Résumé confidentiel / Résumé confidentiel

Modern separation and spectrometric techniques for biological sample lipidom investigation Due recent progress in field of mass spectrometry the lipidomics, part of metabolomics, is increasing its importance for broad fields of biological study. The aim of this study is to test the lipid extraction techniques and to optimize the preseparation and separation of lipids suitable for mass spectrometry detection. The fragmentation patterns of four, the most abundant lipid classes of glycerolipids (PC, PE, TG, DG), were acquired for the proposed system. These patterns were compared with literature. The most appropriate method for extraction was declared technique according Folch based on methanol and chloroform solution. The preseparation due SPE method is very useful tool for lipid determination. The optimized were focused to reach higher recovery especially in polar lipid fraction. Proposed HPLC system is based on methanol with ammonium buffer, water and isopropanol. The testing was done on three columns with different type of sorbents (Gemini, Syncronis and Kinetex). The separation was evaluated according mass spectrometer response, shape and wide of particular analytes peaks. Composition contains 20% of water was determinate as the best and also the best separation was achieved by Kinetex column. The proposed...

The autogenous shrinkage due to self-desiccation of high- and ultra-high performance concretes with very low water-cement ratio in case of restraint leads to considerable stresses starting from very early age. The resultant risk of cracking presently cannot be adequately investigated. Parameters that are particularly difficult to capture experimentally are the concrete temperature and the viscoelasticity. The primary objective of this work was to assess as precise as possible the autogenous shrinkage cracking propensity of representative concretes at strong restraint and constant room temperature. Test methods needed to be chosen and enhanced in a way that preferably allowed for the efficient and precise investigation of all relevant factors in the future. Ideally, a method suitable for a complete empirical modeling was provided. First the methodological requirements and the advantages and disadvantages of existing test methods were discussed. Based on this, optimized test methods were proposed. Their suitability was verified using the example of ultra-high strength concrete. The choice of concrete compositions considered the essential measures for reducing shrinkage (internal curing, shrinkage-reducing admixtures, reduction of the fraction of Portland cement in the binder). The autogenous shrinkage was measured with the shrinkage cone method. This new test method was validated by investigations of the repeatability and reproducibility and proved efficient and precise. It allows for measurements under non-isothermal conditions; no established test method exists for that purpose to date. The autogenous shrinkage of the ultra-high strength concretes at the age of 24 h, investigated under quasi-isothermal conditions (20 °C), was between 0,25 mm/m and 0,70 mm/m. It was particularly low when a shrinkage-reducing admixture was added and when superabsorbent polymers were used. The stresses due to restraint were determined with the restrained ring test. A large part of the stresses to be expected according to Hooke’s Law were eliminated by creep and relaxation. The relaxation capacity being very pronounced at very early age was the main reason that no visible cracking occurred, not even with the concretes with high autogenous shrinkage. The development of the autogenous shrinkage cracking propensity was described as ratio of restraint stress and splitting tensile strength. By means of modified ring tests, used to determine the maximum tensile stress, it could be shown that the ratio of stress to strength is an appropriate failure criterion. However, the cracking propensity can be calculated correctly only if the strongly age-dependent ratio of uniaxial to splitting tensile strength is accounted for. Besides, it needs to be considered that at very early age a plastic stress redistribution may occur in restrained ring tests. The reference concrete showed a high cracking propensity of up to 0.68. The fact that shrinkage-reducing measures led to significantly lower values reveals their relevance for the safe application of ultra-high strength concrete. However, the investigations carried out here at 20 °C do not allow for a final assessment of the cracking propensity under typical on-site conditions. To empirically model the autogenous shrinkage cracking propensity as a function of temperature and stress level in the future, an analytical stress solution for non-isothermal restrained ring tests and a new approach for investigating the residual stress and relaxation capacity by means of non-passive restrained ring tests was suggested.:1 Introduction 2 Autogenous shrinkage 5 2.1 Shrinkage and hydration 5 2.2 Definitions and research approaches 10 2.3 Metrological issues 14 2.3.1 Multitude of test methods 14 2.3.2 Time-zero 16 2.3.3 Other metrological issues 18 2.4 Corrugated tube method 19 2.5 Influencing parameters 21 2.5.1 Concrete composition 21 2.5.2 Temperature 23 2.5.3 Specific countermeasures 25 2.6 Summary and conclusions with respect to the own work 25 3 Concretes used in the own investigations 27 3.1 Preliminary remarks 27 3.2 Concrete compositions 27 3.3 Constituents 28 3.3.1 Cement 28 3.3.2 Ground-granulated blast furnace slag 28 3.3.3 Silica fume 28 3.3.4 Admixtures 29 3.3.5 Aggregates 29 3.4 Mixing 29 3.5 Basic properties 30 3.5.1 Compressive strength 30 3.5.2 Splitting tensile strength 31 3.5.3 Modulus of elasticity 33 3.5.4 Analysis of mechanical properties 35 3.5.5 Coefficient of thermal expansion 38 3.5.6 Isothermal calorimetry 39 3.6 Summary 39 4 Shrinkage cone method for measuring autogenous shrinkage 41 4.1 Introduction 41 4.2 Setup and measurement procedure 41 4.3 Temperature control 44 4.4 Precision under quasi-isothermal conditions 47 4.4.1 Repeatability 47 4.4.2 Reproducibility 49 4.4.3 Shrinkage cone method vs. corrugated tube method 49 4.5 Autogenous shrinkage of the investigated concretes at 20 °C 54 4.6 Tests under non-isothermal conditions 55 4.7 Summary 56 5 Stress and cracks due to restrained autogenous shrinkage 58 5.1 Introduction 58 5.2 Degree of restraint 58 5.3 Formation of cracks 60 5.4 Very early age and importance of stress relaxation 63 5.5 Creep and cracking - further methodological aspects 65 5.6 Autogenous shrinkage cracking propensity 69 5.7 Role of temperature history 70 5.8 Further state of knowledge 72 5.8.1 Preliminary remarks on test methods 72 5.8.2 Quantitative investigations under restraint conditions 73 5.8.3 A full-scale model for assessing the cracking risk at very early age 77 5.9 Summary 78 6 Investigation of the autogenous shrinkage cracking propensity 80 6.1 Introduction 80 6.2 Suitability of temperature-stress testing machines 80 6.2.1 Development, setup and use 80 6.2.2 Results of round robin tests 83 6.3 Restrained ring test - methodological foundations 86 6.3.1 Setup and use 86 6.3.2 Evaluation of restrained ring tests 90 6.3.3 Use of temperature changes for the investigation of creep and relaxation 96 6.4 Own investigations with the restrained ring test 97 6.4.1 Setup 97 6.4.2 Compensation of disturbing temperature effects 99 6.4.3 Repeatability 100 6.4.4 Measured steel ring strains 101 6.4.5 Simple stress analysis 102 6.4.6 Autogenous shrinkage cracking propensity - further analysis 106 6.4.7 Thermal stress component 116 6.4.8 Period of maximum cracking propensity 118 6.4.9 Restraint stress versus autogenous shrinkage 119 6.4.10 Cracking propensity versus autogenous shrinkage 120 6.4.11 Further considerations on creep 121 6.5 Summary 126 7 Summary, conclusions and outlook 128 7.1 Summary and conclusions 128 7.2 Outlook 130 8 Literature 131 9 Annex 159 / Das durch Selbstaustrocknung verursachte autogene Schwinden von besonders leistungsfähigen Betonen mit sehr niedrigem Wasserzementwert führt bei Dehnungsbehinderung bereits in sehr frühem Alter zu erheblichen Zwangsspannungen. Die Gefahr der Rissbildung, die sich daraus ergibt, lässt sich bislang nur unzureichend untersuchen. Experimentell besonders schwer zu erfassende Faktoren sind die Betontemperatur und die Viskoelastizität. Das vorrangige Ziel der Arbeit war die möglichst genaue Ermittlung der autogenen Schwindrissneigung repräsentativer Betone bei starker Dehnungsbehinderung und konstanter Raumtemperatur. Dabei waren die Prüfverfahren möglichst so zu wählen und weiterzuentwickeln, dass sich zukünftig alle relevanten Faktoren effizient und genau untersuchen lassen. Im Idealfall sollte eine Methode entstehen, die eine vollständige empirische Modellierung erlaubt. Zunächst wurden die methodischen Anforderungen und die Vor- und Nachteile existierender Prüfverfahren diskutiert. Darauf aufbauend wurden optimierte Verfahren vorgeschlagen. Ihre Eignung wurde an ultrahochfestem Beton überprüft. Bei der Auswahl der Betone wurden die wesentlichen Maßnahmen zur Schwindreduzierung berücksichtigt (innere Nachbehandlung, schwindreduzierende Zusatzmittel, Verringerung des Portlandzementanteils am Bindemittel). Das autogene Schwinden wurde mit dem Schwindkegelverfahren gemessen. Das neue Verfahren wurde durch Untersuchungen zur Wiederhol- und Vergleichsgenauigkeit validiert und erwies sich als effizient und genau. Es ermöglicht Messungen unter nicht-isothermen Bedingungen; hierfür existiert bisher kein etabliertes Verfahren. Das autogene Schwinden der untersuchten ultrahochfesten Betone unter quasi-isothermen Bedingungen (20 °C) betrug im Alter von 24 h zwischen 0,25 mm/m und 0,70 mm/m. Besonders gering war es bei Zugabe eines schwindreduzierenden Zusatzmittels bzw. Verwendung superabsorbierender Polymere. Mit dem Ring-Test wurden die bei Dehnungsbehinderung entstehenden Spannungen ermittelt. Ein großer Teil der gemäß Hooke’schem Gesetz zu erwartenden Spannungen wurde durch Kriechen und Relaxation abgebaut. Die im sehr frühen Alter stark ausgeprägte Relaxationsfähigkeit war der wesentliche Grund dafür, dass es selbst bei Betonen mit hohem autogenen Schwinden zu keiner erkennbaren Rissbildung kam. Die Entwicklung der autogenen Schwindrissneigung wurde als Verhältnis von Zwangsspannung und Spaltzugfestigkeit beschrieben. Durch modifizierte Ring-Tests, mit deren Hilfe die maximale Zugspannung ermittelt wurde, konnte gezeigt werden, dass das Verhältnis von Spannung und Festigkeit als Versagenskriterium geeignet ist. Die Rissneigung lässt sich aber nur dann korrekt berechnen, wenn das stark altersabhängige Verhältnis von einaxialer Zugfestigkeit und Spaltzugfestigkeit berücksichtigt wird. Außerdem ist zu beachten, dass es im sehr frühen Alter zu einer plastischen Spannungsumlagerung in Ring-Tests kommen kann. Der Referenzbeton wies eine hohe Rissneigung von bis zu 0,68 auf. Dass die schwindreduzierenden Maßnahmen zu deutlich geringeren Werten führten, zeigt deren Bedeutung für den sicheren Einsatz von ultrahochfestem Beton. Die hier bei 20 °C durchgeführten Untersuchungen erlauben allerdings keine abschließende Bewertung der Rissneigung unter baustellentypischen Bedingungen. Um die autogene Schwindrissneigung zukünftig als Funktion der Temperatur und des Lastniveaus empirisch modellieren zu können, wurden eine analytische Spannungslösung für nicht-isotherme Ring-Tests und ein neuer Ansatz zur Untersuchung der Resttrag- und Relaxationsfähigkeit mit Hilfe nicht-passiver Ring-Tests vorgeschlagen.:1 Introduction 2 Autogenous shrinkage 5 2.1 Shrinkage and hydration 5 2.2 Definitions and research approaches 10 2.3 Metrological issues 14 2.3.1 Multitude of test methods 14 2.3.2 Time-zero 16 2.3.3 Other metrological issues 18 2.4 Corrugated tube method 19 2.5 Influencing parameters 21 2.5.1 Concrete composition 21 2.5.2 Temperature 23 2.5.3 Specific countermeasures 25 2.6 Summary and conclusions with respect to the own work 25 3 Concretes used in the own investigations 27 3.1 Preliminary remarks 27 3.2 Concrete compositions 27 3.3 Constituents 28 3.3.1 Cement 28 3.3.2 Ground-granulated blast furnace slag 28 3.3.3 Silica fume 28 3.3.4 Admixtures 29 3.3.5 Aggregates 29 3.4 Mixing 29 3.5 Basic properties 30 3.5.1 Compressive strength 30 3.5.2 Splitting tensile strength 31 3.5.3 Modulus of elasticity 33 3.5.4 Analysis of mechanical properties 35 3.5.5 Coefficient of thermal expansion 38 3.5.6 Isothermal calorimetry 39 3.6 Summary 39 4 Shrinkage cone method for measuring autogenous shrinkage 41 4.1 Introduction 41 4.2 Setup and measurement procedure 41 4.3 Temperature control 44 4.4 Precision under quasi-isothermal conditions 47 4.4.1 Repeatability 47 4.4.2 Reproducibility 49 4.4.3 Shrinkage cone method vs. corrugated tube method 49 4.5 Autogenous shrinkage of the investigated concretes at 20 °C 54 4.6 Tests under non-isothermal conditions 55 4.7 Summary 56 5 Stress and cracks due to restrained autogenous shrinkage 58 5.1 Introduction 58 5.2 Degree of restraint 58 5.3 Formation of cracks 60 5.4 Very early age and importance of stress relaxation 63 5.5 Creep and cracking - further methodological aspects 65 5.6 Autogenous shrinkage cracking propensity 69 5.7 Role of temperature history 70 5.8 Further state of knowledge 72 5.8.1 Preliminary remarks on test methods 72 5.8.2 Quantitative investigations under restraint conditions 73 5.8.3 A full-scale model for assessing the cracking risk at very early age 77 5.9 Summary 78 6 Investigation of the autogenous shrinkage cracking propensity 80 6.1 Introduction 80 6.2 Suitability of temperature-stress testing machines 80 6.2.1 Development, setup and use 80 6.2.2 Results of round robin tests 83 6.3 Restrained ring test - methodological foundations 86 6.3.1 Setup and use 86 6.3.2 Evaluation of restrained ring tests 90 6.3.3 Use of temperature changes for the investigation of creep and relaxation 96 6.4 Own investigations with the restrained ring test 97 6.4.1 Setup 97 6.4.2 Compensation of disturbing temperature effects 99 6.4.3 Repeatability 100 6.4.4 Measured steel ring strains 101 6.4.5 Simple stress analysis 102 6.4.6 Autogenous shrinkage cracking propensity - further analysis 106 6.4.7 Thermal stress component 116 6.4.8 Period of maximum cracking propensity 118 6.4.9 Restraint stress versus autogenous shrinkage 119 6.4.10 Cracking propensity versus autogenous shrinkage 120 6.4.11 Further considerations on creep 121 6.5 Summary 126 7 Summary, conclusions and outlook 128 7.1 Summary and conclusions 128 7.2 Outlook 130 8 Literature 131 9 Annex 159

Im Mittelpunkt der vorliegenden Arbeit stehen Bauelemente, die auf der Basis von sog. akustischen Oberflächenwellen, in der Fachsprache üblicherweise mit dem Begriff SAW (surface acoustic wave) bezeichnet, arbeiten. In den vergangenen ca. 40 Jahren haben SAW-Bauelemente einen außerordentlich starken Aufschwung erlebt. Den Beginn markierte ein neuartiger Zwischenfrequenz-Filter für Fernsehgeräte am Ende der 1960er Jahre. Heute finden sich unterschiedliche Arten dieser Bauelemente in nahezu jedem Bereich unseres täglichen Lebens wieder. Als Beispiele können hier allgemein die draht-, funk- und fasergestützte Daten- und Signalübertragung und im Speziellen Mobil- und Schnurlostelefone oder Fernbedienungen genannt werden. Inzwischen sind auch neue Anwendungen in der Sensorik sowie der Identifikationstechnik hinzugekommen. Es gibt für SAW-Bauelemente eine Entwicklung hin zu höheren Arbeitsfrequenzen, steigenden Leistungen, erhöhter Zuverlässigkeit, weiterer Miniaturisierung und zunehmender Modulintegration, wobei alle Anforderungen bei gleichzeitig sinkenden Herstellungskosten realisiert werden müssen. Dabei zeichnet sich ab, dass mit den herkömmlichen Herstellungstechnologien nicht alle Bedürnisse erfüllt werden können. So ist z.B. die Lift-off-Technik, mit der ein Großteil der Bauelemente hergestellt wird, nicht auf beliebig kleine Strukturen anwendbar. Eine Alternative bildet die sog. Damaszentechnologie, die auch zur Herstellung modernster Mikroprozessoren eingesetzt wird. Dabei werden die Metallelektroden anstatt auf dem Substrat aufzuliegen, in das Substrat eingelassen, woraus sich für zukünftige SAWBauelemente Vorteile ergeben können, wie z.B. eine erhöhte Leistungsbeständigkeit, kostengünstige Abscheideverfahren, eine Reduktion der Strukturgrößen und eine planare Oberfläche. Das Ziel der vorliegenden Arbeit liegt darin, die Damaszentechnologie erstmalig auf SAW-Strukturen anzuwenden und mit den Vorteilen der Cu-Technologie zu kombinieren. Als inhaltliche Schwerpunkte wurden die Herstellung von Demonstratorbauelementen und die Bewertung der Prozessschritte, die Eigenschaftsbestimmung der Strukturen sowie deren Schädigungsverhalten bei Leistungsbelastung definiert.

Die Vision bei diesem Projekt bestand darin, zukünftig anstelle massiver Betontragsysteme mit meist ungleichmäßiger Materialausnutzung am Kraftfluss orientierte, filigrane, stabartige Tragwerke zu entwerfen, die sich neben der Gewichtsreduktion und einer höheren Transparenz auch durch eine bessere Ressourcennutzung auszeichnen. Dabei wurde eine modulare Bauweise angestrebt, bei der die Einzelkomponenten Druckstab und vorgespannter Zugstab sowie Teile des Verbindungsknotenelements vorgefertigt und am Einsatzort zusammengefügt werden. Sowohl im Hinblick auf die Tragfähigkeits- und Verbundeigenschaften als auch auf die Dauerhaftigkeit sollten die Stäbe aus faserverstärktem Ultrahochleistungsbeton (UHPFRC) hergestellt sowie ausschließlich mit nichtmetallischen Elementen aus faserverstärkten Kunststoffen (FVK) bewehrt bzw. vorgespannt werden. Im geförderten Zeitraum lag das Hauptaugenmerk auf der Entwicklung filigraner, formoptimierter Druck- und vorgespannter Zugstäbe. Zum Knotenelement wurden theoretische Überlegungen sowie erste Tastversuche angestellt. [Aus: Projektidee und Zielsetzung] / The vision of this project was to replace massive concrete structures with mostly inhomogeneous material utilization in the future by designing filigree concrete truss supporting structures in accordance with the principle form follows force instead. Thus, besides weight reduction and a higher transparency also a higher resource efficiency can be achieved. A modular construction method, in which the components compression strut, prestressed tie and connection joint elements are prefabricated and joined together at the construction site, was aspired. With regard to load-bearing capacity and bonding behaviour as well as durability, the struts and ties are made of Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC) and are reinforced or prestressed exclusively with non-metallic elements made of f bre-reinforced polymers (FRP). Within the funding period, the focus was on the development of f ligree, shape-optimized struts and prestressed ties. Regarding the connection joint element, theoretical considerations were made and first basic tests were carried out. [Off: Vision and objective]

Byggindustrin har i dagsläget en negativ klimatpåverkan och infrastrukturen likaså. Många länder har därför försökt undersöka möjligheten att hitta ett långsiktigt och hållbart alternativ till det konventionella reparationsmaterialet. Olika material undersöks, olika optimerade betongrecept testas för att förstå hur miljöpåverkan har minimeras för att förlänga livslängden hos betongkonstruktioner. Vid reparation av en bro är det viktigt att ta hänsyn till både kostnader och miljöpåverkan under hela dess livscykel. Kostnader som uppstår är investeringskostnader samt drift- och underhållskostnader. Miljöpåverkan från betongkonstruktioner i produkt skedet består av materialframställning, byggtransporter och produktion på byggarbetsplatserna. totala växthusgasutsläppet summeras och beräknas i kg CO2-ekv. Syftet med detta examensarbete är att studera den långsiktiga hållbarheten hos UHPC med hjälp av beräkningsmodeller såsom livscykelanalys och livscykelkostnadsanalys med avsikt att applicera reparationstekniken. Flera UHPC recept ställs mot det konventionella reparationsmaterialet detta för att kunna bedöma miljöpåverkan och kostnadseffektiviteten hos materialen. Dvs om det går det att minska klimatutsläppet och kostnaderna. De jämförda recepten är olika UHPC-recept samt traditionell betong. Recepten appliceras slutligen på en befintlig bropelare för att undersöka de olika receptens tillämpbarhet som reparationsmaterial ur ett hållbarhetsperspektiv. Det saknas tillräckligt med kunskap om UHPC:s långtidseffekter, speciellt om reparationsintervall. Med åtanke på materialets höga draghållfasthet och beständighet tillsammans med UHPC:s strukturella egenskaper har antaganden gjorts att materialet är reparationsfri under konstruktionens livslängd. Det vill säga att bropelaren som undersökts med UHPC i studien inte behövt repareras under sin livslängd. Resultatet från livscykelkostnadsanalysen visar att UHPC är dyrare i både kubikmeter (m3) och kvadratmeter (m2) med tanke på täckskiktets tjocklek än traditionell betong i materialpriset. Men med tanke på att UHPC är underhållsfritt har den en mindre livscykelkostnad. Resultatet från livscykelanalysen visar att UHPC blandningarna har större miljöpåverkan per kubikmeter. Då de olika täckskiktetstjocklek relateras till pelarens längd erhålls resultat där UHPC medför slankare konstruktioner och besparingar upp emot 50% mindre betongvolym (för den 6 m långa pelaren i fallstudien). Med UHPC som reparationsmaterial medför det till att bron inte behöver repareras under dess livslängd. Bropelaren som repareras med UHPC kommer därför ha en mindre miljöpåverkan än den traditionella betongen. Långsiktig hållbarhet och mindre totala växthusgasutsläpp (som är i riktlinje med EU:s och regeringens klimatkrav) erhålls för anläggningskonstruktioner med UHPC. / The construction industry has a negative climate impact and so does the infrastructure. Which is due to frequent repairs that are not sustainable. Many countries have therefore tried to explore the possibility of finding a long-term and sustainable alternative to conventional repair materials. Different materials are examined, different optimized concrete recipes are tested to understand how the environmental impact can be minimized and the service life of concrete structures extended. When repairing a bridge, it is important to take into account both costs and environmental impact throughout its life cycle. Costs that arise are investment costs as well as operating and maintenance costs. The environmental impact from concrete structures in the product phase consists of material production, construction transports and production at construction sites. The total greenhouse gas emissions are summed up and calculated in kg CO2 eq. The purpose of this thesis is to study the long-term sustainability of UHPC using calculation models such as life cycle analysis and life cycle cost analysis with the intention of applying the repair technique. Several UHPC prescriptions are set against the conventional repair material in order to be able to assess the environmental impact and cost-effectiveness of the materials. That is, if it is possible to reduce climate emissions and costs. The compared recipes are different UHPC recipes and traditional concrete. The recipes are finally applied to an existing bridge pillar to investigate the applicability of the various recipes as repair materials from a sustainability perspective. There is a lack of knowledge about the long-term effects of UHPC, especially about repair intervals. Given the high tensile strength and durability of the material together with the structural properties of the UHPC, it has been assumed that the material is repair-free for the life of the structure. That is, the bridge pillar examined with UHPC in the study did not need to be repaired during its lifetime. The results from the life cycle cost analysis show that UHPC is more expensive in both cubicmeters (m3) and square meters (m2) given the thickness of the cover layer than traditional concrete in the material price. However, given that UHPC is maintenance free, it has a lower lifecycle cost. The results from the life cycle analysis show that the UHPC mixtures have a greater environmental impact per cubic meter when the cover layer varies. As the thickness of the different cover layers is related to the length of the pillar, results are obtained where UHPC leads to slimmer constructions and savings of up to 50% less concrete volume (for the 6 m long pillar in the case study). With UHPC as repair material, this means that the bridge does not need to be repaired during its service life. The bridge pillar that is repaired with UHPC will therefore have a smaller environmental impact than the traditional concrete. Long-term sustainability and smaller total greenhouse gas emissions (which are in line with EU and government climate requirements) are obtained for plant constructions with UHPC.

Tesis por compendio / [ES] Todas estructuras, especialmente las conformadas con hormigón armado, no solo deben cumplir con la seguridad necesaria bajo los Estados Límites Últimos (ULS), además es imprescindible que garanticen un comportamiento adecuado frente a condiciones de servicio. En general, los requisitos fundamentales de servicio que debe cumplir este tipo de estructuras son: la funcionalidad, comodidad para el usuario y la apariencia. Sin embargo, estos no se pueden verificar de forma directa; por lo tanto, ha sido necesario definir criterios de desempeño tales como control de deflexión, control de vibración y control de agrietamiento para dar cumplimiento a lo indicado anteriormente. Además, se dificulta el cálculo de la capacidad de servicio debido al fenómeno de agrietamiento, el efecto de rigidez por tensión, la contracción y los efectos de fluencia. Por lo tanto, el control de la fisuración en estructuras de hormigón armado generalmente se logra limitando la tensión en el refuerzo de acero y la matriz de hormigón. Siendo así que, en los diseños incluidos en códigos relevantes a hormigón, especifican la tensión máxima del refuerzo de acero después de la fisuración y el ancho máximo de fisura para los miembros estructurales de CR o FRC, no obstante los aspectos de capacidad de servicio del diseño para el hormigón reforzado con fibras de ultra alto rendimiento reforzado (R-UHPFRC), no han sido incluidos en los códigos o recomendaciones de UHPFRC. A pesar de que se han realizado muchos esfuerzos en la investigación tanto experimental como teórica sobre el comportamiento de servicio de los elementos estructurales de CR o FRC durante las últimas décadas, para el R-UHPFRC se debe desarrollar aún más su conocimiento relacionado con los requisitos para el diseño de capacidad de servicio, incluyendo su comportamiento de tensión y agrietamiento. En este marco, el objetivo principal de la presente tesis doctoral es evaluar el comportamiento de servicio de R-UHPFRC. Por tal razón, es fundamental realizar la evaluación del comportamiento de deformación y fisuración de los elementos de tracción R-UHPFRC. Para ello, se abordaron y cumplieron adecuadamente dos puntos principales. El primero, diseñar una metodología de prueba innovadora y adecuada para ejecutar los experimentos requeridos para este proyecto de doctorado. En segundo lugar, se llevó a cabo la evaluación de la respuesta de rigidez a la tensión y el comportamiento de agrietamiento del R-UHPFCR, que son parámetros primordiales para el diseño de capacidad de servicio. Para estudiar estos dos parámetros, se consideraron algunos parámetros importantes tales como: el efecto del volumen del contenido de fibra, el tipo de fibra, el efecto del tamaño, el efecto de la relación de refuerzo y el efecto de la contracción. Finalmente, para evaluar los parámetros mencionados, se presentan cuatro campañas experimentales. Cada una de ellas, representa un nivel diferente de estudio. El primero corresponde a la validación de la metodología de ensayo de tracción propuesta y examinar los datos experimentales obtenidos, para emplearlos en futuros estudios de este proyecto. El segundo nivel consistió en establecer y realizar experimentos completos con dos tipos de fibra de acero, modificando además su cantidad, es así como se utilizaron diferentes proporciones de refuerzo y sección transversal para evaluar el efecto tanto del tamaño como del contenido de fibra, respectivamente. También, en un estudio experimental específico se indagó sobre el efecto de la combinación de micro y microfibras de acero en la deformación y el comportamiento de agrietamiento de los elementos R-UHPFRC de tracción. El tercer nivel corresponde a una prueba de contracción intensiva, necesaria para obtener el valor de contracción del UHPFRC utilizado en esta investigación. El último nivel comprende la modificación de la geometría de la probeta y el uso de probetas en forma de hueso de perro para evaluar el ancho medio y máximo de fisura (valor / [CA] Totes les estructures, especialment les conformades amb formigó armat, no només han de complir amb la seguretat necessària sota els Estats Límits Últims (ULS), a més és imprescindible que garanteixin un comportament adequat davant de condicions de servei. En general, els requisits fonamentals de servei que ha de complir aquest tipus d'estructures són: la funcionalitat, la comoditat per a l'usuari i l'aparença. Això no obstant, aquests no es poden verificar de forma directa; per tant, ha calgut definir criteris d'acompliment com ara control de deflexió, control de vibració i control d'esquerdament per a donar compliment al que s'ha indicat anteriorment. A més, es dificulta el càlcul de la capacitat de servei a causa del fenomen d'esquerdament, l'efecte de rigidesa per tensió, la contracció i els efectes de fluència. Per tant, el control de la fissuració en estructures de formigó armat generalment s'aconsegueix limitant la tensió al reforç d'acer i la matriu de formigó. És així que en els dissenys inclosos en codis rellevants a formigó, especifiquen la tensió màxima del reforç d'acer després de la fissuració i l'amplada màxima de fissura per als membres estructurals de CR o FRC, no obstant els aspectes de capacitat de servei del disseny per al formigó reforçat amb fibres d'ultra alt rendiment reforçat (R-UHPFRC), no han estat inclosos als codis o recomanacions d'UHPFRC. Tot i que s'han realitzat molts esforços en la investigació tant experimental com teòrica sobre el comportament de servei dels elements estructurals de CR o FRC durant les últimes dècades, per al R-UHPFRC s'ha de desenvolupar encara més el seu coneixement relacionat amb els requisits per al disseny de capacitat de servei, incloent el comportament de tensió i esquerdament. En aquest marc, l'bjectiu principal de la present tesi doctoral és avaluar el comportament de servei de R-UHPFRC. Per aquesta raó, és fonamental fer l'avaluació del comportament de deformació i fissuració dels elements de tracció R-UHPFRC. Per això, es van abordar i van complir adequadament dos punts principals. El primer, dissenyar una metodologia de prova innovadora i adequada per executar els experiments requerits per a aquest projecte de doctorat. En segon lloc, es va fer l'avaluació de la resposta de rigidesa a la tensió i el comportament d'esquerdament del R-UHPFCR, que són paràmetres primordials per al disseny de capacitat de servei. Per estudiar aquests dos paràmetres, es van considerar alguns paràmetres importants com ara l'efecte del volum del contingut de fibra, el tipus de fibra, l'efecte de la mida, l'efecte de la relació de reforç i l'efecte de la contracció. Finalment, per avaluar els paràmetres mencionats, es presenten quatre campanyes experimentals. Cadascuna representa un nivell diferent d'estudi. El primer correspon a la validació de la metodologia dassaig de tracció proposada i examinar les dades experimentals obtingudes, per a emprar-les en futurs estudis daquest projecte. El segon nivell va consistir a establir i realitzar experiments complets amb dos tipus de fibra d'acer, modificant-ne a més la quantitat, és així com es van utilitzar diferents proporcions de reforç i secció transversal per avaluar l'efecte tant de la mesura com del contingut de fibra, respectivament. També, en un estudi experimental específic, es va indagar sobre l'efecte de la combinació de micro i macrofibres d'acer en la deformació i el comportament d'esquerdament dels elements R-UHPFRC de tracció. El tercer nivell correspon a una prova de contracció intensiva, necessària per obtenir el valor de contracció de l'UHPFRC utilitzat en aquesta investigació. L'últim nivell comprèn la modificació de la geometria de la proveta i l'ús de provetes en forma d'os de gos per avaluar l'amplada mitjana i màxima de fissura (valor real detectat) provocat per esforços de tracció en els elements de tracció R-UHPFRC . És important esmentar que es van fer diferents anàlisis per a cada investigació experimental i es van ac / [EN] All structures, particularly reinforcement concrete structures, apart from meeting necessary security against Ultimate Limit States (ULS), must exhibit appropriate behaviour under service conditions. Generally, the fundamental serviceability requirements that concrete structures should meet are functionality, user comfort and appearance. These requirements cannot, however, be directly checked. Therefore, performance criteria, such as deflection control, vibration control and cracking control, are defined to meet these requirements. Serviceability calculation is complicated because of the cracking phenomenon, the tension stiffening effect, shrinkage, and creep effects. Cracking control in reinforced concrete (RC) structures is generally achieved by limiting stress in steel reinforcement and the concrete matrix. Many concrete code designs specify a maximum steel reinforcement stress after cracking and a maximum crack width for RC or fibre-RC (FRC) structural members, while the design serviceability aspects for Reinforced Ultra-High Performance Fibre-Reinforced Concrete (R-UHPFRC) are poorly considered in UHPFRC codes or recommendations. Many efforts have been made in experimental and theoretical research into the serviceability behaviour of RC or FRC structural elements in the last few decades. However, for R-UHPFRC, knowledge about tension and cracking behaviour must improve and serviceability design requirements have to be further studied. Within this framework, the main purpose of the present PhD thesis is to evaluate the serviceability behaviour of R-UHPFRC. For this purpose, the evaluation of the deformation and cracking behaviour of R-UHPFRC tensile elements is essential. To that end, two main items were addressed and adequately met. The first one was to design an innovative and adequate test methodology to carry out the experiments required for this PhD project. The second involved evaluating the tension stiffening response and cracking behaviour of R-UHPFRC, which are fundamental parameters for R-UHPFRC structures' serviceability design. To study these two parameters, important parameters were considered, such as fibre content, fibre type, size effect, reinforcement ratio and shrinkage effect. In order to evaluate the aforementioned parameters, four experimental campaigns are presented. Each campaign represents a different study level. The first corresponds to the validation of the proposed tensile test methodology and to the examination of the obtained experimental data for future studies required for this PhD project. The second experimental study level corresponds to establishing and undertaking comprehensive experimental programmes with two different steel fibre types and fibre contents. Different cross-section and reinforcement ratios were used to evaluate the size effect and fibre content effect, respectively. The effect of the micro- and macro-steel fibres combination on the deformation and cracking behaviour of tensile R-UHPFRC elements was investigated in a specific experimental study. The third level corresponds to an intensive shrinkage test, which was conducted to obtain the shrinkage value of the UHPFRC used in this PhD study. The final level corresponds to a specific experimental study, done by modifying the specimen's geometry and using the dog bone-shaped specimens to evaluate the average and maximum crack width (real detected value) caused by tensile stresses in R-UHPFRC tensile elements. It is worth mentioning that different analyses were performed for each experimental research and appropriate results were achieved to fulfil the thesis aims. Keywords: cracking behaviour, design criteria, durability, fragility curve, post-cracking tensile stiffness, serviceability behaviour, shrinkage, SLS requirements, structural design, tensile elements, tension stiffening, test method, tie, UHPFRC. / This work is part of Project “BIA2016-78460-C3-1-R” supported by the State Research Agency of Spain / Khorami, M. (2023). Serviceability Behaviour of Reinforced UHPFRC Tensile Elements [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/192683 / Compendio

This thesis presents HELIOS, an in-house laboratory for time-resolved pump-probe spectroscopy with extreme-ultraviolet (XUV) probe radiation. A wide span of pump wavelengths can be generated using commercial laser equipment while XUV probe radiation is generated via a high harmonic generation process in a noble gas delivering probe photons with energies between 20 eV and 72 eV. The XUV beam path features a time-preserving monochromator and was constructed and built in-house. HELIOS features an overall time resolution of about 50 fs when using 800 nm pump and 41 eV probe photons. An energy resolution of 110 meV at 41 eV photon energy can be achieved. HELIOS features two beamlines. One µ-focus beamline with an XUV focal size of about 20 µm can be used with experiments that require such a small XUV focal size as well as with different end stations. The other beamline features a semi-permanently mounted end station for angle-resolved photoelectron spectroscopy under ultra-high vacuum conditions. Experiments demonstrating the usability of HELIOS and the two beamlines are presented. A pump-probe measurement on graphene demonstrates the capability of determining a large part of the k-space in only one measurement due to the use of an ARTOF angle-resolved time-of-flight electron spectrometer. A non-angle-resolved pump-probe measurement on the conducting polymer PCPDTBT demonstrates the high signal-to-noise ratio achievable at this beamline in non-angle-resolved photoelectron-spectroscopy pump-probe measurements. The usability of the µ-focus beamline is demonstrated with time-resolved measurements on magnetic samples employing an in-house-designed spectrometer. These experiments allow the retrieval of element-specific information on the magnetization within a sample employing the transversal magneto-optical Kerr effect (T-MOKE). Additionally, a Fourier transform spectrometer for the XUV is presented, the concept was tested at a synchrotron and it was used to determine the longitudinal coherence of the XUV radiation at HELIOS.

We present the development of a novel, UHV-compatible device fabrication strategy for the realisation of nano- and atomic-scale devices in silicon by harnessing the atomic-resolution capability of a scanning tunnelling microscope (STM). We develop etched registration markers in the silicon substrate in combination with a custom-designed STM/ molecular beam epitaxy system (MBE) to solve one of the key problems in STM device fabrication ??? connecting devices, fabricated in UHV, to the outside world. Using hydrogen-based STM lithography in combination with phosphine, as a dopant source, and silicon MBE, we then go on to fabricate several planar Si:P devices on one chip, including control devices that demonstrate the efficiency of each stage of the fabrication process. We demonstrate that we can perform four terminal magnetoconductance measurements at cryogenic temperatures after ex-situ alignment of metal contacts to the buried device. Using this process, we demonstrate the lateral confinement of P dopants in a delta-doped plane to a line of width 90nm; and observe the cross-over from 2D to 1D magnetotransport. These measurements enable us to extract the wire width which is in excellent agreement with STM images of the patterned wire. We then create STM-patterned Si:P wires with widths from 90nm to 8nm that show ohmic conduction and low resistivities of 1 to 20 micro Ohm-cm respectively ??? some of the highest conductivity wires reported in silicon. We study the dominant scattering mechanisms in the wires and find that temperature-dependent magnetoconductance can be described by a combination of both 1D weak localisation and 1D electron-electron interaction theories with a potential crossover to strong localisation at lower temperatures. We present results from STM-patterned tunnel junctions with gap sizes of 50nm and 17nm exhibiting clean, non-linear characteristics. We also present preliminary conductance results from a 70nm long and 90nm wide dot between source-drain leads which show evidence of Coulomb blockade behaviour. The thesis demonstrates the viability of using STM lithography to make devices in silicon down to atomic-scale dimensions. In particular, we show the enormous potential of this technology to directly correlate images of the doped regions with ex-situ electrical device characteristics.

We present the development of a novel, UHV-compatible device fabrication strategy for the realisation of nano- and atomic-scale devices in silicon by harnessing the atomic-resolution capability of a scanning tunnelling microscope (STM). We develop etched registration markers in the silicon substrate in combination with a custom-designed STM/ molecular beam epitaxy system (MBE) to solve one of the key problems in STM device fabrication ??? connecting devices, fabricated in UHV, to the outside world. Using hydrogen-based STM lithography in combination with phosphine, as a dopant source, and silicon MBE, we then go on to fabricate several planar Si:P devices on one chip, including control devices that demonstrate the efficiency of each stage of the fabrication process. We demonstrate that we can perform four terminal magnetoconductance measurements at cryogenic temperatures after ex-situ alignment of metal contacts to the buried device. Using this process, we demonstrate the lateral confinement of P dopants in a delta-doped plane to a line of width 90nm; and observe the cross-over from 2D to 1D magnetotransport. These measurements enable us to extract the wire width which is in excellent agreement with STM images of the patterned wire. We then create STM-patterned Si:P wires with widths from 90nm to 8nm that show ohmic conduction and low resistivities of 1 to 20 micro Ohm-cm respectively ??? some of the highest conductivity wires reported in silicon. We study the dominant scattering mechanisms in the wires and find that temperature-dependent magnetoconductance can be described by a combination of both 1D weak localisation and 1D electron-electron interaction theories with a potential crossover to strong localisation at lower temperatures. We present results from STM-patterned tunnel junctions with gap sizes of 50nm and 17nm exhibiting clean, non-linear characteristics. We also present preliminary conductance results from a 70nm long and 90nm wide dot between source-drain leads which show evidence of Coulomb blockade behaviour. The thesis demonstrates the viability of using STM lithography to make devices in silicon down to atomic-scale dimensions. In particular, we show the enormous potential of this technology to directly correlate images of the doped regions with ex-situ electrical device characteristics.