Continuous longitudinal and transverse U-bar joint connections between flanges of the decked bulb-Ts (DBTs) or between precast panels for accelerated bridge construction are investigated. The procedure for selecting durable closure pour (CP) materials for the connections is discussed firstly. The accelerated construction is quantified as two categories: overnight cure and 7-day cure of CP materials. Candidate materials are selected first based on literature review as well as tests of compressive strength and flow and workability. Then, performance criteria for selecting durable CP materials for both categories are developed based on durability tests of selected candidate materials. These durability tests include freezing-and-thawing durability, shrinkage, bond, and permeability tests. To investigate the longitudinal U-bar joint details, four pairs of full-scale slabs connected by a U-bar detail with one of the selected CP materials, overnight cure and 7-day cure, were tested. The loading demand necessary in the slab testing is determined based on the maximum forces in the longitudinal joint from an analytical parametric study. Static and fatigue tests under four-point flexural loading and three-point flexural-shear loading were conducted. Test results were evaluated based on flexural capacity, curvature behavior, cracking, deflection and steel strain. The transverse U-bar joint details are investigated to provide negative moment continuity in the multi-span bridges. Four full-scale specimens connected by a U-bar detail with one of the selected CP materials, overnight cure and 7-day cure, were tested. Static and fatigue tests under tension loading were conducted. The loading demand necessary in the beam testing is determined based on the maximum forces in the transverse joint from an analytical study. Test results were evaluated based on tension capacity, cracking, displacement and steel strain. Based on the test results, the developed longitudinal and transverse U-bar joint details are viable connection systems.

The gluing of unseasoned wood, called green gluing, is a relatively new sawmill process, implying a radically changed order of material flow in the production of value-added wood-based products. It facilitates the enhancement of raw material recovery and value yield by integrating defect elimination and gluing already before kiln drying. The present study evaluates green glued adhesive bonds in flatwise glued beams and finger joints. The main part of this work deals with green gluing using a moisture curing polyurethane adhesive (PUR). Standardised test methods and specially designed, small scale, specimens were used for the determination of the strength, fracture energy and the ductility of both dry- and green glued bonds in tension and in shear. Using the small scale specimens it was possible to capture the complete stress versus deformation curves, including also their unloading part. An optical system for deformation measurement was used for the analysis of bond behaviour. The influence of moisture content during curing and temperature after curing on the adhesive chemical composition and on the mechanical properties was investigated. Furthermore, the moisture transport through the adhesive bond during curing was tested. Finally, microscopy studies were performed for analysis of bond morphology and fracture. The results show that two significant factors influence the shear strength of green glued bonds: wood density and adhesive spread rate. Bonds which fulfil the requirements according to EN 386 could be obtained within a wide range of process parameters. The small specimen tests showed that green glued PUR bonds can reach the same strength and fracture energy, both in shear and in tension, as dry glued bonds with the same adhesive amount. The local material properties of the bonds could be determined, thanks to the failure in the tests taking place within the adhesive bond itself and not in the wood. Following process factors were shown to cause lower bond strength: a) a low adhesive spread rate, b) high pressure and c) short pressing time in combination with low wood density and high moisture content. Moreover, the heat treatment of the cured PUR adhesive during drying influenced the chemical composition of the adhesive, providing for higher strength, stiffness and Tg of the adhesive, caused by an increased amount of highly ordered bidentate urea.

Biobased materials made from renewable resources, such as wood, play an important role in the sustainable development of society. One main challenge of biobased building materials is their inherent moisture sensitivity, a major cause for fungal decay, mold growth and dimensional instability, resulting in decreased service life as well as costly maintenance. A new building material known as wood-plastic composites (WPCs) has emerged. WPCs are a combination of a thermoplastic matrix and a wood component, the former is usually recycled polyethylene or polypropylene, and the latter a wood processing residual, e.g. sawdust and wood shavings. The objective of this thesis was to gain more insight about characteristics of WPCs containing a modified wood component. The hypothesis was that a modified wood component in WPCs would increase the moisture resistance and durability in outdoor applications. The study comprises both injection molded and extruded WPC samples made with an unmodified, acetylated, thermally modified or furfurylated wood component in a polypropylene (PP), high density polyethylene (HDPE), cellulose ester (CAP, a cellulose ester containing both acetate and propionate substituents) or polylactate (PLA) matrix. The WPCs were prepared with 50-70 weight-% wood. The emphasis was on studying the moisture sorption, fungal resistance and micromorphological features of these new types of composites. Water sorption in both liquid and vapor phases was studied, and the biological performance was studied both in laboratory and in long term outdoor field tests. Micromorphological features were assessed by analyzing of the wood component prior to and after processing, and by studying the composite microstructure by means of a new sample preparation technique based on UV excimer laser ablation combined with scanning electron microscopy (SEM). Results showed that the WPCs with a modified wood component had a distinctly lower hygroscopicity than the WPCs with unmodified wood, which resulted in less wood-plastic interfacial cracks when subjected to a moisture soaking-drying cycle. Durability assessments in field and marine tests showed that WPCs with PP or CAP as a matrix and 70 weight-% unmodified wood degraded severely within a few years, whereas the corresponding WPCs with a modified wood component were sound after 7 years in field tests and 6 years in marine tests. Accelerated durability tests of WPCs with PLA as a matrix showed only low mass losses due to decay. However, strength losses due to moisture sorption suggest that the compatibility between the PLA and the different wood components must be improved. The micromorphological studies showed that WPC processing distinctly reduces the size and changes the shape of the wood component. The change was most pronounced in the thermally modified wood component which became significantly reduced in size. The disintegration of the modified wood components during processing also creates a more homogeneous micromorphology of the WPCs, which may be beneficial from a mechanical performance perspective. Future studies are suggested to include analyses of the surface composition, the surface energy and the surface energy heterogeneity of both wood and polymer components in order to tailor new compatible wood-polymer combinations in WPCs and biocomposites. / <p>QC 20121119</p>

This thesis concerns various aspects of the durability offibre optic sensors embedded in composite. Since repair orreplacement of embedded sensors is not generally possible, thefunctional reliability of embedded sensors is one of the mostimportant prerequisites for successful use. The main researchobjective was to investigate the interaction between the sensorand the composite, and how this is affecting the mechanical andoptical sensor response. Fibre optic sensors embedded incomposite structures induce local stress concentrations whenthe composite is subjected to mechanical loads andenvironmental changes such as temperature and moisture. Acomplex transfer of stresses through the interfaces between theembedded sensor and the composite occurs and can result inlarge local stresses in the composite and a significant changein the response of the embedded sensor. These stressconcentrations make the interfaces susceptible todebonding. The sensor performance was studied experimentally andnumerically. Some basic results were generated for the EFPI andBragg grating sensors. The phase-strain response was determinedduring static and fatigue loading. The results showed that thesensors were more reliable in compression than in tensilestatic and fatigue loading. Generally, the sensor reliabilityduring loading was significantly improved for the Bragg gratingsensors over that of the EFPI sensor, as an effect of thesensor geometry. This was also demonstrated in theinvestigations on impacts. Impacts do not necessarily result indamage in the composite, but might cause debonding or otherfailure modes in the sensor area. Large, local stressconcentrations occur at several positions in the EFPI sensor,which pointed out that this sensor type was not suitable forembedded applications. The shift in focus from the sensor concept based on the EFPIsensor to that based on the Bragg grating sensor manifesteditself in several studies. The calculated deformation fieldaround an embedded optical fibre was verified in experimentsusing a high-resolution moiré interferometric technique.Furthermore, the improvement in the coating technology wasverified. A significant higher interfacial strength wasobtained with the silane-treated glass surface. The resultsindicated that at least a twofold improvement of the shearstrength was obtained. To simultaneously measure the in-plane strain components andthe temperature change, embedded Bragg grating sensors werearranged in a rosette configuration. The relationship betweenthe optical response from each sensor and the strains in thelaminate was numerically and analytically established. Damage lead to stress redistribution in the sensor region,which may influence the output from the embedded Bragg gratingsensor. The effect was numerically evaluated for interfacialdamage, and was compared to that of a sensor with undamagedinterface. The results showed that debonding might have asignificant influence, in particular for combined thermal andmechanical loading. <b>Keywords</b>: composites, fibre optic sensor, embedded, EFPIsensor, Bragg grating sensor, durability, fatigue, impact,strain measurement, interface, stress analysis

The built environment usually constitutes a very important part of the real capital of a nation, and the construction sector represents more than 10% of the yearly Gross National Product of the industrialised world. Good planning of all construction is important, and consideration of the service life of the work is of great interest and is a significant aspect of sustainability considerations. The need for more knowledge about degradation of materials, for structured methodology, and for working tools for those involved in the planning process, has resulted in an extensive effort in pre-normative research and standardisation regarding this field. This thesis presents a discussion on service life planning and the role of the Factor Method in such work, and especially, discussion of modification and development of the methodology. In the design process, the need to evaluate the service life of products is a great challenge, as the results will depend on both material properties and the environment in which the material is placed or used. A practical solution has to be based on a good knowledge in the field, but also on a sound working strategy, to ensure that different design scenarios can be compared in a standardised or structured way. The Factor Method is a promising working tool for such an evaluation and comparison, but is as such, still more of a methodology, than a method. Examples of the use of the methodology are still very limited, and the method as such, is much discussed by researchers. However, its future will depend upon how practical it will be to apply in use. The method is useful to estimate the service life of products, based on a known reference service life and a number of modifying factors. These factors in turn depend on the conditional differences between the specific project and the reference, in-use conditions. This thesis discusses the required precision of such a methodology, especially in light of inherent distributions in material properties, and the fact that the consequences of failure are often very limited. In such cases, the standardised Factor Method is considered to be quite useful, and should give the parties involved a good means for working in a structured and systematic way. / QC 20101019

The characteristics of cement kiln dusts (CKDs) and their effects as partial replacement of Portland Cement (PC) were studied in this research program. The materials used in this study were two different types of PC (normal and moderate sulfate resistant) and seven CKDs. The CKDs used in this study were selected to provide a representation of those available in North America from the three major types of cement manufacturing processes: wet, long-dry, and preheater/precalciner. Two fillers (limestone powder and quartz powder) were also used to compare their effects to that of CKDs at an equivalent replacement of PC. It was found that CKDs can contain significant amounts of amorphous material (>30%) and clinker compounds (>20%) and small amounts of slag and/or flyash (<5%) and calcium langbeinite (<5%). The study found that CKDs from preheater/precalciner kilns have different effects on workability and heat evolution than CKDs from wet and long-dry kilns due to the presence of very reactive and high free lime contents (>20%). The blends with the two CKDs from preheater/precalciner plants had higher paste water demand, lower mortar flows, and higher heat generation during initial hydrolysis in comparison to all other CKD-PC blends and control cements. The hardened properties of CKD as a partial substitute of PC appear to be governed by the sulfate content of the CKD-PC blend (the form of the CKD sulfate is not significant). According to analysis of the ASTM expansion in limewater test results, the CKD-PC blend sulfate content should be less than ~0.40% above the optimum sulfate content of the PC. It was also found that the sulfate contribution of CKD behaves similar to gypsum. Therefore, CKD-PC blends could be optimized for sulfate content by using CKD as a partial substitute of gypsum during the grinding process to control the early hydration of C3A. The wet and long-dry kiln CKDs contain significant amounts of calcium carbonate (>20%) which could also be used as partial replacement of limestone filler in PC.

The characteristics of cement kiln dusts (CKDs) and their effects as partial replacement of Portland Cement (PC) were studied in this research program. The materials used in this study were two different types of PC (normal and moderate sulfate resistant) and seven CKDs. The CKDs used in this study were selected to provide a representation of those available in North America from the three major types of cement manufacturing processes: wet, long-dry, and preheater/precalciner. Two fillers (limestone powder and quartz powder) were also used to compare their effects to that of CKDs at an equivalent replacement of PC. It was found that CKDs can contain significant amounts of amorphous material (>30%) and clinker compounds (>20%) and small amounts of slag and/or flyash (<5%) and calcium langbeinite (<5%). The study found that CKDs from preheater/precalciner kilns have different effects on workability and heat evolution than CKDs from wet and long-dry kilns due to the presence of very reactive and high free lime contents (>20%). The blends with the two CKDs from preheater/precalciner plants had higher paste water demand, lower mortar flows, and higher heat generation during initial hydrolysis in comparison to all other CKD-PC blends and control cements. The hardened properties of CKD as a partial substitute of PC appear to be governed by the sulfate content of the CKD-PC blend (the form of the CKD sulfate is not significant). According to analysis of the ASTM expansion in limewater test results, the CKD-PC blend sulfate content should be less than ~0.40% above the optimum sulfate content of the PC. It was also found that the sulfate contribution of CKD behaves similar to gypsum. Therefore, CKD-PC blends could be optimized for sulfate content by using CKD as a partial substitute of gypsum during the grinding process to control the early hydration of C3A. The wet and long-dry kiln CKDs contain significant amounts of calcium carbonate (>20%) which could also be used as partial replacement of limestone filler in PC.

This diploma work on D-level is made in cooperation with Varnäsföretagen AB in Eskilstuna. The company performs contract manufactured aluminium goods. This work is a continuation on earlier diploma work in Varnäsföretagen AB. Even if the industry process consumes much energy for melting the aluminium goods, they consume a great amount of oil to warm up the building. The purpose of this work is to examine some places in the building and the process to see how much energy it is possible to recycles to the heating system and reduce the costs for heating. The places have all a big heat excess and recycling will get more acceptable thermal comfort for the staff.  Studies of efficiency, the variation in power and temperatures is made to see how much energy it is possible to recycle. Many systems could with small measures be more efficient. A general problem for many places is that the energy is in the indoor air and has low temperature. It means that most of the energy is difficult to use in other places than for preheating of the intake air in the air handling units.

This thesis will compare and examine three different chainsaw models with re-spect to price, elasticity, price discrimination, product differentiation and durabili-ty. The three different saws are all aiming at different customer groups; hobby users, leisure users and professional users. The demands and needs of this groups differs a lot. The hobby users have the largest amount of different saws to choose from, this is a field with many different brands and the quality varies a lot, this implies that here is a fierce competition with respect to price. This indirect affects the elastic-ity and possibilities to price discriminate and product differentiation. I found that this model has the highest elasticity which is perfectly inline with the theory. Here is also a low possibility to price discriminate and the durability is the low-est. The other two models examined, the leisure and professional, are located in less competitive segments and from this follows that the professional model which has the smallest amount of competitors also has the lowest elasticity. Here was also the possibility to price discriminate the highest, durability the best and the product were viewed as differentiated.

This paper examines family owned tourism businesses with a special focus on succession. In Nordic countries tourism has been widely promoted and used in rural development as a replacement economy for ‘traditional’ livelihoods based on rural production. Because the tourism and hospitality industry, especially in rural areas, is dominated by family enterprises, the topic of succession is of great relevance for tourism and tourism destinations. This paper looks at family businesses’ special characteristics, challenges and advantages in terms of ownership structure, lifestyle, motivations, employees and destination impact. This paper concludes that, while family-owned Small and Medium-sized enterprises make up the backbone of the tourism industry, especially in rural destinations, there exists insufficient research on their significance within tourism. A small percentage of family owned tourism businesses are successfully handed over to succeeding generations. Those that do are exceptional and more sustainable both in financial and marketing terms and therefore extremely advantageous for destinations. On the other hand, family businesses that fail to be passed on to following generations can have a devastating effect on tourism and destinations in general. / Den här uppsatsen behandlar familjeägda turistföretags betydelse för varaktigheten i landsbygdsdestinationer med fokus på succession. I våra nordiska länder har turism på senare år använts som landsbygdsutveckling och i viss mån som ersättning för de mer traditionella näringarna som jordbruk och fiske. Eftersom turism och besöksindustrin, speciellt i de perifera områdena, domineras av familjeföretag är succession inom dessa av stor betydelse för turism och turistdestinationer. Uppsatsen tar i övrigt upp familjeföretagens kännetecken, utmaningar och fördelar beträffande ägarstrukturer, livsstil, motivation, medarbetare och destinationspåverkan. Familjeföretag utgör ryggraden för turismindustrin i allmänhet och landsbygdsdestinationer i synnerhet men trots det saknas forskning om den här typen av företags betydelse för turism. Endast en liten andel av familjeägda turistföretag genomgår ett generationsskifte. Det gör att de som klarar en succession är unika och mer varaktiga både ur finansiell och ur marknadsmässig synpunkt vilket är mycket fördelaktigt för destinationen. Å andra sidan kan de företag som inte lyckas med en succession vara förödande för hela samhället där de verkar.