Master's thesis consists of two parts, theoretical and practical. In the theoretical section are listed basic information about alternative aggregates used for concrete mixture, like polystyrene, cinder and recycled concrete. Further, the influence of these alternative aggregates, used as secondary raw materials, on the behaviour and properties of fresh respectively hardened concrete. Possibilities of application concrete containing secondary raw materials are mentioned. In the practical part are experimentally verified physical and mechanical properties of concrete containing crushed waste polystyrene beads, furthermore thermal insulation properties and resistance to elevated temperatures is tested. Influence of heating plant cinder powder as active addition to concrete mixture was tested. As a next is prepared concrete with replacement of coarse aggregate by cinder and recycled concrete and tested. The influence of these secondary raw materials on workability, compressive strength, frost resistance and water permeability of concrete is also defined. The last part of research is focused on recycled concrete such as main material used in mixture of aggregates bonded with cement, dispose for base layers in roads. In conclusion are discussed results from experimental research and summary of knowledge’s about using polystyrene, cinder and recycled concrete as aggregates for concrete mixtures.

La qualité des pièces découpées pour les industries électroniques et micromécaniques est appréciée via trois critères principaux : le niveau de bavure, l’aspect du bord découpé et la précision dimensionnelle. Or, l’étude de la qualité des pièces découpées ne peut se faire sans une compréhension de l’usure des poinçons. Ainsi, des méthodes de mesure en continu et in situ de l’usure ont été mises au point et validées, soit l’activation superficielle et la mesure par double réplique. Ainsi, il a été possible de suivre l’influence d’un certain nombre de paramètres du procédé sur l’évolution de l’usure lors du découpage. Par ailleurs, nous avons mis au point une méthode de quantification de la bavure sur la totalité du contour découpé. Il a ainsi été possible d’étudier l’évolution de la bavure au cours de la découpe. L’aspect des bords découpés a été examiné grâce à des relevés topographiques permettant le suivi de son évolution. Ainsi, une corrélation entre la cinétique d’usure des poinçons et l’apparition de la bavure a été établi. De plus, une simulation expérimentale de l’usure des poinçons a été entreprise. Un dispositif expérimental de tribométrie a été conçu et installé sur la ligne de presse, simulant les conditions de frottement d’un poinçon sur une tôle. Il a permis d’évaluer l’abrasivité des tôlesminces vis-à-vis des poinçons. Par ailleurs, une modélisation numérique de l'opération de découpage par éléments finis a été entreprise, permettant d’approcher le profil d’usure d’un poinçon de géométrie cylindrique. Et par conséquent la possibilité de prédire son évolution en fonction du nombre de pièces découpées devient accessible en fonction des paramètres du procédé / The blanked parts quality for electronic and amicromechanical industry is assessed using threemain criterions: the burr amount, the appearance ofthe cut edge and dimensional accuracy. However, thestudy of the quality of the blanked pieces can not bedone without an understanding of the punches wear.Thus, methods for continuous and in-situ wearmeasurements have been developed and validated:Thin Layer Activation and measurement by doublereplica. Thus, it was possible to follow the influenceof process parameters on the wear evolution duringblanking.In addition, we have developed a method forquantifying the burr on the entire blanked contour. Itwas thus possible to study the evolution of the burrduring blanking. The appearance of the cut edges wasexamined by means of topographic survey for monitoringits evolution. Thus, a correlation between the kinetics ofpunches wear and the appearance of the burr has beenestablished. In addition, an experimental simulation ofpunches wear was undertaken. An experimentaltribometry was designed and installed on the press line,simulating the conditions of friction of a punch on onesheet. It evaluated the abrasiveness of thin sheets againstthe punches.Additionally, a numerical modelling of blanking wasundertaken to approach the wear profile of a punch ofcylindrical geometry. And therefore the ability to predictits evolution contingent on the number of blanked pieces becomes available depending on process parameters

Introduction. Stone crushing in Dar-es-Salaam Tanzania is largely an informal occupational activity, with approximately 7000 workers exposed to varying level of respirable dust. A highly marginalized, self employed, informal stonecrusher is prone to multiple work related risks, particularly dust related respiratory diseases. Aim. This study, the first to be done among informal stone crushers in Southern Africa, aimed at determining the prevalence of dust related respiratory outcomes and relationships between these health endpoints and exposure to respirable dust in this sample of stonecrushers. Methods. This was primarly a cross-sectional descriptive study with analytic components. This study analysed a subset of data collected in a health survey of stone crushers in Kigamboni informal stone quarry in Dar-es-Salaam, Tanzania in 2007. All 200 workers working in the quarry were interviewed. A subset of 86 and 59 workers underwent exposure assessment and health assessments (spirometry and chest radiography) respectively. Associations were investigated between exposure measures and respiratory outcomes. Results. The average age of the workers was 36.3 years with 51.5% males participating in the study. Smoking was common with 30.1% male, 8.25% female smokers, with 2% ex-smokers. Personal dust sampling showed varying dust levels ranging from 0.5-2.8mg/m3 with geometric mean of 1.2gm/m3. The exposure duration of workers in the quarry ranged from 1-62 years with mean of 7.8 years. No single worker was found to use personal protective equipment at work. Reported prevalence of doctor diagnosed respiratory diseases was low: pulmonary tuberculosis (2%), chronic bronchitis (2%), asthma (3%), pneumonia (3%). In contrast, there was high prevalence of respiratory symptoms: chronic cough (13.5%), phlegm production (14.5%), productive cough (10%), wheezing (14%), mild breathlessness (9.5% ) and coughing blood (7.5%). Mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) adjusted for age, height and sex was 2.6L/min and 3.7 L respectively, among males and 2.1L/min and 3.0L respectively among females. Adjusted exposure odds ratios for symptoms were statistically significant for mild and moderate breathlessness with odds ratios of 3.4 and 3.1 respectively. Linear regression showed statistically significant decline of 2.3mls in FEV1 with years of exposure while controlling for sex, age, height , doctor diagnosed TB and smoking showing that with prolonged exposure in the quarry, workers are at a risk of developing obstructive lung disease. This trend was not evident for FVC. The majority of films were normal (60.9%), with 19.6% read as 1/0 and 19.9% as 0/1. Discussion. This study identified adverse respiratory outcomes among informal stonecrushers, particularly a high prevalence of respiratory symptoms and clinically important lung function deficits. These are in keeping with other environment studies where workers were exposed to respirable dust. Recommendations. Urgent policy initiatives for developing cost effective hazard control, engineering interventions to protect these marginalized self-employed informal sector stonecrushers are needed. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2010.

O objetivo desse trabalho é identificar o comportamento da areia de britagem de rocha calcária na argamassa de revestimento Foram propostas cinco composições de traço, a primeira com 100% areia natural, que será usado como traço de referência, a segunda composição com 80% areia natural, e 20% areia de britagem de rocha calcária, o terceiro com 60% areia natural e 40% areia de britagem de rocha calcária, o quarto com 40% areia natural e 60% areia de britagem de rocha calcária, e o quinto com 20% areia natural e 80% areia de britagem de rocha calcária. Os traços das argamassas foram compostos com cimento, areia, água e aditivo, sem a presença da cal, e estas foram ensaiadas no estado fresco e endurecido e apresentaram os seguintes resultados: Os traços compostos com a areia de britagem de rocha calcária apresentaram melhor desempenho que o traço de referência, composto apenas com areia natural. O traço com 60% de areia natural e 40% de areia de britagem de rocha calcária apresentou melhor desempenho em 70% dos ensaios realizados, tendo apresentado uma curva granulométrica dentro da zona ótima superior e inferior exigido pela norma. A relevância desse estudo se deve ao fato de que, a areia de britagem é um resíduo que gera um importante passivo ambiental, e o uso da areia de extração provoca a degradação do meio ambiente. Utilizar a areia de britagem para substituir a areia natural é uma forma de contribuir para a preservação ecológica. / The goal of this resarch is to identify the behavior of limestone crushed sand in coating mortar. Five trace compositions were proposed and tested: the first one made up of 100% natural sand, which will be used as reference trace, the second composition presented 80% natural sand and 20% limestone rock crushed sand, the third one 60% natural sand and 40% limestone rock crushed sand, the fourth one with 40% natural sand and 60% limestone rock crushed sand, and the fifth trace 20 % natural sand and 80% limestone rock crushed sand. The mortar traces were composed of cement, sand, water and additive, without the presence of lime, and these were tested in the wet and hardened state and presented the following results: Composite traces with limestone rock crushed sand presented better performance than the reference trace, which had only natural sand. The traces with 60% natural sand and 40% limestone crushed sand showed better performance in 70% of the tests performed, and presented a grain size curve within the optimal upper and lower zone, as required by the standard rules. The relevance of this study is due to the fact that crushed sand is a waste that generates important environmental liability, and natural sand extraction leads to the environmental degradation. Using crushed sand to replace natural sand is one way to contribute to environmental preservation.

O objetivo desse trabalho é identificar o comportamento da areia de britagem de rocha calcária na argamassa de revestimento Foram propostas cinco composições de traço, a primeira com 100% areia natural, que será usado como traço de referência, a segunda composição com 80% areia natural, e 20% areia de britagem de rocha calcária, o terceiro com 60% areia natural e 40% areia de britagem de rocha calcária, o quarto com 40% areia natural e 60% areia de britagem de rocha calcária, e o quinto com 20% areia natural e 80% areia de britagem de rocha calcária. Os traços das argamassas foram compostos com cimento, areia, água e aditivo, sem a presença da cal, e estas foram ensaiadas no estado fresco e endurecido e apresentaram os seguintes resultados: Os traços compostos com a areia de britagem de rocha calcária apresentaram melhor desempenho que o traço de referência, composto apenas com areia natural. O traço com 60% de areia natural e 40% de areia de britagem de rocha calcária apresentou melhor desempenho em 70% dos ensaios realizados, tendo apresentado uma curva granulométrica dentro da zona ótima superior e inferior exigido pela norma. A relevância desse estudo se deve ao fato de que, a areia de britagem é um resíduo que gera um importante passivo ambiental, e o uso da areia de extração provoca a degradação do meio ambiente. Utilizar a areia de britagem para substituir a areia natural é uma forma de contribuir para a preservação ecológica. / The goal of this resarch is to identify the behavior of limestone crushed sand in coating mortar. Five trace compositions were proposed and tested: the first one made up of 100% natural sand, which will be used as reference trace, the second composition presented 80% natural sand and 20% limestone rock crushed sand, the third one 60% natural sand and 40% limestone rock crushed sand, the fourth one with 40% natural sand and 60% limestone rock crushed sand, and the fifth trace 20 % natural sand and 80% limestone rock crushed sand. The mortar traces were composed of cement, sand, water and additive, without the presence of lime, and these were tested in the wet and hardened state and presented the following results: Composite traces with limestone rock crushed sand presented better performance than the reference trace, which had only natural sand. The traces with 60% natural sand and 40% limestone crushed sand showed better performance in 70% of the tests performed, and presented a grain size curve within the optimal upper and lower zone, as required by the standard rules. The relevance of this study is due to the fact that crushed sand is a waste that generates important environmental liability, and natural sand extraction leads to the environmental degradation. Using crushed sand to replace natural sand is one way to contribute to environmental preservation.

This diploma thesis deals with the design of an inclined three-sided vibrating screen, which is designed for sorting bulk aggregates. The aim of the diploma thesis is primarily to make a construction design with a specific comparison of various design solutions, considering the calculated operating parameters. In the construction design, is used not only the experience of the manufacturer of this type of machine, but also recommendations based on the manu-facturers of screens component. The design also includes a comparison of two types of flex-ible mounting, which is one of the basic structural units of the entire vibrating screen. The thesis is conceived from the basics, with emphasis on the simplicity and functionality of the device.

MESMEG / Department of Mining and Environmental Geology / See the attached abstract below

Constitués de plusieurs composants (granulats naturels et pâte de ciment adhérente), les GBR ne sont à l’heure actuelle pas utilisés largement dans la formulation de nouveaux bétons. Les propriétés médiocres des GBR compliquent considérablement la détermination de la quantité d’eau efficace dans le béton frais. Tout d’abord, une étude bibliographique va mettre en évidence la grande dispersion des résultats des essais de caractérisation des GBR et des propriétés des bétons recyclés à l’état frais et durci. Ensuite, une étude vise à analyser l’hétérogénéité des GBR et des granulats de béton concassé (GBC) par rapport à différents paramètres : aux impuretés granulaires, à la densité et à la teneur en pâte de ciment, au malaxage du béton parent, et au niveau de la capacité d’absorption d’eau des GBC en fonction de leur état de pré-humidification. Enfin, une dernière partie est destinée à améliorer la maîtrise de l’eau efficace réelle dans la fabrication du béton recyclé. La cinétique d’absorption des GBC dans une pâte de ciment est tout d’abord étudiée. Ensuite, l’évolution de l’eau efficace durant le malaxage de bétons à base de GBC est investiguée au moyen d’une méthode originale basée sur le suivi des courbes de puissance du malaxeur. Finalement, l’effet d’un malaxage sous vide relatif sur les propriétés des bétons à base de granulats naturels et des bétons à base de GBC est étudié. / Composed of several components (natural aggregates and adherent cement paste), RCA are not widely recommended in new concrete formulations. Their poor properties considerably complicate the determination of the effective water in fresh concrete. In a first part, a bibliographic study will highlight the wide dispersion of the results of characterization tests of RCA and the properties of fresh and hardened recycled concrete. In a second part, the heterogeneity of RCA and crushed concrete aggregates (CCA) is studied according to different parameters: granular impurities, density, cement paste content, mixing of parent concrete, and water absorption capacity according to their pre-humidification. The third part consists of three experimental studies that intend to improve effective water control in the manufacture of recycled concrete. The absorption kinetics of CCA in a cement paste is first studied. Then, the evolution of effective water in fresh concrete during mixing is studied using an original method based on the power evolution of the mixer. Finally, the effect of vacuum mixing on the properties of ordinary and recycled concretes is investigated.

The Portland Cement Association commissioned a research project at Brigham Young University to compare selected laboratory durability tests available for assessing stabilized aggregate base materials. The laboratory research associated with this project involved two granular base materials, three stabilizers at three concentration levels each, and three durability tests in a full-factorial experimental design. The granular base materials consisted of an aggregate-reclaimed asphalt pavement blend obtained from Interstate 84 (I-84) and a crushed limestone obtained from U.S. Highway 91 (US-91), while the three stabilizer types included Class C fly ash, lime-fly ash, and Type I/II Portland cement. Specimens were tested for durability using the freeze-thaw test, the vacuum saturation test, and the tube suction test. Analyses of the test results indicated that the unconfined compressive strength (UCS) and retained UCS were higher for specimens tested in freeze-thaw cycling than the corresponding values associated with vacuum saturation testing. This observation suggests that the vacuum saturation test is more severe than the freeze-thaw test for materials similar to those evaluated in this research. The analyses also indicated that the I-84 material retained more strength during freeze-thaw cycling and vacuum saturation and exhibited lower final dielectric values during tube suction testing than the US-91 material. Although the I-84 material performed better than the US-91 material, the I-84 material required higher stabilizer concentrations to reach the target 7-day UCS values specified in this research. After freeze-thaw testing, the Class C fly-treated specimens were significantly stronger than both lime-fly ash- and cement-treated specimens. In the vacuum saturation test, none of the three stabilizer types were significantly different from each other with respect to either UCS or retained UCS. Dielectric values measured during tube suction testing were lowest for cement-treated specimens, indicating that cement performed better than other stabilizers in reducing the moisture/frost susceptibility of the treated materials. The results also show that, as the stabilizer concentration level increased from low to high, specimens performed better in nearly all cases. A strong correlation was identified between UCS after the freeze-thaw test and UCS after the vacuum saturation test, while very weak correlations were observed between the final dielectric value after tube suction testing and all other response variables. Differences in variability between test results were determined to be statistically insignificant. Engineers interested in specifying a comparatively severe laboratory durability test should consider vacuum saturation testing for specimens treated with stabilizers similar to those evaluated in this research. The vacuum saturation test is superior to both the freeze-thaw and tube suction tests because of the shorter duration and lack of a need for daily specimen monitoring. Although the Class C fly ash used in this research performed well, further investigation of various sources of Class C fly ash is recommended because of the variability inherent in that material. Similar research should be performed on subgrade soils, which are also routinely stabilized in pavement construction. Research related to long-term field performance of stabilized materials should be conducted to develop appropriate thresholds for laboratory UCS values in conjunction with vacuum saturation testing.

The works deals with the possibilities of using non-standard fraction of fine crushed aggregate in route base layers. Goal of my thesis is research of using material from specific location. Theoretical part summarizes basic knowledge regarding bound mixtures and their normative requirements. Practical part of my thesis describes my various mixture design and following testing and determination of design properties by official and experimental tests. The conclusion summarizes the researched outputs and findings, which confirm the future possibilities of using this material in base layers.