• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 20
  • 9
  • 9
  • 5
  • 4
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 66
  • 26
  • 16
  • 12
  • 11
  • 11
  • 11
  • 10
  • 9
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 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.
21

Produtividade e qualidade dos frutos do tomateiro do grupo cereja cultivado em substratos à base de areia

Fernandes, Carolina [UNESP] 20 January 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-01-20Bitstream added on 2014-06-13T20:25:24Z : No. of bitstreams: 1 fernandes_c_dr_jabo.pdf: 1086601 bytes, checksum: 5d8944bd49d4e986c8d08f3ddcbcea51 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo deste trabalho foi avaliar o potencial de utilização e reutilização de substratos à base de areia, para o cultivo do tomateiro do grupo cereja, cultivar Sindy, com dois volumes de água aplicados por irrigação. Definiu-se V1 como o volume de água necessário para promover a drenagem dos vasos preenchidos com o substrato areia. O volume de água aplicado por irrigação V2 correspondeu a 75% do volume de V1. Os sete substratos resultaram da combinação de diferentes proporções volumétricas de três componentes: areia, bagaço de cana-de-açúcar e casca de amendoim. Os substratos foram utilizados em um cultivo e reutilizados em um segundo cultivo. O bagaço de cana-de-açúcar e a casca de amendoim podem ser utilizados na composição de substratos à base de areia, para o cultivo do tomateiro do grupo cereja. A maior produtividade foi obtida nos substratos não reutilizados e com o volume de água aplicado por irrigação V1. A reutilização do substrato composto por partes iguais dos três componentes promoveu aumento da densidade e do volume de água facilmente disponível, e redução da porosidade total, do espaço de aeração e do volume de água remanescente. Os teores de nutrientes foram maiores nos substratos reutilizados. A redução de 25% no volume de água aplicado por irrigação não alterou as propriedades físicas, mas proporcionou aumento dos teores de nutrientes nos substratos. A qualidade dos frutos não foi afetada pelos substratos, pelos volumes de água aplicados por irrigação e pela reutilização dos substratos. Pode-se propor a classificação, para tomate cereja, associando-se o diâmetro e o peso dos frutos. / The objective of this work was to evaluate the use and reuse of substrates consisted of sand, for cherry tomato growth, with two irrigation rates, at Jaboticabal, São Paulo, Brazil (21°14'05 S, 48°17'09 W). The substrates were used during a growth period and reuse in the second one. The irrigation rate I1 was defined as the amount of water necessary to fall in drops from the pots filled up with sand. The irrigation rate I2 was 75% of the irrigation rate I1. The seven substrates were consisted of different combinations of three materials: sand, crushed sugar-cane and peanut bark. The crushed sugar-cane and peanut bark can be used to compose the substrates consisted of sand for cherry tomate growth. The highest cherry tomato yield was obtained from the non reused substrate and with the irrigation rate I1. The reuse of the substrate consisted of equal parts of the three components caused an increasing of the bulk density and easily available water content, and a decreasing of the total porosity, aeration space and remaining water content. The nutrients levels were higher in the reused substrates. A 25% reduction in the irrigation rate did not affect the physical properties of the substrates, but increased the nutrient levels of them. The fruit quality was not affected by the substrates, the irrigation rates and the reuse of substrates. It is possible to classify the cherry tomato by diameter and weight.
22

Produtividade e qualidade dos frutos do tomateiro do grupo cereja cultivado em substratos à base de areia /

Fernandes, Carolina. January 2005 (has links)
Resumo: O objetivo deste trabalho foi avaliar o potencial de utilização e reutilização de substratos à base de areia, para o cultivo do tomateiro do grupo cereja, cultivar Sindy, com dois volumes de água aplicados por irrigação. Definiu-se V1 como o volume de água necessário para promover a drenagem dos vasos preenchidos com o substrato areia. O volume de água aplicado por irrigação V2 correspondeu a 75% do volume de V1. Os sete substratos resultaram da combinação de diferentes proporções volumétricas de três componentes: areia, bagaço de cana-de-açúcar e casca de amendoim. Os substratos foram utilizados em um cultivo e reutilizados em um segundo cultivo. O bagaço de cana-de-açúcar e a casca de amendoim podem ser utilizados na composição de substratos à base de areia, para o cultivo do tomateiro do grupo cereja. A maior produtividade foi obtida nos substratos não reutilizados e com o volume de água aplicado por irrigação V1. A reutilização do substrato composto por partes iguais dos três componentes promoveu aumento da densidade e do volume de água facilmente disponível, e redução da porosidade total, do espaço de aeração e do volume de água remanescente. Os teores de nutrientes foram maiores nos substratos reutilizados. A redução de 25% no volume de água aplicado por irrigação não alterou as propriedades físicas, mas proporcionou aumento dos teores de nutrientes nos substratos. A qualidade dos frutos não foi afetada pelos substratos, pelos volumes de água aplicados por irrigação e pela reutilização dos substratos. Pode-se propor a classificação, para tomate cereja, associando-se o diâmetro e o peso dos frutos. / Abstract: The objective of this work was to evaluate the use and reuse of substrates consisted of sand, for cherry tomato growth, with two irrigation rates, at Jaboticabal, São Paulo, Brazil (21°14'05" S, 48°17'09" W). The substrates were used during a growth period and reuse in the second one. The irrigation rate I1 was defined as the amount of water necessary to fall in drops from the pots filled up with sand. The irrigation rate I2 was 75% of the irrigation rate I1. The seven substrates were consisted of different combinations of three materials: sand, crushed sugar-cane and peanut bark. The crushed sugar-cane and peanut bark can be used to compose the substrates consisted of sand for cherry tomate growth. The highest cherry tomato yield was obtained from the non reused substrate and with the irrigation rate I1. The reuse of the substrate consisted of equal parts of the three components caused an increasing of the bulk density and easily available water content, and a decreasing of the total porosity, aeration space and remaining water content. The nutrients levels were higher in the reused substrates. A 25% reduction in the irrigation rate did not affect the physical properties of the substrates, but increased the nutrient levels of them. The fruit quality was not affected by the substrates, the irrigation rates and the reuse of substrates. It is possible to classify the cherry tomato by diameter and weight. / Orientador: José Eduardo Corá / Coorientadora: Leila Trevizan Braz / Banca: Arthur Bernandes Cecílio Filho / Banca: Cleide Aparecida de Abreu / Banca: Atelene Normann Kampf / Banca: Luiz Carlos Pavani / Doutor
23

Impacts of Using Crushed Rocks in Concrete.

Horta, Andre January 2011 (has links)
Concrete in Sweden has traditionally been manufactured with natural aggregate from glaciofluvial eskers. There is a need to preserve the remaining eskers because of their cultural value and importance for water filtration, thus natural aggregate has to be replaced. The most realistic alternative is to use crushed rocks. The major problem with crushed rocks in concrete production is the workability. This is because crushed rocks have less favorable properties. The fragments are flakier and have a rougher surface than natural aggregates that have been rounded in water. Without any amelioration of the crushed rock, to reach a certain workability and strength, the amount of cement in the mix has to be increased. Cement production requires large amounts of energy and the decarbonation of limestone releases large amounts of CO2. Combined, the release of CO2, due to burning and decarbonation of limestone, accounts for about 5% of the global CO2 emissions. An increase in cement consumptions is less desirable. Thus to replace natural aggregates, the use of crushed rocks has to be optimized as regard cement consumption. Several crushed aggregates, most from granitic rocks, from all over Sweden were analysed in this study. These crushed rocks were characterized according to their grading, specific surface, shape and petrography and compared to natural sand. Rheological tests that reveals the workability in detail was performed on mortars. The tests showed that as regard workability the 0-2 mm fraction is the most important factor. Further, the maximum aggregate size was gradually increased up to 16 mm, to have a more realistic approach to the concrete produced by the building industry. The results showed that with grading optimization and superplasticizer, some crushed rocks can be used for concrete production without increasing, and even decreasing, the cement consumption. This research also contemplated the use of filler. As a mineral admixture it can improve the compressive strength. It can also be used to replace cement; a replacement up to 20 kg/m3 of cement by filler can be done without significant effect on compressive strength.
24

Propuesta de aplicación del método de auto-curado adicionando ladrillo triturado al agregado grueso para disminuir las fisuras superficiales y aumentar la resistencia a la compresión del concreto en zonas cálidas (Lima Norte) / Proposal for the application of the self-curing method by adding crushed brick to the coarse aggregate to reduce surface cracks and increase the compressive strength of concrete in warm areas (North Lima)

Pinchi Morey, Sanddy Rocío, Ramirez Mejia, Hosvick Jeffer 17 February 2020 (has links)
El concreto es uno de los materiales más utilizados en el mundo de la construcción, de las cuales cada material en la mezcla depende de la resistencia que se requiera de acuerdo al análisis estructural. Dentro del proceso de producción de concreto debemos garantizar que el cemento reaccione químicamente y desarrolle la resistencia para la cual fue diseñada, para esto es importante mantenerlo hidratado en ese tiempo mediante el proceso de curado. Una técnica aún no tan conocida es el auto-curado del concreto, por lo cual es una necesidad saber cuál es su influencia en el desarrollo de la resistencia y en la disminución del porcentaje de agrietamiento del concreto en estado plástico. El objetivo de esta tesis es determinar la influencia que tiene el reemplazar un cierto porcentaje de ladrillo triturado como reemplazo del agregado grueso; evaluando la resistencia a la compresión, resistencia a la flexión, y el agrietamiento por contracción plástica del concreto. Se desarrolló con 3 diferentes porcentajes de reemplazo de ladrillo triturado que son: 15%, 21%, 27% del peso del agregado grueso para la resistencia a la compresión (f’c) de 280 kg/cm2. Se concluyó que reemplazo del agregado grueso por ladrillo triturado es efectivo cuando es usado hasta un máximo de 21%. Los resultados obtenidos son óptimos y viables en el tiempo, mostrándonos un aumento en la resistencia a la compresión, resistencia a la flexión y la disminución del porcentaje de fisuras en estado plástico. / Concrete is one of the most used materials in the world of construction, of which each material in the mixture depends on the strength required according to the structural analysis. Within the concrete production process, we must ensure that the cement reacts chemically and develops the resistance for which it was designed, for this it is important to keep it hydrated at that time through the curing process. A technique not yet so well known is the self-curing of concrete, so it is a necessity to know what its influence is in the development of resistance and in the reduction of the percentage of cracking of concrete in the plastic state. The objective of this thesis is to determine the influence of replacing a certain percentage of crushed brick as a replacement for coarse aggregate; evaluating the compressive strength, flexural strength, and cracking by plastic shrinkage of concrete. It was developed with 3 different percentages of crushed brick replacement that are: 15%, 21%, 27% of the weight of the coarse aggregate for the compressive strength (f’c) of 280 kg / cm2. It was concluded that replacement of coarse aggregate with crushed brick is effective when used up to a maximum of 21%. The results obtained are optimal and viable over time, showing an increase in compressive strength, flexural strength and a decrease in the percentage of cracks in the plastic state. / Tesis
25

The Effects of Coarse Aggregate Cleanliness on Asphalt Concrete Compactability and Moisture Susceptibility

Williams, Kevin Lamar 11 August 2012 (has links)
Twelve field projects were studied where fortyour locations were evaluated to assess the cause or causes of asphalt concrete that exhibits ‘tender zone’ characteristics and to investigate the tendency of these mixes to be susceptible to moisture damage. Data was collected during construction and samples were obtained to conduct laboratory tests. Field and laboratory data was used to develop multiple regression equations to predict final in place air voids and moisture susceptibility. The overall conclusion was that compactability appeared to be predicted in a reasonable manner while moisture susceptibility did not. The Methylene Blue test appears promising when used in conjunction with cold feed and/or mix moisture as a means of providing guidance for achieving higher in place density. The tensile strength ratio (TSR) test as performed in this research on laboratory compacted specimens was found to be questionable in terms of its ability to predict field moisture susceptibility.
26

KOLDIOXIDUPPTAG I KROSSAD BETONG : - Kvantifiera samt effektivisera karbonatiseringsprocessen / CARBON DIOXIDE UPTAKE IN CRUSHED CONCRETE : - Quantify and optimize the carbonation process

Freudendal, Simon, Fransson, Jakob January 2023 (has links)
Strängbetong krossar kasserade håldäckselement som sedan används som ballast i nya gjutningar. Den krossad betong ligger i en hög utomhus innan den används. Det första materialet krossades under 2020 och det senaste vintern 2022. Betongen karbonatiserar, en process som tar upp koldioxid från luften. Arbetet går ut på att kvantifiera den mängd koldioxid som tas upp samt finna förbättringsåtgärder för att kunna öka karbonatiseringen.  För att förstå hur karbonatisering fungerar utfördes informationssökning genom att leta efter tidigare forskningsrapporter som behandlar ämnet. Då det är brist på information om karbonatisering av krossad betong har antaganden gjorts för att komma vidare i arbetet. Vilket innebär att beräkningarna behöver mer korrekt indata för att visa ett mer rimligt resultat.  Den krossade betongen analyserades med karbonatiseringsindikator för att se om ytan av materialet karbonatiserat beroende på hur länge materialet varit orört.  Teoretiska beräkningar utfördes utifrån två olika exponeringar, regn och skyddad från regn, samt olika exponeringstid, resultatet visar att koldioxidupptaget blir högre om högen är skyddad från regn. Att strukturerat plocka material runt högen medför en längre exponeringstid för materialet, därmed ett högre koldioxidupptag jämfört med hur materialet plockas idag där allt material plockas från samma sida. / Strangbetong crushes discarded hollow core slabs, which are used for filling materials in new castings. The crushed concrete is stored in a pile outside before it is used. The first material was crushed during 2020 and the latest material were crushed in the winter of 2022. The concrete carbonates, a process where the concrete absorbs carbon dioxide from the air. The point of this project is to quantify the carbon dioxide which is absorbed and find solutions to make the carbonation more efficient.  To understand how concrete carbonation works, information has been searched for by studying already existing research reports. As there is a lack of information about carbonation of crushed concrete assumptions have been made to move the project forward. Which means that the calculations need more specific data to show a more reasonable result.  The crushed concrete was analyzed with a carbonation indicator to see how far the material had carbonated, depending on how long the material had been untouched.  Theoretic calculations were made throughout two different exposures, rain and covered from rain and different exposure time, the carbon dioxide uptake increases if the pile is covered from rain. Structured picking of material around the pile results in a longer exposure time for the material, therefore a higher uptake of carbon dioxide compared to how the material is picked today where the material is picked from the same side all the time.
27

Contribuição à petrografia de pedra britada / Contribution to Crushed Stone Petrography

Pinho, Deyna 11 April 2007 (has links)
O conhecimento das propriedades físico-químicas da composição mineralógica dos agregados é de extrema importância para o não comprometimento da obra em que serão empregados. Desse modo, o conhecimento da petrografia, mineralogia e geologia das rochas-fonte para brita também são extremamente necessárias. O principal objetivo deste trabalho foi gerar informações sobre a geologia, mercado produtor e petrografia das rochas-fonte da pedra britada nas principais regiões produtoras do país. As informações disponíveis neste segmento da mineração são escassas, principalmente devido às próprias características do setor onde os investimentos em pesquisas geológicas geralmente são escassas e por vezes pouco exigidas. Os cinco principais pólos produtores de pedra britada, alvos de estudo deste trabalho, incluem as cinco maiores regiões metropolitanas do país: São Paulo,Minas Gerais, Rio de Janeiro , Paraná , Rio Grande do Sul. São locais que possuem diferentes rochas-fonte de brita para cada centro produtor, devido à diversidade geológica e abundância daquelas nestes centros. Assim sendo, na região de São Paulo capital a principal rocha-fonte utilizada são granitos e gnaisses provenientes do Embasamento; na região de Belo Horizonte são os calcários provenientes do Grupo Bambuí; na região do Rio de Janeiro capital são os sienitos alcalinos, localizados em diversos corpos alcalinos intrusivos e gnaisses; na região de Curitiba (RMC) são calcários (Formações Perau e Votuverava) e migmatitos extraídos de complexos migmatíticos; e na região de Porto Alegre (RMPA) são predominatemente basaltos e dacitos da Formação Serra Geral. Neste trabalho foi gerado um mapa geológico com localização das pedreiras ativas no período de 2004-2006 para cada região metropolitana relativa à capital de cada Estado. Em cada região foram selecionadas as minerações representativas de acordo com a geologia (rocha-fonte) e produtividade e feitas amostragens e mapeamento em frentes de lavra para a realização de análises petrográficas. As 180 amostras coletadas nas diferentes regiões metropolitanas foram analisadas petrograficamente de forma macroscópica, selecionadas e analisadas na forma microscópica, com base nas normas ABNT e recomendações do Laboratório de Petrologia e Tecnologia de Rochas do IPT. As principais características observadas foram: a composição mineralógica, texturas, estruturas, presença de minerais deletérios, grau de alteração deutérica e estado microfissural. Essas características intrínsecas da rocha-fonte influenciam diretamente a forma e a composição do material britado, e podem dificultar sua aplicação ou mesmo comprometê-la, tanto por motivo de geração de reação álcali-agregado com ligantes quanto por comprometer a resistência mecânica exigida na mistura. O desconhecimento dessas características muitas vezes gera um baixo aproveitamento dos materiais, principalmente finos de pedreira, que se acumulam em pilhas de rejeito ao derredor das empresas mineradoras podendo causar sérios problemas ambientais. Portanto, o trabalho gerou informações para uma melhor otimização e utilização das matérias-primas ou rochas-fonte de brita, contribuindo também indiretamente na redução desses problemas ambientais que atingem as principais regiões urbanas do país. / It is extremely important to know the physical and chemical properties of aggregate mineralogical composition so that the construction where they will be used is not compromised. In this sense, knowing the petrography and mineralogy is as necessary as knowing the geology of the rock deposit to be developed as a source of crushed stone. The main purpose of this work was to generate information on the geology, market and petrography of the rock source of crushed stone in the main producing areas of Brazil. This type of information is not commonly available, especially due to this sector?s characteristics, where investments in geological research are usually scarce and rarely required. The five main states that are crushed stone producers and that therefore contain the centers of production on which this present work focused as case study are: São Paulo, Minas Gerais, Rio de Janeiro, Paraná and Rio Grande do Sul. Each production center presents different types of crushed stone, mainly because of the geological diversity and abundance of the source rock in these places. In the region of the capital of São Paulo the main source rocks are granite and gneiss extracted from the embasement; in Belo Horizonte they are carbonates from the Bambuí group; in Rio de Janeiro, the alkali sienites, localized in diverse intrusive alkaline rocks and gneiss; in the region of Curitiba they are carbonates (Perau and Votuverava Formations) and migmatites extracted from migmatite complex; finally, in the region of Porto Alegre (RMPA), they are basalts and dacites from the Serra Geral Formation. The rock mines in urban regions, related to the state capitals and which were active in the period from 2004 to 2006, are shown on the geological maps generated for the present work. One map has been made for each urban region. The most important mines are shown according to the geology of the source-rock and the productivity. Samples and mapping or description of the benches from the over feet were also made in order to further proceed in petrographic analysis. The 180 samples collected in each urban region suffered macroscopic petrographic analysis after which they were selected and analysed microscopically, according to the ABNT norms and to the recommendation of the Laboratory of Petrology and Rock Technology of IPT. The main observed characteristics were: mineral composition, texture, structure, presence of deleterious minerals, degree in metheoric alteration and microfissural mapping. These intrinsic characteristics of the source rock influence directly the form and composition of the crushed stones and might cause difficulty or even compromise its use due to alkali-aggregate reaction or because of mechanical resistance lower than that required in the mixture. The lack of acknowledgement of these characteristics will often cause the poor use of material, especially of the stone quarry fines, which will end up as reject piled up around mines, causing environmental problems. Therefore, the present work has generated relevant information that can be used to optimize and better use raw material and source rock of crushed stone. It might also contribute indirectly to diminish the environmental problems which are evident in the main urban regions of the country.
28

Contribuição à petrografia de pedra britada / Contribution to Crushed Stone Petrography

Deyna Pinho 11 April 2007 (has links)
O conhecimento das propriedades físico-químicas da composição mineralógica dos agregados é de extrema importância para o não comprometimento da obra em que serão empregados. Desse modo, o conhecimento da petrografia, mineralogia e geologia das rochas-fonte para brita também são extremamente necessárias. O principal objetivo deste trabalho foi gerar informações sobre a geologia, mercado produtor e petrografia das rochas-fonte da pedra britada nas principais regiões produtoras do país. As informações disponíveis neste segmento da mineração são escassas, principalmente devido às próprias características do setor onde os investimentos em pesquisas geológicas geralmente são escassas e por vezes pouco exigidas. Os cinco principais pólos produtores de pedra britada, alvos de estudo deste trabalho, incluem as cinco maiores regiões metropolitanas do país: São Paulo,Minas Gerais, Rio de Janeiro , Paraná , Rio Grande do Sul. São locais que possuem diferentes rochas-fonte de brita para cada centro produtor, devido à diversidade geológica e abundância daquelas nestes centros. Assim sendo, na região de São Paulo capital a principal rocha-fonte utilizada são granitos e gnaisses provenientes do Embasamento; na região de Belo Horizonte são os calcários provenientes do Grupo Bambuí; na região do Rio de Janeiro capital são os sienitos alcalinos, localizados em diversos corpos alcalinos intrusivos e gnaisses; na região de Curitiba (RMC) são calcários (Formações Perau e Votuverava) e migmatitos extraídos de complexos migmatíticos; e na região de Porto Alegre (RMPA) são predominatemente basaltos e dacitos da Formação Serra Geral. Neste trabalho foi gerado um mapa geológico com localização das pedreiras ativas no período de 2004-2006 para cada região metropolitana relativa à capital de cada Estado. Em cada região foram selecionadas as minerações representativas de acordo com a geologia (rocha-fonte) e produtividade e feitas amostragens e mapeamento em frentes de lavra para a realização de análises petrográficas. As 180 amostras coletadas nas diferentes regiões metropolitanas foram analisadas petrograficamente de forma macroscópica, selecionadas e analisadas na forma microscópica, com base nas normas ABNT e recomendações do Laboratório de Petrologia e Tecnologia de Rochas do IPT. As principais características observadas foram: a composição mineralógica, texturas, estruturas, presença de minerais deletérios, grau de alteração deutérica e estado microfissural. Essas características intrínsecas da rocha-fonte influenciam diretamente a forma e a composição do material britado, e podem dificultar sua aplicação ou mesmo comprometê-la, tanto por motivo de geração de reação álcali-agregado com ligantes quanto por comprometer a resistência mecânica exigida na mistura. O desconhecimento dessas características muitas vezes gera um baixo aproveitamento dos materiais, principalmente finos de pedreira, que se acumulam em pilhas de rejeito ao derredor das empresas mineradoras podendo causar sérios problemas ambientais. Portanto, o trabalho gerou informações para uma melhor otimização e utilização das matérias-primas ou rochas-fonte de brita, contribuindo também indiretamente na redução desses problemas ambientais que atingem as principais regiões urbanas do país. / It is extremely important to know the physical and chemical properties of aggregate mineralogical composition so that the construction where they will be used is not compromised. In this sense, knowing the petrography and mineralogy is as necessary as knowing the geology of the rock deposit to be developed as a source of crushed stone. The main purpose of this work was to generate information on the geology, market and petrography of the rock source of crushed stone in the main producing areas of Brazil. This type of information is not commonly available, especially due to this sector?s characteristics, where investments in geological research are usually scarce and rarely required. The five main states that are crushed stone producers and that therefore contain the centers of production on which this present work focused as case study are: São Paulo, Minas Gerais, Rio de Janeiro, Paraná and Rio Grande do Sul. Each production center presents different types of crushed stone, mainly because of the geological diversity and abundance of the source rock in these places. In the region of the capital of São Paulo the main source rocks are granite and gneiss extracted from the embasement; in Belo Horizonte they are carbonates from the Bambuí group; in Rio de Janeiro, the alkali sienites, localized in diverse intrusive alkaline rocks and gneiss; in the region of Curitiba they are carbonates (Perau and Votuverava Formations) and migmatites extracted from migmatite complex; finally, in the region of Porto Alegre (RMPA), they are basalts and dacites from the Serra Geral Formation. The rock mines in urban regions, related to the state capitals and which were active in the period from 2004 to 2006, are shown on the geological maps generated for the present work. One map has been made for each urban region. The most important mines are shown according to the geology of the source-rock and the productivity. Samples and mapping or description of the benches from the over feet were also made in order to further proceed in petrographic analysis. The 180 samples collected in each urban region suffered macroscopic petrographic analysis after which they were selected and analysed microscopically, according to the ABNT norms and to the recommendation of the Laboratory of Petrology and Rock Technology of IPT. The main observed characteristics were: mineral composition, texture, structure, presence of deleterious minerals, degree in metheoric alteration and microfissural mapping. These intrinsic characteristics of the source rock influence directly the form and composition of the crushed stones and might cause difficulty or even compromise its use due to alkali-aggregate reaction or because of mechanical resistance lower than that required in the mixture. The lack of acknowledgement of these characteristics will often cause the poor use of material, especially of the stone quarry fines, which will end up as reject piled up around mines, causing environmental problems. Therefore, the present work has generated relevant information that can be used to optimize and better use raw material and source rock of crushed stone. It might also contribute indirectly to diminish the environmental problems which are evident in the main urban regions of the country.
29

Vztah mezi petrografickými charakteristikami a vybranými technologickými vlastnostmi klastických sedimentárních hornin pro výrobu drceného kameniva / Relationship between petrographic parameters and technological properties of clastic sedimentary rocks used for crushed stone

Čermák, Martin January 2012 (has links)
This diploma thesis is focused on the finding and describing of the relationships between petrological parameters and technological properties of rocks used for the production of aggregates (crushed stone). Rock specimens were selected from a geological area of Culm (Lower Carboniferous age) in the area of Nízký Jeseník Mts. and Drahanská vrchovina uplands in the Czech Republic. Studied localities were selected on the basis of the current quarrying operations and also to represent the different strata. The six studied localities encompass Kobylí, Chabičov, and Bělkovice where Horní Benešov formation of Nízký Jeseník is exposed. Locality Valšov represents Andělské Hory formation and locality Nová Ves and Loštice represent Protivanov formation of Drahanská vrchovina uplands. Two specimens were taken from the locality Loštice (one from the second cut because there are produced low-grade aggregates and the third cut where high quality crushed stone is produced). A detailed mineralogical-petrographic examination of the samples was the first step, in an attempt to obtain their mineralogical composition and to identify the major rock-forming clasts. Thin sections were examined by standard polarizing microscopy. The auxiliary UV lamp and thin sections saturated by fluorescent substance were used for the...
30

Laboratory Evaluation of Recycled Crushed Glass Cullet for Use as an Aggregate in Beach Nourishment and Marsh Creation Projects in Southeastern Louisiana

Wildman, John C 20 December 2018 (has links)
To combat the rapid degradation of the Louisiana coast, the Louisiana Coastal Protection and Restoration Authority has planned strategic land building initiatives throughout the Louisiana Gulf coast, including beach nourishment and marsh creation projects. It is commonly agreed that the state lacks sufficient renewable sediment resources to maintain the planned CPRA land building program. However, Louisiana, the state that commonly ranks last in state recycling percentage, recycles an estimated 0.6% of the waste glass consumed in the state. Glass is predominantly silica sand. This thesis evaluates laboratory‑determined characteristics of recycled crushed glass cullet to assess its suitability as a renewable aggregate for beach nourishment and marsh creation projects. Specifically, the research herein evaluates geotechnical and settling characteristics of recycled crushed glass cullet produced in Pearl River, Louisiana. Additionally, this research evaluates the effects on beach nourishment and marsh creation design parameters of blending this material with Gulf coastal sediments.

Page generated in 0.0533 seconds