Rozprawy doktorskie na temat „Concrete tensile strength”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Concrete tensile strength”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Fields, Kelvin L. "Tension stiffening response of high-strength reinforced concrete tensile members". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0002/MQ35492.pdf.
Pełny tekst źródłaMahjoub-Moghaddas, Hamid. "Tensile and shear impact strength of concrete and fibre reinforced concrete". Thesis, Cardiff University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261439.
Pełny tekst źródłaZheng, Wei, i 鄭偉. "Shock vibration resistance and direct tensile strength of concrete". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242753.
Pełny tekst źródłaZheng, Wei. "Shock vibration resistance and direct tensile strength of concrete". Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23273124.
Pełny tekst źródłaSrinivasan, Geetha. "Evaluation of indirect tensile strength to identify asphalt concrete rutting potential". Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3477.
Pełny tekst źródłaTitle from document title page. Document formatted into pages; contains vii, 65 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-53).
JUNIOR, JOAQUIM NUNES MARTINS. "TENSILE STRENGTH OF A CONCRETE ANCHORING SUBJECTED TO IMPACT LOAD". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8724@1.
Pełny tekst źródłaEste trabalho tem como objetivo estudar a resistência de um sistema de ancoragem composto de pinos com cabeça embutidos no concreto, quando submetidos a cargas de impacto. A variável adotada foi a taxa de carregamento cujos valores mínimo e máximo foram 0,015 kN/s (estático) e 54.885 kN/s, respectivamente. O sistema de ancoragem foi projetado de forma que a ruptura fosse governada pelo arrancamento do cone de ruptura. Foram ensaiados onze blocos de concreto com um pino embutido no concreto, sujeitos a diferentes taxas de aplicação de carga. Foram também ensaiados quinze corpos-de-prova de concreto à compressão diametral e nove pinos à tração, também sujeitos a diferentes taxas de aplicação de carga. O objetivo desses ensaios foi verificar a influência da taxa de carregamento sobre as resistências dos materiais - concreto e aço - que participam do sistema de ancoragem. Os resultados mostraram que a área da superfície e a inclinação do cone de ruptura não sofrem grandes alterações. A carga de ruptura do cone de concreto cresce com a taxa de carregamento, e que esse crescimento pode ser descrito por uma função logarítmica. O mesmo foi observado para a resistência à tração do concreto por compressão diametral e para os pinos.
This work investigates the strength of a concrete anchor system constituted of headed studs embedded in concrete subjected to impact tension load. The main variable was the loading rate which varied from a minimum of 0,015 kN/s (static) to a maximum of 54885 kN/s. The anchor system was designed so that the failure was governed by concrete cone breakout. Eleven concrete blocks with a single headed stud were tested under different loading rates. In addition, fifteen concrete cylinders subjected to compression along a diameter (split cylinder test) and nine headed studs subjected to tension were tested under different loading rates in order to investigate the effects of the loading rate on the strength of concrete and steel separately. The results showed that the area and the angle of the concrete cone were not affected by the loading rate. The failure load of the concrete cone increases as the loading rate increases and this phenomenon can be described by a logarithmic function. The concrete split tensile strength and the steel tensile strength also increase as the loading rate increases.
Mahawish, Ali Hassan. "Axisymmetric compression testing of concrete by nitrogen". Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316326.
Pełny tekst źródłaOLIVEIRA, WALTER EDGLEY DE. "EXPERIMENTAL STUDY ON THE TENSILE STRENGTH OF ANCHORAGE PLATES EMBEDDED IN CONCRETE". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4239@1.
Pełny tekst źródłaELETROBRAS TERMONUCLEAR S.A - ELETRONUCLEAR
Placas de ancoragem embutidas em concreto são empregadas, geralmente, com a finalidade de permitir a fixação de elementos para a introdução de cargas concentradas nas estruturas de concreto, bem como viabilizar as ligações estruturais entre componentes pré-fabricados. As placas são ancoradas no concreto através de pinos soldados a elas. Estas placas são bastante empregadas em estruturas de usinas nucleares onde um grande número de equipamentos e tubulações são apoiados na estrutura de concreto. A pesquisa é de natureza experimental e tem como objetivo investigar a redução da resistência à tração de placas de ancoragem com grupo de chumbadores, placas instaladas com pequena distância dos bordos do elemento de concreto, e também de duas placas adjacentes, devido a interferência de seus cones de ruptura. A eficiência de uma armadura de suspensão (que transmite a carga além do cone de ruptura), também é verificada. Os resultados experimentais sugerem uma notável redução da resistência à tração para placas com grupo de chumbadores, e que o uso da armadura de suspensão para placa instalada nas proximidades do bordo do elemento de concreto não é muito eficiente. A armadura de suspensão apresentou um bom rendimento quando foi empregada em placas com grupo de chumbadores. Os resultados teóricos obtidos através de equações desenvolvidas para estimativa da carga de ruptura, apresentaram, de maneira geral, uma boa aproximação quando comparados com os resultados experimentais.
Anchorage plates embedded in concrete are used with the purpose of allowing the fixation of elements for the introduction of concentrated loads into concrete structures, as well as to make possible the structural connections between prefabricated components. The plates are anchored in the concrete through studs welded to them. These plates are used in structures of nuclear power stations where a great number of equipments and pipings are fixed in the concrete structure. The research is of experimental nature and its objective is to investigate the reduction of the tensile strength of multiple studs group, anchorage plates located close to a free edge, and also of two adjacent plates, due to interference of failure concrete cones. The efficiency of an additional reinforcement (that transfers the load beyond the concrete cone), is also addressed. The experimental results suggest a significant reduction of the tensile strength for plates with studs group, and that the use of the additional reinforcement for anchorage plates located close to a free edge is not too efficient. The additional reinforcement presented a good efficiency when it was used in plates with studs group. The theoretical results obtained from equations developed to estimate the concrete failure load show, in a general way, a good agreement with the experimental results.
Azizipesteh, Baglo Hamid Reza. "Effect of various mix parameters on the true tensile strength of concrete". Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12560.
Pełny tekst źródłaLi, Guang. "The effect of moisture content on the tensile strength properties of concrete". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0004782.
Pełny tekst źródłaRoth, Michael Jason 1975. "Flexural and tensile properties of thin, very high-strength, fiber-reinforced concrete panels". Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-11062007-215816.
Pełny tekst źródłaConroy-Jones, Gene A. "The effects of curing, and aggregate type upon the tensile strength measurement of medium to high strength concrete". Thesis, Cardiff University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301797.
Pełny tekst źródłaAxson, Daniel Peter. "Ultimate Bearing Strength of Post-tensioned Local Anchorage Zones in Lightweight Concrete". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/33711.
Pełny tekst źródłaMaster of Science
Annam, Ramyasree. "Study of Mechanical Properties of PVA Fiber-Reinforced Concrete With Raman Spectroscopic Analysis". TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1460.
Pełny tekst źródłaHassan, Husseen, i Abdifatah Sahal. "Experimental Tests of Pre - placed Aggregate Concrete for Concrete Repairs". Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278540.
Pełny tekst źródłaDå en stor del av vattenkraftsdammarna i Sverige byggdes på 1950 och 1960-talet börjar många av dessa sakta men säkert brytas ner. Vattenkraftföretagen står inför stora utmaningar och investerar följaktligen i effektiva reparationsmetoder då dammbrott skulle kunna få allvarliga konsekvenser för människor, den omgivande miljön och för samhället. Flertalet konstruktioner inom vattenkraften är gjorda av betong och kraven på den nya kompletterande betongen är höga. En betong med potentialen att möta och uppfylla dessa höga krav är injekteringsbetongen som i tidigare studier uppvisat lovande resultat beträffande dess mekaniska egenskaper. Med anledning av detta är injekteringsbetongen av intresse att undersöka. Fokus har inte varit på att optimera injekteringsbetongen i syfte att genomföra fullskaliga försök. Istället har huvudsyftet med detta examensarbete varit att studera och analysera injekteringsbetongens mekaniska egenskaper såsom krympning, tryckhållfasthet, spräckhållfasthet, frostbeständighet samt undersöka viktiga parametrar i skapandet av ett homogent och lättflytande cementbruk som med god framgång kunde fylla ut hålrummen mellan grova ballasten. Undersökningarna utfördes genom laboratorieförsök på Vattenfalls betonglaboratorium i Älvkarleby. Vidare har skapandet och utvecklandet av bruket utförts i enlighet med metoder och krav angivna i American Society for Testing and Materials, ASTM standards, samt i Svenska institutet för Standarder, SiS. Totalt gjordes 15 bruksblandningar, dock användes enbart de sista fem till gjutning av provkroppar då lufthalten visade sig vara för låg i dem första tio. Resultaten indikerade på att det är nödvändigt att ersätta luftporbildare med mikrosfärer för att erhålla en lufthalt som uppfyller kraven för betong i exponeringsklass XF3 samt XC4. Injekteringbetongens avflagning efter 56 dygn var mindre än 0.1 kg/m2 och frostbeständigheten kunde därmed klassas som mycket god. Användningen av slagg minskade cementbrukets vattenseparation avsevärt och bidrog även till förbättrade gjutresultat. Dock bidrog det å andra sidan till en ökad krympning hos injekteringsbetongen. En effektivitetsfaktor på 0.6 visade sig vara för låg då injekteringsbetongen med slagg hade en cirka 50 % högre tryckhållfasthet än dem utan. Dessutom visade sig injekteringsbetongens krympning vara mindre än den konventionella betongens efter 63 dagar. Tryckhållfastheten hos injekteringsbetongen utan slagg uppvisade även en cirka 15 % lägre tryckhållfasthet än den konventionella betongens. Vibrering under gjutning visade sig höja tryckhållfastheten hos injekteringsbetongen samt förbättra gjutresultaten. En låg vattenseparation i kombination med en flödestid på cirka 45 sekunder för 1.7 liter bruk visade sig ge bästa gjutresultaten. Resultaten från laboratorieförsöken har visat på att injekteringsbetongen besitter stor potential. Dock bör ytterligare undersökningar genomföras för att bedöma huruvida en mindre ballastfraktion för sanden påverkar brukets förmåga att penetrera den grova ballasten. Vidare bör bruket pumpas in istället för att hällas över den grova ballasten, detta för att se huruvida gjutresultaten samt de mekaniska egenskaperna hos injekteringsbetongen skulle förbättras.
Brahmachari, Koushik, of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty i School of Construction and Building Sciences. "Connection and flexural behaviour of steel RHS filled with high strength concrete". THESIS_FTA_CBS_BRAHMACHARI_K.xml, 1997. http://handle.uws.edu.au:8081/1959.7/526.
Pełny tekst źródłaDoctor of Philosophy (PhD)
Zhang, Xuesong, i n/a. "Punching Shear Failure Analysis of Reinforced Concrete Flat Plates Using Simplified Ust Failure Criterion". Griffith University. School of Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20051104.153239.
Pełny tekst źródłaAdhikari, Sudeep. "Mechanical and Structural Characterization of Mini-Bar Reinforced Concrete Beams". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1386682169.
Pełny tekst źródłaFernández, Sánchez Pablo Gonzalo. "Study on the shear and punching-shear strength of reinforced concrete slabs subjected to point loads and in-plane tensile forces". Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673351.
Pełny tekst źródłaLos elementos de hormigón armado, especialmente cuando están sometidos a la acción de cargas puntuales, pueden alcanzar su resistencia última a esfuerzo cortante, lo cual limita su capacidad para deformarse y resistir valores de carga mayores. Este es un modo de fallo frágil y repentino, por lo que debe ser evitado. Así pues, es importante seguir investigando y comprender la naturaleza de la respuesta de vigas y losas de hormigón armado ante solicitaciones de este tipo, sobre todo cuando no están provistas de armadura de cortante. A pesar de la gran cantidad de campañas experimentales llevadas a cabo desde principios del siglo XX, el comportamiento a cortante y punzonamiento de los elementos estructurales de hormigón armado no está todavía del todo claro. La compleja cinemática y la diferente contribución de los mecanismos resistentes ampliamente aceptados, la cual depende, entre otros factores, del nivel de carga y de la geometría de los especímenes, son parte de esas incertidumbres que han provocado la falta de consenso que existe actualmente dentro del campo de la ingeniería estructural. En este contexto, esta tesis se centra en el comportamiento a cortante de losas de hormigón armado sin armadura de cortante sometidas a la acción de cargas puntuales. Por un lado, parte del trabajo realizado durante esta investigación está orientado al cortante en losas unidireccionales apoyadas sobre apoyos lineales. Gracias a todas las campañas experimentales realizadas en las últimas dos décadas, una significativa base de datos de resultados experimentales se encuentra disponible en la literatura, lo que ha permitido desarrollar y verificar un nuevo modelo mecánico para predecir la resistencia última a cortante de este tipo de elementos. Dicho modelo tiene en cuenta un número importante de variables involucradas en el fenómeno y es aplicable a losas simplemente apoyadas, en ménsula, y apoyadas en apoyos con restricción parcial al giro. El modelo se ha dividido en dos sub-modelos para facilitar su desarrollo. Uno para cargas aplicadas cerca de los apoyos, donde la transmisión directa de la carga al apoyo juega un papel importante, y un segundo para cargas aplicadas lejos de los apoyos, en donde se asume que la posibilidad del fallo por cortante coexiste con la posibilidad de un fallo local por punzonamiento. Por otro lado, la segunda parte de la investigación está focalizada en el comportamiento a cortante de losas de hormigón armado sometidas simultáneamente a la acción de cargas puntuales y tracciones en su plano. Este caso de carga no ha sido demasiado investigado a lo largo de las últimas décadas, y con la intención de contribuir a comprender esta compleja interacción, el modelo mecánico recientemente desarrollado en la UPC, para la predicción de la resistencia a punzonamiento en losas bidireccionales, ha sido extendido a este caso particular de cargas y validado con los resultados de campañas experimentales disponibles en la literatura y el conjunto de ensayos realizados como parte de esta investigación para el caso particular de tracciones unidireccionales. Adicionalmente, el efecto de las tracciones transversales en el plano en la resistencia a cortante de losas unidireccionales también ha sido estudiado experimentalmente. Esta combinación de cargas no ha sido apenas investigada y un nuevo grupo de ensayos experimentales puede contribuir a comprender el comportamiento global de este tipo de elementos ante este caso particular de carga.
Enginyeria de la construcció
Hinzen, Marcus, i Wolfgang Brameshuber. "Improvement of Serviceability and Strength of Textile Reinforced Concrete by using Short Fibres". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1244046356375-03273.
Pełny tekst źródłaTazaly, Zeinab. "Punching Shear Capacity of Fibre Reinforced Concrete Slabs with Conventional Reinforcement : Computational analysis of punching models". Thesis, KTH, Bro- och stålbyggnad, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118825.
Pełny tekst źródłaYahya, Mohmed Alkilani. "The effect of polymer materials on the fracture characteristics of high performance concrete (HPC)". Thesis, Edinburgh Napier University, 2015. http://researchrepository.napier.ac.uk/Output/464157.
Pełny tekst źródłaMondo, Eleonora. "Shear Capacity of Steel Fibre Reinforced Concrete Beams without Conventional Shear Reinforcement". Thesis, KTH, Bro- och stålbyggnad, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-41016.
Pełny tekst źródłaÅkergren, David. "RC Trough Bridges: A Parametric Study using FEM and an Analysis of their Current State". Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-87260.
Pełny tekst źródłaLukic, Bratislav. "Mise au point d'une technique de mesure de champs pour la caractérisation du comportement dynamique du béton en traction". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI028/document.
Pełny tekst źródłaIn this thesis a recently proposed photomechanical spalling experiment has been used in light of identifying concrete failure properties under dynamic tension.The experimental technique uses ultra-high speed imaging, the grid method and the virtual fields method.First, in order to investigate the accuracy and validate the processing technique, a methodology of using simulated experiments has been developed by numerically simulating the entire identification process.In this way, several potential sources of errors have been investigated allowing to place guidelines on how to perform the experiment in a more reliable manner.Second, several latest ultra-high speed acquisition systems have been used in order to investigate their contribution to a possible measurement refinement.In this case, the trial experiments have been conducted on a material of known characteristics which allowed investigating the metrological performance of the acquisition system on the entire identification chain.Finally, the experimental methodology has been applied to testing several grades of concrete in light of identifying the material constitutive response as well as their fracturing characteristics under dynamic tension.The identified tensile strengths in this work were found to be consistently lower than those obtained from the standard processing of the rear-face velocity profile.Moreover, the values of the identified specific fracture energy were also found to be markedly lower than the ones often reported in the literature
Assali, Mirella Pennacchi. "Emprego de agentes retardadores em substituição aos desmoldantes convencionais na moldagem de concreto para recebimento do revestimento de argamassas". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-18072013-154420/.
Pełny tekst źródłaThe concrete structures are cast in molds treated with a release agent (demolding product), and its presence hinders the mortars initial adhesion in the plastic state, as well as the bond strength after hardening. The study aims is to explore the potential use of retarding agents to replace conventional release agents in the concrete formwork. The technical viability of using a retarding agent was verified by comparing the tensile bond strength of rendering mortars applied on concrete surfaces cast with a conventional release agent and on concrete surfaces cast with a retarding release agent. The results showed that, through the use of retarding products, the removal of the concrete surface layer was possible by increasing the surface roughness, the surface water absorption and the tensile bond strength of the mortar to this concrete. Performance tests were also done with retarding products commercially available in the Brazilian market to verify the behavior of such products during application on molds, their impact on workers health and on the environment, and the retarding effect in cement hydration. It was also evaluated the applicability of these products and their influence on surface preparation to receive mortar when treated with retarding and conventional products, in three types of molds. Retarding products showed to be a viable technique for reducing the detachment problems of rendering mortars applied on concrete surfaces. Through the specific tests developed and adapted for this study, it was observed that there are differences in behavior between the conventional or retarding products, and also observed how these types of molds can influence the performance of the products. It was also observed that the simplest molds with lower cost can be more suitable in this application.
Láník, Jaromír. "Vliv rozptýlené výztuže na fyzikálně-mechanické parametry výsledného kompozitu". Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-234541.
Pełny tekst źródłaVelásquez, Pacco Lucio Martin. "Propiedades físico mecánicas del concreto reciclado para Lima Metropolitana". Bachelor's thesis, Universidad Ricardo Palma, 2015. http://cybertesis.urp.edu.pe/handle/urp/1261.
Pełny tekst źródłaPanenková, Monika. "Reaktivní práškové kompozity a cementové kompozity bez makropórů". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372126.
Pełny tekst źródłaEppers, Sören. "Assessing the autogenous shrinkage cracking propensity of concrete by means of the restrained ring test". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-65454.
Pełny tekst źródłaDas 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
Myšičková, Lucie. "Vývoj a zkoušení vysokohodnotných betonů pro subtilní konstrukce". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226971.
Pełny tekst źródłaBrameshuber, Wolfgang, i Marcus Hinzen. "Tragverhalten von Textilbeton mit Kurzfasern". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-77905.
Pełny tekst źródłaThe load bearing behaviour of textile reinforced concrete can be significantly improved by the addition of short fibres. Investigations show an increase of the first crack strength, a strain-hardening behaviour, a better crack pattern distribution as well as an increase of the load carrying capacity. However, the exact mechanisms leading to this behaviour are not yet known such that a prediction of the load bearing behaviour is not possible. This paper summarises the investigations on the different parts of the stress-strain curve of textile reinforced concrete with short fibres and tries to describe general relationships. In this context the increase of the first crack stress, the crack bridging behaviour and the influence on the load-bearing behaviour in general are considered. Finally, the dynamic flexural behaviour of textile reinforced concrete with short fibres in state II is presented
Correia, Pedro Miguel de Medeiros. "Comportamentos à tracção de betões com muito elevado teor de fibras de aço". Master's thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/11514.
Pełny tekst źródłaMoura, Cristiane Borges. "Aderência de revestimentos externos de argamassa em substratos de concreto : influência das condições de temperatura e ventilação na cura do chapisco". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/13517.
Pełny tekst źródłaThe prevention of pathological manifestations in mortar renderings, in special case the detachment, reflected a concern of researches and construction companies aiming the knowledge of materials and rendering systems properties, as well as any other external factors. In this case, some variables that intervene (however not-controllable) in the bond strength mechanisms can be cited, as the temperature, humidity and ventilation. In this context, this work objective to analyze the influence of wind and high temperature during the slurry mortar cure and this relationship with the bond of external mortar renderings in concrete substrates. Concrete prisms of 40x45x10cm had been molded, with strength at 28 days of 37MPa. Three mixes of slurry mortars had been used, one proportioned in situ with a cement/aggregate proportion of 1:5,67(in mass) and two other different pre-mixed slurry mortars. Also three mixes of rendering mortars had been used, one proportioned in situ with a cement/limestone/aggregate proportion of 1:0,78: 6,5 (in mass), and two other different premixed mortars. A total of 45 prisms with 90 combinations (with the different slurry and rendering mortars, as well as different sample preparations) had been produced. For each prism, one of the rendered faces had been assayed simulating the wind action during the three days cure of the slurry mortar and in 18 from both them the faces covered also had been assayed with the action of 40ºC temperature (the others were cured at 23°C). Rendering mortars were cured at 23±2°C during 28 days, without wind influence. The humidity was fixed in 60±5%. The mortars (according NBR 13281/05) and concrete substrata characterization, as well as assays of tensile bond strength of the rendering (according NBR 13528/95) had been carried through. Samples of slurry mortars were also cured over the same conditions the prisms were submited. All data obtained had been statistically analyzed trough variance analysis (ANOVA). The results had demonstrated that the wind effect and the heat condition had influenced significantly the bond strength. The type of slurry or rendering mortar had also revealed significant effect in the bond strength.
Gasperin, Josiane. "Aderência de revestimentos de argamassa em substrato de concreto : influência da forma de aplicação e composição do chapisco". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/35609.
Pełny tekst źródłaAlthough widely used, mortar wall coverings still generate interest by both academia and construction companies. This fact is caused by the ever-present need for improved technology, having as principal objective the more refined knowledge about the constituents of the coating system and also the large number of pathologies occurring in this type of siding, in particular its detachment. In this context, this study had the objective of analizing the influence of the application form and composition of slurry mortar on the bonding strength of coatings applied over concrete substrate. For this, concrete plates of 35x25x5cm were molded, with compressive strength at 28 days of, approximately, 30MPa. After that, the plates were coated with coating mortar and slurry mortar. In order to isolate the effect of slurry mortar in this research, the concrete substrate and mortar coating were kept fixed, and the slurry mortar is the only variable element of the system. It was varied the form of application (manual and mechanized), the composition, where were analyzed the change of sand granulometry (a continuous and well-graded, a discontinuous and bad-graded), the introduction of silica and water retaining additive. The concrete substrate was curing in water and lime for 28 days, and mortar coating and slurry mortar were cured at 23±2°C and relative humidity of 60±10%, for 3 and 28 days, respectively. After 59 days from the start of the molding of concrete plates, the "substrate+slurry mortar+mortar coating" samples were subjected to tests of tensile bond strength and shear. From the results obtained, were is can be said that the mechanized application form used did not generate satisfactory results, possibly due to high water/cement ratio of the slurry mortar used, resulting in an uneven layer, showing that manual application, even rustic, for slurry mortar is still the best choice. For the composition of slurry mortar, the best results for bond strength were obtained with slurry mortars made with well-graded sand with a continuous granulometric. The introduction of silica in the slurry mortar showed a tendency to increase the tensile bond strength and a significant increase, proven by statistical analysis, in shear bond strength. The introduction of water retaining additive, a significant improvement in tensile bond strength and a tendency to increase the shear bond strength.
Zanella, Andrigo Kemel. "ANÁLISE DAS PROPRIEDADES MECÂNICAS DE CONCRETOS PARA PAVIMENTAÇÃO EMPREGANDO DIFERENTES PROCESSOS DE CURA". Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/7861.
Pełny tekst źródłaPara o desenvolvimento de um projeto de dimensionamento de pavimentos de concreto é necessário conhecer as propriedades mecânicas e os diferentes processos de tratamento do material a ser utilizado. Este trabalho teve por objetivo analisar as propriedades mecânicas, tais como, resistência à tração na flexão, resistência à compressão axial, resistência à tração por compressão diametral e módulo de elasticidade estático em concretos para pavimentação. Foram estudados os três tipos de concretos: um concreto referência, (tipicamente empregado em pavimentação, outro com a adição de fibras de polipropileno (prática comum em pavimentos) e um concreto de alta resistência, utilizado para rápida liberação ao tráfego. Diferentes métodos de cura foram aplicados: cura química com e sem a utilização de sacos de aniagem úmidos (largamente aplicados em pavimentos) e cura em câmara úmida (conforme preconizado por norma). A avalição das propriedades mecânicas para os concretos estudados, nos diferentes métodos de cura aplicados, mostrou que a microestrutura dos concretos, está interferindo de forma significativa nos resultados obtidos, principalmente nos concretos curados para condições de pista (cura química sem e com a colocação de sacos de aniagem), onde fatores como a absorção e reabsorção da água de evaporação para hidratação do cimento, a fissuração da interface pasta/agregado, as condições ambientes relacionadas à temperatura e umidade, estejam interferindo na resistência à tração na flexão, resistência à compressão axial, resistência à tração por compressão diametral e principalmente no módulo de elasticidade estático e ainda, a partir dos resultados obtidos na presente pesquisa e daqueles apresentados por outros autores que estudaram um concreto de alta resistência, é possível verificar que existem particularidades ainda desconhecidas sobre o comportamento do concreto de alta resistência.
Alexa, Martin. "Vliv mnohonásobného zatěžování na vybrané parametry lehkého betonu". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371809.
Pełny tekst źródłaCáceres, Alan Renato Estrada. "Caracterização geométrica e mecânica de macrofibras poliméricas". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-21062016-143713/.
Pełny tekst źródłaA wide variety of synthetic macrofibers for concrete reinforcement are available nowadays. By nature, these fibers exhibit great diversity of properties and characteristics. These variations affect its performance as reinforcement in concrete. However, there are no Brazilian standards on the subject and characterization methodologies available in foreign standards present divergences. Some standards define that the characterization of the mechanical behavior should be made in the original filaments and others that the test should be performed according methods for metallic materials characterization. The standard EN14889-2:2006 provides greater coverage about the subject, but leaves doubts about the suitability of the geometric characterization criteria of the fibers and does not set a specific testing method for its mechanical characterization. Thus, there is a need to establish a methodology that allows to carry out a quality control program of the fiber in the onsite conditions. This approach would also provide a way of materials characterization for experimental studies, which would allow better scientific basis of these works, which often rely exclusively on data taken from manufacturers. Thus, an experimental study focusing on the characterization of two polymer macrofibers available in Brazil was developed. The study aims at the determination of the geometrical and mechanical characteristics, such as the tensile strength and the elastic modulus. The geometric characterization was based on the prescriptions of the European standard EN14889- 2:2006. Measurements of length were made by two methods: the caliper method and digital image analysis method, employing software for image processing. For the measurement of the diameter, besides the aforementioned methodologies, the density method was also used. It is concluded that the caliper method, taking care to stretch the macrofibers previously, and the method of digital images can also be used to measure the length. To determine the diameter, it is recommended the density method. As for the mechanical characterization, a methodology was developed taking in consideration the previous information related to other tests. Thus, the direct tensile test was carried out in macrofibers glued in textile fabric frames. In addition, it was also evaluated the effect of the abrasive contact of macrofibers with the aggregates during mixing on the mechanical behavior of the material. Also, the effect of the method of determining the cross-sectional area in the results measured in fiber tensile test was evaluated. It is concluded that the proposed method for direct tensile test of the fiber is feasible, especially for tensile strength assessment. The value of the modulus of elasticity, in turn, has been underestimated. The determination of the fiber section area through the density method also gave the best results. Furthermore, it was found that the friction of the fibers with aggregate during mixing compromises the mechanical behavior reducing both strength and elastic modulus. Thus, it can be said that the proposed methodology for the geometric and mechanical control of polymer macrofibers is suitable for the material characterization.
Mikulíková, Petra. "Nestmelené a stmelené směsi z betonového recyklátu dálnice D1". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226617.
Pełny tekst źródłaPlochý, Ondřej. "Vývoj sklobetonů s vysokými mechanickými vlastnostmi". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371943.
Pełny tekst źródłaSchröder, Steffen. "Der Einfluss einer zweiaxialen Zugbelastung auf das Festigkeits- und Verformungsverhalten von Beton und gemischt bewehrten Bauteilen". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-103866.
Pełny tekst źródłaThe tensile load-bearing characteristics of structural elements made of reinforced or non-reinforced concrete is influenced by a number of factors. Mainly it depends on the strength of the concrete, the interaction between the concrete and the rebar, and the state of stress in the concrete element. Traditionally the designing engineer examines uni-axial stress conditions under consideration of the material properties of the concrete based on standard tests. However, multiple-stress conditions apply for a number of application of such elements, e.g. in concrete slabs designed for bi-axial load bearing, in the joints of frames, in axial symmetrical constructions, or in the intersections of column and deck of multi-span bridges. The commonly used design standard recommends the increase of the compression strength of the concrete or the bond stress for cases of bi-axial load-bearing caused by compression. However, no recommendations are given for the design strength of a concrete under bi-axial tensile stress. Therefore it is interesting to know how a bi-axial tensile stress is influencing the load-bearing and deformation behaviour of structural elements made of reinforced or non-reinforced concrete. This has been investigated for two commonly used concretes (C20/25 and C40/50). Part of an earlier research programme was to perform trials on slabs made of reinforced and non-reinforced concrete. In result a model CEB-FIP MODELL CODE 90 was introduced to describe the deformation of the slab due to a uni-axial stress. However, the model does not satisfactory describe the real behaviour of the slab under a bi-axial tensile stress. In this dissertation a new model will be presented to describe the deformation behaviour of a Concrete C20/25 and a Concrete C40/50 under bi-axial tensile stress. Furthermore, criteria for the two concretes are introduced to describe the ultimate limit state under bi-axial tensile stress. It has been found the bi-axial tensile strength of a Concrete C20/25 is comparable to its uni-axial strength. In difference, the tensile strength of a Concrete C40/50 is decreased by 25% when subject to bi-axial stress. The ultimate limit stress due to bi-axial tensile stress decreases with increasing ratio of the stress 1 : 2. The Strains 1 and 2 are the strains as a result of the biaxial tensile forces in the main directions. The presented model to describe the strain-stress behaviour of an unreinforced concrete is found to agree well with the observations from the trials. Based on the results of this thesis it is possible to describe the strain-stress behaviour of concrete under bi-axial tensile stress. The stress-strain behaviour of structural elements has been investigated under bi-axial tensile stresses. Strains have been monitored with strain-gauges fixed to the surface of the concrete, to the rebars and to the post-tensioning tendons. Therefore, the influence to the interaction of tendon and concrete has been demonstrated indirectly. Furthermore, it has been shown the strain of the tendon decreases following the development of cracks along the grout tube due to the application of bi-axial tensile stress. It can be concluded the bound of the tendon is influenced adversely by tensile stresses applied in perpendicular direction. Recommendations are given for the application of strain-gauges to measure strains of rebars set in concrete. Based on these trials, the estimation of the critical stress to develop initial cracks has been found in good agreement to the presented criteria
Stavař, Tomáš. "Změna trvanlivosti betonu z recyklovaného betonu variantní adicí silikátových příměsí". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225883.
Pełny tekst źródłaHlaváček, Jaroslav. "Příměsi ovlivňující tuhnutí portlandského cementu". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216898.
Pełny tekst źródłaKallel, Hatem. "Influence de la température et de l'hygrométrie sur le comportement instantané du béton". Thesis, Pau, 2016. http://www.theses.fr/2016PAUU3013/document.
Pełny tekst źródłaIn case of severe accident, confinement chambers are submitted to thermodynamic variations of their internal environment. Pressures can increase up to 5 bars, temperature reaches 140 °C and relative humidity attains saturation. Beyond regulatory calculations, the complexity of the solicitation needs a good knowledge of the thermo-mechanical behaviour of concrete under the imposed conditions of temperature and relative humidity. This, in turns allows to develop numerical simulations as realistic as possible. The present study investigates the evolution of the mechanical and thermal characteristics of concrete. These properties are essential to develop numerical computations under the levels of pressure, temperature and relative humidity imposed during a severe accident. Mechanical and thermal tests are carried out under controlled hydro-thermal conditions. Temperature (T) is fixed at five target values: 30, 90, 110, 140 and 160 °C. Five levels of degree of saturation (Sw) range from 36 % to 100 %. The different target values of degree of saturation are attained by controlling relative humidity in the surrounding environment of the specimens during curing. DCT (Disk-shape Compact tension) tests was chosen to determine the dependence of the fracture energy, elastic modulus and traction resistance on temperature and degree of saturation of concrete because of its compact shape that is more suitable for testing under pressure (temperature above 100°C). Thermal properties are determined by means of the Transient Plane Source (TPS) method. This technique allows to determine thermal conductivity, thermal diffusivity and hence to deduct specific heat. The dependence of the permeability to liquid nitrogen on temperature up to 90 °C and on the degree of saturation was also analysed. After determining thermal and mechanical properties of concrete, numerical simulations have been developed in order to pass from laboratory scale to the structure scale. A coupled hydro-mechanical model and a damage model are proposed
Maziliguney, Levent. "Tensile Behavior Of Chemically Bonded Post-installed Anchors In Low Strength Reinforced Concretes". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608439/index.pdf.
Pełny tekst źródłaDvořák, Richard. "Studium efektu aplikace celulózových vláken v cementových kompozitech". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240420.
Pełny tekst źródłaFabiánová, Lucie. "Přepočet a variantní návrh nosných konstrukcí objektů administrativního centra". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226643.
Pełny tekst źródłaJoudi-Bahri, Imène. "Influence des sables fillérisés calcaires sur les propriétés des bétons courants et superplastifiés. Un exemple tunisien". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0156/document.
Pełny tekst źródłaThe objective of this work is to study the effect of the quantity of fillers on the rheological, mechanical and dimensional properties of calcareous concretes. These concretes were made with the same coarse aggregates and same sand coming from the same production, in order to avoid any artifact. Sand was used to manufacture five sands representative of the categories defined in the EN 12260 norm for aggregates for concretes, by mixture with its fine fraction or its grained fraction extracted beforehand by washing. The employed sands contain approximately 0, 6, 12, 18 and 24 % of fillers. The concretes were formulated with the BetonlabPro2 software, whose algorithms take into account the presence of the fillers limestones. Concretes were realized at first without superplastifiant, then in the presence of a superplastifiant measured in 2/3 of saturation. The obtained results showed that a quantity of fillers limestones from 100 to 130 kg/m3 for the concretes and from 60 to 80 kg / m3 for superplasticizred concretes allows obtaining optimal properties, in equal consistency. But, higher quantities of fillers do not deteriorate significantly the properties of the concretes, even if their packing density decreases. One explains this behavior not only by the binding effect allotted to the fillers limestones, but also by an improvement of the paste-aggregates bond. Mixtures containing the strongest rates of fillers were again studied to formulate self compacting concretes SCC, which require a big quantity of fillers. Crushed sands bring then the major part of this constituent, what opens to them a new way of use
Hampel, Torsten. "Experimentelle Analyse des Tragverhaltens von Hochleistungsbeton unter mehraxialer Beanspruchung". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1168424399352-63668.
Pełny tekst źródłaThe subject of this paper is the experimental analysis of the behavior of High Performance Concrete under multiaxial loading. Thereby the behavior under bi- and triaxial compression as well as the behavior under combined compression-tension stresses were examined. Three concrete grades were examined, C 55/67, C 70/85 and C 90/105. Within the test series, the ultimate loads and the stress-strain-relationships were determined. The results of the examinations were compared to the results which are already known for normal strength concrete. From these comparisons conclusions for the usage of high performance concrete were made. For the examined states of stress mathematical approximations are specified
Hampel, Torsten. "Experimentelle Analyse des Tragverhaltens von Hochleistungsbeton unter mehraxialer Beanspruchung". Doctoral thesis, Technische Universität Dresden, 2006. https://tud.qucosa.de/id/qucosa%3A24996.
Pełny tekst źródłaThe subject of this paper is the experimental analysis of the behavior of High Performance Concrete under multiaxial loading. Thereby the behavior under bi- and triaxial compression as well as the behavior under combined compression-tension stresses were examined. Three concrete grades were examined, C 55/67, C 70/85 and C 90/105. Within the test series, the ultimate loads and the stress-strain-relationships were determined. The results of the examinations were compared to the results which are already known for normal strength concrete. From these comparisons conclusions for the usage of high performance concrete were made. For the examined states of stress mathematical approximations are specified.