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569 Uppsatser om Concrete dams - Sida 2 av 38
Behuggning av betongytor: ett test av hantverksmetoder
During the latter half of the 18th century, when concrete started seeing general use in
modern cities, the use of different methods to give the concrete a finished surface texture
saw use. One of these was using different methods of mechanically altering the surface using
a slew of cutting and crushing techniques with mallet and chisel. This was done in order to
hide the often dull and gray look of concrete, and allude to other more expensive and
luxurious stones. The work would possibly have been done by experienced stonemasons,
using much of the same techniques and tools they would have used while working natural
stones. Or did they? This essay explores, through the use of traditional handcrafts and tools,
the claim that the working of concrete surfaces can be done with the same tools and skillset
as the working of natural stone.
Fotogrammetrisk analys av kornstorleksfördelningeni erosionsskydd vid kraftverksdammar
This master thesis was made to investigate the possibilities of using the Matlab-basedsoftware Basegrain to determine grain size distributions of erosion protections onhydropower dams. Basegrain is a photogrammetric tool developed to generate grainsize distributions and other information about coarse flood sediments by analyzing adigital photo of the stone bed. The investigation was made by validating the ability forBasegrain to assess grain size distributions of various materials smaller than the blocksused in an erosion protection by comparing sieving results or manual measurementswith the results obtained by the program. A statistical comparison was then made bycomparing the results from sieving and the program. The possibilities of using thesame method on existing hydropower dams were then investigated by determiningwhether the method was practically viable or not.The results showed that Basegrain generated grain size distributions for coarse gravelthat were very close to the sieving results.
Att påverka en samhällsdebatt : En retorisk studie av organisationen Ruter Dams strategiska kommunikation
Det har aldrig varit så lätt att uttrycka sin åsikt och samtidigt så svårt att faktiskt göra sin röst hörd som det är idag. För att nå ut med sin åsikt måste man uttrycka sig på rätt sätt och i rätt forum. Den här uppsatsen granskar hur man kan påverka en samhällsdebatt genom strategisk kommunikation och uppnå en förändring som kommer från publiken man riktar sig till. Uppsatsen sammanför retorik med strategisk kommunikation och undersöker specifikt hur organisationen Ruter Dam arbetar för att påverka jämställdhet inom svenskt näringsliv. Analysen åskådliggör hur Ruter Dam arbetar mot ett jämställt näringsliv med utgångspunkt i den retoriska situationen, publiker, core message och stakeholders.
EN TOTALKOSTNADSJÄMFÖRELSE MELLAN CELL-, SKUM- OCH LECA-BETONG
This report provides a comparison between the products cellular concrete, foam concrete and LECA concrete. The questions to be answered during the work is how the cellular concrete stands up in cost terms to the existing competitors on the market, how the concrete products differ in design work, and in which situations the concrete varieties are preferred to use.Cellular concrete is a variant of ordinary concrete, with the difference that the ballast is exchanged from stone materials to expanded polystyrene beads (EPS). This substitution gives a product with higher insulation values but lower weight than ordinary concrete.The work was carried out by designing a survey which was sent to two hundred randomly chosen companies across Sweden, to see the building industry?s opinion of the product cellular concrete. The survey showed that cellular concrete was equals its competitors in terms of price, while the product was said to be more flexible, quicker and easier to cast.Then some of the companies, who participated in the survey, were interviewed to see more carefully, how the price, the workmanship and the time for casting and dehydration differed between the products.
Betong - Förvånansvärt lättflytande!
Concrete is a very common construction material. It´s characteristics are strength, durability and formablility. Superplasticizer is a common admixture, which changes the properties of concrete.
Today (spring 2007) there are no certian mathematical methods to calculate the required percentage of this admixture needed to give the necessary set slump flow in the overall concrete recipe.
Concrete batching companies must therefor experiment with different amount of superplasticizer in order to meet the specified slump and strength.
The purpose og this report is to investigate if any mathematical relation can be established between the amount of superplasticizer used and the slump flow achieved.
After carrying out some practical experiments using four different superplasticizers a direct relationship can be establish between the percentage of admixture used and the slump/flowability achieved. Unfortunatly at present due to the numerous variables, the calculation of mathematical formula can not be achieved..
Utmattning av vägbroar i armerad betong enligt eurokoder
Since 1 January 2010 it is a requirement to use the European standards, Eurocodes, in Sweden when constructing bridges. One chapter that has caused an extra amount of problems for the engineers is the one about fatigue analysis, which resulted in us doing this thesis.To do this we had to read all of the Eurocodes that direct, or indirect deals with fatigue and calculating of such. We have read the background documents for the Eurocodes and master?s thesis in the subject. We also studied the calculations of bridges constructed by different construction firms.We have chosen to limit the thesis to discuss only road bridges made of concrete due to the lack of method for verification of concrete in the national appendix.
Hisskärna av skalväggar i höga byggnader : Ett alternativ till den platsgjutna kärnan
A common way to stabilize high rise buildings is to use an elevator core built of concrete. Today, we use to build these elevator cores of in-situ concrete. Precast concrete twin wall (double wall) is a semi-finished product that has become more common in recent years. This diploma work studies how the twin wall works out as structural elements in an elevator core. The work also shows some possible ways of designing twin walls and highlights some important parts of the design that will be vital to the stability of the building. The result shows that it is important to think through where the element joints should be placed.
Milk yield and composition in Swedish landrace goats (Capra hircus) kept together with their kids in two different systems
Swedish goats are mainly held for cheese production and therefore, both milk quality and composition are of great importance for dairymen. Today, only few data exists on milk composition from Swedish dairy goats and the casein content is still unknown. One way to reduce the work load for goat farmers and increase animal welfare can be to keep goats and kids together for longer periods. The aims of this study were to investigate how milk yield and composition were affected when kids suckled their dams during 8 weeks, and to measure the casein content on farm level by a mid-infrared spectroscopy method, previously calibrated for goat milk. Lactating goats were kept in two different MIX- systems where the dams are both suckled and milked.
Prefabricerade stödmurar i betong :
This is a booklet with information and inspiration about precast retaining walls. The three chapters contain information about concrete as a material, how the surface of the wall can be altered, and a chapter with ideas for a new precast wall. I have obtained information through books, interviews, lectures and fairs. The retaining walls on the market do not correspond to the requirements of the Landscape Architects I have interviewed. I have therefore considered their opinions in the chapter containing my new ideas for new retaining walls.
Lek och lärande : En studie av vad lärare och elever associerar ett laborativt arbetssätt i matematik med
During recent years, the trend of Swedish students? negative performance and results in mathematics has been discussed. It is agreed that a change in teaching methods is necessary in order to solve this issue. Thus we found it interesting to take a closer look at an alternative way of teaching. The purpose of this study was to find out what teachers and students associate concrete mathematics with and make a comparison between them.
Partialkoefficienter för stabilitetsanalys av betongdammar
I Sverige finns det idag ett stort antal dammar och nära hälften av Sveriges elproduktion kommer ifrån vattenkraft. Höga säkerhetskrav ställs på dammarna då konsekvenserna av ett dammbrott kan orsaka stor ekonomisk skada både i form av minskad produktion och som uppbyggnadskostnader. Dammbrott kan även utgöra risk för skador på människor och omkringliggande miljö samt byggnader.Det finns flera dimensioneringsmetoder för att uppfylla gällande säkerhetskrav på konstruktioner. De tillämpningsvägledningar som används vid stabilitetsanalys av betongdammar baseras på gamla deterministiska metoder med säkerhetsfaktorer. Det arbetas med att ta fram nya tillämpningsvägledningar baserat på sannolikhetsbaserade metoder.
Försöksmetod för automatisering av kvalitetssäkring av SKB
Within all industries, there is a change in working time required; this also includes the construction sector. However, the way construction sectors are differentiated is by not having been given the opportunity to be practiced or tested. The aim of this thesis that we have done in collaboration with the Concrete Industry was to investigate the possibility of developing an automated method for quality assurance of SKB at the site. The idea is to make the O-funnel to be more utilized and therefore ensuring that the appropriate concrete quality is provided which eventually would lead to a better development in the production process.The project has involved theoretical work and laboratory experiments. The theoretical work gave us a good foundation at the beginning of the project. After gathering the information and material, the laboratory experiments began by SCC in their laboratory in Hammarby. The collected data from the various laboratory tests formed the foundation for trying to relate measurements for consistency of SCC with each other and therefore find out how measurements from O-funnel varies with different concrete mixtures.
Stenmjöl eller naturgrus i betong : En jämförande studie
The objective of this thesis is to examine the difference in workability in fresh concrete, when crushed fine aggregate replaces natural gravel. The shape of the fine aggregate, packing and flow of six crushed material and three natural materials will be determined by easy studies, the results will be compared with a slump cone test..
Datormodellering av en värmelagrande betongväggs inverkan på det termiska klimatet i ett växthus
This report describes the building of a computer model that makes it possible to simulate the thermal climate in a greenhouse. The computer model is built on the physical theory of heat exchange that occur in a greenhouse, such as radiation and convective heat exchange. The model also includes the heat storage that is active in a greenhouse.The computer model is used to simulate the thermal climate in a greenhouse under three periods, winter, spring and summer. It also investigates which effect a concrete wall has on the thermal climate in a greenhouse. The purpose of putting a concrete wall in the greenhouse model is to investigate the possibility to store heat during the day and then use this heat when the temperature drops during the night.The result from the simulations shows that a concrete wall levels the big difference in temperature that normally occurs under a day in a greenhouse.
Samverkan mellan nya cementtyper och tillsatsmedel för betongtillverkning
Cement manufacture accounts for 3-5 percent of total global carbon emissions. There is a growing interest in reducing the environmental impact and conserve limited natural resources. In cement production, clinker productions consume 87.5 percent of the total energy consumed in the cement manufacture.Cementa has since many years, focused on reducing the environmental impact of cement production. The work has involved the entire production process from selection of alternative fuels to the development of cement with less clinker content. During 2013/2014, two new types of cement (Bascement and CEM II / B) will be introduced to the Swedish market.