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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Diagonal Tension Testing of Interlocking Compressed Earth Block Panels

Pringle, Sean Anthony 01 June 2016 (has links)
This thesis examines the use of diagonal tension (shear) testing to determine factors affecting shear strength of Interlocking Compressed Earth Block (ICEB) panels. This work expands on the current information available about strength properties of ICEB assemblies, which are dry-stacked, as opposed to having mortared beds. Variables such as block strength, grout strength and grouting pattern can influence the results of these types of tests and are examined in this investigation. To study variables affecting diagonal shear strength, 9 panels were tested, consisting of blocks produced by a manual block press. Strength testing was adopted from common ASTM standards to determine constituent material properties. A modified version of ASTM E519 test procedure is used to perform diagonal tension testing. Imaging analysis, using a high resolution camera, was run simultaneously during testing to capture displacement histories of select panels. It was determined that both block and grout strength significantly affect the shear strength of ICEB panels. Additionally, vertical grouting and block type also have a strong influence. Imaging analysis results confirm that the dominant failure mode in ICEB panels is bed joint sliding both pre and post peak load, with noticeable displacements at head joint locations on a few panels. Lastly, diagonal cracking along the block face was noticeable on several panels following peak load. Further testing remains to determine other factors affecting shear strength, namely, the application of normal pre-compression loads to the panel.
2

Seismic Design Manual for Interlocking Compressed Earth Blocks

Kennedy, Nicholas Edwards 01 June 2013 (has links) (PDF)
Seismic Design Manual for Interlocking Compressed Earth Blocks Nicholas Edwards Kennedy This thesis presents a comprehensive seismic design manual to be used to design and construct simple Interlocking Compressed Earth Block (ICEB) structures in seismically active regions. ICEBs are earth blocks made primarily of soil and stabilized with cement. They have female and male stud mechanisms designed to interlock when stacked, eliminating the need for mortar. The blocks can accept reinforcement and grout after they are placed. While ICEB construction is similar to conventional masonry construction, current design code standards for masonry only partially capture the actual behavior of ICEB structures. This thesis seeks to supplement the existing masonry design procedures and tailor them for use with ICEBs. Additionally, this paper presents a preliminary design of ICEB shear walls for a disaster reconstruction project in the Philippines. While many structures in Southeast Asia and the Malay Archipelago are constructed from earthen blocks, very few are engineered. Of those that are, a lack of formal design guidance specific to ICEB construction leaves most engineers and designers with conventional concrete masonry design practices, some of which are not applicable for use with ICEBs.
3

Efeito da ativação alcalina dos aluminossilicatos nas propriedades mecânicas e microestruturais de compósitos argilosos prensados / Effect of alkaline activation of the aluminosilicates on the mechanical and microstructural properties of compressed clay composites

Sousa, Soenia Marques Timoteo de 31 March 2011 (has links)
Made available in DSpace on 2015-05-08T14:59:39Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5053819 bytes, checksum: 17706f3ce2da78369a2da9e99266b131 (MD5) Previous issue date: 2011-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the chain of energy and motor fuel, in agreement with the policy to adopt green technologies, Brazilian government has encouraged the installation of biodiesel plants to produce an alternative, less polluting and less cost fuel to replace diesel and gasoline. In Paraíba State, the Biodiesel Program was created by the Law 7761 of June 15, 2005. This program initially aims to accomplish two goals: generating clean energy and social inclusion of family farmers. A plant will be built in Campina Grande and will occupy a total area of 704 m2 with a production capacity of approximately 134,000 liters/day (40 million liters/year). These biodiesel plants generate by product in the production process. Some of then, as the water from purification of the biodiesel, have high pH. It is necessary to find a way to avoid that these waste causes high environmental impact. The alkaline activation of certain materials has been studied as an alternative to Portland cement binder. In this work clay-based alkaline activated composites were investigated, with the aim to produce construction blocks. Soil available locally and metakaolin were used. As alkaline activators the Na2SiO3 (sodium silicate) and the NaOH (sodium hydroxide) were obtained commercially, but the KOH (potassium hydroxide) was obtained from the wash water from biodiesel production process. The activators and some small percentage of metakaolin are mixed with the soil and water, and the mix was compressed by a static strength of about 2 MPa, which is commonly provided by hand presses for the fabricate compressed earth blocks. The results show the feasibility of such use of liquid waste from biodiesel. The mechanical strength depends on the concentration of metakaolin, which can reach up to 17 MPa for composites with 22% activated alkaline soil. The durability, physical properties and microstructures of samples with different compositions were also studied. / Na cadeia da energia e do combustível automotor, dentro da política mundial de adoção de tecnologias verdes, o governo brasileiro vem incentivado à instalação de usinas de biodiesel, material que está sendo empregado como uma alternativa, menos poluente e de menor custo em substituição ao diesel e à gasolina. Na Paraíba, o Programa de Biodiesel foi criado através da Lei Estadual 7.761 de 15 de junho de 2005. O projeto visa inicialmente cumprir duas metas: geração de energia limpa e inclusão social de agricultores familiares. Uma usina será construída em Campina Grande, com capacidade de produção de cerca de 134 mil litros/dia. Estas usinas geram, no processo produtivo, resíduos. Faz-se necessário encontrar uma alternativa para que os resíduos tenham o menor impacto possível no ambiente. Aqueles provenientes da purificação do biodiesel são alcalinos. A ativação alcalina de certos materiais tem sido estudada como um ligante alternativo ao cimento Portland. Neste trabalho estudou-se a formação de um compósito à base de argila alcalinamente ativada para confecção de blocos para construção, nos quais foi usado um solo local e metacaulinita. Como ativadores alcalinos empregaram-se o silicato de sódio, hidróxido de sódio e o hidróxido de potássio proveniente da água de lavagem de biodiesel. Os ativadores são misturados com o solo e a mistura recebe uma compactação estática da ordem de 2 MPa, que é a comumente fornecida por prensas manuais para a fabricação de blocos prensados de terra crua. Os resultados mostram a viabilidade desse tipo de emprego do resíduo líquido de biodiesel. A resistência mecânica depende do teor de ligantes, podendo atingir valores de até 17 MPa para compósitos com 22%de solo alcalinamente ativado. A durabilidade, as propriedades físicas e microestruturais de amostras com diferentes composições foram estudadas.
4

Estabilização de blocos de terra crua através de ativação alcalina

Oliveira , Leandro Santos de 01 August 2015 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2017-07-20T11:55:59Z No. of bitstreams: 1 arquivototal.pdf: 4568394 bytes, checksum: e97b9998d4bc4f2616a4dd3b63447fe8 (MD5) / Made available in DSpace on 2017-07-20T11:55:59Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4568394 bytes, checksum: e97b9998d4bc4f2616a4dd3b63447fe8 (MD5) Previous issue date: 2015-08-01 / Stabilization is important in earthen construction in order to improve mechanical strength, volumetric stability, workability and even ductility. Currently, the products used to stabilize the earth are lime, Portland cement and bitumen emulsions. Due to the environmental problems that the mankind faces nowadays, the use of earthen construction is increasing. Adobe is the most traditional type of block used in masonry. To improve strength against water, a new way to stabilize this kind of unburned earth block is proposed by the alkaline activation of earth. This paper presents the first results about the experimentation made in the stabilization of soil with alkali activator. Two cure temperatures were tested: room temperature and oven at 50ºC. The amounts of stabilizer used were 3% and 6% activator by mass of earth. Results show that it is possible for adobe blocks to be resistant to compression and water action using the alkaline activation. / Para utilização da terra na construção civil, se faz necessário sua estabilização. Tal processo é de fundamental importância para se obter um material em conformidade com as normas vigentes de construção, atendendo a requisitos como: resistência mecânica, estabilidade volumétrica, trabalhabilidade e ductilidade. Atualmente, os produtos mais utilizados para estabilizar a terra são cal, cimento Portland e emulsões betuminosas. Sendo as argilas de fundamental importância para a construção com terra crua, por ser ela o ligante natural, trabalhos têm sido desenvolvidos com intuito de torná-las auto-estabilizantes. Dessa forma, a estabilização de blocos de terra por ativação alcalina tem ganhado especial atenção uma vez que, a eliminação de agregados, influenciará diretamente no custo do material final além da eliminação de processos caros, de tecnologia complexa e de auto grau poluidor em sua elaboração. Neste trabalho, os resultados obtidos, mostram que é possível a obtenção de blocos de adobe resistentes a compressão e a ação da água com uso de ativação alcalina.
5

Mejora de las propiedades mecánicas de los bloques de tierra comprimida (BTC) reforzados con cemento y fibra natural

Cabrera Vargas, Marlo Manuel, Tello Ormeño, Jose Daniel 11 January 2021 (has links)
Existe en la actualidad una intensa búsqueda constante de recursos y tecnologías menos contaminantes, que consumen menos energía en la construcción. El bloque de tierra comprimida (BTC) reforzado con fibra natural puede ser una alternativa efectiva. Este estudio presenta los resultados de una investigación para establecer las propiedades mecánicas del BTC estabilizado con cemento y reforzado con fibra de bagazo de caña. Se consideró evaluar las siguientes combinaciones BTC, BTCE (6% de cemento), BTCB-I (4% de cemento y 0.5% de fibra) y BTC-II (4% de cemento y 1% de fibra). Además, los resultados de las pruebas mecánicas se compararon con normas establecidas y con otras investigaciones relacionadas al tema. Se observó que, con el aumento de cemento, la resistencia de los bloques de tierra comienza a incrementarse gradualmente. Sin embargo, se puede reducir la cantidad de cemento reemplazándola con un mínimo de 0.5% de fibra natural en estado seco, representando bajas pérdidas de resistencia. De la investigación se sugieren analizar coeficientes de diseño a diferentes condiciones, considerando que con un mínimo de 4% de cemento y un 0.5-1% de fibra fue suficiente para producir BTC que cumplan con los requisitos estipulados en la norma peruana. / There is currently an intense constant search for less polluting resources and technologies, which consume less energy in construction. Natural fiber reinforced compressed earth block (BTC) can be an effective alternative. This study presents the results of an investigation to establish the mechanical properties of BTC stabilized with cement and reinforced with cane bagasse fiber. It was considered to evaluate the following combinations BTC, BTCE (6% cement), BTC-I (4% cement and 0.5% fiber) and BTC-II (4% cement and 1% fiber). In addition, the results of the mechanical tests were compared with established norms and with other research related to the subject. It was observed that, with the increase of cement, the strength of the earth blocks begins to increase gradually. But nevertheless, the amount of cement can be reduced by replacing it with a minimum of 0.5% natural fiber in the dry state, representing low resistance losses. From the reach it is suggested to analyze design coefficients at different conditions, considering that a minimum of 4% cement and 0.5-1% fiber was enough to produce BTC that comply with the provisions of the Peruvian standard. / Trabajo de investigación
6

Étude expérimentale du comportement hydro-mécanique de la terre crue compactée pour la construction / Experimental study of the hydro-mechanical behaviour of compacted earthen material for construction

Champiré, Florian 19 September 2017 (has links)
Le matériau terre peut apporter une réponse face aux problèmes que les constructions modernes rencontrent en termes d’enjeux sociétaux, économiques et écologiques. Cependant, les difficultés à comprendre et à prédire son comportement représente un obstacle au développement de cette technique dans les pays développés. Cette thèse s’insère dans un projet de recherche appelé « Primaterre » et financé par l’Agence Nationale de la Recherche française (ANR). Il vise à apporter les connaissances scientifiques nécessaires afin de pallier ce manque et aider à établir des règlementations adaptées. Ce travail s’intéresse plus particulièrement à l’impact de l’eau sur le comportement mécanique de la matrice fine du matériau, qui a un impact essentiel sur le comportement du matériau dans son ensemble. Cette matrice est constituée de sables, de limons, et d’argiles, et ce sur trois types de terres prélevées sur d’anciennes constructions en pisé. Afin de réaliser des échantillons les plus identiques et homogènes possible, un moule a tout d’abord été conçu, ce qui a permis de travailler avec des échantillons cylindriques de 3,5cm de diamètre et 7cm de hauteur. Une cellule triaxiale a été utilisée et, la seconde étape a été de concevoir les dispositifs permettant la mesure des déformations axiales et radiales, le conditionnement à température contrôlée et l’imposition d’un flux d’air humide variable de part et d’autre de l’échantillon. Différents types d’essais ont alors pu être réalisés : des essais triaxiaux à différent taux d’humidité relative ainsi que des essais de gonflement. Les paramètres mécaniques obtenus ont pu être analysés à la lumière des caractéristiques matériaux mesurées en parallèle. Enfin, l’analyse des essais de gonflement a été menée à bien à l’aide d’un modèle numérique, et ce afin de pouvoir évaluer des paramètres caractéristiques plus complexes. Ce travail de thèse se conclut par une étude supplémentaire, visant à évaluer l’impact du changement de taille d’échantillon sur les paramètres mécaniques mesurés précédemment. Ces essais ont été effectués sur des échantillons approximativement deux fois plus grands, et grâce à un dispositif expérimental plus simple, utilisant la mesure par corrélation d’images. / Earthen buildings can provide an answer to face difficulties in modern constructions in both terms of sociology, economics as well as ecology. However, the difficulty to understand and to predict their behavior prevent the spreading of this technique in developed countries. This PhD is part of a research program called “Primaterre” and founded by the French National Agency for Research. It aims at providing the necessary scientific knowledge to overcome this lack and at helping the creation of appropriate standards. This work is more precisely focusing on the impact of water on the mechanical behavior of the fine proportion of the material, including sand, silt and clay, and on three different earths coming from existing rammed earth constructions. In order to be able to produce samples as identical and homogeneous as possible, a mold has first been designed, which enable to manufacture cylindrical samples with diameter of 3.5cm and height of 7cm. A triaxial cell was used and, the second step was to design different devices allowing the measurement of axial and radial deformations, the conditioning at constant temperature, and the command of a variable moist air flux at both sides of the sample. Different types of tests have thus been realized : triaxial tests at different relative humidity, as well as swelling tests. The mechanical parameters thus obtained have been analyzed in comparison with material characteristics measured in parallel. Finally, results of swelling tests have been analysed using numerical modelling, in order to assess more complex material characteristics. This thesis work ends with an additional study, aiming at evaluating the impact of scale change on the mechanical parameters previously measured. Tests have been conducted on sample approximatively twice larger, and thanks to a simpler experimental device using measurement through image correlation.

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