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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.
41

Vytrvalostní schopnosti ve veslování / Endurace abilities in rowing

Chovaňáková, Petra January 2018 (has links)
This bachelor thesis deals with the basic criminal activities of the police department by examining the crime scene in the conditions of the basic unit of the Police of the Czech Republic. The first part of the thesis deals with the examination in general, its types and principles. The second part concerns the division of the crime scene investigation by subject matter between the basic police unit and the Criminal Police and Investigation Service. The third part deals with the actual investigation of the crime scene, namely its concept, purpose, procedures and stage of investigation. The fourth part describes the crime scene documentation. The fifth part focuses on the conditions and problems in examining the crime scene performed by the basic body. Key words rowing, rowing ergometer, endurance, methods of endurance testing, Cooper test, Multi stage shuttle run
42

An investigative study on physical sulfate attack and alkali-silica reaction test methods

Lowe, Travis Evans 05 August 2011 (has links)
This thesis is unique in that it investigated two completely different forms of concrete deterioration: physical sulfate attack and the alkali-silica reaction (ASR). Research was undertaken to better understand physical sulfate attack in order to provide much needed guidance on how to prevent durable this form of deterioration. A testing regime was designed to evaluate and analyze different concrete mixtures with varying water to cementitious material ratios (w/cm), cement types (Type I and V), and use of supplementary cementing materials (SCMs) in accelerated laboratory exposure and outdoor exposure testing. The accelerated laboratory testing evaluated the performance of concrete cylinder segments fully submerged in 30% (by mass of solution) sodium sulfate solution exposed to a temperature and humidity cycle that would promote cycles of alternative conversion between anhydrous sodium sulfate (thenardite) and decahydrate sodium sulfate (mirabilite). In the outdoor exposure site, two different sized concrete cylinders per mixture proportion were partially submerged in 5% (33,000 ppm) sodium sulfate solution and exposed to alternative wetting and drying conditions, along with, temperature fluctuations that would promote conversion between thenardite (Na2SO4) and mirabilite (Na2SO4∙10H2O). With regard to ASR test methods, it has been shown with past research that it is not possible to evaluate “job mixtures” or determine alkali thresholds using ASTM C 1293 (Concrete Prism Test) with evaluating aggregates and concrete mixture proportions for the susceptibility of ASR when testing job mixtures. The most commonly cited issue with the concrete prism test is excessive leaching of alkalis during the course of the test, which may not be a major issue when using the standard, high-alkali concrete mixtures as per ASTM C 1293 but is clearly an issue when testing lower-alkali concrete mixtures. For low-alkali mixtures, alkali leaching can reduce the internal alkali content below the threshold that triggers expansion for a given aggregate. A comprehensive study was initiated that evaluated various modifications to ASTM C 1293, with the intention of developing a testing regime better suited to testing “job mixes” and/or low-alkali concrete mixtures. / text
43

Estudo da propriedade resistência superficial em revestimentos de argamassa / Study of surface strength property of mortar rendering

ALVES, Amália Silva 20 September 2009 (has links)
Made available in DSpace on 2014-07-29T15:18:26Z (GMT). No. of bitstreams: 1 capa_rosto_sumario_amalia silva alves.pdf: 117785 bytes, checksum: dfedb23b6700048a2384032a36be6cee (MD5) Previous issue date: 2009-09-20 / The lack of cohesion in mortar renderings corresponds to the loss of mechanical strength among theirs layers due to the weakening of particles bond, a fact which is reflected, among other events, by a low surface resistance of these renderings. Thus, poor surface strength of mortar renderings accelerates their degradation process, leading to a significant reduction in the level of their performance and leading to failures in the functions assigned to them. In this context, this basically experimental research aimed to study the property of surface strength in mortar renderings. So, was investigated the applicability of some test techniques, pendulum hammer, dynamometer traction and ultrasounds (by indirect method) to evaluate surface characteristics of the mortar renderings. In addition, were also evaluated the effects of moisture absorbed by the renderings, the influences of composition, air entrained content and application way in the surface strength of the mortar renderings. In this study, the experimental program was divided into two stages. In the first stage, were used: one mortar mixed (cement: lime: sand) and one industrial mortar (with air entrained content equal 20%) applied in one type of substrate (concrete surface - standard substrate ABCP) by compressed air projection, so that their produced coverings were tested under different conditions of moisture (oven-dry, dry environment, wet and saturated). In the second stage, were used: one mortar mixed (cement: lime: sand) and three industrial mortars (with air entrained content equal 20%, 30% and 40%) applied to the substrate standard in three ways (manually, by means fall box and by compressed air projection). Using statistical criteria, the main results have shown a significant effect of the four mentioned factors on the surface strength, in view of the testing techniques used. However, only showed no significant the effect of moisture in the hardness index. / A falta de coesão dos revestimentos de argamassa corresponde à perda da resistência mecânica entre as suas camadas devida ao enfraquecimento das ligações entre partículas, fato que se traduz, dentre outras ocorrências, pela baixa resistência superficial desses revestimentos. Dessa maneira, a deficiente resistência superficial dos revestimentos de argamassa acelera o processo de degradação, conduzindo a uma queda significativa do nível de desempenho e ao não cumprimento das funções que lhe são atribuídas. Nesse contexto, o presente trabalho, eminentemente experimental, tem como objetivo geral estudar a propriedade resistência superficial em revestimentos de argamassa. Assim, foi investigada a aplicabilidade dos ensaios de esclerometria de pêndulo, de ultra-som (método indireto) e de determinação da resistência superficial empregando-se o dinamômetro de tração na avaliação das características da superfície dos revestimentos de argamassa. Alem disso, foram também avaliados os efeitos da umidade absorvida pelos revestimentos e ainda a influência da composição, do teor de ar e da forma de aplicação da argamassa na resistência superficial. Neste estudo, o programa experimental foi dividido em duas etapas. Na primeira etapa, foram utilizadas: uma argamassa mista (cimento: cal: areia) e uma argamassa industrializada (com teor de ar incorporado igual a 20%) aplicadas sobre um único tipo de substrato (superfície de concreto substrato-padrão da ABCP) por meio de projeção mecânica a ar comprimido, de modo que os respectivos revestimentos produzidos foram ensaiados sob diferentes condições de umidade (seco em estufa, seco ao ambiente, úmido e saturado). Na segunda etapa, foram utilizadas: uma argamassa mista (cimento: cal: areia) e três argamassas industrializadas (com teores de ar iguais a 20%, 30% e 40%), aplicadas ao substrato-padrão de três maneiras distintas (manual por meio de lançador de queda e por projeção mecânica ar comprimido). Como resultado, foi constatado, empregando-se critérios estatísticos, o efeito significativo na resistência superficial dos quatro fatores testados, tendo em vista as técnicas de ensaio empregadas. Não se mostrou significativo, contudo, o efeito da umidade nos valores de índice esclerométrico.
44

To evaluate fire properties of a facade : - a study on semi natural test methods

Martinsson, Emma January 2018 (has links)
Due to an increase in the number of large-scale façade fires around the world the interest in the fire hazards of façades has also increased. The hazards of such fires have been acknowledged since earlier and many different test methods have therefore been developed to enable evaluation of the fire properties of wall assemblies. The purpose of this study is to map differences and similarities between existing full-scale test methods that are currently used to evaluate façade systems based on their performance when influenced by fire. The study also includes a review of previous research into parameters and conditions that influence a façade fire. Some past incidents will be used to enable comparison between the tests and a real fire scenario. The review of previous research has been focused in the areas fire spread, fire properties influencing the heat flux from a fire, and comparative studies evaluating differences between existing test methods. For the study of parameters in existing test methods 21 test methods have been identified and included in the study. A detailed compilation of information on each of the included test methods can be found in the tables included in appendix A. The mapping of the differences and similarities of the included methods has resulted in comparisons of wall and specimen specifications, ignition source parameters, measuring points and approval criteria. The increase in interest for façade fire hazards has also led to some new methods being developed and old methods being revised. New methods and unfinished revisions have not been included in the comparison study but are mentioned.  The conclusion of this study is that although the variation between the tests on the detailed methodology level are very high, if you consider the conditions used for approval and evaluation, they can all be linked to identified hazards of façade fires. However, there are some parameters that need to be re-examined. Previous research indicates that the fire load may be the parameter with most influence on the fire scenario. This is one of the parameters that vary the most and at same time it is likely to contribute to different results between the test methods. Another parameter is the influence of wall openings representing windows to overlaying compartments. This is a parameter that could have a significant effect on the outcome of a test.
45

Characterizing phosphate desorption kinetics from soil : an approach to predicting plant available phosphorus

Mengesha, Abi Taddesse 21 January 2009 (has links)
Many agricultural fields that have received long-term applications of P often contain levels of P exceeding those required for optimal crop production. Knowledge of the effect of the P remaining in the soil (residual effect) is of great importance for fertilization management. In order to characterize P forms in soils, a wide variety of methods have been proposed. The use of dialysis membrane tubes filled with hydrous ferric oxide (DMT-HFO) has recently been reported as an effective way to characterize P desorption over a long-term in laboratoty studies. However, there is little information on the relationship between kinetics of P release using this new method and plant P uptake. This method consist of a procedure of shaking a sample for a long period of time there by exploiting the whole volume of the soil which is in contrast to the actual plant mode of uptake. This method has also practical limitations in employing it for a routine soil analysis, as it is very expensive and time consuming. The objectives of this study were (i) to study the changes in labile, non-labile and residual P using successive P desorption by DMT-HFO followed by a subsequent fractionation method (combined method) (ii) to assess how the information gained from P desorption kinetic data relates to plant growth at green house and field trials (iii) to investigate the effect of varying shaking time on DMT-HFO extractable P and (iv) to propose a short cut approach to the combined method. The release kinetics of the plots from long term fertilizer trials at the University of Pretoria and Ermelo were studied. P desorption kinetics were described relatively well by a two-component first-order model (R2 = 0.947, 0.918,&0.993 for NPK, MNK,&MNPK treatments respectively). The relative contributions of both the labile pool (SPA) and the less labile pool (SPB) to the total P extracted increased with increased P supply levels. Significant correlations were observed between the rate coefficients and maize grain yield for both soil types. The correlation between the cumulative P extracted and maize yield (r = 0.997**) however was highly significant for Ermelo soils. This method was also used to determine the changes in the different P pools and to relate these P fractions with maize yield. Highly significant correlations were observed between maize grain yield and the different P fractions including total P. In both soil types the contribution of both the labile and non-labile inorganic P fractions in replenishing the solution Pi was significant where as the contributions from the organic fractions were limited. The C/HCl-Pi is the fraction that decreased most in both cases as well. Investigation was carried out to evaluate the effect of varying shaking periods on the extractable DMT-HFO-Pi for UP soils of varying P levels. Four shaking options were applied. Significant difference was observed for the treatment of high P application. Shaking option 2 seemed relatively better than the others since it showed the strongest correlation. Thus for soils with high releasing kinetics and high total P content, provided that the P release from the soil is a rate limiting step, reducing the length of shaking time could shorten the duration one needs to complete the experiment with out influencing the predicting capacity of the methodology. The other objective of this thesis was also to present a short cut method alternative to the combined fractionation method. Comparison of the sum of DMT-HFO-Pi, NaHCO3-Pi, NaOH-Pi, D/HCl-Pi and C/HCl-Pi extracted by a conventional step-by-step method with the sum of DMT-HFO-Pi and a single C/HCl-Pi extraction as a short cut approach for all extraction periods resulted in strong and significant correlations. The C/HCl-Pi fraction extracted by both methods was correlated with maize grain yield and it was found to be highly significant. This study revealed that this short cut approach could be a simplified and economically viable option to study the P dynamics of soils especially for soils where the P pool acting as a source in replenishing the labile portion of P is already identified. The method employed here therefore could act as an analytical tool to approximate successive cropping experiments carried out under green house or field condition. However, data from a wider range of soils is needed to evaluate the universality of this method. More work is also required in relating desorption indices of this method with yield parameters especially at field level. / Thesis (PhD)--University of Pretoria, 2009. / Plant Production and Soil Science / PhD / unrestricted
46

Customer focused development of a variable bent-axis pump/motor for open circuit hydrostatic transmissions, e.g. in hydraulic hybrid drives

Hugosson, Conny, Kayani, Omer, Krieg, Mark January 2016 (has links)
The paper presents the development methodology of a hydrostatic pump/motor for use in Parker Hannifin’s advanced series hydraulic hybrid transmissions for medium and heavy duty commercial vehicles. With Parker’s established bent-axis pump/motor technology for heavy duty mobile applications as a basis, it describes the main stages of further development and qualification for demanding automotive main drive transmissions. Parker’s APQP based, customer focused product development model was employed for this development which resulted in the variable bent-axis pump/motor C24 for open circuit hydrostatic transmissions. Positive customer results from a large fleet of in-service refuse collection trucks and parcel delivery vans with Parker advanced hydraulic hybrid drive systems using C24 pumps/motors serve as evidence of Parker’s product development model effectiveness. High reliability, good fuel economy, increased productivity and long brake life of the vehicles can directly be traced back to the streamlined, front-loaded and iterative development model.
47

Contribuição ao estudo dos métodos de ensaio na avaliação das reações álcali-agregado em concretos. / Contribution to the study of test methods in assessing alkali-aggregate reactions in concrete.

Sanchez, Leandro Francisco Moretti 05 May 2008 (has links)
Muitas estruturas e elementos estruturais de concreto vêm sofrendo nas últimas décadas reações químicas deletérias do tipo álcali-agregado (RAA) no Brasil e no mundo. Essas reações geram expansões que podem comprometer a capacidade portante da estrutura, assim como o seu desempenho em serviço e sua durabilidade. Diagnosticar uma estrutura deteriorada pela RAA in loco é um assunto ainda pouco estudado, mas perfeitamente possível. Propor uma solução em termos de recuperação e/ou reforço é difícil e geralmente tem custo muito elevado, correndo-se o risco de que a solução, na maioria das vezes, seja ineficiente ou parcial. Até os dias atuais, não existe um consenso no meio técnico-científico no que tange a recuperação de estruturas afetadas por tal manifestação deletéria, devendo ser cada caso analisado de maneira única. No entanto, é consenso no meio técnico-científico que o ideal para combater a RAA é a prevenção. Para isto, torna-se necessário o desenvolvimento e a utilização de métodos experimentais, que possam de maneira antecipada detectar o risco da eventual futura reação deletéria. Este trabalho estuda os principais e mais utilizados métodos de ensaio para a análise de agregados e de combinações cimento/agregados em laboratório, fazendo ao seu final, uma análise crítica no que tange a eficiência e confiabilidade de cada um deles. Para o presente estudo, são utilizados seis agregados encontrados no Brasil, com quatro litologias diferentes (dois granitos, dois basaltos, um milonito e um quartzito). Entre os ensaios estudados, podem ser citados os métodos AMBT, (método acelerado de barras de argamassa), CPT (método dos prismas de concreto), ACPT (método acelerado de prismas de concreto) e ACPST (método acelerado de prismas de concreto imerso em solução), além de análises petrográficas através do microscópio ótico. Além da análise comparativa entre métodos de ensaio existentes, esta dissertação propõe ao meio técnico um novo método de ensaio, denominado ABCPT (método acelerado brasileiro de prismas de concreto). Este método foi desenvolvido com o intuito de possuir a confiabilidade de resposta do método CPT e a agilidade do ensaio ACPST. Os resultados demonstram que todos os métodos de ensaio realizados em concreto (CPT, ACPT, ACPST e ABCPT) possuem grande correlação entre si, podendo ser utilizado qualquer um deles para classificação da reatividade potencial de agregados em laboratório. Já o ensaio de barras de argamassa (AMBT) apresenta incongruências na análise e classificação de agregados quando comparado com os métodos realizados em concreto e a análise petrográfica. Portanto, os parâmetros que envolvem o ensaio como suas condições. / Many concrete structures have been suffering from alkali-aggregate reactions (AAR) since the last decades in Brazil and around the world. The reactions generate expansions that could compromise the strength of a concrete structure as well as its performance in service and its durability. Nowadays, it is completely possible to detect AAR in the field, but repair and reinforce a damaged structure is difficult, very expensive and in most cases inefficient or partial. There is no consensus in the market on how to repair and reinforce damaged structures. However, there is a consensus that the best way to face the problem is the prevention. This work studies the main test methods used to analyze aggregates and the combinations cement/aggregates in the laboratory and finally comparing them. In this work six Brazilian aggregates with four different lithologies (two granites, two basalts, one granite-gneiss and one quartzite) were used. Among the test methods studied were AMBT (accelerated mortar bar test), CPT (concrete prism test), ACPT (accelerated concrete prism test), ACPST (accelerated concrete prism soaked test) and petrographic analysis. Beyond the comparison among used tests, this work presents the attempt to develop a new accelerated test method. The test was called ABCPT (accelerated Brazilian concrete prism test), and it was developed with the aim of being as reliable as CPT and as fast as the ACPST. The results show that all concrete test methods (CPT, ACPT, ACPST and ABCPT) have good correlation among them, and anyone can be used to classify and analyze aggregates in the laboratory. On the other hand, the AMBT test method has showed different classifications for the same aggregates when compared to the concrete test methods and petrographic analysis. Therefore, its parameters need to be rethought and improved.
48

Systemutveckling och användbarhet -Att utnyttja användbarhetstester i systemutvecklingsprocessen / Systems development and usability -Using methods for testing usability during the system development process

Forsberg, Per, Klasson, Isak January 2002 (has links)
<p>Den här rapporten behandlar frågeställningen om hur man kan anpassa systemutvecklingav ett informationssystem enligt livscykelmodellen till att inkludera användbarhetstester. </p><p>Frågeställningen grundar sig i att god användbarhet inte är ett explicit uttryckt mål i Andersens beskrivning av livscykelmodellen. För att besvara frågeställningen har vi utvecklat och testat ett bokningssystem åt en mindre verksamhet. Utvecklingsarbetet har bedrivits enligt en egen anpassning av livscykelmodellen. Testerna har utförts enligt metoden c<i>ooperativ evaluation. </i></p><p>Frågeställningen besvaras genom att vi presenterar hur vi har gått tillväga för att inbegripa testerna i utvecklingsprocessen. De delar av informationssystemet som vi utvärderat beskrivs i rapporten. </p><p>Testerna hjälpte till att identifiera problem i systemets gränssnitt som annars troligen inte skulle ha upptäckts förrän slutanvändarna fått tillgång till systemet. </p><p>Slutsatserna är att det är möjligt, och dessutom önskvärt ur användbarhetssynpunkt, att innefatta användbarhetstester i utveckling av informationssystem. </p> / <p>This reports regards the question of how one can adjust system development according to the Systems Development Life Cycle (SDLC) to include usability testing. </p><p>The question is based on the fact that usability isn’t an explicit goal in Andersen description of the SDLC. To answer this question we have developed and tested an information system for a small business. The development has been carried on according to an own adaptation of the SDLC. The testings have been performed in accordance with the Cooperativ evaluation method. </p><p>The question is answered by the presentation of our adaptation to include the tests in the development process. The parts of the information system we have evaluated are described in the report. </p><p>The tests helped to identify problems in the user interface which otherwise probably would not have been discovered until the end user gotten access to the system. </p><p>The conclusions are that it is possible, and furthermore desirable from a usability point of view, to include usability testing duringthe development of information systems.</p>
49

Comparação da determinação da tenacidade do concreto reforçado com fibras de aço por meio do ensaio de abertura por encunhamento e da ASTM C1609 / Comparison of the determination of the toughness of the reinforced concrete with steel fibers through the aperture test by ASTM C1609

Dias, Raphael 26 February 2018 (has links)
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo geral dessa pesquisa é analisar o comportamento mecânico, com foco na tenacidade à tração, de corpos de provas de concreto reforçado com fibras de aço, por meio do ensaio de abertura por encunhamento, patenteado por Elmar K. Tschegg, comparando os resultados com os valores obtidos pelo método da ASTM C1609. Deseja-se ainda, avaliar a influência do teor de fibra de aço e da resistência à compressão na tenacidade do compósito. E também contribuir com a regulamentação e o controle na aplicação do material. O programa experimental foi composto de 112 corpos de prova (64 cilíndricos para caracterização, 24 prismáticos para ASTM C1609 e 24 cúbicos para encunhamento) que foram ensaiados no Laboratório de Estruturas da Faculdade de Engenharia Civil da Universidade Federal de Uberlândia. Todos os corpos de prova foram moldados e ensaiados com idade mínima de 60 dias. Após a realização dos ensaios e análise dos resultados, conclui-se que as fibras de aço conferem ao concreto um aumento na tenacidade à tração. Observou-se também o comportamento strain-hardening à tração do concreto com teor de fibras de 0,64%. O ensaio de abertura por encunhamento apresenta indicativos de reprodutibilidade e coerência, quando comparado com o teste ASTM C1609 (2012), ou seja, há uma correlação e confirma-se como um procedimento alternativo para o controle tecnológico do compósito. / The general objective of the research is to analyze the mechanical behavior, focusing on the tensile strength, of concrete reinforced concrete test bodies with steel fibers, by means of the Elmar K. Tschegg patented aperture test by comparing the results with The values obtained by the method of ASTM C1609. It is also desired to evaluate the influence of the steel fiber content and the compressive strength on the composite toughness. And also contribute with a regulation and control in the application of the material. The experimental program was composed of 112 test specimens (64 cylindrical characterization, 24 prismatic for ASTM C1609 and 24 cubic for encouragement) that were tested in the Structures Laboratory of the Faculty of Civil Engineering of the Federal University of Uberlândia. All specimens were molded and assayed at least 60 days old. After the tests and analysis of the results, it is concluded that the steel fiber gives the concrete an increase in tensile toughness. The strain-hardening behavior of the concrete with a fiber content of 0.64% was also observed. The Wedge Splitting Test presents indications of reproducibility and coherence, when compared with ASTM C1609 (2012), that is, there is a correlation and it is confirmed as an alternative procedure for the technological control of the composite. / Dissertação (Mestrado)
50

Contribuição ao estudo dos métodos de ensaio na avaliação das reações álcali-agregado em concretos. / Contribution to the study of test methods in assessing alkali-aggregate reactions in concrete.

Leandro Francisco Moretti Sanchez 05 May 2008 (has links)
Muitas estruturas e elementos estruturais de concreto vêm sofrendo nas últimas décadas reações químicas deletérias do tipo álcali-agregado (RAA) no Brasil e no mundo. Essas reações geram expansões que podem comprometer a capacidade portante da estrutura, assim como o seu desempenho em serviço e sua durabilidade. Diagnosticar uma estrutura deteriorada pela RAA in loco é um assunto ainda pouco estudado, mas perfeitamente possível. Propor uma solução em termos de recuperação e/ou reforço é difícil e geralmente tem custo muito elevado, correndo-se o risco de que a solução, na maioria das vezes, seja ineficiente ou parcial. Até os dias atuais, não existe um consenso no meio técnico-científico no que tange a recuperação de estruturas afetadas por tal manifestação deletéria, devendo ser cada caso analisado de maneira única. No entanto, é consenso no meio técnico-científico que o ideal para combater a RAA é a prevenção. Para isto, torna-se necessário o desenvolvimento e a utilização de métodos experimentais, que possam de maneira antecipada detectar o risco da eventual futura reação deletéria. Este trabalho estuda os principais e mais utilizados métodos de ensaio para a análise de agregados e de combinações cimento/agregados em laboratório, fazendo ao seu final, uma análise crítica no que tange a eficiência e confiabilidade de cada um deles. Para o presente estudo, são utilizados seis agregados encontrados no Brasil, com quatro litologias diferentes (dois granitos, dois basaltos, um milonito e um quartzito). Entre os ensaios estudados, podem ser citados os métodos AMBT, (método acelerado de barras de argamassa), CPT (método dos prismas de concreto), ACPT (método acelerado de prismas de concreto) e ACPST (método acelerado de prismas de concreto imerso em solução), além de análises petrográficas através do microscópio ótico. Além da análise comparativa entre métodos de ensaio existentes, esta dissertação propõe ao meio técnico um novo método de ensaio, denominado ABCPT (método acelerado brasileiro de prismas de concreto). Este método foi desenvolvido com o intuito de possuir a confiabilidade de resposta do método CPT e a agilidade do ensaio ACPST. Os resultados demonstram que todos os métodos de ensaio realizados em concreto (CPT, ACPT, ACPST e ABCPT) possuem grande correlação entre si, podendo ser utilizado qualquer um deles para classificação da reatividade potencial de agregados em laboratório. Já o ensaio de barras de argamassa (AMBT) apresenta incongruências na análise e classificação de agregados quando comparado com os métodos realizados em concreto e a análise petrográfica. Portanto, os parâmetros que envolvem o ensaio como suas condições. / Many concrete structures have been suffering from alkali-aggregate reactions (AAR) since the last decades in Brazil and around the world. The reactions generate expansions that could compromise the strength of a concrete structure as well as its performance in service and its durability. Nowadays, it is completely possible to detect AAR in the field, but repair and reinforce a damaged structure is difficult, very expensive and in most cases inefficient or partial. There is no consensus in the market on how to repair and reinforce damaged structures. However, there is a consensus that the best way to face the problem is the prevention. This work studies the main test methods used to analyze aggregates and the combinations cement/aggregates in the laboratory and finally comparing them. In this work six Brazilian aggregates with four different lithologies (two granites, two basalts, one granite-gneiss and one quartzite) were used. Among the test methods studied were AMBT (accelerated mortar bar test), CPT (concrete prism test), ACPT (accelerated concrete prism test), ACPST (accelerated concrete prism soaked test) and petrographic analysis. Beyond the comparison among used tests, this work presents the attempt to develop a new accelerated test method. The test was called ABCPT (accelerated Brazilian concrete prism test), and it was developed with the aim of being as reliable as CPT and as fast as the ACPST. The results show that all concrete test methods (CPT, ACPT, ACPST and ABCPT) have good correlation among them, and anyone can be used to classify and analyze aggregates in the laboratory. On the other hand, the AMBT test method has showed different classifications for the same aggregates when compared to the concrete test methods and petrographic analysis. Therefore, its parameters need to be rethought and improved.

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