Esta pesquisa tem por objetivo contribuir para o melhor entendimento dos efeitos do fíler mineral sobre o comportamento mecânico de misturas asfálticas densas, particularmente em relação ao tipo e teor de fíler. O comportamento mecânico de misturas asfálticas densas foi avaliado em função do tipo e teor de fíler (diferentes propriedades físicas, geométricas, mineralógica e comportamento físico-químico), do tipo de agregado (diferentes origens mineralógicas) e do tipo de ligante asfáltico (diferentes consistências). Para alcançar o objetivo geral, a pesquisa foi dividida em três partes: o estudo da mistura asfáltica completa, através de ensaios mecânicos; o estudo do mástique, resultante da mistura de fíler com ligante asfáltico, através dos ensaios comumente aplicados aos ligantes asfálticos puros; e o estudo do comportamento de trincamento dos mástiques nas temperaturas intermediárias, através das características de energia fratura. A análise de variância dos resultados auxiliou na identificação dos fatores com influência significativa nas propriedades apresentadas pelas misturas e mástiques asfálticos. Quanto aos resultados de vida de fadiga, as misturas asfálticas compostas com cal hidratada apresentaram as maiores vidas de fadiga e quanto maior o teor de fíler, maior a vida de fadiga. Em relação à deformação permanente, as misturas asfálticas contendo o menor teor de fíler apresentam os menores valores de deformação não recuperável, enquanto que as misturas contendo o valor intermediário de fíler apresentam os maiores valores. As propriedades reológicas dos mástiques mostraram que a adição de fíler torna o ligante asfáltico mais rígido e a cal hidratada é o fíler que provoca o maior aumento do valor do G*. A elasticidade do mástique aumenta com a adição dos fileres e é mais expressivo para os mástiques compostos pelo fíler de cal hidratada e cimento Portland. Quanto maior o teor de fíler utilizado, maior a temperatura correspondente a G*/sen \'delta\' \'> ou =\' 1,0 kPa da especificação Superpave, o que pode se refletir em misturas asfálticas com maior resistência à deformação permanente. Nas propriedades a baixa temperatura, a utilização de maiores teores de fíler prejudicam a resposta ao trincamento a baixas temperaturas e diminuem a eficiência na dissipação das tensões formadas durante a contração do ligante asfáltico, quando a temperatura do pavimento cai abruptamente, aumentando a formação de trincas e fissuras. Analisando os resultados da energia de fratura, a adição de fíler no mástique diminui a resistência ao trincamento por fadiga nas temperaturas intermediárias, porém a presença de fíler na mistura durante o envelhecimento torna seus efeitos menos prejudiciais. / The objective of this research is to contribute to the better understanding of mineral filler effects on the mechanical behavior of hot mix asphalt (HMA), particularly related to the filler type and content. The hot mix asphalt mechanical behavior was evaluated according to: the filler type and content (different physical, geometrical, mineralogical properties, and the physical-chemical behavior); the aggregate type (different mineralogical source); and the asphalt binder type (different consistency). To reach the global objective, the research was divided in three parts: the study of the complete HMA, through the mechanical tests; the study of the mastic, resulting from mixture of mineral filler and asphalt binder, through tests commonly applied to pure asphalt binder; and the study of cracking performance behavior at intermediate temperature, through the fracture energy characteristics. The analysis of variance of the results assisted to identify the factors with significant influence in properties of the hot mix and mastic asphalt. Regarding the results of the fatigue life, the HMA composed with the hydrated lime presented the longer fatigue life and the higher the filler content the longer the fatigue life. Related to the permanent deformation, the HMA containing the lowest content of filler presented the lowest non-recoverable strain, while the HMA containing an intermediate value of filler presented the highest values. The mastics rheological properties showed that addition of filler makes the asphalt binder stiffer, and the hydrated lime causes the greatest increase of G*. The mastic elasticity increases with the filler, and its more notorious when the mastic is composed by the hydrated lime and Portland cement. The higher the filler content, the higher the temperature corresponding to G*/sen \'delta\' \'> ou =\' 1,0 kPa of the Superpave specification, which may be reflected in HMA with higher permanent deformation resistance. At low temperature properties, the use of higher filler content prejudice the low temperatures cracking response, and decrease the efficiency of stress dissipation formed during contraction of the asphalt binder when the pavement temperature drops abruptly, increasing the formation of cracks and fissures. Analyzing the energy fracture results, adding filler to the mastic decrease the cracking resistance by fatigue at intermediate temperature, but the filler presence in the mixture during aging makes the effect less damaging.

Orientadores: Itamar Ferreira, Vitor Antonio Ducatti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia mecanica / Made available in DSpace on 2018-08-04T09:07:42Z (GMT). No. of bitstreams: 1 PompeuNeto_BernardoBorges_D.pdf: 11029694 bytes, checksum: ca41ccc67517e5d7b47d00507d3aaa15 (MD5) Previous issue date: 2004 / Resumo: Este trabalho expõe os resultados de um estudo conduzido para avaliar os efeitos do tipo, tamanho e consumo de agregado graúdo no comportamento do concreto de moderada e de alta resistência, e as relações entre a resistência à compressão, resistência à tração, resistência à flexão e a energia de fratura. As misturas de concreto estudadas continham agregados britados de basalto e de granito com dimensões máximas características de 9,5 mm e 19 mm e fração volumétrica no traço entre 0,65 e 0,75. A relação águalaglomerantes variou de 0,35 a 0,50. Nas misturas de alta resistência foi empregado um teor fixo de sílica ativa de dez porcento da massa do cimento de alta resistência inicial e teores adequados de aditivo superplastificante. Foram feitas dezesseis (16) misturas e realizados cento e noventa e dois ensaios mecânicos para medir a resistência à compressão, a resistência à flexão, resistência à tração, módulo de elasticidade e energia de fratura. As propriedades de fratura foram determinadas de acordo com Comitê Técnico 89-FMT e FMC-50 da RILEM. A resistência à compressão do concreto de acordo com os materiais empregados foi de 40 a 60 MPa para os concretos de resistência média e de 70 a 110 MPa, para os concretos de alta resistência. Os resultados mostram que a resistência. à compressão, tração, flexão e a energia de fratura do concreto para uma dada relação águaJaglomerante depende do tipo, dimensões e teor de agregado. Para o concreto de alta resistência o comprimento característico do concreto aumenta com o tamanho do agregado graúdo / Abstract: This thesis presents the results of the experimental study carried out for considering the effects of the type, size and amount of coarse aggregate on the behavior of nonnal and high strength concretes, and on relationship among the fracture energy and typical mechanical strength of concrete. The experimental concrete mixtures were made with basalt and granite coarse aggregates having maximum size partic1e 9.5 mm e 19 mm and volumetrically fraction in the mixture ranging from 0.65 to 0.75. The water to cementation materiaIs ratio ranged from 0.35 to 0.50. The high strength concrete mixtures contained a tixed amount of 10 percent of si1ica fume in relation to the weight Portland cement used and a proper addition of superplasticizing agent. Sixteen (16) concrete batching, and one hundred and ninety two tests were carried out to measure the mechanical resistance of concrete (compressive strength, flexure strength, spittling tensile strength, modulus of elasticity) and fracture energy. The fracture properties measured in agreement of the RILEM test methods. The concrete compressive strength ranged from 40 to 60 MPa, and from 70 to 110 MPa, for moderate and hi~ strength concretes, respectively, depending on the type of coarse aggregate utilized. The results showed that the concrete resistance (compressive, flexure, spittling tensile) and fracture energy, at given water to binder ratio, depend on type, particle dimension and content of coarse aggregate. The characteristic length of Hillerborg's tictitions cracks model increases with the variation in the partic1e dimension of coarse aggregate / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Because of an eventual ban of creosote-impregnated products, alternative materials for poles used in the electrical grid are needed. Concrete is one alternative and spun concrete poles have been manufactured for the Swedish grid before. These poles are still in use since the high strength and good functioning. However, they weigh too much in terms of the way that poles are assembled on the grid today. Therefore, a study comparing the capacity of different geometries, resulting in lower weight, is of interest.  In this Master’s Thesis, crack initiation and compressive failure in concrete poles are examined by creating FE-models in the software BRIGADE/Plus, using concrete damage plasticity. Thus, guidance is provided about how thin the concrete walls can be made without risking failure – which also means how low the weight of such a pole can be. The failure most likely to occur is a compressive failure in the concrete with a ductile behavior. The result shows that a geometry change, which implies a thinner concrete wall, is possible. This means a weight reduction between 30-75 % or even more, depending on which network the poles are designed for.

[pt] A utilização dos concretos de alto desempenho na indústria da construção civil está se tornando muito freqüente ultimamente. Este fato impõe cada vez mais a necessidade de um melhor conhecimento sobre o comportamento deste material relativamente novo, visando principalmente manter os níveis de segurança adequados nas estruturas. As vantagens apresentadas por tal material, notadamente a sua resistência à compressão, permitiram uma melhoria generalizada nos processos construtivos e conseqüente aumento nos vãos dos elementos estruturais. Somado o fato de que os concretos de alto desempenho apresentam um comportamento reconhecidamente mais frágil, começou-se recentemente a aplicar conceitos da teoria da Mecânica da Fratura para a análise do comportamento destas estruturas, já que passa a haver a necessidade de se considerar adequadamente o efeito de escala no dimensionamento. Portanto, o objetivo principal do presente estudo é verificar experimentalmente a ocorrência do efeito de escala em concretos de alto desempenho e comparar estes resultados com resultados numéricos encontrados na literatura. Objetiva-se também estudar o comportamento dos referidos concretos nos ensaios à flexão em três pontos e calcular a sua energia de fraturamento através de dois métodos diferentes. Durante o estudo foram executados ensaios à flexão em três pontos em vigas de concreto simples com entalhe, de acordo com as especificações dadas pela recomendação do comitê RILEM 50-FMC. As vigas foram moldadas no Laboratório de Estruturas da PUC-Rio e os ensaios realizados no Instituto de Tecnologia (ITUC) desta Universidade. Os ensaios foram executados em uma máquina Instron com controle de deslocamentos. Ao todo foram ensaiadas 60 vigas, em 4 tamanhos diferentes, com alturas variando de 38mm a 304mm. Os concretos utilizados apresentaram fator água/cimento variando entre 0.37 e 0.25 e resistência à compressão entre 64 MPa e 88 MPa. / [en] The use of high performance concrete as a construction material is becoming very common lately. This fact imposes the need of a better knowledge of this material, aiming to keep the structural design with an appropriate safety level. The advantages provided by this material, specially its compressive strength, allowed a generalized improvement in the building processes e the consequent increase in the structural members size. Added the fact that the high performance concrete has a recognizably more brittle behavior, it`s started to apply some Fracture Mechanics theory concepts to analyze the structures behavior. Then, the fracture mechanics size effect should be suitably considered in design. Therefore, the main objective of this study is to verify experimentally the occurrence of the size effect phenomenon on high performance concrete and to carry out a comparison with numerical results found in the literature. It`s also objectified to study the behavior of the referred concrete in three point bent tests and to calculate its fracture energy by means of two different methods. During this study three point bend tests in notched beams made with unreinforced concrete were carried out. These tests comply with the specifications given by RILEM 50-FMC committee. The specimens were cast at the PUC- Rio Structures Laboratory and the tests were conducted at the Technology Institute (ITUC) of this university. The tests were performed in a servo-controlled materials testing system. It were tested 60 specimens, with 4 different sizes and with heights varying from 38mm to 304mm. The concrete had a water/cement ratio varying from 0.37 to 0.25 and a compressive strength between 64 MPa and 88MPa. / [es] La utilización de los concretos de alto desempeño en la industria de la construción civil se ha hecho frecuente en los últimos tiempos. Este hecho impone cada vez más la necesidad de un mayor conocimiento sobre el comportamiento de este material relativamente nuevo, con el objetivo de mantener los níveles de seguridad adecuados en las extructuras. Las ventajas presentadas por dicho material, notadamente su resistencia a la compresión, permitirán una mejoría generalizada en los procesos. Sumando el hecho de que los concretos de alto desempeño presentan un comportamiento reconocidamente más frágil, se comenzó recientemente a aplicar conceptos de la teoría de la Mecánica de la Fractura para el análisis del comportamiento de estas extructuras, debido a la necesidad de considerar adecuadamente el efecto de escala en el dimensionamiento. Por lo tanto, el objetivo principal del presente estudio es verificar experimentalmente la ocurrencia del efecto de escala en concretos de alto desempeño y comparar estos resultados con los resultados numéricos encontrados en la literatura. Se trata también de estudiar el comportamiento de los referidos concretos en los ensayos a la flexión en tres puntos y calcular su energía de fractura a través de dos métodos diferentes. Durante el estudio se ejecutaron ensayos a la flexión en tres puntos en vigas de concreto simple con entalladura, de acuerdo con las especificaciones dadas por la recomendación del comité RILEN 50-FMC. Las vigas fueron moldeadas en el Laboratorio de Extructuras de la PUC-Rio y los ensayos realizados en el Instituto de Tecnología (ITUC) de esta Universidad. Los ensayos fueron ejecutados en una máquina Instron con control de desplazamientos. Fueron ensayadas 60 vigas, en 4 tamaños diferentes, con alturas variando de 38mm la 304mm. Los concretos utilizados presentaran factor agua/cemento variando entre 0.37 y 0.25 y resistencia a la compresión entre 64 MPa y 88 MPa.

Cracking is one of the most severe distress modes of asphaltpavements. Thus characterising the fracture resistance properties of asphaltmixtures is the key issue for improving the performance relatedmixture design. The present master thesis project addresses the implementationof the theoretical framework, which is used to characterise thefracture resistance of mixtures based on the SuperPave indirect tensiletest (IDT). An open source Matlab-based software for analysing resilientmodulus, Poisson’s ratio, creep parameters and fracture resistance parametershas been developed. The software analyses the the IDT results, toestimate mixture’s fracture resistance based on hot mix asphalt FractureMechanics. Predictions form the field specimens concerning the fractureresistance obtained from IDT are compared with observed field performance.

In this dissertation, four test approaches were developed to characterize the adhesion performance and durability of adhesive bonds for specific applications in areas spanning from structural adhesive joints to popular confectionaries such as chewing gum. In the first chapter, a double cantilever beam (DCB) specimen geometry is proposed for combinatorial fracture studies of structural adhesive bonds. This specimen geometry enabled the characterization of fracture energy vs. bondline thickness trends through fewer tests than those required during a conventional "one at a time" characterization approach, potentially offering a significant reduction in characterization times. The second chapter investigates the adhesive fracture resistance and crack path selection in adhesive joints containing patterns of discreet localized weak interfaces created using physical vapor deposition of copper. In a DCB specimen tested under mode-I conditions, fracture energy within the patterned regions scaled according to a simple rule of mixture, while reverse R-curve and R-curve type trends were observed in the regions surrounding weak interface patterns. Under mixed mode conditions such that bonding surface with patterns is subjected to axial tension, fracture energy did not show R-curve type trends while it was observed that a crack could be made to avoid exceptionally weak interfaces when loaded such that bonding surface with defects is subjected to axial compression. In the third chapter, an adaptation of the probe tack test is proposed to characterize the adhesion behavior of gum cuds. This test method allowed the introduction of substrates with well-defined surface energies and topologies to study their effects on gum cud adhesion. This approach and reported insights could potentially be useful in developing chewing gum formulations that facilitate easy removal of improperly discarded gum cuds from adhering surfaces. In the fourth chapter we highlight a procedure to obtain insights into the long-term performance of silicone sealants designed for load-bearing applications such as solar panel support sealants. Using small strain constitutive tests and time-temperature-superposition principle, thermal shift factors were obtained and successfully used to characterize the creep rupture master curves for specific joint configurations, leading to insights into delayed failures corresponding to three years through experiments carried out in one month. / Ph. D.

Understanding the interactions of polymer interfaces is essential to improve polymer-based designs, as the properties of the interface are often different than those of the bulk material. This thesis explores the interfacial interactions of polymer interfaces for two classes of materials, additive manufacturing materials and fiber-reinforced composites. Additive manufacturing (AM) refers to a number of processes which rely on data generated from computer-aided design (CAD) programs to construct components by adding material in a layer-by-layer fashion. AM continues to generate a substantial amount of interest to produce fully functional products while reducing tooling costs associated with traditional manufacturing techniques such as casting and welding. Recent advancements in the field have led to the production of multi-material printing that has the potential to create products with enhanced mechanical properties and additional functionality. This thesis attempts to characterize the fracture resistance of AM materials produced by the PolyJet process. Test standards established for mode I fracture testing of adhesive joints are adapted to evaluate the fracture resistance and interface between two printed acrylic-based photopolymers. Significant differences in fracture energy and loci of failure between the selected test configurations were observed depending on the print orientation. Failures were nominally seen to occur at the interface, alternating from one adherend interface to another in a random fashion. Results demonstrated a decreasing trend in fracture energy at slower crack propagation rates, indicating that such dependency is associated with the fracture resistance of the interface. T-peel tests conducted on specimens prepared with both constant and graded interlayers revealed enhanced peel resistance with gradient interlayers, suggesting design opportunities of enhanced fracture toughness by implementing intricate material patterns at the interface of the two photopolymers. Fiber reinforced composite (FRCs) materials have become increasingly desirable in a number of industrial applications where weight reduction is critical for increased payloads and higher performance. When manufacturing structures from these materials, the presence of friction in the composite forming process is seen to have a major effect on the finished quality. Friction between the plies, or between the composite laminate and forming tool, can be undesirable as shape distortions such as wrinkles can appear and compromise the structural integrity of the finished product. To evaluate these frictional processes, a standard rheometer is used to evaluate tool-ply friction on dry textile fabrics and graphite/epoxy prepregs over a range of temperatures, pressures, and sliding velocities. The results provide some general insights into the frictional response of composite prepregs as a function of the manufacturing environment. The materials tested are shown to have different mechanisms that govern the frictional processes. In particular, the results of friction testing on the prepreg indicate that friction comes from a contribution of both Coulomb and viscous-related mechanisms, the latter which become especially at higher temperatures. / Master of Science

Fracture mechanics is an effective approach for characterizing material resistance to interfacial failure and for making interface reliability predictions. Because interfacial bond integrity is a major concern for performance and reliability, the need to evaluate the fracture and delamination resistance of an interface under different environmental conditions is very important. This study investigates the effects of temperature, solution chemistry and environmental preconditioning, in several solutions on the durability of silicon/epoxy and glass/epoxy systems. A series of experiments was conducted using wedge test specimens to investigate the adhesion performance of the systems subjected to a range of environmental conditions. Both silicon and glass systems were relatively insensitive to temperature over a range of 22-60°C, but strongly accelerated by temperatures above 60°C, depending on the environmental chemistry and nature of the adhesive system used. Silicon/commercial epoxy specimens were subjected to preconditioning in deionized (DI) water and more aggressive solution mixtures prior to wedge insertion to study the effect of prior environmental exposure time on the system. The wedge test data from preconditioned specimens were compared with standard wedge test results and the system was insensitive to preconditioning in DI water but was affected significantly by preconditioning in aggressive environments. Plots describing - G (crack velocity versus applied strain energy release rate) characteristics for a particular set of environmental conditions are presented and a comparison is made for different environmental conditions to quantify the subcritical debonding behavior of systems studied. A kinetic model to characterize subcritical debonding of adhesives for microelectronic applications is also proposed based on molecular interactions between epoxy and a silane coupling agent at the interface and linear elastic fracture mechanics, which could help predict long-term deterioration of interfacial adhesion. / Master of Science

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: This research investigates the flexibility and the performance properties of bitumen stabilised materials under the influence of mix variables. The laboratory testing consisted of two main phases. During the first phase (mix design), the strength and the flexibility of the mixes were assessed through ITS (Indirect Tensile Strength), UCS (Unconfined Compressive Strength), displacement at break, strain at break and fracture energy. The second phase consisted of a series of triaxial tests done to assess the performance properties (shear strength: cohesion and angle of internal friction; and stiffness: resilient modulus) of the mixes. The mineral aggregates used in this study were milled from different locations of the R35, near Bethal. This was a blend of granular material (dolerite, from various locations of the existing base and subbase layer of the R35) and Reclaimed Asphalt (RA) milled from the existing surfacing. During the mix design phase, two types of bituminous binders were used (bitumen emulsion and foamed bitumen) at bitumen content ranges of 2%, 2.4% and 2.8% each. Two types of active filler were used separately and in combination at a proportion of 1% and 2%. Finally, specimens were tested in wet and dry conditions for each mix combination. During the triaxial testing phase, only the optimum bitumen content of 2.4% was used, both for bitumen emulsion and foamed bitumen, with only cement as active filler in a proportion 1% and 2%. The specimens were tested at different ranges of densities and saturation levels. The flexibility of the mix was assessed through the fracture energy, the strain and the displacement at break parameters. An analysis of variance (ANOVA) was conducted on the data to assess the significance of experimental variables on this property. This property was found to be very sensitive to bitumen and cement content added to the mix. When assessing the combined effect and the significance of the variables on the flexibility of the mixes, it was found that fracture energy is mostly influenced by the cement content, followed by the bitumen content, then the type of treatment and finally the testing condition. However, the level of significance was not in the same order for the other two parameters (displacement and strain at break). It was also found that the combined effect of some independent variables (cement content + testing condition, type of treatment + cement content + bitumen content) had a significant effect on the fracture energy and the strain at break respectively. From the ITS and UCS tests, an increase in strength was noticed with the increase of cement content. On the other hand, the increase in bitumen content led to a decrease in strength of the material. The statistical analysis on the ITS and UCS values show that the independent variable with the most significant effect on the ITS is the cement content, followed by the testing conditions, then the bitumen content and finally the type of treatment. The combined effect of cement content + bitumen content was found to be significant both for ITS and UCS. In the second phase triaxial tests were performed in order to evaluate the performance properties of the mixes. It was found that the increase of the active filler content significantly improves the shear strength of the material. It was also found that at a fixed cement content, specimens tested at low density and/or high level of saturation show low shear strength. The Mr-θ model was used to model the resilient modulus of the mixes and the model coefficients used to evaluate the effect of experimental variables on the resilient modulus. It was found that the resilient modulus of the mixes increases as the bulk stress increases. This confirms the stress dependent behaviour of bitumen stabilised materials. The analysis show that increasing the percentage of active fillers content results in a significant increase in the resilient modulus values. An increase in relative density also resulted in an increase in the resilient modulus of the mixes, while the opposite effect was observed with the increased of the saturation level. Besides the engineering properties and the mechanical test parameters, other parameters such as the Tensile Strength Ratio (TSR) was calculated in order to evaluate the moisture sensitivity of the mixes. Weakening due to moisture was found to be more predominant in the mixes with less active filler. In addition, bitumen emulsion mixes were found to have a better resistance to moisture weakening effects compared to foamed bitumen. In addition, a comparison between the rapid curing and the accelerated curing was done. Higher ITS and UCS results were obtained for specimens cured using long term curing compared to specimens cured using the accelerated curing method. In conclusion, flexibility is an important property of bitumen road construction material (bitumen stabilised material include) however, it is not an easy property to measure. Although, displacement/strain at break and fracture energy from ITS and UCS were able to give us some indications on the main factors governing the flexibility of bitumen stabilised materials (the bitumen and active filler content), more accurate and adequate tests are required to evaluate the parameter. / AFRIKAANSE OPSOMMING: Die buigsaamheid en gedragseienskappe van bitumen gestabiliseerde materiale was getoets om sodoende die invloed van verskeie mengselveranderlikes te evalueer. Die ondersoek het uit twee fases bestaan. Tydens die eerste fase (mengfase) is die sterkte en buigsaamheid deur middel van indirekte treksterkte toetse (ITS), onbegrensde druksterkte toetse (UCS), verplasing – en vervorming by breekpunt sowel as breek-energie toetse gedoen en ondersoek. Die tweede fase het bestaan uit ʼn reeks drie-assige triaksiaal toetse. Triaksiaaltoetse is uitgevoer om die gedragseienskappe soos die skuifsterkte, kohesie, hoek van interne wrywing, styfheid en weerstand modulus te ondersoek. Die gemaalde mineraal-aggregaat wat in hierdie ondersoek gebruik is, was verkry op verskeie areas van die R35, geleë naby Bethal. Die materiaal is ʼn mengsel van granulêre materiaal (van die bestaande kroonlaag en stutlaag van die pad) en herwonne asfalt (RA). Tydens die mengontwerp fase is twee tipes bitumen gebruik naamlik bitumenemulsie en skuimbitumen in hoeveelhede van 2%, 2.4% en 2.8%. Twee tipes aktiewe vulstof (hoeveelhede van onderskeidelik 1% en 2%) was saam met elk van die verskeie bitumen-hoeveelhede gebruik. Proefstukke van elk van hierdie mengsel kombinasies is onder beide nat en droë kondisies getoets. Tydens die tweede fase, is slegs die optimum binder inhoud (2.4%) gebruik vir beide emulsie- en skuimbitumen, gekombineer met 1% en 2% aktiewe vulstof. Proefstukke was getoets by ʼn reeks van verskillende digthede en versadigingvlakke. Die buigsaamheid was ondersoek deur middel van breek-energie, vervorming en die verplasing by breekpunt. ʼn Analise van variasie (ANOVA) is uitgevoer op die toetsdata om sodoende die te evalueer of die veranderlikes beduidend is ten opsigte van buigsaamheid. Daar is gevind dat die buigsaamheideienskap sensitief is vir beide bitumen en sement inhoud. Met assessering van die gekombineerde effek en betekenis van die veranderlikes op die buigsaamheid van die mengsels, is daar gevind dat die hoogste beduidende veranderlike t.o.v breek-energie die sement inhoud is, gevolg deur die bitumeninhoud, tipe behandeling en laastens die toetskondisie. Die orde van belangrikheid verskil vir die ander twee parameters (verplasing en vervorming by breekpunt). Daar is ook gevind dat die gekombineerde effek van sommige veranderlikes (sement inhoud en toets kondisie, tipe behandeling en sement inhoud tesame met bitumen inhoud) ook beduidend was t.o.v breek-energie en vervorming by breekpunt. Vanuit die ITS en UCS toetse was daar ʼn toename in sterkte waargeneem soos die sementinhoud toeneem. Aan die anderkant, het ʼn toename in bitumeninhoud ‘n afname in sterkte veroorsaak. Die statistiese analise van ITS en UCS resultate, toon dat die grootste beduidende onafhanklike t.o.v ITS waardes ook die sement inhoud was, gevolg deur toets kondisies die grootste effek, bitumen inhoud en die tipe behandeling. Die gekombineerde effek van sementinhoud en bitumeninhoud, was betekenisvol vir beide ITS en UCS. Drie-assige triaksiaaltoetse was uitgevoer om die gedragseienskappe van die mengsels te evalueer. Daar is gevind dat die toename in sement inhoud, die skuif sterkte van die materiaal grootliks verbeter. By ʼn konstante sementinhoud, wys toetsresultate van proefstukke wat getoets is by lae digthede en hoë vlakke van versadiging, lae skuif sterkte. Die Mr – θ model was gebruik om die veerkragsmodulus van die mengsels te moduleer en die modelkoëffisiënte is gebruik om die effek van eksperimentele veranderlikes op die weerstand modulus te evalueer. Met toename in die omhullende spanning is ‘n toename in die veerkragsmodulus waargeneem, wat bevestig dat die gedrag van bitumen gestabiliseerde materiale spannings afhanklik is. ʼn Toename in die sement en relatiewe digtheid het ʼn merkwaardige toename in die veerkragsmodulus tot gevolg gehad, terwyl die teenoorgestelde waargeneem is met toename in versadigingsvlakke. Buiten die ingenieurseienskap en meganiese toetsfaktore, is ander faktore (soos die trekspanning verhouding) bereken om die vogsensitiwiteit van die mengsels te evalueer. Mengsels met laer sement inhoud het groter verswakking ervaar met blootstelling aan water. Bitumenemulsie proefstukke toon beter weerstand teen water as skuimbitumen. Vergelyking tussen versnelde en korttermyn nabehandelingsprosedure van proefstukke, toon hoër ITS en UCS waardes vir die versnelde nabehandelingsprosedure prosedure. Buigsaamheid is ‘n belangrike eienskap van bitumen in padkonstruksie materiale (insluitend bitumen gestabiliseerde materiale), maar word moeilik gemeet. Alhoewel verplasing/vervorming by breekpunt en breek energie, bepaal vanaf ITS en UCS, ‘n indikasie toon van die hooffaktore (binder en sement) wat buigsaamheid van bitumen gestabiliseerde materiaal beïnvloed, word meer akkurate toetse benodig om die eienskap te ondersoek.

Les enceintes de confinement sont sollicitées lors d'un accident grave par la modification thermodynamique du milieu interne qui génère une pression pouvant monter jusqu'à 5 bars, une température évaluée au maximum à 180 °C et une humidité relative pouvant aller jusqu'à la saturation. Au-delà de calculs réglementaires, la complexité de la sollicitation nécessite une bonne connaissance du comportement mécanique et thermique des matériaux et en particulier du béton dans la gamme de température et d'hygrométrie imposée afin d’être capable de mener les simulations numériques les plus réalistes possibles.Notre étude présente les évolutions des caractéristiques mécaniques et thermiques essentielles pour les simulations numériques d'un béton dans la plage de pression, température et humidité imposées lors d'un accident grave. Les essais mécanique et thermique sont réalisés sous chargement thermo-hydrique contrôlées. La température (T) est fixée à cinq valeurs cibles : 30, 90, 110, 140 et 160 °C. Les cinq degrés de saturation en eau liquide du béton (Sw) varient entre 36 % et 100 %. Les différents degrés de saturation en eau liquide des éprouvettes sont obtenus par le contrôle de l’humidité relative de l’ambiance entourant l’éprouvette pendant leur cure. L’essai DCT (Disk-shape Compact Tension) a été choisi pour déterminer l’évolution de l’énergie de fissuration, du module d'élasticité et de la résistance en traction en fonction de la température et de Sw, en raison de son caractère très compact favorable pour la mise en oeuvre des essais sous pression (essai au-delà de 100 °C). Les propriétés thermiques sont évaluées par la méthode de la Source Plane Transitoire (TPS). C’est une technique permettant de déterminer la conductivité thermique, la diffusivité thermique et d'en déduire la chaleur spécifique. L’évolution de la perméabilité relative à l’azote du béton en fonction de la température jusqu'à 90 °C et du degré de saturation en eau du béton a été évaluée également. Après avoir déterminé les propriétés thermiques et mécaniques du béton, une modélisation numérique a été réalisée afin de passer de l’échelle de laboratoire à l’échelle de la structure. Un couplage entre un modèle hydrique et un modèle d’endommagement a été réalisé. / In 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.