This thesis describes the novel test techniques that were developed to measure the parameters associated with the plastic shrinkage, and subsequent possible plastic shrinkage cracking, of high strength concrete. The parameters measured during the first 24 hours after placing were the stress- strain relationship, negative pore pressure and free shrinkage strain development. The plastic behaviour of eight high strength concrete mixes was quantified and these mixes were then tested to assess their propensity towards plastic shrinkage cracking, using restrained ring tests. A review of the parameters associated with plastic shrinkage cracking was carried out. The general view was that as the particle size in a cement matrix gets smaller, then the negative pore pressures developed are greater and hence shrinkage increases. This meant that the presence of secondary cementing materials, of very small diameter, such as microsilica, in high strength concretes would explain their apparent susceptibility to plastic shrinkage cracking. Eight high strength concrete mixes were tested in exposed and sealed conditions. It was found that when tested in sealed conditions none of the parameters measured presented itself as the sole driving force behind plastic shrinkage or plastic shrinkage cracking. Also, when cured in sealed conditions, none of the mixes tested in the restrained ring test apparatus cracked. When tested in exposed conditions, the presence of wind had little effect on the stress-strain relationship of the mixes tested. However the presence of wind seemed to cause negative pore pressures to develop earlier than in the sealed samples and increased free shrinkage by 3 to 40 times depending on the mix. The samples that exhibited the highest free shrinkage strains, in exposed conditions, were the mixes that cracked when tested in the restrained shrinkage rings. The mixes that cracked all contained microsilica and these mixes did not crack when the same mixes were tested without microsilica. Polypropylene fibres were found to reduce the cracked area of the samples that cracked. The supplementary cementing materials used in this study were ground granulated blast furnace slag, metakaolin, microsilica and pulverised fuel ash.

Foram determinadas condições operacionais de temperatura e pressão sob as quais ocorre desidratação térmica do minério de gipsita que dá origem a um tipo de gesso beta reciclável. Com a resolução do CONAMA n 307, de 05 de julho de 2002, o resíduo de gesso proveniente da construção civil tornou-se um rejeito de difícil descarte, uma vez que esse material é considerado como contaminante para os demais componentes de um entulho e consideram que ainda não foi desenvolvida tecnologia para sua reciclagem. Neste trabalho foi elaborado e confeccionado um reator batelada em escala de laboratório para produção de gesso beta a partir do minério de gipsita e sob pressão manométrica acima da pressão atmosférica. Esse excedente de pressão foi obtido retendo-se parte do vapor produzido com a desidratação do minério, por meio de uma válvula do tipo alívio automático. A desidratação do minério de gipsita nessas condições dá origem a um gesso beta com características mecânicas superiores ao gesso convencionalmente produzido pela maioria dos processos produtivos existentes no Pólo Gesseiro do Araripe, Pernambuco. Sob pressão controlada a 0,65 atm acima da pressão atmosférica e a aproximadamente 150 C, os cristais do gesso devem apresentar-se isentos de esfacelamentos, provocados pela saída abrupta da água combinada da molécula de gipsita ou di-hidrato do sulfato de cálcio. Foram testadas algumas importantes propriedades do gesso beta produzido sob a pressão manométrica proposta e comparadas aquelas obtidas de um gesso obtido sob condições convencionais de fabricação. Os testes verificaram valores da água de hidratação para confirmar a obtenção da conversão da reação e de propriedades como massa unitária, módulo de ruptura à flexão, dureza e tempo de pega. Os gessos beta produzidos sob pressão foram testados em dois ciclos de vida e em ambos apresentaram características de um gesso com cristais bem formados, homogeneamente dispostos e de baixas porosidades inter- e intracristalina. Sua comparação com gessos convencionais mostraram superioridade quanto às propriedades mecânicas, principalmente em relação a ambos em seus segundos ciclos de vida. Obteve-se um índice de reciclagem de 100 %. Dessa forma, acredita-se que os processos produtivos industriais praticados no Pólo Gesseiro necessitam de intervenções técnicas, caso se deseje a reciclagem de parte dos gessos originados em resíduos das construções e demolições, tais como, placas para tetos, blocos para divisórias, gessos acartonados, etc., e aqueles também originados nos próprios processos de fabricação desses pré-moldados / Operational conditions of temperature and pressure had been determined under which the thermal dehydration of the gypsum ore occurs producing a type of recyclable beta plaster. With the resolution of the CONAMA n 307, of July 5th of 2002, the plaster waste proceeding from the civil building became one waste of difficult discarding, a time that this material is considered such as contaminante for the excessively component ones of a rubbish and considers that technology for its recycling still was not developed. In this work it was elaborated and confectioned a batch reactor in laboratory scale for beta plaster production from the ore gypsum and under pressure above of the atmospheric pressure. This excess of pressure was gotten holding back part of the water vapor produced with the dehydration of the ore, by means of a valve of the automatic relief type. The dehydration of the gypsum ore in these conditions gives origin to a beta plaster with superior mechanical characteristics to the plaster conventionally produced by the majority of the existing productive processes in the Polar Region Plasterer of the Araripe - Pernambuco. Under controlled pressure of 0.65 atm above of the atmospheric pressure and approximately 150 C, the plaster does not present breaked crystals, provoked for the abrupt exit of the dehydration water of the calcium sulphate di-hydrate. Some important properties of the beta plaster, produced under pressure had been tested and compared with plaster produced under conventional conditions of manufacture. The tests had verified values of the dehydration water, to confirm the final conversion of the dehydration reaction, and properties as unitary mass, flexion rupture modulus, hardness and setting time. The beta plasters produced under pressure had been tested in two life cycles and in both they had presented characteristics of a plaster with well formed crystals, homogeneously distributed and of low inter- and intra-crystals porosities. Its comparison with conventional plasters had shown superiority how much to the mechanical properties, mainly in relation to both in its second life cycles. The recycling index was of 100 %. So is given credit that the industrial productive processes practiced in the Polar Region Plasterer need technique adaptations, if it desires to the recycling of part of plasters originated in building and demolition, such as waste of the plates, blocks, plaster walls, and so on, and the wastes also originated in the proper processes of manufacture of these plaster premoldeds

Made available in DSpace on 2014-10-09T12:51:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:12Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Orientador: Vitor Antonio Ducatti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-04T21:50:26Z (GMT). No. of bitstreams: 1 Santos_DenerAlthemandos_M.pdf: 4256378 bytes, checksum: 360a381356b373441dd49a72a6ac2e7d (MD5) Previous issue date: 2005 / Resumo: Apresenta-se, neste trabalho, o estudo desenvolvido sobre o fenômeno da aderência em Concretos de Alto Desempenho, através de ensaios à flexão de vigas de concreto armado com CAD. A aderência foi analisada sob os aspectos de ancoragem e fissuração na região das barras longitudinais emendadas por transpasse. Os modelos das vigas ensaiadas foram de três tipos, conforme a maneira em que as barras foram transpassadas. Para cada modelo, foram avaliados os parâmetros de: resistência do concreto, diâmetro das barras, comprimento de emenda, cobrimentos das barras e o comportamento das variadas emendas. Os resultados foram, ainda, analisados com as equações internacionais para predição da aderência e com a NBR 6118:2003 / Abstract: This paper presents the study about the bond phenomenon in High Performance Concrete, through the analisys of the flexibility of reinforced concrete beams with HPC. The bond was analyzed under the anchorage and cracking aspects, on longitudinal bars part spliced by transfix. Three types of beam models were analyzed, according to the manner which they were transfixed. For each model, the parameters adopted were: concrete strength, bar diameter, development lengths, cover of the bars and the behavior of the various splices. The results were also analyzed with the international equations for the bond prediction and NBR 6118:2003 / Mestrado / Arquitetura e Construção / Mestre em Engenharia Civil

Made available in DSpace on 2014-10-09T12:37:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:11Z (GMT). No. of bitstreams: 1 05443.pdf: 1296896 bytes, checksum: 57802bf1d2d111c3bfe5cbeead28558a (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:51:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:12Z (GMT). No. of bitstreams: 0 / A utilização da lama residual de marmoraria em cerâmica vermelha foi colocada em prática visando à diminuição do impacto ambiental, causado tanto pelo descarte da lama como também pela quantidade de argila extraída no setor cerâmico. Foram coletadas amostras em 12 marmorarias localizadas na Grande São Paulo. No entanto, apenas as amostras de quatro foram selecionadas para serem incorporadas, levando em consideração suas características distintas. O argilito foi a matéria-prima escolhida para confecção da massa padrão de cerâmica vermelha, devido à sua grande utilização no setor. Tanto as amostras a serem incorporadas, quanto o argilito, foram caracterizados por meio de análise granulométrica, análise química por fluorescência de raios X e análise mineralógica por difração de raios X; além de análises segundo à norma NBR 10004 nas lamas. Após a caracterização das matérias-primas, foi aplicado às misturas o ensaio de plasticidade; em seguida, confeccionados corpos-de-prova com diversos teores de lama incorporada, os quais foram queimados e submetidos a ensaios tecnológicos, como resistência mecânica, absorção de água, porosidade, massa específica aparente e retração, dilatação do material seco e microscopia eletrônica de varredura. Os resultados demonstraram a viabilidade de aproveitamento destas lamas, apontando vantagens de sua utilização, porém levando em consideração algumas condições adotadas. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Les enjeux liés aux problématiques de développement durable encouragent de plus en plus d'industriels, dans le secteur du bâtiment, à se lancer dans une politique de réduction de la consommation énergétique de leurs procédés industriels. C'est dans ce cadre qu'est menée cette étude, où nous nous intéressons au cas particulier de la fabrication des plaques de plâtre, qui de par les qualités qu'elles présentent liées à leur caractère pratique et rapide à poser (temps pour le neuf que la rénovation), sont parmi les matériaux de construction les plus utilisés à l'heure actuelle. En effet pour leur fabrication, on récupère d'abord du gypse depuis la carrière que l'on calcine pour avoir de l'hémihydrate, que l'on mélange ensuite avec de l'eau pour en faire du gypse, que nous rencontrons dans les plaques de plâtre. Cependant, pour avoir une meilleure ouvrabilité lors de la préparation, on est obligé d'ajouter une quantité d'eau excédentaire par rapport à celle que nécessite la stoechiométrie de la réaction d'hydratation – quantité qu'il faudrait évacuer par la suite par séchage. Ainsi, la fabrication des plâtre s'avère être très énergivore ; c'est tout l'intérêt de la thèse où il s'agira de mieux comprendre la physique qui régit le séchage du plâtre de façon à réduire cette surconsommation énergétique. Pour mener cette étude, nous nous sommes d'abord intéressés au cas du séchage de milieux poreux assez simples (empilement de billes de verre, tubes capillaires), nous servir ensuite de la compréhension des mécanismes physiques qui régissent le séchage de ces dits-milieux, d'une part, et des observations locales (RMN, IRM, microtomographie), d'autre part, pour expliquer les différents mécanismes physiques qui entrent en jeu lors du séchage du plâtre. Cette démarche nous a donné la possibilité d'avoir une bonne maîtrise de la physique du séchage du plâtre, c'est-à-dire l'identification des différents leviers et paramètres qui régissent sa cinétique. Ceci nous a permis de mettre en place un modèle physique pour la prédiction de cette cinétique - modèle qui peut être utilisé pour une démarche d'optimisation énergétique de la fabrication des plaques de plâtre / Issues related to sustainability encourage more building material industries to engage policies in making processes energy consumption reduction. This study is conducted in this purpose, and is focused on the case of plasterboard. Indeed for plasterboard manufacturing, gypsum from quarry are first calcined to get hemihydrate, which is then mixed with water to make again gypsum we find in plasterboard. However, to get a good workability during the preparation process, it is necessary to add an excess amount of water relative to that required by the stoichiometry of the hydration reaction. This excess water should be evacuated thereafter drying. Thus, the manufacture of gypsum proved to be very energy intensive : that is the cornerstone of this thesis, during which we will try to understand the physics that govern the drying of plaster in order to reduce its energy consumption. To conduct this study, we are primarily interested in understanding of simple porous media drying (stack of glass beads, capillary tubes). Then based on our understanding of the physical mechanisms that govern their drying, on one hand, and on local observations (NMR, MRI, microtomography), on the other hand, we give an explanation to the different physical mechanisms of plaster drying. This allows us to establish a physical model to predict the drying kinetics of plaster - model that can be used for energy optimization approach during the manufacturing process of plasterboard. Its can also be used for the drying kinetics prediction of other building materials

In recent years distribution has undergone dramatic changes. Some industries have experienced revolutionary changes, others minor, but in all industries distribution has become an extremely vital area. One of the reasons for the recent prominence of distribution is the increasingly competitive environment experienced by many industries. As competition increases within an industry, manufacturers often find it necessary to improve their efficiency, and distribution is an area with vast potential. The wholesaler is one of the most important institutions in a distribution system. He has also been confronted with more competition than many other institutions. The wholesaler will be the focus of attention in this study of the British Columbia Building Materials Industry. It is the objective of the thesis to study the competitive environment of the independent wholesaler in British Columbia, and to determine whether or not he will continue to perform a function in future years. To accomplish the objective, it is necessary to determine the nature of competition with which the wholesaler is confronted, why it exists, and whether or not it is unique to this industry. It is also necessary to determine distribution trends in other industries and whether there exist patterns that are common to this industry. The analysis of changing patterns of distribution focused on United States industries, with particular attention devoted to the Building Materials Industry. The conclusion was that certain trends pre-dominate distribution patterns, including integration, franchising, direct selling and the formation of buying groups for direct buying. Many of these trends are common to the B.C. building materials industry. There are two main types of competition that all wholesalers, (including the building materials wholesaler) are confronted with. The first is the tendency for manufacturers to sell direct to retailers and final users. The second is the desire of retailers to form buying groups and through bulk purchasing establish direct contacts with manufacturers, thereby circumventing the wholesaler. Aside from these two types of competition there are other pressures the building materials wholesaler faces that appear to be unique to this industry, one of these being an allowable margin of operation that is more historical than relevant to costs of operation. There are two primary reasons why the building materials wholesaler is confronted with this competition. The first reason is the wholesalers failure to give manufacturers and retailers the service they require and desire. The second reason is the feeling of manufacturers and retailers that they can perform the functions of distribution more efficiently than the wholesaler, and in the case of manufacturers, they can also attain more control of the marketing of their products. It has been proven to wholesalers that they are dispensable, and this has brought forth a self assessment of their functions in many industries. Those that realize they must be flexible to the changing environment have attained a new and prominent position in the distribution system, by offering the services their customers desire. Those that have remained static have been phased out. This study concludes that the Building Materials Industry will always have need of the wholesaler. However, to have a successful operation the wholesaler must be flexible to the dynamic environment, and offer the service manufacturers and retailers desire. This must also be accomplished at a reasonable level of cost. It is argued that this can best be attained through implementation of the physical distribution concept, (offering efficiency in operating methods) and a sound merchandising program. / Business, Sauder School of / Graduate

<div>Digital Forestry uses digital technology and multidisciplinary expertise to measure, monitor, and manage urban and rural forests to maximize social, economic, and ecological benefits. </div><div><br></div><div>In chapter 2, we investigated the potential use of CNNs for hardwood lumber identification based on tangential plane images. In chapter 3, we developed deep bark, a lightweight tree species identification application, by using deep learning. In chapter 4, we first introduced a new dataset of images of hardwood species annotated for tree ring detection. We applied the state-of-art semantic segmentation models to the dataset. In chapter 5, we combined the observed classes and non-observed classes by distinguishing the attributes of objects and applied zero-shot learning to microscopic wood images. <br></div><div> </div><div>The results above chapters demonstrated the potential and effectiveness of machine learning in many forestry-related tasks. Those applications help both the research community and industry to conduct better digital forestry business. However, we still need to point out that the availability, quality, and quantity of data and annotation are critical factors in conducting meaningful research and applications in forestry.</div>

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