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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Development and Engineering Properties of Construction Materials Made Using Melted Plastics Wastes as the Only Binding Phase

Thiam, Moussa 07 September 2021 (has links)
Modernization has brought about steady increase in the consumption of goods and services by human societies across the globe, which mostly driven by both population growth and the change of individual living standards. This, of course, leads to an ever-increasing waste production that ends up in landfills and very often as a source of pollution on natural ecosystems, especially in the low and middle-income countries where waste management is almost inexistent. The management of waste streams is a huge challenge for developed countries as well, where societal and environmental impacts are visible despite massive investments in waste management. One of the most problematic waste materials is plastic, which can remain in nature for over 100 years without degradation, leading to serious environmental concerns. As one of the most significant innovations of the 20th century, plastic is a widely used and cost-effective material for many applications. After their useful lifetimes, their management is problematic. Thus, robust and innovative approaches of managing such waste material are needed in order to mitigate the problem. One of the innovative approaches of tackling the menace cause by plastic waste is through its incorporation into the construction materials. This thesis seeks to address this problem by exploring the use of melted plastic wastes (High Density Poly Ethylene, HDPE and Low Density Poly Ethylene, LDPE) as binder in developing new construction materials (mortar with melted plastic as the only binder, MPB and Plastic Waste Crete, PWC) as an alternative to partially replace traditional concrete and mortar, or finding other engineering uses for this type of waste. Worldwide, about 190 m3 of concrete is poured every second, which translates to 6 billion m3 per year and making it, one of the most widely used manufactured materials. However, the production of concrete requires water and cement. Cement is expensive, and its production contributes to the emission of environmentally polluting gases. Replacing this binding element with recycled plastic derivatives would have significant economic and environmental benefits. In addition to the elimination of cement cost, this will result in water savings, which is especially important for areas without fresh water scarcity. Some researchers have used plastics in concrete and mortars as additives and/or replacement for fine and coarse aggregates. In addition, different types of plastics have been used in bitumen as an additive to reduce construction cost and improve sustainability by adding value to wastes materials. However, there is paucity of technical information about the use of the melted HDPE and LDPE plastic wastes as the only binding phase in concrete- or mortar-like materials. Moreover, many parameters such as preparation conditions, field variables, constituent elements, and final applications have impacts on the performance of construction materials Thus, the key objective of this PhD research is to develop the mortar with plastic binder (MPB) and PlasticWasteCrete (PWC) by using molten HDPE and LDPE plastic wastes as the only binder as well as to investigate the engineering properties of these new types of construction materials. The plastic contents of 45%, 50%, 60% and 65% and HDPE to LDPE ratios of 40/60, 50/50, and 60/40 were selected for the experimental tests. Clean river sand was used as the only aggregate for the MPB, while both sand and gravel were used for the PWC. Various tests were then performed on prepared MPB and PWC samples at different curing times from early to advanced ages to assess their engineering properties. These tests were conducted in accordance with the ASTM standards to evaluate the mechanical properties (compressive strength and splitting tensile strength), permeability and density of the MPB and PWC materials. Additional tests were carried out to analyze the products at the microstructural level (optical microscope, SEM, MIP and thermogravimetric analysis) to gain an insight into the microstructural properties of the developed materials and how that affect their engineering properties. The compressive strength tests revealed the optimal plastic content for the MPB and PWC with the best strength performance. The average compressive strength values for various optimal formulations after 28 days were found to be in the range of 9 to 18 MPa. The splitting tensile strength for the new materials from 1 to 28 days of curing time, were found to be between 1 and 5 MPa. The average hardened density of the MPB and PWC is about 2 g/cm3, which makes them lightweight material according to RILEM classification. In addition, various absorption tests (capillary and immersion) were performed on different MPB and PWC samples, and the obtained results showed that they are porous materials having lower rate of absorption than the traditional cementitious materials (mortar, concrete). This observation was supported by the results from both MIP and SEM analyses. Finally, thermogravimetric analysis provided interesting details on the thermal decomposition of the new materials, with significant changes or mass loss for these products being observed only at temperatures higher than 300°C. The findings from this study suggest MPB and PWC made with melted plastic waste as the only binder have a promising potentials for use in construction. The research conducted in this PhD study offers a good understanding of the engineering properties of the materials as well as the optimal formulations that yield best performance in terms of strength and durability. In summary, it provides useful technical information and tools on the MPB and PWC that will contribute in setting guidelines on the optimal applications of these products in the field of construction in order to have safe, durable and cost-effective structures. Résumé Avec la modernisation de nos sociétés, les habitudes ont considérablement changé, ainsi, on observe une forte consommation des biens et services, due à l’augmentation de la population et l’amélioration de leurs conditions de vie. Ce qui conduit à une augmentation considérable des quantités des déchets qui terminent leurs cycles au niveau des décharges ou dans les océans/fleuves devenant ainsi une source de source de pollution des écosystèmes naturels, surtout dans les pays à revenu faible et intermédiaire avec des systèmes défaillants ou moins performants de gestion des déchets. La gestion des flux de déchets est aussi un défi pour certains pays développés, où les impacts sociaux et environnementaux sont visibles en dépit des investissements massifs dans ce secteur. Parmi ces déchets, nous avons les plastiques, l’une des innovations du 20e siècle avec des qualités versatiles et coût faible, se trouve partout dans nos vies quotidiennes. Après leur utilisation, les plastiques deviennent des déchets qui peuvent rester dans la nature plus de 100 ans sans aucune dégradation, avec des conséquences néfastes sur l’Homme et l’environnement. Ainsi, une approche robuste et innovante de gestion de ces déchets est nécessaire afin d'atténuer leurs impacts. L'une des approches innovantes pour réduire l’impact causé par les déchets plastiques consiste à les incorporer dans les matériaux de construction. Ainsi, le problème est abordé dans cette thèse en développant des technologies permettant de recycler les plastiques fondus comme liant dans les nouveaux matériaux de construction (MPB et PWC), afin d’offrir une alternative pour remplacer partiellement le béton / mortier traditionnel. Le béton est l’un des matériaux les plus utilisés au monde, avec environ 190 m3 coulés chaque seconde, correspondant à 6 milliards de m3 par an. Cependant, la production de béton nécessite de l'eau et du ciment. Le ciment coûte cher et sa production contribue à l'émission de gaz polluants l'environnement. Le remplacement d'une partie du béton traditionnel par un matériau à base des déchets plastique aura des avantages économiques, sociaux et environnementaux importants. Allant dans ce sens, certains chercheurs ont utilisé les plastiques dans le béton et le mortier comme additifs et / ou substituts des matériaux granulaires tels que le sable et le gravier. Aussi, différents types de plastiques ont été utilisé dans le bitume comme additif pour réduire les coûts de construction et améliorer la durabilité, ainsi contribuer à donner de la valeur aux déchets. Cependant, jusqu'à présent, il existe peu d’informations techniques sur l'utilisation de déchets plastiques (HDPE et LDPE) fondus comme seuls liants pour développer de nouveaux types de matériaux de construction. En plus, plusieurs facteurs (les conditions de préparation, les éléments constitutifs, les applications finales, etc.) ont un impact sur les caractéristiques des matériaux de construction. Ainsi, l'objectif de cette recherche doctorale est de développer des nouveaux matériaux de construction (MPB et PWC) en utilisant les déchets plastiques fondus (HDPE et LDPE) comme seul liant, puis déterminer les propriétés caractéristiques de ces matériaux afin de trouver la formulation optimale conduisant à la meilleure résistance. En plus de l'élimination du coût du ciment, cette technologie permet aussi de faire des économies d'eau, bénéfique surtout pour les zones avec des difficultés d'accès à l’eau potable. Cela contribuera à la réduction des coûts de la construction en utilisant les produits innovants comme alternative au béton / mortier conventionnel. Un vaste programme expérimental, comprenant des tests à petite et grande échelle, a été développé afin d'atteindre les objectifs de cette étude de doctorat. La campagne expérimentale a comporté différentes étapes comprenant la sélection des matériaux, la détermination de la formulation optimale et les conditions appropriées pour la préparation des matériaux susmentionnés. Par la suite, pour une meilleure compréhension du comportement technique et des propriétés du produit final, divers tests ont été effectué sur les matériaux préparés à différents temps de durcissement. Ces tests ont été menés conformément aux normes ASTM pour évaluer les propriétés mécaniques (résistance à la compression et à la traction), la perméabilité et la densité des nouveaux matériaux. Les expériences ont été approfondies en analysant les produits au niveau microstructural (microscope optique, SEM, MIP et analyse thermique) pour avoir un aperçu des propriétés microstructurales des matériaux développés et essayer de comprendre les relations avec leur comportement mécanique. Les essais de compression ont permis de trouver la teneur en plastique optimale pour les matériaux (MPB et PWC) avec les meilleures valeurs de résistance. Les résistances moyennes à la compression à 28 jours pour diverses formulations étaient comprises entre 9 et 18 MPa. La résistance à la traction par fendage des nouveaux matériaux entre 1 et 28 jours se situait entre 1 et 5 MPa. La densité moyenne du béton et mortier écologique est proche de 2 g / cm3, ils peuvent donc être considérés comme des matériaux légers selon la classification RILEM. De plus, divers tests d'absorption (capillaire et par immersion) ont été réalisé sur différents échantillons de MPB et PWC, les résultats obtenus ont montré qu'il s'agit de matériaux poreux ayant un taux d'absorption plus faible que les matériaux traditionnels contenant du ciment. Plusieurs analyses microstructurales ont été réalisées sur différents échantillons des nouveaux produits (MPB et PWC) et les matériaux cimentaires traditionnels ont été utilisés pour renforcer notre compréhension. Enfin, l'analyse thermique a fourni des détails intéressants sur la décomposition thermique de ces nouveaux matériaux ; des changements significatifs avec une perte de masse considérable ont été observés seulement pour des températures supérieures à 300 ° C. Les résultats de ces essais permettent d'acquérir une bonne compréhension des propriétés techniques des nouveaux matériaux (MPB et PWC) ainsi que de déterminer les teneurs optimales en plastique conduisant aux meilleures performances en termes de résistance et de durabilité. Ainsi, les recherches menées dans cette étude de doctorat fournissent des informations techniques et des outils utiles sur le MPB et le PWC; et contribueront à installer des bases pour guider les applications optimales de ces nouveaux produits dans le domaine de la construction afin d'avoir des structures sûres, durables et rentables.
22

Comparative life cycle assessment of organic building materials

Yossef, Delav, Hot, Dino January 2021 (has links)
The ever-increasing awareness of global warming has made the building industry startlooking for alternative building solutions in order to meet the changing demands. Thesechallenges have given rise to organization which aim to go further and construct moresustainable alternatives in the form of Ecovillages. This thesis is conducted in collaborationwith Bysjöstrans Ekoby and aims to investigate what type of organic alternatives exist andhow they perform in building elements.The study was carried out through a comparative LCA where a base case construction forboth roof and wall was established. Followed by comparing different organic materials toeach other and the base case materials in order to determine low-impact materials. The goalwas to replaces as many layers within the structure such as insulation, structure, roofcladding, façade, wind and vapor barrier.This was later followed by combing the materials together in order to identify whichalternative construction options would perform the best in regard to greenhouse gasemissions (CO2 eq kg) and primary energy use (MJ).The results of the study show that the performance or organic materials vary significantly.Whit a lot of materials being better but also worse than traditional materials. It showed thatfor internal wall and roof surface adding clay plater can reduce the GHG emission with 68%, timber frame with 98 %, façade with 43 %, roof cladding with 93 %, vapor barrier with76 % and insulation with 79 %. The best preforming construction option could reduce thebase case emission with 68 %.
23

Conception de la matérialisation en architecture : l'expérimentation comme facteur d'innovation industrielle / The design of materialization in architecture : industrial innovation through experiments

Sallé-Hoyet, Nadia 29 November 2007 (has links)
Cette thèse porte sur le rapport qu'entretient la démarche architecturale avec le matériau de construction et ses techniques de mise en œuvre. L’architecture envisagée comme un "art de bâtir" est questionnée à la lumière des avancées récentes de la recherche sur les processus de conception innovante. Le corpus de la thèse, constitué d'entretiens avec des architectes et des industriels, est soumis à une analyse qui aborde les thématiques où s’opère la "matérialisation" de l'œuvre: la conceptualisation, l’expérimentation, l’organisation du protocole et le prototype. Le recours à la modélisation des différentes démarches identifiées rend possible la confrontation de l’expérimentation sur les matériaux dans la démarche d’architecture, aux processus d’innovation répertoriés dans la production manufacturière. Les activités de conception sont représentées par leur capacité à mettre en relation les quatre espaces cognitifs sollicités par le projet : problèmes , concepts, représentations et connaissances / This thesis questions the architectural process about its interrelation with building materials and techniques. An analysis of the corpus of the thesis based on interviews of architects and industry specialists is made throught the different steps where the 'embodiment' of the work takes place: design, experiments, protocol and prototype set up. To be able to compare them with innovative processes coming from the industry, we used their modelization. Design activities are then represented by the possibilities they offer to interrelate the four cognitive spaces that t he project deals with: problems, concepts, representations and knowledge. Two main action systems emerged from case studies and have to be linked: one heading the architectural project development and one organizing innovation in manufacturing industries
24

Economic and environmental input-output modeling: building material recycling

Choi, Taelim 14 November 2012 (has links)
A key dimension to improving urban economic and environmental sustainability is the efficient use of resources through recycling. A thriving recycling system requires not only effective institutional policies and community-wide diversion efforts, but also a competent local and regional recycling industry. Although the recycling industry has traditionally been recognized as a local service and fringe industry, it has noticeably transformed into an integral segment of industrial production systems as manufacturers have increasingly begun to adopt the principle of extended producer responsibility. Despite such changes, urban and regional theory and planning research has largely disregarded the industrial aspect of recycling, contributing to the dearth of information about the organizational and spatial patterns of the recycling industry and the impact of the establishment of recycling systems on local and regional scales. Given the knowledge gap, this dissertation addresses two questions: 1) What is the logic of the industry organization and spatial pattern of recycling industry in different institutional contexts? and 2) How is the economic and environmental impact of recycling systems determined in cases of construction and demolition waste recycling and waste carpet recycling? To answer the first question, this research develops a theoretical model that explains how recycling industrial activities are spatially distributed in light of institutional and organizational theories. The theoretical model characterizes organizational decisions pertaining to recycling functions and suggests spatial patterns of recycling systems. With respect to the second question, this research constructs a regional environmental input-output model on the metropolitan scale. It estimates regionalized energy use coefficients and greenhouse gas emission coefficients using various sources of data mainly compiled from the Manufacturing Energy Consumption Survey 2006, the State Energy Consumption Estimates, and the Commodity Flow Survey 2007. Based on regional input-output tables coupled with the regionalized environmental coefficients, this research quantifies, through simulations, the net economic and environmental impact of a localized construction and demolition waste recycling system in the San Francisco metropolitan area and regional carpet recycling systems in the Atlanta and Seattle metropolitan areas. Results of the simulations reveal that 1) the localized construction and demolition waste recycling system provides moderate economic benefits because of the limited job creation potential of mechanized recycling processes and yields relatively small environmental benefits with respect to the total weight processed; 2) wider adoption of the deconstruction technique expands job opportunities, increases energy savings, and reduces greenhouse gas emissions during the course of construction and demolition waste recycling; 3) regional-scale waste carpet recycling systems, in particular recycled nylon 6 production, create sizable new job opportunities and provides environmental benefits of energy savings and greenhouse gas emission reduction despite the long-distance transportation of waste carpet. These results suggest that policies that promote recycling industrial activities can significantly contribute to the economic and environmental sustainability of metropolitan areas.
25

Study of Rural Housing in Mamba District Kilimanjaro, Tanzania / Studie av Bostadsbyggande på Landsbygden i Distriktet Mamba Kilimanjaro, Tanzania

Mattsson, Jenny January 2009 (has links)
As one of the poorest countries in the world, Tanzania faces various kinds of problems. The housing situation is poor in the whole country, especially in rural areas where the main part of the population lives in mud houses. The report is focused on modern houses and is aimed at finding sustainable low cost solutions to be used as alternatives for existing techniques. The report is based on a field study in the Mamba district, Tanzania during 8 weeks in 2009. The traditional mud houses are poor and do not live up to a decent standard of living. The living conditions are extremely primitive in these houses and pose a health risk to the occupants. Modern houses provide a better standard of living and are good investments for future generations. The building design and technology can be rationalised and improved and building costs can be reduced through alternative methods. There are several ways in which building costs can be reduced. Focus should be on using local materials to minimise expensive transport costs. Cement is the single most expensive building material and should be replaced by other materials where possible. However, it is important that sustainability of the construction is not impaired. In the long term, it is better to invest in proper sustainable building structures even if the costs will increase. This study has resulted in sustainable low cost alternatives to the current building technology that the local builders can benefit from. Tradition is strong in Tanzania and changes may take long to implement. The alterations suggested and discussed in this report can be considered as a good basis for development of the current building design and technology in the Mamba district.
26

Varför sågas så lite björk i Sverige? : Why isn't more birch wood being sawn in Sweden?

Ödlund, Lars-Olof January 2009 (has links)
Sammanfattning   Björk kan ge ett bra virke och med undantag för sämre fukttålighet finns endast formella restriktioner i virkets användning i relation till tall och gran. Trots detta och trots att det finns gott om björkråvara i landet är den sågade och använda björkvolymen påfallande liten. Björken utgör därför en underskattad skoglig och industriell resurs vars utnyttjande skulle kunna öka kraftigt.   Björken har varit ett lågprioriterat virke vilket sannolikt på grund av dålig skötsel påverkat kvalitén på våra nuvarande björkskogar och plantmaterialet. Det har också lett till att vi saknar tradition i vid mening att arbeta med björken. Forskning och utbildning fokuserar på barrvirke varför lövets, och då särskilt björkens möjligheter inte tillvaratas.   Björken kräver andra skötselmetoder än barrträden men utnyttjas dessa finns förutsättningar att skapa bra produktionsskogar både med avseende på volym och kvalitet. Mer forskning behövs dock i frågan om betesskador och hur dessa kan reduceras. Bra björktimmer kan pris- och lönsamhetsmässigt vara intressantare för skogsägaren än motsvarande barrtimmer. Dessa kunskaper måste nå ut till skogsägarna för att de skall förstå att det finns attraktiva alternativ till att slentrianmässigt anlägga nya tall- eller granskogar efter en föryngringsavverkning. Utöver det goda arbetet som Skogsstyrelsen gör med allmänna skötselråd gällande björkskogen borde de mer aktivt arbeta med skogsägarna för att stimulera till ett mer kommersiellt utnyttjande av björken. Denna uppmaning gäller även andra berörda parter vilket inkluderar skogsägarens alla rådgivare.   Den helt dominerande volymen av avverkad björk går i dagsläget till massabruken. Det finns flera skäl till detta. Ett kan vara att kvaliteten inte alltid svarar mot sågverkens krav men andra skäl är hanterings- och logistikproblem med att hantera små volymer sågtimmer och bristande kunskaper både hos skördarföraren och hos skogsägaren. Hade skogsägaren haft de goda förtjänstmöjligheterna på björktimmer klar för sig vid avverkningen hade han kunnat ge noggrannare instruktioner om hur björkvirket skulle hanteras.   Sågverken som hanterar björk är få och relativt små. För en verklig volymproduktion av björktimmer behövs en resurs- och teknikutbyggnad. Vissa satsningar görs men mer behövs. Dessa satsningar måste göras utifrån ett verkligt marknadsmässigt perspektiv. Vem skall svara för nödvändiga investeringar? Var finns industrin, riskkapitalisterna och investerarna som är beredda att satsa på en fabrik för svensk björkplywood eller byggsystem som inkluderar björk? Lönsamheten är inget att skryta med och branschen utövar ingen stor lockelse för nya entreprenörer. Även här kommer marknadsaspekterna in. Det behövs industriell efterfrågan på stora volymer sågad björk för att konstituera en verklig marknad. För att skapa denna räcker det inte med en satsning på snickeriindustrin utan björk måste även i Sverige användas som ett naturligt virke i byggsammanhang. Boverket har här en nyckelroll och måste anpassa svenska normer till motsvarande europeiska så att det blir möjligt att interiört bygga också med björk. Vem driver den frågan? Vem stimulerar arkitekter och byggnadskonstruktörer till att bygga med björk? På samma sätt som det sätts upp priser för bästa trähus kunde det möjligen också skapas ett pris för bästa anläggning byggd i björk. Hur kan man skapa intresse hos en kommun, ett företag eller organisation att genomföra ett profilbygge i björk? Sveriges Träbyggnadskansli är en lämplig mottagare av detta budskap men det borde finnas fler.   I takt med att skogens miljömål accentueras blir lövskogen än viktigare. Lika viktigt är då att alla parter samverkar för att skogsägaren som sköter sin lövskog på ett bra sätt skall få avsättning för sitt virke till acceptabla villkor. Skogsstyrelsen måste också ha en positiv syn på lövavverkningen och inte av miljöskäl i en framtid stoppa denna när den blir aktuell. Blotta misstanken hos skogsägaren att så kan bli fallet kommer att leda till ett minskat intresse för lövskogen.   Lövträ är inget homogent begrepp och egenskaperna skiljer sig märkbart mellan t.ex. al, alm, ask, lönn å ena sidan och björk å den andra. Det finns ingen anledning att i detta sammanhang tala om björk i allmänna ordalag som ett lövträd utan björk är björk och inget annat och skall så behandlas.   Sammanfattningsvis har vi gott om björk vars virke kan användas på mångahanda sätt. Att så inte sker kan inte förklaras av någon enstaka faktor. För att få en ändring till stånd krävs i första hand ett renodlat marknadsmässigt tänkesätt med ökad information och kunskap i alla led. Det talas om att skogsnäringen måste marknadsorientera sig i sin verksamhet. Detta gäller hela kedjan från skogsägaren till slutkonsumenten av skogsprodukten. / Summary in English   Sweden is a forest country with a standing wood balance of more than 3 000 million m3sk. Pine and spruce are dominating species but there is also a wood balance of some 420 million m3sk of birch. Birch is offering excellent timber properties and is well matching both pine and spruce with the exception of its sensitivity to moisture. Despite of this, quite small quantities of birch timber are being used in Sweden. Most birch wood being cut is used for the production of paper and pulp (95%). Although the birch tree is an old species in Sweden it was during the 2000th century until the end of the 1970s treated as a weed and was struggled with by means of herbicides. Subsequently Sweden lost knowledge and experience in how to deal with this wood which in turn leads to a poor quality of now existing clumps of birch trees. Compared to coniferous trees little research has been done of broadleaf trees but it’s anyhow known that the clearing and thinning of birch trees have to be stricter than that of softwood. Birch trees have an interesting potential with a shorter production cycle than pine and spruce. Used for timber the yield for the forest owner could be quite interesting. Broadleaf trees are also playing an important role to improve the overall environment.   To increase the use of birch wood more information about this specific timber has to be spread to all parties concerned. That involves owners of forest land, silviculture, sawmills, industry and distributors. Activities along the chain of actors have to be market oriented and include economic incentives for parties concerned. To be able to increase the volume of birch timber used new areas of deployment have to be found outside the traditional production of furniture etc. An interesting area is then the building industry.
27

Study of Rural Housing in Mamba District Kilimanjaro, Tanzania / Studie av Bostadsbyggande på Landsbygden i Distriktet Mamba Kilimanjaro, Tanzania

Mattsson, Jenny January 2009 (has links)
<p>As one of the poorest countries in the world, Tanzania faces various kinds of problems. The housing situation is poor in the whole country, especially in rural areas where the main part of the population lives in mud houses.</p><p>The report is focused on modern houses and is aimed at finding sustainable low cost solutions to be used as alternatives for existing techniques.</p><p>The report is based on a field study in the Mamba district, Tanzania during 8 weeks in 2009.</p><p>The traditional mud houses are poor and do not live up to a decent standard of living. The living conditions are extremely primitive in these houses and pose a health risk to the occupants. Modern houses provide a better standard of living and are good investments for future generations. The building design and technology can be rationalised and improved and building costs can be reduced through alternative methods.</p><p>There are several ways in which building costs can be reduced. Focus should be on using local materials to minimise expensive transport costs. Cement is the single most expensive building material and should be replaced by other materials where possible. However, it is important that sustainability of the construction is not impaired. In the long term, it is better to invest in proper sustainable building structures even if the costs will increase.</p><p>This study has resulted in sustainable low cost alternatives to the current building technology that the local builders can benefit from. Tradition is strong in Tanzania and changes may take long to implement. The alterations suggested and discussed in this report can be considered as a good basis for development of the current building design and technology in the Mamba district.</p>
28

Varför sågas så lite björk i Sverige? : Why isn't more birch wood being sawn in Sweden?

Ödlund, Lars-Olof January 2009 (has links)
<h1>       Sammanfattning</h1><p> </p><p>Björk kan ge ett bra virke och med undantag för sämre fukttålighet finns endast formella restriktioner i virkets användning i relation till tall och gran. Trots detta och trots att det finns gott om björkråvara i landet är den sågade och använda björkvolymen påfallande liten. Björken utgör därför en underskattad skoglig och industriell resurs vars utnyttjande skulle kunna öka kraftigt.</p><p> </p><p>Björken har varit ett lågprioriterat virke vilket sannolikt på grund av dålig skötsel påverkat kvalitén på våra nuvarande björkskogar och plantmaterialet. Det har också lett till att vi saknar tradition i vid mening att arbeta med björken. Forskning och utbildning fokuserar på barrvirke varför lövets, och då särskilt björkens möjligheter inte tillvaratas.</p><p> </p><p>Björken kräver andra skötselmetoder än barrträden men utnyttjas dessa finns förutsättningar att skapa bra produktionsskogar både med avseende på volym och kvalitet. Mer forskning behövs dock i frågan om betesskador och hur dessa kan reduceras. Bra björktimmer kan pris- och lönsamhetsmässigt vara intressantare för skogsägaren än motsvarande barrtimmer. Dessa kunskaper måste nå ut till skogsägarna för att de skall förstå att det finns attraktiva alternativ till att slentrianmässigt anlägga nya tall- eller granskogar efter en föryngringsavverkning. Utöver det goda arbetet som Skogsstyrelsen gör med allmänna skötselråd gällande björkskogen borde de mer aktivt arbeta med skogsägarna för att stimulera till ett mer kommersiellt utnyttjande av björken. Denna uppmaning gäller även andra berörda parter vilket inkluderar skogsägarens alla rådgivare.</p><p> </p><p>Den helt dominerande volymen av avverkad björk går i dagsläget till massabruken. Det finns flera skäl till detta. Ett kan vara att kvaliteten inte alltid svarar mot sågverkens krav men andra skäl är hanterings- och logistikproblem med att hantera små volymer sågtimmer och bristande kunskaper både hos skördarföraren och hos skogsägaren. Hade skogsägaren haft de goda förtjänstmöjligheterna på björktimmer klar för sig vid avverkningen hade han kunnat ge noggrannare instruktioner om hur björkvirket skulle hanteras.</p><p> </p><p>Sågverken som hanterar björk är få och relativt små. För en verklig volymproduktion av björktimmer behövs en resurs- och teknikutbyggnad. Vissa satsningar görs men mer behövs. Dessa satsningar måste göras utifrån ett verkligt marknadsmässigt perspektiv. Vem skall svara för nödvändiga investeringar? Var finns industrin, riskkapitalisterna och investerarna som är beredda att satsa på en fabrik för svensk björkplywood eller byggsystem som inkluderar björk? Lönsamheten är inget att skryta med och branschen utövar ingen stor lockelse för nya entreprenörer. Även här kommer marknadsaspekterna in. Det behövs industriell efterfrågan på stora volymer sågad björk för att konstituera en verklig marknad. För att skapa denna räcker det inte med en satsning på snickeriindustrin utan björk måste även i Sverige användas som ett naturligt virke i byggsammanhang. Boverket har här en nyckelroll och måste anpassa svenska normer till motsvarande europeiska så att det blir möjligt att interiört bygga också med björk. Vem driver den frågan? Vem stimulerar arkitekter och byggnadskonstruktörer till att bygga med björk? På samma sätt som det sätts upp priser för bästa trähus kunde det möjligen också skapas ett pris för bästa anläggning byggd i björk. Hur kan man skapa intresse hos en kommun, ett företag eller organisation att genomföra ett profilbygge i björk? Sveriges Träbyggnadskansli är en lämplig mottagare av detta budskap men det borde finnas fler.</p><p> </p><p>I takt med att skogens miljömål accentueras blir lövskogen än viktigare. Lika viktigt är då att alla parter samverkar för att skogsägaren som sköter sin lövskog på ett bra sätt skall få avsättning för sitt virke till acceptabla villkor. Skogsstyrelsen måste också ha en positiv syn på lövavverkningen och inte av miljöskäl i en framtid stoppa denna när den blir aktuell. Blotta misstanken hos skogsägaren att så kan bli fallet kommer att leda till ett minskat intresse för lövskogen.</p><p> </p><p>Lövträ är inget homogent begrepp och egenskaperna skiljer sig märkbart mellan t.ex. al, alm, ask, lönn å ena sidan och björk å den andra. Det finns ingen anledning att i detta sammanhang tala om björk i allmänna ordalag som ett lövträd utan björk är björk och inget annat och skall så behandlas.</p><p> </p><p>Sammanfattningsvis har vi gott om björk vars virke kan användas på mångahanda sätt. Att så inte sker kan inte förklaras av någon enstaka faktor. För att få en ändring till stånd krävs i första hand ett renodlat marknadsmässigt tänkesätt med ökad information och kunskap i alla led. Det talas om att skogsnäringen måste marknadsorientera sig i sin verksamhet. Detta gäller hela kedjan från skogsägaren till slutkonsumenten av skogsprodukten.</p><p> </p><p> </p> / <h1>Summary in English</h1><p> </p><p>Sweden is a forest country with a standing wood balance of more than 3 000 million m<sup>3</sup>sk. Pine and spruce are dominating species but there is also a wood balance of some 420 million m<sup>3</sup>sk of birch. Birch is offering excellent timber properties and is well matching both pine and spruce with the exception of its sensitivity to moisture. Despite of this, quite small quantities of birch timber are being used in Sweden. Most birch wood being cut is used for the production of paper and pulp (95%). Although the birch tree is an old species in Sweden it was during the 2000th century until the end of the 1970s treated as a weed and was struggled with by means of herbicides. Subsequently Sweden lost knowledge and experience in how to deal with this wood which in turn leads to a poor quality of now existing clumps of birch trees. Compared to coniferous trees little research has been done of broadleaf trees but it’s anyhow known that the clearing and thinning of birch trees have to be stricter than that of softwood. Birch trees have an interesting potential with a shorter production cycle than pine and spruce. Used for timber the yield for the forest owner could be quite interesting. Broadleaf trees are also playing an important role to improve the overall environment.</p><p> </p><p>To increase the use of birch wood more information about this specific timber has to be spread to all parties concerned. That involves owners of forest land, silviculture, sawmills, industry and distributors. Activities along the chain of actors have to be market oriented and include economic incentives for parties concerned. To be able to increase the volume of birch timber used new areas of deployment have to be found outside the traditional production of furniture etc. An interesting area is then the building industry.</p>
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Compósitos à base de gesso incorporados com resíduos de borracha proveniente do processo de recauchutagem de pneus /

Pinto, Nayra Alberici. January 2017 (has links)
Orientador: Jorge Luís Akasaki / Resumo: O gesso é o material sintético construtivo mais antigo que se tem notícia, e sua ampla utilização é devido as suas boas propriedades termoacústicas e de resistência ao fogo. No Brasil, seu emprego concentra-se em forros, revestimentos e paredes divisórias, conhecidas como gesso acartonado. Todavia, o gesso é um material sobre o qual existe pouco conhecimento ao nível da investigação. E este projeto se propõe a estudar mais esse material, através da confecção de compósitos a base de gesso com a incorporação de borracha de pneus, tornando-o assim um material sustentável. A borracha proveniente do processo de recauchutagem de pneus inservíveis tem ampla aplicação em pesquisas com concretos e argamassas; porém pouco se sabe sobre sua aplicação no gesso. Para atingir o objetivo proposto nesse trabalho serão feitos ensaios de microscopia eletrônica de varredura, resistência à ruptura na flexão, resistência à compressão, dureza superficial, absorção de água, densidade superficial de massa, consistência (mini-slump) e comportamento térmico. Dessa maneira, é possível afirmar que a incorporação de borracha pode ser interessante para a produção de placas de gesso, uma vez que pode incorporar um resíduo sem destino totalmente adequado, produzindo placas com características semelhantes das já utilizadas e ainda contribuindo em aspectos como densidade, dureza superficial e isolamento térmico. Sendo assim, dentre as granulometrias utilizadas neste estudo, a borracha grossa pode ser consider... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
30

Compósitos à base de gesso incorporados com resíduos de borracha proveniente do processo de recauchutagem de pneus / Gypsum composite incorporated with rubber residues from the tire recovery process

Pinto, Nayra Alberici [UNESP] 30 May 2017 (has links)
Submitted by Nayra Alberici Pinto null (nayra_alberici@hotmail.com) on 2017-07-19T18:45:02Z No. of bitstreams: 1 dissertação nayra completa.pdf: 5169626 bytes, checksum: 36827a2bda72e89406c13683ad5a0b5d (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-07-19T19:11:12Z (GMT) No. of bitstreams: 1 pinto_na_me_ilha.pdf: 5169626 bytes, checksum: 36827a2bda72e89406c13683ad5a0b5d (MD5) / Made available in DSpace on 2017-07-19T19:11:12Z (GMT). No. of bitstreams: 1 pinto_na_me_ilha.pdf: 5169626 bytes, checksum: 36827a2bda72e89406c13683ad5a0b5d (MD5) Previous issue date: 2017-05-30 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O gesso é o material sintético construtivo mais antigo que se tem notícia, e sua ampla utilização é devido as suas boas propriedades termoacústicas e de resistência ao fogo. No Brasil, seu emprego concentra-se em forros, revestimentos e paredes divisórias, conhecidas como gesso acartonado. Todavia, o gesso é um material sobre o qual existe pouco conhecimento ao nível da investigação. E este projeto se propõe a estudar mais esse material, através da confecção de compósitos a base de gesso com a incorporação de borracha de pneus, tornando-o assim um material sustentável. A borracha proveniente do processo de recauchutagem de pneus inservíveis tem ampla aplicação em pesquisas com concretos e argamassas; porém pouco se sabe sobre sua aplicação no gesso. Para atingir o objetivo proposto nesse trabalho serão feitos ensaios de microscopia eletrônica de varredura, resistência à ruptura na flexão, resistência à compressão, dureza superficial, absorção de água, densidade superficial de massa, consistência (mini-slump) e comportamento térmico. Dessa maneira, é possível afirmar que a incorporação de borracha pode ser interessante para a produção de placas de gesso, uma vez que pode incorporar um resíduo sem destino totalmente adequado, produzindo placas com características semelhantes das já utilizadas e ainda contribuindo em aspectos como densidade, dureza superficial e isolamento térmico. Sendo assim, dentre as granulometrias utilizadas neste estudo, a borracha grossa pode ser considerada a que teve melhor desempenho, uma vez que apresentou características de ser mais trabalhável, menos absorvente e mais isolante termicamente, além de apresentar resistências à compressão e a flexão adequadas para sua utilização (não estrutural), menores mossas e maior leveza do material. / Gypsum is the oldest constructive synthetic material ever heard, and their widespread use is due to its good thermoacoustic properties and fire resistance. In Brazil, its use is focused on linings, coating and partitions, known as drywall. However, the gypsum is a material on which there is little knowledge in terms of research. And this project aims to study more this material through the production of composite gypsum with tire rubber incorporation, thus making it a sustainable material. The rubber from the retreading process scrap tires has wide application in research on concrete and mortar; but little is known about its application in gypsum. In order to reach the objective proposed in this work, scanning electron microscopy, flexural strength, compressive strength, surface hardness, water absorption, bulk density, consistency (mini-slump) and thermal behavior will be performed. In this way, it is possible to affirm that the incorporation of rubber can be interesting for the production of gypsum boards, since it can incorporate a residue without destination completely, producing plates with characteristics similar to those already used and still contributing in aspects such as density, surface hardness and thermal insulation. Thus, among the granulometries used in this study, the thick rubber can be considered the one that had better performance, since it presented characteristics of being more workable, less absorbent and more thermally insulating, besides presenting resistance to compression and flexion adequate for its use (non-structural), smaller dents and greater lightness of the material. / FAPESP: 2015/17658-4

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