Sök:

Sökresultat:

5243 Uppsatser om High-strength concrete - Sida 1 av 350

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.

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..

Inverkan av flisig krossballast på betong

Concrete is one of the world?s most common construction materials and is composed of 70-80 % stone material. Today crushed stone is used as aggregate in concrete in order to replace natural aggregates due to strong environmental reasons. Stone crushing yields flaky material and in this thesis studies are made on the flaky particle shape and how it influence properties of concrete such as workability, rheology and strength. The concrete recipes used in this thesis have fixed values, the only variable is the flakiness of the crushed stone.

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.

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.

Grundläggning med cellglas : En studie av byggtid och lönsamhet

This report describes a new foundation method and compares it with a traditional founding of concrete. This new method is called the Koljern technique and uses cellular glass which is called Foamglas. The Foamglas is compounded to founding elements by lightweight steel beams. Foamglas is an insulation material with high compressive strength, and is rot, insect, vermin and acid proof. The cellular glass is also fire proof and watertight, which makes it a very good construction material.The report contains a study of a number of cases for which the Koljern technique is compared with a foundation of concrete.

Hur påverkar byggnadsmaterial av stål en induktiv hörslingas fältstyrka samt frekvensgång?

This research analyzed differences in measurements of magnetic field strength and frequency response in five audio induction loops installed in rooms of wooden construction materials and five audio inductive loops installed in rooms of steel reinforced concrete constructions. The inductive loops were installed at floor level and the measurements were made at the listening height of 1.2m. Measurements of background noise, field strength and frequency response were made at fifteen different measurement points across the room. The research measurements showed that there are differences in field strength and frequency response between these two conditions, whether the audio induction loop is installed in a wooden construction or the audio induction loop is installed in a reinforced concrete construction. The results had a significance level of p=0,05..

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.

Valsningsteknik för extremt höghållfasta tunna stål

New high strength steels require improved cold rolling techniques. The aim of this degree project was to develop a new and money saving cold rolling technique to manufacture steel strip for saw blades. The work is based on earlier rolling experiments made with a high carbon steel grade at LuCoil Steel AB. The work also focused on the mill requirements to cold roll high strength steels. The results show that LuCoil?s existing cold rolling mill was actually designed for rolling low carbon steel.

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.

Development of concrete compressive strength: a study of Swedish bridges constructed during the 20th century

Tryckhållfasthetsutveckling hos broar. En studie av svenska broar byggda under 1900-talet.

Betongpelare och brand : En utvärdering av 500 °C isotermmetoden

At the beginning of 2011, Sweden started using the European rules for structural design, the Eurocodes, instead of the previous national rules. In both the previous rules and the Eurocodes, it is possible to dimension concrete columns using tabled values. However, the required cross section measurements have increased considerably. Moreover, it is possible to dimension concrete columns using calculations, however, this is unusual.The development of a fire in a fire cell can be divided into the growth stage, the fully developed fire and the cooling phase. The duration of each phase, as well as the temperature, is dependent on a number of factors, e.g.

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.

Den ultimata träningsmetoden?

Crossfit is a recently developed form of training which is based on a number of functional resistance exercises performed at high intensity, often to the point of muscular failure. Crossfit has since its introduction 30 years ago, reached vast popularity all around the world, including Sweden. Its practitioners considers Crossfit to be an effective training method for achieving a functional and total trained physique thru improvements in VO2max, muscle strength, endurance, balance and speed. Few scientific studies has been published in the subject which is why this study sets out to examine the effect of Crossfit on VO2max (measured with Åstrands submaximal cyclingtest), maximal strength capacity in lower- and upper body muscles (measured with 1 RM tests in bench press and leg press), rapid strength capacity and strength endurance capacity in upper body muscles (measured with push-up test in 30 seconds) and explosive strength capacity in lower body muscles (measured with sergeant jump test). Five women with an average of 33(±5) years of age all new to Crossfit, performed these tests at two separate occasions with a training period of four weeks consisting of 12(±3,67) Crossfit sessions in between.The result showed a significant improvement in the maximal strength capacity of the leg extension muscles (p=0,025).

Radon i betongkonstruktioner : - Kan det undvikas?

The following article consists of two parts; one part is about house construction and the other is a specialization about radon. The house construction part describes how to project a house from start. It contains the conformation of the house, the installations needed, calculations considering the strength of the construction, energy calculation and what materials were chosen. Calculations considering the costs of building and operate the house has been carried out. The result showed that the house would cost approximately two million Swedish kroner to build and thirteen thousand kronor a year to operate.

1 Nästa sida ->