Thesis (MEngSc)--University of Melbourne, Dept. of Chemical and Biomolecular Engineering, 2010. / Typescript. Includes bibliographical references (p. 105-110)

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 206-219). Available also in a digital version from Dissertation Abstracts.

Vid byggprojekt har det uppdagats fuktproblem i betongplattor där plastmattor har släppt från underlaget. Ett av problemen som beskyllts i media är förändringen från byggcement till bascement. Bascement är en cementsort som 14 % flygaska blandat med portlandklinker. Anledningen till att cementtillverkarna använder flygaska, som är en restprodukt från pulvereldade kolkraftverk, är att det ger minskade mängder portlandklinker som vid tillverkningen släpper ut stora mängder koldioxid. Cement är bindemedlet i betong och när flygaska används binds mindre mängd i vatten i betongens hydrationsprocess. För att undersöka vilken skillnad i uttorkning det finns i betong med bascement och byggcement gjöts två betongprover med samma betongrecept och VCT, men med respektive bascement och byggcement som bindemedel. Dessa betongprover förvarades i en uppvärmd lokal med låg relativ fuktighet. Fuktmätningarna utfördes enligt rådet för byggkompetens fuktmätningsmanual som är det gällande regelverket. Dessa resultat jämfördes med fuktprognoserna från TorkaS och BI Dry, som är de vanligaste fuktberäkningsprogrammen som används. Samtidigt intervjuades olika aktörer från byggbranschen för att undersöka hur de uppfattade problemet med uttorkning i betong. Fuktmätningarna visade ingen markant skillnad mellan betong med bascement och byggcement. Vid jämförelse med de prognosticerade värdena från fuktberäkningsprogrammen framkom att TorkaS värden var väldigt nära de uppmätta fuktvärdena, medans BI Dry:s värden låg långt under de uppmätta värdena. Vid intervjuerna framkom att byggbranschen har många frågor kring uttorkning i betong. Däremot finns svårigheter att avgöra vad som ligger till grund för problemen. Om det är bytet från byggcement till bascement eller om hanteringen av betongen i ett tidigt skede efter gjutningen som påverkar. Däremot om fuktfrågan tas upp i ett tidigt stadium i byggprocessen går det att bespara både tid och pengar. Byggbranschen behöver utbildas hur uttorkningens process ser ut för att öka förståelsen för problemet. / In construction projects, moisture problems have been discovered in concrete slabs where plastic mats have been released from the substrate. One of the problems reported in the media is the change from Portland cement to fly ash cement. Fly ash cement is a cement with 14% fly ash mixed with portland clinker. The reason that cement manufacturers use fly ash, which is a residual product from powder-fired coal power plants, is that it reduces the amount of portland clinkers that release large amounts of carbon dioxide during production. Cement is the concrete binder and when fly ashes are used, less amount of water is bound in the concrete's hydration process. To investigate the difference in dehydration found in concrete with fly ash cement and Portland cement, two concrete samples were obtained with the same concrete recipe and VCT numbers, but with different cement types. These concrete samples were stored in a heated local with low relative humidity. Moisture measurements were carried out according to the current regulations. These results were compared with the moisture predictions from TorkaS and BI Dry, which are the most commonly used moisture calculation programs. At the same time, various actors from the construction industry were interviewed to investigate how they perceived the problem of dehydration in concrete. The moisture measurements showed no significant difference between concrete with base cement and building cement. When compared with the forecasted values from the moisture calculation programs, it was found that the Dry values were very close to the measured moisture values, while BI Dry's values were well below the measured values. The interviews revealed that the construction industry has many questions about dehydration in concrete. On the other hand, there are difficulties in determining what is the basis for the problems. If there is a change from the portland cement to the fly ash cement, or the handling of the concrete at an early stage after the casting affects. However, if the moisture issue is taken up early in the construction process, it is possible to save both time and money. The construction industry needs to be educated how the process of desiccation works to increase understanding of the problem.

In the production of cement, to increase the cement/clinker ratio and decrease CO2 emission, the most important alternative is to produce mineral admixture incorporated cements (CEM II-III-IV-V) instead of portland cement (CEM I). These cements are usually produced by intergrinding the portland cement clinker and the mineral admixtures. However, the difference between grindabilities of the different components of such cements may cause significant effects on the particle size distribution and many other properties. For this reason, separate grinding of additives and clinker may be thought as an alternative. In this study, the effects of intergrinding and separate grinding on the particle size distribution and consequently on the strength of portland composite cements which contained natural pozzolan (trass), granulated blast furnace slag (GBFS) and limestone besides portland cement clinker were studied.

Made available in DSpace on 2014-12-17T14:06:52Z (GMT). No. of bitstreams: 1 AbimaelLM.pdf: 1998740 bytes, checksum: 3bd1ad1da777ebc532ac1fcc9b0a96f4 (MD5) Previous issue date: 2009-03-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The low tenacity presented by the Portland cement pastes used in the oil wells cementation has been motivating several researches with attention focused on alternative materials. Additives have been developed to generate flexible pastes with mechanical resistance capable to support the expansions and retractions of the metallic covering of the wells that submit to the steam injection, technique very used to increase the recovery factor in oil reservoirs with high viscosity. A fresh paste with inadequate rheological behavior may commit the cementation process seriously, involving flaws that affect the performance of the paste substantially in the hardened state. This work proposes the elaboration and the rheological analysis of Portland cement pastes with addition of residues of rubber tire in several proportions, with the aim of minimizing the damages provoked in the hem cementing of these wells. By thermogravimetric analysis, the particles of eraser that go by the sieve of 0,5mm (35 mesh) opening and treated superficially with NaOH solution of 1 mol/L presented appropriate thermal resistance for wells that submit to thermal cyclic. The evaluation of the study based on the results of the rheological analysis of the pastes, complemented by the mechanical analysis, thickening, stability, tenor of free water and filtrate loss, being used as parameter a paste reference, without rubber addition. The results showed satisfactory rheology, passive of few corrections; considerable loss of mechanical resistance (traction and compression), compensated by earnings of tenacity, however with established limits for its application in oil wells; satisfactory stability, free water and thickening time / A baixa tenacidade apresentada pelas pastas de cimentos Portland utilizadas na cimenta??o de po?os de petr?leo tem motivado v?rias pesquisas voltadas para materiais alternativos. Aditivos t?m sido desenvolvidos para gerar pastas flex?veis e com resist?ncia mec?nica capaz de suportar as expans?es e retra??es do revestimento met?lico dos po?os que se sujeitam ? inje??o de vapor, t?cnica muito utilizada para aumentar o fator de recupera??o em reservat?rios de ?leo com alta viscosidade. Uma pasta fresca com comportamento reol?gico inadequado pode comprometer seriamente o processo de cimenta??o, implicando em falhas que afetam substancialmente o desempenho da pasta no estado endurecido. Este trabalho prop?e a elabora??o e a an?lise reol?gica de pastas de cimento Portland com adi??o de res?duos de borracha de pneu em diversas propor??es, com o objetivo de minimizar os estragos provocados na bainha cimentante destes po?os. Por an?lise termogravim?trica, as part?culas de borracha passantes na peneira de abertura 0,5 mm (35 mesh) e tratadas superficialmente com solu??o 1 mol/L de NaOH, apresentaram resist?ncia t?rmica adequada para po?os sujeitos ? ciclagem t?rmica. A avalia??o do estudo baseou-se nos resultados da an?lise reol?gica das pastas, complementadas pela an?lise mec?nica, espessamento, estabilidade, teor de ?gua livre e perda de filtrado, utilizando-se como par?metro uma pasta refer?ncia, sem adi??o de borracha. Os resultados mostraram reologia satisfat?ria, passiva de poucas corre??es; consider?vel perda de resist?ncia mec?nica (tra??o e compress?o), compensada por ganho de tenacidade, por?m dentro dos limites estabelecidos para sua aplica??o em po?os de petr?leo; satisfat?ria estabilidade, ?gua livre e tempo de espessamento

Made available in DSpace on 2014-12-17T14:07:03Z (GMT). No. of bitstreams: 1 AndrezaKC.pdf: 2477387 bytes, checksum: 5eafbea5e547e68eaf6513cad9b400ba (MD5) Previous issue date: 2009-10-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Primary cementing is one of the main operations in well drilling responsible for the mechanical stability and zonal isolation during the production of oil. However, the cement sheath is constantly under mechanical stresses and temperature variations caused by the recovery of heavy oil. In order to minimize fracture and wear of the cement sheath, new admixtures are developed to improve the properties of Portland cement slurries and avoid environmental contamination caused by leaking gas and oil. Polymers with the ability to form polymeric films are candidates to improve the properties of hardened cement slurries, especially their fracture energy. The present study aimed at evaluating the effect of the addition of a chitosan suspension on cement slurries in order to improve the properties of the cement and increase its performance on heavy oil recovery. Chitosan was dissolved in acetic ac id (0.25 M and 2 M) and added to the formulation of the slurries in different concentrations. SEM analyses confirmed the formation of polymeric films in the cementitious matrix. Strength tests showed higher fracture energy compared to slurries without the addition of chitosan. The formation of the polymeric films also reduced the permeability of the slurry. Therefore, chitosan suspensions can be potentially used as cementing admixtures for heavy oil well applications / A cimenta??o prim?ria ? uma das principais opera??es na perfura??o do po?o de petr?leo. A fixa??o do revestimento e o isolamento zonal garantir? seguran?a e diminui??o dos custos na fase de produ??o de ?leo. No entanto, ? constante a ocorr?ncia de problemas na bainha ciment?cia devido a esfor?os mec?nicos e a varia??o de temperatura, causada pela recupera??o de ?leos pesados. Visando minimizar as fraturas e desgaste da bainha, novas adi??es est?o sendo desenvolvidas para melhorar as propriedades do cimento Portland e evitar a contamina??o ambiental decorrente de vazamento de g?s e ?leo pelo anular. Pol?meros com a capacidade de formar filmes polim?ricos s?o op??es de adi??es, pois a poss?vel forma??o da teia polim?rica na matriz ciment?cia melhora as propriedades e a energia de fratura da pasta. O presente trabalho, tem como objetivo adicionar ?s pastas ciment?cias suspens?o de quitosana para melhorar as propriedades da pasta ciment?cia e aumentar seu desempenho em opera??es de recupera??o de ?leo pesado. A quitosana foi dilu?da em ?cido ac?tico (0,25 M e 2 M) e adicionada na formula??o das pastas em diferentes concentra??es. A an?lise do MEV confirmou a forma??o de redes polim?ricas na matriz ciment?cia e os testes deresist?ncia mec?nica comprovaram uma energia de fratura elevada em rela??o ? pasta sem adi??o do pol?mero. A forma??o da teia polim?rica tamb?m reduziu a permeabilidade da pasta. Com isso, a suspens?o de quitosana torna-se uma solu??o polim?rica com potencial para ser aplicado em cimenta??o de po?os de petr?leo

Orientador: Rita Moura Fortes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-12T06:54:45Z (GMT). No. of bitstreams: 1 BarbosaJunior_AlvaroSergio_M.pdf: 1121830 bytes, checksum: e02fb4a353bc75b1933fd3e74153b6ea (MD5) Previous issue date: 2008 / Resumo: O objetivo da presente pesquisa e apresentar uma contribuição ao estudo da utilização de agregados reciclados em misturas de concreto de cimento Portland (CCP) para pavimentação. São comparados os desempenhos de misturas utilizando-se agregados oriundos do gnaisse e também do entulho de laboratórios de controle tecnológico, para avaliar o potencial de sua utilização, minimizando a sua problemática deposição em aterros sanitários, contribuindo dessa maneira para a preservação do meio ambiente. Os agregados originados pela moagem desses entulhos serão estudados separadamente, ou seja, os provenientes de corpos de prova de concreto, de blocos de concreto e blocos de materiais cerâmicos. Pretende-se conhecer o potencial de utilização desse material reciclado como agregado contribuindo para a preservação do meio ambiente. E importante enfatizar que este material e de boa qualidade e tem sido usualmente descartado, ou melhor, desperdiçado. Este trabalho avalia os resultados levando em conta a sua seleção, dosagem e mistura, de maneira a atender as propriedades necessárias para a pavimentação / Abstract: The objective of this research is to contribute to the study of the recycled aggregate use in concrete Portland. It is compared the performance of these mixtures presented with the deriving aggregates and the rubbish of technological control laboratories, which the use minimizes the problematic deposition in sanitary earthworks, contributing in this way to the environment's preservation. The aggregates originated for the milling of these tested specimens will be studied separately, in other words, the preceding from specimens of concrete test, of concrete blocks and ceramic materials. In this research is studied the potential use of these recycled materials as aggregate contributing for the environment preservation. It is important to emphasize that this material presents good quality and is usually discarded or wasted. This paper evaluates the results taking into account the selection and mixing for the adequate pavement properties. / Mestrado / Transportes / Mestre em Engenharia Civil

Se viene buscando optimizar la elaboración del concreto lanzado, pero en el proceso se deja de lado el control de calidad por lo cual es indispensable comparar la influencia de un componente primario como el cemento tipo IP y HE. La presente tesis tiene por objetivo realizar el estudio comparativo de concreto lanzado con cemento portland puzolanico tipo IP vs tipo HE en el revestimiento del túnel de la mina Orcopampa–Arequipa. Nos ha impulsado a investigar la necesidad de obtener la relevancia en el desempeño y las implicancias del cemento para shotcrete desde una visión técnica, a través de ensayos de campo y laboratorio. Considerando el enfoque técnico al determinar las diferencias entre el concreto lanzado con cemento Tipo IP y Tipo HE desde el análisis de resistencia a tenacidad y resistencia a la compresión. Realizando un tipo de Investigación básica, cuantitativa, descriptivo, aplicada, de campo con un diseño experimental, según el estudio es cuasi experimental, prospectivo por la cronología de observación, transversal según el número de mediciones, descriptiva, comparativa y explicativa. Los resultados estadísticos nos demuestran que si existen diferencias significativas de 62 % entre los resultados de la resistencia a la compresión del concreto lanzado cemento Tipo HE sobre el concreto lanzado con cemento Tipo IP en su totalidad de edades ensayadas. En el análisis estadístico de los ensayos de tenacidad se observa que el cemento Tipo HE tiene una mejor capacidad para absorber energía ya que tiene la característica de desarrollar resistencias a edades tempranas. It has sought to optimize the development of the shotcrete, but in the process neglects quality control so it is essential to compare the influence of a primary component such as cement type IP and HE. This thesis aims to conduct a comparative study of shotcrete with IP pozzolanic Portland cement type HE vs kind in the lining of the tunnel Arequipa Orcopampa mine. It has prompted us to investigate the need for relevance in the performance and the implications of cement shotcrete from a technical view, through field and laboratory tests. Whereas the technical approach to determine the differences between the shotcrete cement type HE type IP and from the analysis of toughness and resistance to compression. He made a type of Basic, quantitative, descriptive research, applied field with an experimental design, the study is quasi-experimental, prospective timeline for observation cross as the number of measurements, descriptive, comparative and explanatory. The statistical results show that if there are significant differences between the results 62% of the compressive strength of cement Type HE shotcrete shotcrete on cement type IP fully tested age. In the statistical analysis of toughness tests it shows that the cement type HE has a better ability to absorb energy and which has the characteristic of developing resistance at early ages.

The work is focused on the possibilities of using FBC fly ash for composite cements, monitoring their hydration processes, especially the creation of AFt phase. The possibility of preparing synthetic ettringite and thaumasite and their detection.

One of the most prominent measurable parameters of the development of phases and phase transformations in inorganic systems are undoubtedly the volume changes of silicate matrix. The study of volume changes is crucial in the terms of usable durability of final product. They represent shrinkage or expansion of the material and may lead to significant decrease of technological and ecological parameters and often to complete destruction of these materials. Most often the volume changes can be observed when cement is used as a binder and in concretes, mortars, artificial aggregates and other similar materials. There are many methods to detect, define and determine the volume changes qualitatively or quantitatively. The development of phases was investigated as a part of the dissertation thesis and hence the volume changes were observed under the conditions closest to the real state in the construction industry. The raw materials and admixtures were selected which model the content of hazardous components present in conventional materials (both natural and secondary), used in construction and the relationship with volume changes was searched and demonstrated. The contacts for measuring the volume changes were attached to test surfaces of specimens and the physical - mechanical tests (volume changes, phase changes, strength, etc.), chemical analysis and ecotoxicity tests depending on the length of hydration were performed.