking lots. The aim of this master thesis was to develop a temperature-dependent thermal conductivity (for mastic asphalt BPGJA-11) which resulted in temperature development curves that correlated well with the results presented in Ellinor Sanned’s bachelor thesis “Insulation of timber with concrete and cast asphalt”. Sanned performed laboratory work were two different samples of mastic asphalt was tested in a cone calorimeter. The cone calorimeter was set to 51 kW/m2 and Sanned measured the temperature development beneath the mastic asphalt. The thermal conductivities for mastic asphalt were, in this master thesis, developed by using inverse calculation in the finite element program TASEF (Temperature Analysis in Structures Exposed to Fire). To form a reliable setup in TASEF, a sensitivity analysis was initially conducted. Information regarding thermal properties of mastic asphalt at elevated temperatures was in general considered challenging to find. Due to this, assumptions of the parameters set in TASEF had to be made. The thermal conductivities were developed at 0 ℃, 300 ℃ and 660 ℃. The results indicates that the thermal conductivity of the mastic asphalt (BPGJA-11) tested by Sanned decreases between 0 ℃ and 300 ℃, and then more or less stabilizes.  The presented thermal conductivities should however be used with great caution. The reason for this is due to uncertainties in the experimental cone calorimeter results, uncertainties within the setup in TASEF as well as within the specific method used. In particular the application on materials which both melts and boils (such as mastic asphalt) should be made with great care. To increase the reliability of the results, more research and laboratory work should therefore be performed within the area.  The method used within this master thesis (inverse calculation using TASEF) is simple and cost effective when determining the thermal conductivity. / Mastic asphalt (som i denna sammanfattning benämns som gjutasfalt) är ett material som i Sverige huvudsakligen används som beläggning för broar, parkeringshus, gårdsplaner och terrasser. Gjutasfalt är ett material som är byggt upp av en kombination av bitumen (en typ av bindemedel), välgraderat stenmaterial (består av både grov och fin ballast), filler, sand och ibland även finmakadam. Gjutasfalt beskrivs som ett material som i Sverige har stor potential att expandera.  Samtidigt blir det alltmer populärt att konstruera byggnader med solida träkonstruktioner. År 2019 analyserades den svenska marknaden för skog och lantbruk, varpå kors-laminerat trä visade sig vara det konstruktionsmaterial som ökar mest i popularitet.  I konstruktioner kan gjutasfalt och trä kombineras. Parkeringshuset Limnologen i Växjö Sverige är ett exempel på en träkonstruktion som kombinerats med gjutasfalt som beläggning. Ett annat exempel är ett enormt parkeringshus i Studen, Schweiz, som har 2142 parkeringsplatser.  Målet med denna masteruppsats var att bestämma den temperaturberoende termiska konduktiviteten (för gjutasfalt BPGJA-11) vilken resulterar i en temperaturutvecklingskurva som korrelerar väl med resultaten presenterade i Ellinor Sanneds examensarbete ”Isolering av trä med betong och gjutasfalt”. Sanned genomförde en laboration där två olika prov av gjutasfalt testades i en konkalorimeter. Konkalorimetern var inställd på 51 kW/m2 och Sanned uppmätte temperaturutvecklingen på undersidan av gjutasfalten.  De termiska konduktiviteterna för gjutasfalt i denna masteruppsats arbetades fram genom ”inversberäkning” i det finita elementprogrammet TASEF (Temperature Analysis in Structures Exposed To Fire). För att bilda en tillförlitlig uppsättning i TASEF, genomfördes inledningsvis en känslighetsanalys. Information gällande termiska egenskaper av gjutasfalt vid förhöjda temperaturer var generellt sätt svåra att finna. För parametrarna som användes i TASEF gjordes därför antaganden.  De termiska konduktiviteterna arbetades fram vid 0 ℃, 300 ℃ and 660 ℃. Resultaten indikerar att den termiska konduktiviteten för den gjutasfalt (BPGJA-11) som testades av Sanned minskar mellan 0 ℃ och 300 ℃, för att därefter mer eller mindre stabiliseras. De termiska konduktiviteterna som har presenteras bör dock användas med stor försiktighet. Anledningen till detta beror på osäkerhet för de resultat som presenterades av Sanned, osäkerheter för uppsättningen i TASEF samt för den specifika metod som används. Speciellt anbefalles försiktighet med att använda metoden för material som både smälter och kokar (såsom gjutasfalt). För att öka resultatens tillförlitlighet bör därför mer forskning och laboratoriearbete utföras inom området. Metoden som har använts inom denna masteruppsats (inversberäkning med TASEF) är enkel och kostnadseffektiv för att bestämma den termiska konduktiviteten.
5

Posouzení nízkohlučného asfaltového koberce mastixového s CRmB / Evaluation of Low Noise Stone Mastix Asphallt with CRmB

Zavřel, Tomáš January 2012 (has links)
The aim of diploma thesis is to design mixture SMA LA 8 with crumb rubber modified bitumen (9,9 %) and a modifier additive TecRoad (22 %) and the test of water sensitivity, the resistance to permanent deformation and to frost cracking, the determination of the stiffness and fatigue characteristics. Test methods are described and evaluated.
6

Nové směry v oblasti asfaltových koberců mastixových / New trends in the field of stone mastic asphalts

Pfeiferová, Magdaléna January 2012 (has links)
The work consists of two parts. The first part is focused on the determination of an anti-skid properties of the test section on Vídenská street. The anti-skid properties will be measured using a pendulum tester and macrotexture will be set at the same time. Microtexture will be measured using a volumetric patch technique. In the second part we will try to gain an initial experience with design and testing of a low noise stone mastic asphalt. We will set basic characteristics and at the same time compare with a standard stone mastic asphalt. For the comparison two various bituminous binders are used. The water sensitivity, resistance against rutting and stiffness moduli are compared.
7

Nízkohlučné povrchy vozovek / Low - noise pavements

Mojžíš, Martin January 2013 (has links)
Master´s thesis is interested in the problems of low-noise road surfaces. The theoretical part describes noise, sources of noise, the low-noise road surfaces and the practical part describes two proposals of low-noise stone mastic asphalt SMA 8 LA.
8

Untersuchungen zur Klauengesundheit in einem Sächsischen Milchviehbetrieb

Griebsch, Anne 17 April 2020 (has links)
Die Abschlussarbeit beschäftigt sich mit der Klauengesundheit von Deutschen Holsteins Kühen in einem Sächsischen Milchviehbetrieb. Ziel war die Erfassung und Bewertung der Klauenmaße und Klauen­gesund­heit bei unterschiedlicher Laufflächengestaltung. Aufgrund einer hohen Prävalenz von 89,1 % im Bereich Klauen und Gliedmaßen und der starken Abnutzung des vorhandenen Gussasphaltes im Laufstall, wurde nach der Ist-Aufnahme (Klauenschnitt, Erfassung von Klauenkrankheiten und –maßen) im Mai 2016 eine Stallhälfte am Futtertisch komplett mit Gummiboden (Kraiburg Kura P) ausgelegt und zwei Versuchsgruppen (N=178) gebildet. Während der 93-tägigen Versuchsphase wurden Daten zum Locomotion Score, Hygienescore, Anzahl aktiver Kühe, Gruppenstärke sowie Klimadaten erhoben. Am Ende der Beobachtungsphase wurden alle Versuchstiere einer weiteren Klauenpflege unterzogen, die Klauenmaße und eventuelle Klauenerkrankungen erfasst. Im Ergebnis konnte gezeigt werden, dass sich die Klauengesundheit der Versuchsgruppe, auf einer Kombination von Gummiboden und Gussasphalt, im Vergleich zur Kontrolle, bei der nur Gussasphalt berücksichtigt wurde, verbessert hatte. Zudem konnte verdeutlicht werden, dass Klauenerkrankungen multifaktoriell sind. Der Einbau von Gummiboden kann gesundheitsfördernd wirken, z. B. durch geringere Belastung und besseres Wohlbefinden, aber das Management hat einen essentiellen Anteil der Klauen- und Gliedmaßen­gesundheit. Als Empfehlung wird eine Kombination aus weichen und abrasiven Laufflächen als sinnvoll angesehen. Jedoch wird eine Analyse des gesamten Managements und der Haltungsumwelt der Tiere unerlässlich, da der Mensch der wichtigste Einflussfaktor auf die Klauen- und Gliedmaßengesundheit ist.:Inhalt Abkürzungsverzeichnis V Abbildungsverzeichnis VI Tabellenverzeichnis VIII 1. Einleitung 1 2. Literaturteil 2 2.1 Physiologische Grundlagen der Hornqualität und des Hornwachstums 2 2.1.1 Anatomie der Klaue und der Klauenhaut 2 2.1.2 Hornqualität 5 2.1.3 Messung der Klauenhornhärte zur Darstellung der Hornqualität 6 2.1.4 Erfassung der Klauenmaße zur Überprüfung des Hornschuhs 9 2.2 Übersicht zu den wichtigsten Klauenerkrankungen 12 2.3 Faktorenkrankheit Dermatitis Digitalis 17 2.4 Bewertung des Gangverhaltens mittels Locomotion Score 20 2.5 Bewertung der Stallhygiene mittels Hygienescore 23 2.6 Liegeflächenmanagement und Liegeverhalten 26 2.7 Gussasphalt vs. Gummibelag, Vor- und Nachteile der dargestellten Bodenbeläge 30 2.8 Stallklima 34 2.9 Management der Klauen- und Gliedmaßengesundheit 36 3. Material und Methoden 39 3.1 Tierbestand und betriebliche Gegebenheiten 39 3. 2 Versuchsaufbau 41 3.3 Datenerfassung 46 3.3.1 Bestimmung der Klauenmaße 46 3.3.2 Erfassung der Klauenbefunde 48 3.3.3 Erfassung Locomotion Score 49 3.3.4 Erfassung Hygienescore 50 3.3.5 Erfassung weiterer Parameter für die Beurteilung Klauengesundheit 50 3.3.6 Bestimmung Klimadaten 51 3.4 Datenauswertung 52 4. Ergebnisse 53 4.1 Prävalenz 53 4.1.1 Auswertung aller Klauenerkrankungen 53 4.1.2 Auswertung Dermatitis Digitalis 56 4.2 Klauendaten 57 4.3 Locomotion Score 59 4.4 Hygienescore 61 4.5 Auswertung weiterer Parameter für die Beurteilung der Klauengesundheit 62 4.6 Klimadaten 67 5. Diskussion und Schlussfolgerungen 69 5.1 Ist-Situation der Klauengesundheit in Bezug auf die gesamte Herde 69 5.2 Entwicklung der Klauengesundheit und Klauenmaße in den Untersuchungsgruppen 70 5.3 Weitere Einflussfaktoren auf die Klauengesundheit 75 5.4 Locomotion Score 79 5.5 Hygienescore 80 5.6 Schlussfolgerungen für die Praxis 81 6. Zusammenfassung 83 Literaturverzeichnis 85 Anhang 97 / The current work focuses on claw health within a herd of German Holsteins on a Saxon dairy farm. The aim was to record and evaluate the claw dimensions and claw health on different flooring systems. Due to a high prevalence of 89.1% in the area of the claws and limbs and the heavy wear of the existing mastic asphalt in the playpen, the operational management decided to carry out a partial renovation of the flooring system. Thus, after recording the actual condition (claw cut, recording of claw diseases and dimensions) in May 2016, one half of the stable at the feeding table was completely covered with rubber flooring (Kura P by Kraiburg) and two test groups (N=178) were formed. During the 93-day trial period, data were collected on locomotion score, hygiene score, number of active cows, group strength and climate data. At the end of the observation phase, all test animals were subjected to further claw care, claw dimensions and possible claw diseases were recorded. As a result, it was shown that the claw health of the experimental group had improved on a combination of rubber flooring and mastic asphalt compared to the control that only considered mastic asphalt. In addition, it could be shown that claw diseases are multifactorial. The installation of rubber flooring can have a health-promoting effect, e.g. by reducing stress and improving well-being, but management plays a major role in claw and limb health. A combination of soft and abrasive treads is considered reasonable. However, an analysis of the overall management and housing environment of the animals becomes essential as humans are the most important factor influencing claw and limb health.:Inhalt Abkürzungsverzeichnis V Abbildungsverzeichnis VI Tabellenverzeichnis VIII 1. Einleitung 1 2. Literaturteil 2 2.1 Physiologische Grundlagen der Hornqualität und des Hornwachstums 2 2.1.1 Anatomie der Klaue und der Klauenhaut 2 2.1.2 Hornqualität 5 2.1.3 Messung der Klauenhornhärte zur Darstellung der Hornqualität 6 2.1.4 Erfassung der Klauenmaße zur Überprüfung des Hornschuhs 9 2.2 Übersicht zu den wichtigsten Klauenerkrankungen 12 2.3 Faktorenkrankheit Dermatitis Digitalis 17 2.4 Bewertung des Gangverhaltens mittels Locomotion Score 20 2.5 Bewertung der Stallhygiene mittels Hygienescore 23 2.6 Liegeflächenmanagement und Liegeverhalten 26 2.7 Gussasphalt vs. Gummibelag, Vor- und Nachteile der dargestellten Bodenbeläge 30 2.8 Stallklima 34 2.9 Management der Klauen- und Gliedmaßengesundheit 36 3. Material und Methoden 39 3.1 Tierbestand und betriebliche Gegebenheiten 39 3. 2 Versuchsaufbau 41 3.3 Datenerfassung 46 3.3.1 Bestimmung der Klauenmaße 46 3.3.2 Erfassung der Klauenbefunde 48 3.3.3 Erfassung Locomotion Score 49 3.3.4 Erfassung Hygienescore 50 3.3.5 Erfassung weiterer Parameter für die Beurteilung Klauengesundheit 50 3.3.6 Bestimmung Klimadaten 51 3.4 Datenauswertung 52 4. Ergebnisse 53 4.1 Prävalenz 53 4.1.1 Auswertung aller Klauenerkrankungen 53 4.1.2 Auswertung Dermatitis Digitalis 56 4.2 Klauendaten 57 4.3 Locomotion Score 59 4.4 Hygienescore 61 4.5 Auswertung weiterer Parameter für die Beurteilung der Klauengesundheit 62 4.6 Klimadaten 67 5. Diskussion und Schlussfolgerungen 69 5.1 Ist-Situation der Klauengesundheit in Bezug auf die gesamte Herde 69 5.2 Entwicklung der Klauengesundheit und Klauenmaße in den Untersuchungsgruppen 70 5.3 Weitere Einflussfaktoren auf die Klauengesundheit 75 5.4 Locomotion Score 79 5.5 Hygienescore 80 5.6 Schlussfolgerungen für die Praxis 81 6. Zusammenfassung 83 Literaturverzeichnis 85 Anhang 97
9

Použití R-materiálu do asfaltových směsí typu asfaltový koberec mastixový / Usage of reclaimed asphalt pavement in stone mastic asphalt

Coufalíková, Iva January 2019 (has links)
The dissertation deals with the possibilities of adding recycled asphalt pavement (RAP) to the stone mastic asphalt (SMA), which is increasingly being promoted due to its good resistance to permanent deformations and high traffic load. Thanks to the use of high-quality input materials in production, this is a valuable material source. The theoretical part describes composition of SMA mixture and problems of pavement recycling. The practical part deals with SMA 11S laboratory designs with RAP ratio of 0 to 50%. Based on these suggestions, a trial section with 17 variants was placed, which varied with the content and quality of the RAP and the used additives. All variants have been subjected to functional testing not only on mixtures but also on recovered binders. The results obtained during the dissertation were used to build a certified methodology named "Methodology of application RAP to Stone Mastic Asphalt." In conclusion, the results of the dissertation are summarized.
10

Vlastnosti asfaltových směsí typu SMA s R-materiálem / Properties of asphalt mixtures of SMA-type with RAP

Acuna Subia, Luis Carlos January 2018 (has links)
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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