Dissertations / Theses on the topic 'Slag Testing'

Today, a huge part of waste products from pulp and paper industries ends up in landfill which is both economically and environmentally adversely. This report examines the possibilities of using those products as a slag foamer and fuel in different furnaces in the metal industry. The waste products contain valuable elements, especially carbon. Therefore, there is an increased interest in finding possible use for the waste products in the metal industry. The reuse would contribute to preservation of energy as fossil fuel can be replaced. In the report, two waste materials called mixed biosludge and fiber reject are examined. The experiments are performed with the waste products pressed together with a base material and cement forming a briquette. The requirements examined are strength needed for both transportation and use in furnaces and ability to create a foaming slag. The results in strength were ambiguous, no waste material based briquettes met the set criteria. As of now, the briquettes are probably not strong enough to be transported. No foaming occurred during the experiment, but only one experiment was performed. Therefore, further experiments are needed before any conclusions can be drawn. The briquettes can possibly replace coke and coal in applications where strength is not as important. Nevertheless, it is uncertain if the briquettes affect the steel quality.
Idag läggs en stor del av restprodukter från pappers och massaindustrin på deponi, vilket innebär såväl ekonomiska som miljömässiga nackdelar. Den här rapporten undersöker möjligheterna att använda dessa restprodukter som slaggskummare och bränsle i de olika ugnarna inom metallindustrin. Restprodukterna innehåller värdefulla ämnen, framförallt kol. Därför finns det ett ökat intresse för att hitta möjliga användningsområden för restprodukterna inom metallindustrin. Denna återanvändning skulle bidra till energibevarande eftersom fossila bränslen kan ersättas. I den här rapporten undersöks två restmaterial, blandat biologiskt slam och fiberavfall. Experimenten utfördes med dessa restprodukter pressade samman med ett basmaterial och cement till en brikett. Kraven som undersöks är styrka för både transport och användning i ugnarna samt förmågan att skumma en slagg. Resultaten för briketternas styrka var tvetydiga, inga av briketterna innehållande restprodukter satisfierade det uppsatta kriteriet. Styrkan är troligtvis för låg för att transport ska vara möjlig. Ingen skumning skedde under experimentet, men endast ett experiment genomfördes. Därför behöver ytterligare experiment genomföras innan några slutsatser kan dras. Men briketterna tros kunna ersätta koks och kol där styrkan inte är viktig. Men det är osäkert om briketterna påverkar stålkvaliteten.

The presented diploma thesis is focused on defects of castings as well as optimization of production with the aim of reducing the number of defective products. The theoretical part is focused on basic information about cast iron and its production, structure and mechanical properties. Another part of this thesis describes the defects of castings and options for non-destructive testing of cast iron castings. In the experimental part are analyzed three sorts of defective casting. Castings for testing were provided by JMA s.r.o. foundry. The summary contains tests results and proposals for optimization of production.

Construction projects involving the installation or repair of subsurface structures or utilities often require dewatering to induce a temporary lowering of the local groundwater elevation to facilitate construction. In the event that a known contaminant plume is present in an adjacent area, this dewatering may inadvertently draw the contaminant into the previously uncontaminated work area. Uretek Holdings, Inc. has developed its Injectable BarrierSM to be installed prior to dewatering exercises to provide a groundwater cut-off by reducing the potential movement of groundwater due to the hydraulic gradient induced by dewatering. A benefit of Injectable BarrierSM as compared to conventional methods of hydraulic control is that excavation is not required prior to its installation and no excess soils are generated through its installation. Injectable BarrierSM is a proprietary process registered with the United States Patent and Trademark Office by Uretek Holdings, Inc. Since methodical in-situ testing of the effectiveness of the Injectable BarrierSM has not been performed to date, it was the focus of this research to test the performance of the barrier under in-situ conditions utilizing a subsurface environment indicative of a West-Central Florida location. A testing plot to perform this research was selected on Hillsborough County property in Tampa, Florida which provided both a relatively shallow groundwater elevation in addition to a clay confining layer at a relatively shallow depth, making this an ideal location for testing the performance of the Injectable BarrierSM. After establishing the native conditions through baseline pump testing and repeating the testing procedure following the installation of the Injectable BarrierSM, a quantification of the reduction in hydraulic conductivity was achieved. Pumping tests were performed on the Injectable BarrierSM at its standard spacing as well as modified versions of the barrier with variation in the lateral spacing to include 6 foot, 4 foot, 3 foot, and 2 foot injection patterns to determine if a modified injection process could improve its performance. The 3 foot lateral spacing corresponding to the standard Injectable BarrierSM process indicated a 20% reduction in the hydraulic conductivity following its installation. By performing a small scale excavation following the completion of all pumping tests, it was discovered that the dispersion of the material in the subsurface appeared insufficient to provide the coverage needed to establish a barrier capable of further reducing the local hydraulic conductivity, especially at the shallowest injection depth of 3 feet below land surface (ft bls). It is concluded that modified amounts of injected material, closer lateral injection spacing, and potentially modified injection temperatures and component ratios could increase the effectiveness of the Injectable BarrierSM.

Ultra-high performance concrete (UHPC) was evaluated as a potential material for future bridge deck designs. Material characterization tests took place to identify potential challenges in mixing, placing, and curing UHPC. Biaxial testing was performed to evaluate behavior of UHPC in combined tension and compression stress states. A UHPC bridge deck was designed to perform similarly to a conventional concrete bridge deck, and a single unit bridge deck section was tested to evaluate the design methods used for untreated UHPC. Material tests identified challenges with placing UHPC. A specified compressive strength was determined for structural design using untreated UHPC, which was identified as a cost-effective alternative to steam treated UHPC. UHPC was tested in biaxial tension-compression stress states. A biaxial test method was developed for UHPC to directly apply tension and compression. The influence of both curing method and fiber orientation were evaluated. The failure envelope developed for untreated UHPC with random fiber orientation was suggested as a conservative estimate for future analysis of UHPC. Digital image correlation was also evaluated as a means to estimate surface strains of UHPC, and recommendations are provided to improve consistency in future tests using DIC methods. A preliminary bridge deck design was completed for untreated UHPC and using established material models. Prestressing steel was used as primary reinforcement in the transverse direction. Preliminary testing was used to evaluate three different placement scenarios, and results showed that fiber settling was a potential placement problem resulting in reduced tensile strength. The UHPC bridge deck was redesigned to incorporate preliminary test results, and two single unit bridge deck sections were tested to evaluate the incorporated design methods for both upside down and right-side up placement techniques. Test results showed that the applied design methods would be conservative for either placement method.
Ph. D.

This thesis presents the development and validation of a new wireless Impact Echo (IE) system for condition assessment of reinforced concrete slabs. The new IE prototype was compared with other commercially available non-destructive testing (NDT) devices used for similar purposes, namely Ground-Penetrating Radar (GPR) and Ultrasonic Pulse Echo (UPE). Monitoring and structural inspections are critical to effective management of civil infrastructure and NDTs can enhance the quality of condition assessments by providing objective visualizations of the interior of a structural element. The IE method, first developed in the 1980s, has seen few advancements in the last 20 years. The method has been standardized and used on site, but the underlying technology has become outdated. The data obtained from the transducer is difficult to interpret and requires a computer to post-process it before being usable, thus limiting the direct feedback of the method when conducting tests on-site. Because of those limitations and the test being relatively more time consuming than other alternatives, the method is lacking in usability. A new prototype IE device was designed and built by the project industry partner, FPrimeC Solutions. The methodology followed the traditional approach, but it was designed to work with today’s technology. The device is operated wirelessly via a Bluetooth connection, uses smaller-sized electronic components, and connects with a user-friendly interface on a small tablet to set-up the tests and compute the results immediately. The first part of the project focused on product development by testing iterations of the prototype and providing user feedback to improve the device and accompanying software. The second part of the project aimed to validate the new technology using a set of three large reinforced concrete slabs containing artificial defects. The studied points of interest were sound concrete, effect of boundaries and steel reinforcements, vertical cracks, presence of a hollow conduit, artificial voids and delamination. The IE results were also compared with those from commercial GPR and UPE devices. GPR was found to be the quickest method by far, although the results gathered seemed to be limited by the presence of steel reinforcement and also failed to locate certain defects. UPE was a bit slower than GPR, but was generally able to locate more accurately the artificial flaws created in the test specimens. The results showed poor definition of the flaws making it difficult sometimes to properly locate them. The UPE results also seemed to be negatively affected by the presence of reinforcement which were causing frequent abnormal values. Lastly, the IE method was used. This method was greatly improved during the first phase, but it is still a time-consuming method. The value of the data, however, has great potential when compared to the other options. It accurately located most of the flaws generated and was practically unaffected by the presence of steel reinforcing bars. Also, with further analysis of the data, it was possible to determine the depth of some of the flaws accurately. Due to the time-consuming testing phase and the longer analysis of the data required to obtain the higher quality of results, this study suggests that IE is not likely to be the best choice for a general inspection of a large area (depending on the nature of the information needed). Rather, it is suggested to first conduct a general review of the structure using a quicker method like GPR to locate the problematic areas. After that, refining the grid at key locations to test with IE should provide the best quality of data in a reasonable amount of time.

Detta examensarbete syftar till att utveckla ett nytt sätt att använda betong för inredningsändamål. Betong har alltid använts i större byggnader, infrastruktur och andra kategorier. Nyligen började den moderna inredningen använda betong inomhus, till exempel som bänkskiva eller som en hylla. Arbetet fokuserar på en huvudfråga: Är betong ett bra materialval för inredning? För att besvara denna fråga bestämdes några punkter för att komma till huvudfrågan. Följande punkter behövde testat och analyserad för att komma till svaren:    - Beräkna och testa betongens hållfasthet    - Testa slagtålighet    - Analysera hur betong reagerar med kemikalier med olika pH-värde    - Förhållandet mellan miljö och betong    - Studera produktionen av betong Laborationstest, litteraturskällor och fältstudier användes som metoder för att få ett resultat av ovan nämnda punkter. Resultaten visar att betong kan användas som inredningsändamål och kan användas i större utsträckning än vad som är fallet idag. Sammanfattningsvis är betong ett bra material som används för inredningsändamål och den framtida tekniken kommer att minska koldioxidutsläppen som följer med produktionen av betongen. Det kommer att göra betong ännu bättre som material att använda i framtiden.
The following thesis aims to develop a new way to use concrete as interior material. Concrete has always been used in larger scale buildings, infrastructure and in other categories. Recently the modern interior design started to use concrete indoors for example as countertop or as a shelf. This thesis focuses on one main question: is concrete a good material choice for interior use. To answer that question, we decided to have sub questions to help to get to the main question. The following questions needed test and analysis methods to get to the answers:    - Calculate and test the strength of concrete    - Test impact resistance    - Analyze how concrete reacts with chemicals with different PH-values    - Study the production of concrete    - Relation between environment and concrete Lab tests, literature sources, and field studies was used as methods to answer those questions. The results shows that concrete can be utilized as interior material and can be used to a greater extent than is the case today. In conclusion concrete is a good material as used for interior purposes and the future technology will decrease carbon dioxide emissions that comes with production of the concrete. That will make concrete even better as material to use in the future.

Questo elaborato ha lo scopo di presentare la “slam poetry”, una disciplina con la quale solo recentemente il pubblico italiano si è confrontato. Spiegherò di cosa si tratta, quando e perché si è originata, come si è evoluta e perché ha avuto così tanto successo con alcune categorie di persone. Non mancherà anche una riflessione generale sulla traduzione della poesia e verrà dato abbondante spazio alle propostedi traduzione di alcuni brani di slam poetry, scelti tra quelli partecipanti al concorso di Chicago del 2008, con relativo commento alla traduzione.

Traditionally, destructive methods such as coring are used for the condition assessment of an existing concrete structure. Although these methods may yield valid data about the corresponding concrete section, they are quite expensive and time consuming. More important than these, destructive methods damage the structure being investigated and these points usually become focal points for further deterioration. For all these reasons, only a few samples can be collected from a structure and this results in a poor representation of the complete structure. The impact-echo technique is one of the most suitable non-destructive test methods that may be used on concrete for thickness determination or for investigation of possible delaminations in the internal parts of a concrete structure without damaging the surface. It has been observed that reliable results can be obtained quickly. Unlike pulse-echo tests which are commonly used on steel, testing a heterogeneous material like concrete requires the use of low frequency sound waves as in impact-echo, in order to mitigate the effects of paste-aggregate interfaces or small air voids. This method may be used to locate internal cracks or large air voids existing in concrete. It is known that impact-echo has been used successfully on structures with varying geometries and various purposes such as evaluation of concrete pavements, retaining walls and other reinforced concrete sections. Besides the investigation of the internal state, it may also be used when the other side of the section cannot be reached, as in the case of concrete pavements, in order to find the thickness of the section. This is especially important for quality control and for cost calculations. Research conducted in this thesis study was concentrated on the thickness determination of existing concrete pavement sections, produced in the laboratory with dimensions of 1500 x 2000 mm four and varying thicknesses, and the accuracy associated with these results. In order to correctly determine the sensitivity, several other parameters were investigated and optimum ranges were determined for these to be used while on a field test. Among these factors were the steel impactor size, accuracy related to the data acquisition, distance between the impact point and the transducer and the location of the test point. Finally, the accuracy of the impact-echo method for concrete pavement applications was studied. By observing the large number of data points collected, it was found out that an average error of 1.5% exists for a single impact-echo reading regardless of section thickness, but this value reduces to 0.6% when the average of all test results is used while determining pavement thickness. Results of this study show that the impact-echo technique is reliable and may be used with success for the thickness determination of concrete pavements and for locating internal voids.

L'avancée de la technologie des PRF a suscité l'intérêt de l'introduction de nouvelles fibres, comme la fibre de basalte, qui a un potentiel d'offrir une solution efficace, lorsqu’utilisée dans les structures en béton, soit sur la résistance à la corrosion, la durabilité et la rentabilité. En outre, les codes et les guides disponibles, ne fournissent pas de recommandations pour l'utilisation de barres en PRFB puisque les recherches passées dans ce domaine sont limitées. Donc, des travaux de recherche sont nécessaires pour caractériser et comprendre le comportement des barres de PRFB dans les éléments en béton armé. En conséquence, les objectifs principaux sont d'évaluer les caractéristiques à court et long terme des barres de PRFB nouvellement développées, ainsi que d'évaluer les performances structurales de ces nouvelles barres comme renforcement interne dans les poutres et les dalles de pont et d'introduire ce nouveau renforcement dans les codes et les guides de dimensionnement. Les tests expérimentaux ont été faits en trois parties. La première partie porte sur le développement de trois nouvelles barres et tendons en PRFB pour déterminer leurs propriétés physiques et mécaniques. Les performances à long terme et de durabilité ont été réalisées en conditionnant les barres de PRFB dans une solution alcaline simulant les conditions humides dans le béton pour déterminer la compatibilité comme renforcement interne dans les éléments en béton. Par la suite, les propriétés ont été déterminées et comparées avec des spécimens non conditionnés (référence). La seconde partie a porté sur sept dalles de pont en béton armé grandeur réelle avec les bords restreints, simulant les tabliers de pont les plus utilisés en Amérique du Nord, pour évaluer la performance des dalles renforcées de PRFB et d'acier. Les dalles mesurent 3000 mm de long × 2500 mm de large × 200 mm d'épaisseur. Les dalles ont été testées jusqu'à la rupture sous une charge concentrée au centre de celles-ci simulant l'empreinte d'une roue d'un camion. Les capacités en poinçonnement sont prédites en utilisant les exigences réglementaires disponibles, et sont comparées aux résultats expérimentaux. La troisième partie de cette étude portait sur les essais de 14 poutres en béton de 3100 mm de long × 200 mm de large × 300 mm de profond pour examiner le comportement en flexion et les performances en service des barres de PRFB avec deux états de surfaces: fini sablé et crénelé. Les poutres ont été testées en flexion en quatre points avec une portée libre de 2700 mm jusqu'à la rupture. Les résultats sont introduits et discutés en terme : du comportement de la fissuration, des flèches, de la capacité en flexion et des modes de ruptures. De plus, le coefficient d'adhérence (kb) des barres de PRFB est déterminé et comparé avec les recommandations des codes et guides actuels. Les résultats sont introduits et discutés en terme : du comportement de la fissuration, des flèches, de la capacité en flexion et des modes de ruptures. De plus, le coefficient d'adhérence des barres de PRFB est déterminé et comparé avec les recommandations des codes et guides actuels. Les résultats de l'étude concluent sur la viables pour la production des barres de PRFB pour respecter les exigences des codes actuelles. Également, les résultats d'essai indiquent que les barres de PRFB ont de bonnes propriétés mécaniques et peuvent être placées dans la même catégorie que les barres de PRFV, soit grade III. De plus, le comportement des poutres et des dalles de pont renforcées de PRFB est similaire que pour un renforcement en PRFV et PRFC et les exigences réglementaires sont applicables pour les barres de PRFB.
Abstract: The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing new fibers, such as basalt FRP (BFRP), which has the potential to offer an efficient solution when implemented in concrete structure, such as corrosion resistant, durable and cost-effective. Furthermore, the available design codes and guides do not provide any recommendations for the use of BFRP bars since fundamental studies and relevant applications are still limited. Therefore, investigations are needed to characterize and understand the behavior of BFRP bars in concrete members. Consequently, the main objectives of this experimental investigation are to evaluate the short- and long-term characteristics of newly developed BFRP bars, as well as evaluate the structural performance of these new bars as internal reinforcement for concrete beams and bridge-deck slabs to introduce these new reinforcing bars to the design codes and guides. The experimental tests were completed through three parts. The first part was conducted on three newly developed BFRP bars and tendons to investigate their physical and mechanical properties. Durability and long-term performance were assessed by conditioning the BFRP bars in an alkaline solution simulating the moist concrete environment to determine their suitability as internal reinforcement for concrete elements. Thereafter, the properties were assessed and compared with the unconditioned (reference) values. The second part of this study was conducted on seven full-scale edge-restrained concrete bridge-deck slabs simulating actual slab-on-girder bridge-deck that is commonly used in North America to evaluate the performance of concrete bridge-deck slabs reinforced with BFRP and steel bars. The deck slabs measured 3000 mm long × 2500 mm wide × 200 mm deep. The slabs were tested up to failure under single concentrated load acting on the center of each slab simulating the footprint of sustained truck wheel load. The punching shear capacities were predicted using the available provisions, and compared with the experimental results. The third part of this study included testing of fourteen concrete beams of 3100 mm long × 200 mm wide × 300 mm deep to investigate the flexural behavior and serviceability performance of sand-coated and ribbed BFRP bars in concrete beams. The beams were tested under four-point bending over a clear span of 2700 mm until failure. The results are introduced and discussed in terms of cracking behavior, deflection, flexure capacity, and failure modes. In addition, the bond-dependent coefficient (kb) of the BFRP bars was determined and compared with the recommendations of the current FRP design codes and guides. The findings of this study concluded the feasibility of producing BFRP bars meet the requirements of the current FRP standards. Also, the test results revealed that the BFRP bars had good mechanical behavior and could be placed in the same category as grade II and grade III GFRP bars. Moreover, the behavior of the concrete bridge-deck slabs and beams reinforced with BFRP bars was quite similar to the counterparts reinforced with glass- and carbon-FRP bars and the available FRP provisions are applicable for BFRP bars. The beam test results yielded an average bond-dependent coefficient (kb) of 0.76±0.03 and 0.83±0.03 for the sand-coated and ribbed BFRP bars, respectively.

Tato práce se zabývá vytvořením lokalizačního a navigačního systému mobilního robota pro vnitřní prostředí pomocí frameworku ROS. Stručně je zde představen projekt, v rámci kterého diplomová práce vznikla, a jeho cíle. V rešeršní části je v krátkosti popsán ROS framework, simulační prostředí Gazebo a senzory, kterými robot disponuje. Následuje vytvoření modelu robota a simulačního prostředí, v němž jsou vyzkoušeny lokalizační, navigační a další rutiny. V experimentální části je provedeno testování senzorů a popsáno využití jejich výstupů. Následně jsou upraveny a otestovány algoritmy ze simulace na reálném robotovi. V závěru jsou popsány vytvořené vzdělávací minihry. Hlavním výstupem této práce je funkční stavový automat, který umožňuje manuální ovládání, zadávání cílů pro navigaci a v případě potřeby zajistí autonomní nabití robota.

I både kvalitets- och kontrollarbete finns det behov att kunskapsmässigt komma så nära verkligheten som möjligt vid fastställande av defektparametrar för oförstörande provning (OFP). Orsaken är att olika acceptanskrav och bedömningsgränser är svåra att klarlägga när man inte kan förlita sig på att uppgifter är realistiska. I projektet har olika erfarenheter använts för att få en bättre helhetsbild i området för defektparametrar och oförstörande provning.

Denna rapport redovisar den inledande delen av forskning och utvecklingsprojektet PLANT 2, där olika defektparametrar kartlagts och en teoretisk bedömning utförts med avseende på hur signalsvaret påverkas för OFP-metoderna virvelström (ET) och ultraljudsprovning (UT) i form av puls-eko (PE) och ”time-of-flight-diffraction” (TOFD).

Definitionen av redovisade defektparametrar följer i stort SKI-rapport 95:70 [1]. Defektparametrar i denna rapport redovisas i bilaga 1.

Vid bedömningen av defektparametrarnas inverkan på OFP-tekniker, har drift¬inducerande defekter och tillverkningsdefekter hanterats separat. För de driftinducerande defekterna delades bedömningen upp i en generell och en specifik bedömning. De defektparametrar som bedöms specifikt och klassats att påverka signalsvaret betydligt bör vara av mest intresse i nästkommande etapp. Följande defektparametrar bedömdes påverka signalsvaret betydligt:

• Form i ytan, antal sprickor och avstånd i gatstensmönster

(vid termisk ut¬mattning)

• Form i djupled

• Sprickbredd vid sprickspets och sprickspetsradie

För tillverkningsdefekter bedömdes defektparametrarnas form i djupled och geometri påverka signalsvaret betydligt för defekttyperna slagg och bindfel.

Vid utvärdering av UT-PE och UT-TOFD teknikerna överensstämde resultatet helt med den teoretiska bedömningen. För ET-tekniken stämde endast en av tre defektparametrar överens med den teoretiska bedömningen.

In quality control of defect parameters for Non-Destructive Testing (NDT) it’s essential to have good knowledge about the defects. The reason is that different acceptance criteria and assessments must be based on defects that correspond to real defects. In this project different experience has been analyzed to get a better overview between defect parameters and non-destructive testing.

This report shows the beginning of the research & development project PLANT 2. There are different flaw parameters that have been mapped and a theoretical assessment has been performed with regard to how the signal response is influenced by the NDT techniques eddy current, ultrasonic pulse echo and ultrasonic time-of-flight-diffraction.

The definition of the reported flaw parameters does in general follow the one presented in SKI-report 95:70 [1]. The actual flaw parameters in this report are presented in appendix 1.

In the assessment of the influences on the NDT techniques with regard to flaw parameters, service-induced flaws and manufactured flaws have been separated in to two categories. The service-induced flaws have further on been separated in a general and a specific assessment. Those flaw parameters that have been assessed to be specific and classified to influence the signal response considerably should be the ones of most interest in future studies. The following flaw parameters were assessed to affect the signal response considerably:

• Macroscopic shape in the surface direction, number of cracks

and cobblestone stone pattern distance (for thermal fatigue)

• Macroscopic shape in the through thickness direction

• Crack width at the crack tip and the crack tip radius

For flaws caused by the manufacturing process, type slag and lack of fusion, the flaw parameters “Macroscopic shape in the through thickness direction” and “the geometry” were influenced by the signal response considerably.

In the evaluation of signal response with the UT pulse echo and UT TOFD techniques, the result corresponded to the theoretical assessment. For the eddy current technique only one of three flaw parameters corresponded to the theoretical assessment.

Made available in DSpace on 2016-06-02T20:09:20Z (GMT). No. of bitstreams: 1 6039.pdf: 10273984 bytes, checksum: a13219d69346c1e1414f1a71e89cec17 (MD5) Previous issue date: 2014-04-28
Financiadora de Estudos e Projetos
The use of precast elements has become crescent in Brazil, due to the need of haste during production as well as while assembling the structures. Bearing in mind a quick assembly and the competitive price for this kind of frame, precast elements have been growing and spreading in this field throughout the country. There is something special about demanding hollow core slabs, in virtue of their own low weight, in face of the empty spaces generated by the hollows and a better use of materials because of pretension technique, making it economically feasible. The National Technical Code ABNT NBR 9062, which deals with precast concrete structures, shows no more specific criteria as far as hollow core slabs are concerned, but on the other hand the 2011 review in force to ABNT NBR 14861 which covers precast hollow core slabs brings about relevant aspects such as the method used to check the capacity of shear strength on precast hollow core slabs, both with and without concrete structural cover, and furthermore with and without hollow fillings. Considering the reduced amount of national research on this topic, this study aims to develop and perform techniques in different ways of filling the hollows and the slabs and how they behave when exposed to shear strength tests. As a consequence to the manufacturing process of such type of slab and the hollow- filling method, failure in the idealized filling, in virtue of each material own behavior and inappropriate technique are commonly found.
O emprego de elementos pré-fabricados tem se tornado crescente no Brasil, dado a necessidade de velocidade de produção e montagem de estruturas. Tendo em vista a rápida montagem e o preço competitivo deste tipo de estrutura, elementos prémoldados tem ganhado campo no mercado nacional. Há um destaque pela procura de lajes alveolares, devido ao seu baixo peso próprio, decorrente de vazios proporcionados pelos alvéolos e maior otimização dos materiais em virtude da aplicação da técnica de pré-tração, tornando-a economicamente viável. A Norma Técnica Nacional ABNT NBR 9062 que trata de estruturas pré-moldadas de concreto não apresenta critérios mais específicos para lajes alveolares, por outro lado a revisão em vigor de 2011 da ABNT NBR 14861 que aborda lajes alveolares préfabricadas traz aspectos relevantes tais como o método de verificação da resistência à força cortante de lajes alveolares com ou sem capeamento estrutural e com ou sem preenchimento de alvéolos. Tendo em vista o reduzido volume de pesquisas nacionais sobre o tema, esta pesquisa tem como objetivo fazer um estudo teórico-experimental das diferentes técnicas de preenchimento de alvéolos de lajes alveolares e o seu comportamento quando submetidas a ensaios de força cortante. Como consequência do processo de fabricação deste tipo de laje e do método de preenchimento dos alvéolos, falhas no preenchimento idealizado devido ao comportamento distinto dos materiais e técnicas inadequadas são comumente constatadas.

The master’s thesis is focused on serviceability evaluation of historical concrete floor slab realized in the third decade of the 20th century. The assessment of structural performance is based on the results of load testing in situ. The thesis defines contemporary load testing requirements followed by the specifications of measuring instruments and the possibilities of displacement measurements during load testing. In addition, it includes structural and historical investigation of the building, methodology and data evaluation of the load testing. Finally, the theoretical computer simulation of executed load testing is run by using software determined for nonlinear finite elements analysis.

Élaboration de deux stratégies de "détection-localisation" de défauts dans les signaux issus du contrôle par courants de Foulcault des produits sidérurgiques. Validation de ces stratégies dans le contrôle qualité de trois procédés : élaboration de brames de coulée continue, élaboration de blooms de coulée continue et de tubes

The thesis is focused on the overview of the diagnostic methods for engineering surveys reinforced concrete constructions. The practical part explains engineering surveys of industrial building, evaluation of concrete strength on existing building and results from search reinforcements on individual elements. Next part is focused on load testing precast floor slab removed from construction and evaluation load capacity. The last part include structural design of elected parts (precast floor slab and beam).

碩士
國立臺北科技大學
土木與防災研究所
100
The main object of this study is the discussion of slag and slag powder, the waste material produced with iron-smelting, applied to cement mortar. Testing on properties such as compression strength, tensile strength, time of setting, bleeding, shrinkage test and flow test were conducted according to the codes : American Society for Testing and Material (ASTM) and China National Standards (CNS). Different cement-replacement proportions: 10%, 20%, 40% and 60% were designed for the tests and each cement-replacement proportions could be divided into using pure slag powder and using slag mixing slag powder as: 25% slag powder, 50% slag powder and 75% slag powder. The test results show that the cement mortar specimens exhibited the higher compression strength with an elder age when the slag powder was used to the cement replacement. Among the different cement-replacement proportions, specimen of 20% performed better than others specimens. The comparison of the use of slag mixing slag powder with equal replaced proportions indicated that the compression strength increased followed the using amount of the slag powder. Moreover, there was the swelling nature in the slag for the inhibition of the drying shrinkage.

碩士
國立臺北科技大學
土木與防災研究所
100
This research aimed mainly at the study on the engineering properties such as the bleeding, water content at normal consistency and setting times of fresh concrete and compressive strength, tensile strength and shrinkage of hardened concrete in which the cement was partially replaced with reducing slag, and the slag was added as an extra cementitious material in addition to the selected proportion. Firstly, the proportion of standard sand mortar (CNS1010) was adopted as the basis. Then the proportioned cement was separately replaced with 10%, 20%, 40%, 60% and 80% of reducing slag of fineness 5005 and 3008. in other condition, the reducing slag of 10%、20%、30% was separately added as an additional cementitious material to the adopted composition of standard mortar. The mortar specimens were tested at ages of 3 days、7 days、14 days、28 days、42 days、60 days、90 days and 120 days. to find the development of their tensile and compressive strength in short and long term so that to get the optimum proportion of reducing slag. The outcome of test shows : Adding of 5005 and 3008 reducing slag to the cement mortar shows ltttle contribution to its compressive strength. under normal temperature the compressive strength of slag-added standard mortar close to that of standard mortar after 28 days curing when the cement was replaced with 10% and 20% of reducing slag or when the reducing slag was added by 10%、20%、30% as an extra. specimen of cement replaced with 40%、60%、80% of reducing slag has strength less than standard mortar and also has extended setting time.

碩士
國立海洋大學
材料工程研究所
89
This study is to evaluate the quality of fly ash or slag concrete. Tests include compressive strength test, rapid chloride permeability test, chloride ponding test, resistivity test, ultrasonic pulse velocity test, and water absorption test. Testing variables are water to cement ratio, mix proportion ratio of slag and fly ash, and fly ash replacement of cement. Testing results show that for a given water/binder ratio, fly ash concrete has better resistance to chloride ions penetration than ordinary concretes. Higher fly ash replacement of cement is lower permeability. And, Fly ash-Slag concrete is better than fly ash concrete. The best combination of pozzolanas is 15% fly ash plus 15% slag for cement replacement in this study.

Increasing quantities of dredged material (DM) from navigation waterways have led to a growing need to find alternative methods of disposal. Using this material in earthwork construction is a very attractive avenue, but poses concern of quality from a geotechnical standpoint. By blending DM with granular materials like industrial steel slag fines (SSF), studies have showed that the geotechnical properties of the mixture are greatly enhanced. If these materials can be proven to be competitive for use in earthwork construction, they would pose as an economically viable alternative, and would obviate the need for the relatively expensive conventional granular backfill. The scope of this project entailed the characterization of pullout interaction of SSF-DM blends in different proportions with Tensar uniaxial geogrids to determine an optimal combination for usage in earthwork construction. The media used for testing included the individual SSF and DM materials, and the 80/20, 50/50 and 20/80 blends mixed based on dry unit weights of the individual components. The SSF media comprised of particles smaller than 3/8 in. and classified as SW, while the DM was classified OH soil. Two Tensar uniaxial geogrids UX1400 and UX1700 were undertaken for the study. Pullout tests were conducted and performances of all the blends are compared with each geogrid at various normal pressures. Pullout loads and interaction coefficients give an idea of the quality of the interaction, and are studied in this thesis. Also, various variables that could potentially affect the pullout interaction are identified and investigated. Results show remarkably high pullout resistances for the 100% SSF and 80/20 SSF/DM media, and high interaction coefficients indicating excellent pullout interaction, even better than conventional sands. It was also clear that the dredged material exhibits very poor pullout interaction with geogrids. The 50/50 and the 20/80 SSF/DM media were significantly lower than the 80/20 SSF/DM blend in terms of quality of pullout interaction, but still higher than the 100% DM. The results observed with the 80/20 SSF/DM blend show that it is a suitable backfill material and also poses to be a very competitive and cost-effective alternative to be used in earthwork construction.
text

碩士
國立中興大學
土木工程學系所
99
The effects of the fire on safety and durability of concrete structures is profound. This study focuses on the slag concrete with a slag replacement of 60%, and uses different curing methods under different curing periods after the concrete exposed to high temperature for two hours. This research is to investigate the relationship between residual velocity and residual strength by using the ultrasonic pulse velocity method and the impact-echo method. Furthermore, to explore the relationship among heating temperature and the residual strength ration, residual density ration, the residual Poisson ration, the residual static elastic modulus, residual dynamic elastic modulus of slag concrete under fire damage. 　　According to the experimental results, the reduction in residual strength of slag concrete is significant at the temperature over 600 ℃. And the fire-damaged concrete has a better recovery after water-curing, rather than air curing condition. The two aforementioned methods are used to investigate the relationship between residual velocity and residual compressive strength of fire-damaged concrete under different curing conditions. The result also shows that the relationship for the water curing case is not consistent. This might be attributed to the rehydration and crack-healing process during water-curing. The present study can form a basis for the future application of the stress wave velocity technique for assessment of the engineering properties of the fire-damaged slag concrete.

碩士
國立雲林科技大學
營建工程系
104
To study the degradation of joint shear strength, this paper designed four New RC exterior beam-column connections with slabs and transverse beams covers 2/3 or 3/4 width of the joint face using current codes. Four beam-column connections were made with 70 MPa concrete, SD685 longitudinal reinforcement and SD785 transverse reinforcement. Test results showed that the current ACI 318 code is conservative. The transverse beams which covered 2/3 width of the joint face still had some confining effect to enhance the joint shear strength. Typical pushover analysis use beam-column centerline models with rigid joints, which may get unconservative results. This paper also presents nonlinear modeling of the joint with two equivalent compression struts using a commercial structural analysis tool. Following the recommendations of ASCE 41 and ACI 369, the joint keep elastic if the shear demand is less than the nominal shear strength. This paper propose to model the joint shear failure after beam yielding. Using empirical formula obtained by prior database investigation, the joint nonlinear springs are adjusted according to the prediction of failure mode. The proposed skills can improve the results of pushover analysis and well predict the envelopes for the cyclic loading test results. Further calibration and verification of the modeling parameters are recommended to widely use in practice.

碩士
國立雲林科技大學
營建工程系
104
For high-rise buildings, columns made of normal-strength reinforced concrete have large cross-sectional dimensions which cannot be accepted by end users. Using high-strength reinforcement and concrete have many advantages, including smaller member sizes, lighter structure elements, lesser steel reinforcement, longer span capability, and more space available for end users. This paper presents experiments of the sub-project “behavior, design, and modeling of new RC frame joints subjected to seismic loading” in the Taiwan New RC Project. Four new RC interior beam-column connections with transverse beams and slabs were tested according to the acceptance criteria for moment frames, evaluating the effect of transverse beams covers 1/2 or 3/4 width of the joint face. The degradation of the joint shear strength is also investigated. Four beam-column connection specimens were made with 100-MPa concrete, SD685 longitudinal reinforcement, and SD785 transverse reinforcement. Two connection specimens have precast concrete units with cast-in-place concrete joint and slabs, while the other two specimens are monolithic beam-column-slab connections. Test results show that the precast beams and columns with cast-in-place concrete joint perform as well as expected for seismic design of moment frames. Test results shows that the 1/2-column-width-wide transverse beams still have partial confinement effect. It is recommended that the nominal joint strength between calculated by linear interpolation between 1.25√(f_c^' ) MPa(15√(f_c^' ) psi) and 1.67√(f_c^' ) MPa(20√(f_c^' ) psi) for transverse beams cover 1/2 and 3/4 width of the column, respectively.

The aim of this study was to assess the strength, durability properties and corrosion resistance of concrete samples using supplementary cementitious blended materials. In this investigation, three supplementary concrete materials (SCMs) were used together with ordinary Portland Cement (OPC) to form cementitious blends at different proportions. The supplementary materials are silica fume (SF), ground granulated blast furnace slag (GGBS) and fly ash (FA). Sixteen (16) different proportions of the cementitious blends were produced. Tests carried out on concrete samples include slump test, compressive strength, oxygen permeability, sorptivity, porosity, chloride conductivity test, resistance to chloride and sulphate attack. The electrode potentials of tested samples were also observed using electrochemical measurements. Concrete specimens prepared with 10%, 20%, 30%, 40%, up to 60% of blended cements replacement levels were evaluated for their compressive strength at, 7, 14, 28, 90 and 120 days while the specimens were evaluated for durability tests at 28, and 90 days respectively. The results were compared with ordinary Portland cement concrete without blended cement. Voltage, and temperature measurements were also carried out to understand the quality of concrete. The corrosion performance of steel in reinforced concrete was studied and evaluated by electrochemical half-cell potential technique in both sodium chloride, and magnesium sulphate solutions respectively. The reinforced concrete specimens with centrally embedded 12mm steel bar were exposed to chloride and sulphate solutions with the 0.5 M NaCl and MgSO4 concentrations respectively. An impressed voltage technique was carried out to evaluate the corrosion resistance of the combination of quaternary cementitious blended cement, so as to get the combination with optimum performance. Improvement of strength, durability, and corrosion resistance properties of blended concrete samples are observed at different optimum percentages for binary, ternary and quaternary samples. The effect of cementitious blends is recognized in limiting the corrosion potential of the tested SCM concrete samples. Generally, the cementitious blends with limited quantity of SF to 10% have the potential to produce satisfactory concrete. These should however be used for low cost construction, where high quality concrete is not required.
Civil and Chemical Engineering
M. Tech. (Chemical Engineering)

碩士
國立屏東科技大學
工業管理系所
102
Currently, about 200 million people in Taiwan take badminton as fitness and leisure activity. In terms of competition, the trend is to develop a faster, more comprehensive, more offensive, and more variable tactic. In order to increase the speed of the ball, more and more badminton manufacturers have implanted new technology into the design and manufacturing process of the rackets, apart from improving training methods. Domestically, there have been several companies producing badminton rackets. Despite fair quality and the patents, domestic manufacturers cannot stand the competition against foreign companies due to the limited R&;D energy and budget. For a recently established brand facing so many competitors, how to build and deliver the corporate image, and furthermore marketing the brand has become a major challenge. This research together with the case manufacturer, have chosen rackets from Japanese brand Y which has the highest market share, and others from the case company-brand C. In a combination of different pounds and slap shot line frequency, we respectively test the slapping strength from the nine regions on the rackets. Then we use experimental design and analysis to compare the slapping strength and the sweet spot between these two brands. Customers can choose the suitable badminton rackets accordingly.

Submitted in fulfillment for the Master of Engineering, Department of Civil Engineering and Surveying, Durban University of Technology. Durban. South Africa, 2015.
Beam and block slab systems have become a preferred suspended flooring technology in South Africa. Their structural efficiency and relatively low cost makes them suitable for low to medium cost developments. Like all other structural components, they are required to demonstrate sound structural integrity. Concerns were raised by some manufacturers and users in Durban (South Africa) about (a) the lack of basic technical information which makes it difficult to identify methods of improving efficiency and effectiveness of these flooring systems in general, (b) the efficiency and effectiveness of concrete masonry rebated filler blocks - with respect to the load carrying capacity and protecting the structural topping from fire, (c) what constitutes acceptable quality of a deliberately roughened precast concrete surface, (d) interfacial tensile bond strength of special connections and (e) an alternative rib that can span 5 metres without temporary props. These issues were investigated by the student. Thus, this project aimed at improving the structural efficiency and effectiveness in designing, manufacturing and constructing beam and block slab systems was undertaken in Durban, South Africa, between 2012 and 2013. Pilot studies (involving questionnaires), interviews with manufacturers, site visits, and testing of non-structural and structural components were also undertaken. The first aim (in order to address concern (a)) was to provide users of beam and block slab systems with basic technical information about the possible ways to improve efficiency and effectiveness in the design, manufacturing and construction of beam and block slab systems by undertaking an exploratory (pilot) study to better understand users of these systems concerns. The second aim (to address concern (b)) was to investigate, by conducting a series of strength to weight ratio tests, how efficient or inefficient these filler blocks are, examine the structural integrity with respect to the integrity of the manufacturing methodologies and the product thereof, and formulate a method to quantify the fire-resistivity of concrete masonry rebated filler blocks to the structural topping with respect to confining fire. The third aim (to address concern (c)) was to determine what constituted acceptable quality of a deliberately roughened precast concrete surface through a literature review and by conducting a survey to learn about the construction methodologies used by manufacturers. Site visits were undertaken to validate information given by the contractors. The fourth aim (to address concern (d)) was to determine interfacial tensile bond strength through physical testing of deliberately roughened concrete ribs which are sometimes used in special connections. The fifth aim (to address the last concern (e)) was to make an assessment by undertaking a basic comparison study between one local beam and block slab system that uses a shallow rectangular precast pretensioned rib to beam and block slab systems used in the United Kingdom and propose an ideal section (precast pretensioned rib) that spans up to 5 metres without temporary props. With respect to the first aim, it was found that the lack of technical knowledge, including access to critical information about the design philosophy, manufacturing and construction standards of these flooring systems leads to reluctance in selecting them. The outcome of the second aim is that all concrete masonry rebated filler blocks tested were found to be effective because they supported more than the required construction load but some were shown to be inefficient as more materials, such as binders, are wasted in producing over-strength filler blocks and also, undertaking trial mix designs and the testing of samples prior to batch production will reduce costs. A method is formulated in the thesis that could also show that concrete masonry rebated filler blocks provide significant protection to the structural topping thereby preventing fire progression. With respect to the third aim, although a broom or brush is effective in providing a surface roughness (Rz) of 3 mm, it is not always efficient when considering factors like the variation in uniformity, appearance of laitance and roughening frequency, which are not addressed by the South African codes. The outcome of the fourth aim is that connections should be designed such that they do not rely purely on the tensile bond strength but through reinforcing bars (or ties) taking the full tension load causing delamination. With respect to the fifth aim, a basic comparison study indicates that T-section beams are more efficient than common rectangular ribs (±150 mm wide x ±60 mm deep) since they can eliminate completely the use of temporary props for spans of up to 4.51 m. Consequently, further research is underway to design an inverted T-section rib by using high strength precast pretensioned concrete that can span up to 5 m without using temporary props.

This diploma thesis follows my bachelor thesis in which the mother slang was described. This diploma thesis is aimed at the performance of the mother speech research, i.e. the use of specific expressions and language resources used by mothers of small children in Internet discussions in relevant forums or web pages. The diploma thesis aims at creating a questionnaire and establishing five hypotheses. The first part of the thesis describes the methodology of this research, in the following part there are presented the data obtained by the questionnaire survey. The hypotheses are verified in the following section, and the hypothesis testing procedure is described here. The appendix includes the questionnaire and a table of critical values that specifies the data that are needed for verifying hypotheses.