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535 Uppsatser om Self-compacting concrete - Sida 1 av 36

Självkompakterande betong vid platsgjutning av anläggningskonstruktioner

By using modern methods of casting concrete, cast in place can get more effective and industrialized. A modern method is self compacting concrete. By using this type of concrete, advantages like improved working environment and rationalized construction can be reached. Because the concrete doesn?t need to be vibrated, the amount of staff on site and the noise can be reduced.

Vidhäftning mellan prefabelement och pågjutningsbetong : Undersökning hur skrovligheten påverkar vidhäftningskapaciteten vid skjuvning

Self-compacting concrete has soon been around for a decade. Recently the prefabrication industry has started to use this fairly new concrete type in larger scales, mainly because of its distinctive properties.  There are still certain areas that need to be thoroughly examined, such as bond capacity. There have been very few studies regarding shear capacity due to the fact that the procedure is complicated.This report will highlight a method to examine the shear capacity of different surfaces that have been prewetted as well as non-prewetted surfaces. The surface areas follow BBK 04?s and Eurocode 2?s demand for surface roughness.  A smooth surface will be completed in order to confirm if the different shapes influence the bond strength by shear stress or not.                       The purpose of this essay is to measure the bond strength within the shear capacity as well as examine the impact it has on surface roughness and treatment for shear bond.The method used to identify the shear capacity is called L-shaped Push-Off Test.

Inverkan av tvång i gjutfogar och i betongkonstruktioner på
elastiskt underlag: Influence of Restraint in Casting Joints
and in Concrete Structures on Resilient Foundation

In this report, the risk of cracking in joints and/in adjacent concrete is estimated by checking shear forces in joints and the ratio between the actual maximum principal stress ant the actual strength of the concrete. The shear force has been estimated both by simple methods as well as by two-dimensional calculations. The risk of cracking in the concrete and/or in the joints is estimated with the computer program ConStre. The restraint from a resilient foundation or rock on a young concrete construction is estimated by a simple method that is exemplified. It is shown that the restraint can be neglected in some cases.

Användning av högpresterande betong i husbyggnader : Materialförsök och modellering

Idag är intresset för högpresterande betong (HPB) växande runt om världen då fördelarna är många, eftersom slankare, tätare, starkare och lättare konstruktioner kan tillverkas. Detta examensarbete handlar om materialförsök och modellering för en typ av HPB som ska användas i husbyggnation. Arbetet inleddes med materialförsök i färskt tillstånd, där god gjutbarhet och konsistens eftersträvades. Utgångspunkten var från ett grundrecept med två olika ballastsorter (slaggballast med flygaska och krossballast från asfaltindustrin med silikastoft), vilka namngavs till pilotförsök 1 och pilotförsök 2. Vidare valdes pilotförsök 1 att provas i hårdnat tillstånd då det visades att det var mer ekonomiskt lönsam eftersom ballasten inte behövde siktas, lägre vct tillhandhölls och att flygaskan som användes i pilotförsök 1 är billigare än silikastoft som användes i pilotförsök 2. Resultaten efter 28 dygn för de materialförsök som utfördes i hårdnat tillstånd var:Tryckhållfasthet; 141,9 MPaDraghållfasthet; 7,0 MPaBöjdraghållfasthet; 10,0 MPaElasticitetsmodul; 46,4 GPaKrympning efter 56 dygn; 0,5 ?Samtliga försök utfördes enligt svenska standarder (SS). Dessutom vidareutvecklas och förbättrades ett redan arkitektoniskt gestaltat Attefallshus ur ett konstruktions- och hållbarhets perspektiv, där fokus låg på transport- och produktionsförutsättningar.

Icke-linjära modelleringsteknikerav förspänd betongkonstruktion : Reaktorinneslutningen på Forsmark 3

A new material model, for the FE-program ADINA, has been verified against twoexperiments. One unreinforced concrete beam and one reinforced concrete beam.The model, DF-concrete, has the possibility to estimate true concrete. However theresults indicate that in order to be sure that the estimations are true, there ought tobe data from the true concrete to verify against.Two FE-models have simulated the behavior of a ring-shaped part of the nuclearcontainment vessel. The results from the first, frictionless, model agree with similarsimulations and hand calculations for high pressures in the containment vessel. Thesimulations of the nuclear containment vessel show cracking in the concrete after10-11 bars of over pressurization.

Övergång till helkrossballast : En studie för Strängbetongfabrikerna i Veddige och Herrljunga

This exam report has been developed in association with Strangbetong AB, Sweden.The natural gravel that is being used as fine aggregate for concrete production today is an ending natural recourse and the Swedish government has decided to strongly reduce the extraction from the year of 2020. The only reasonable replacement is aggregates from crushed rocks but this material has other properties than natural aggregates. The concrete manufacturers now have to learn how to use these new fine aggregates in a cost effective way in order to ensure the quality of their concrete production.In this project, crushed aggregates and combination of crushed and natural aggregates have been tested with existing formulas for fresh concrete. The two parameters yield stress and plastic viscosity have been measured which gives a good description of the workability of the fresh concrete. Different methods to make measurements on the dry fine aggregates, has also been tested, to find out if there is any correlations between these parameters and the parameters from the measurement on the fresh concrete..

Miljövärdering av resurssnål betong med införande i BIM

This thesis aims to illustrate how environmental impact can be reduced, through the use of lean concrete. It also illustrates how environmental data can be applied to a house through implementation with BIM. In this study a unique concrete structure developed by Swedish Cement and Concrete Research Institute is assessed for environmental impact, by calculating the carbon dioxide equivalents using LCA methodology. The construction is a sandwich element where the concrete is made ??up of three layers.

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.

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.

Självkompakterande betong (SKB : förbättrad arbetsmiljö och konstruktion

Självkompakterande betong (SKB) eller som den också kallas vibreringsfri betong upptäcktes och utvecklades i Japan i slutet av 1980- talet. Anledningen till detta utvecklingsarbete var att betong gjutning väldigt kämpigt och tillgången på erfarna betongarbetare började bli låg. I Sverige använde man självkompakterande betong året 1993 som tekniken hämtades hem av CBI Betonginstitutet.Användning av självkompakterande betong leder till många fördelar som skiljer sig från den vanliga betongen avseende arbetsmiljö t.ex. slipper man vibrering och undviker tungt arbete som i konsekvens minskar antal skador på arbetsplatsen. Utöver detta ger SKB förkortad arbetstid, bättre utförande och möjlighet till arbetskraftbesparing.Sedan 1997 har Sverige ökat användning av SKB i platsgjutning medan andra länder som Danmark har gått fram till ca 30 % av sin platsgjutning.

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.

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.

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