Examensarbeten för masterexamen // Master Theses
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- PostA Method for Cost-Benefit Analysis of Climate Change Adaptation Measures in Railway Projects(2016) Wetterhorn, Kristina; Chalmers tekniska högskola / Institutionen för bygg- och miljöteknik; Chalmers University of Technology / Department of Civil and Environmental Engineering
- PostAssessing the Climate Impact of the Gothenburg Cable Car -A Comparison of Two Alternatives Before and After Design Revision(2020) Larsson, Erik; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Hollberg, AlexanderIn 2019, the previously planned Gothenburg cable car, including towers and stations, was redesigned to cut costs since the project had proved more expensive than previously expected. This thesis compares the climate impact of the two designs before and after the design revision by investigating whether the revision had a positive effect on the climate impact and identifies which parameters of the current design that contributes the most to the climate impact. The materials and amounts in the bill of quantities of stations and towers were used as a basis for a life cycle assessment performed in the tool Klimatkalkyl, developed by the Swedish Transport Administration. A third objective was to see how well the tool Klimatkalkyl can be used for unusual constructions without all material being included in the tool. It was found that the second design alternative had a smaller climate impact than the first. During the redesign the climate impact of the assessed parameters decreased from 37 096 tCO2 eq. to 30 704 tCO2 eq. Not all parts of the stations could be included due to lack of data. Steel and concrete were the materials that contributed most to the climate impact. Important parameters included tower design, geotechnical conditions for foundations and amount of concrete in the stations. It was also found that Klimatkalkyl could be used for assessing the climate impact of the cable car when material quantities were known but that complementary data was needed in cases where specific material quantities were not known. This case study showed that an increased life cycle perspective in the design phase of buildings and infrastructure may help identify climate hotspots and serve as a basis for comparisons and selection between different design alternatives. However, missing or average data are an uncertainty that needs to be considered as project specific data is not always known or available in the design phase, especially for more unusual projects like the Gothenburg cable car.
- PostBarriers to efficient water distribution - A case study of the water distribution system of Distrito 8, Cochabamba, Bolivia(2014) Södersten, Carl-Johan; Chalmers tekniska högskola / Institutionen för bygg- och miljöteknik; Chalmers University of Technology / Department of Civil and Environmental Engineering
- PostChallenges for implementing reuse in the construction sector(2021) Frändberg, Fanny; Nyqvist, Evelina; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Hollberg, Alexander; Rosado, LeonardoReuse in the Swedish building sector is becoming more common and have a high potential of decreasing waste and CO2 emissions from the sector. However, it requires a new way of working in order to be implemented on a big scale. In this study, barriers for implementing reuse and their causes and effects have been evaluated. The aim of the project was to find barriers for reuse, and their causes and effects. A literature study was done in order to obtain understanding of different barriers and was used as a base for the interviews. The interviews consisted of 20 experts from different parts of the building sector value chain, and barriers were identified from these interviews and grouped into categories and sub-categories. The categories are: Technology, Market, Infrastructure, Laws and regulations, Knowledge and Culture and norms. The analysis was done by connecting barriers to each other by the help of a visual tool. The strongest connections could be identified, as well as the barriers that are causing and caused by other barriers. The results show that many barriers are highly interconnected and are strengthening each other or other barriers. Some sub-groups of Culture and Norms and Laws and Regulations were not caused by any other identified barrier, and some were not affecting any other identified barrier. The barriers most strengthened by several connections were identified to be between barriers within Knowledge, within Market and also between Knowledge and Culture and norms. The combined result leads to the conclusion that the sector is experiencing lock-in, which is caused by competition and lack of information and knowledge.
- PostCircular packaging plastic usage at construction sites: A study to increase the circularity of packaging plastic at construction sites in Sweden(2022) Stemberger, Adam; Pothireddy, Vinod Sai; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Wallbaum, Holgern 2017 there were 349 000 000 tonnes of plastics produced worldwide (Plastics Europe, 2022) and 2 411 000 tonnes of plastics were produced and imported in Sweden, with the packaging industry being the single most user of plastic followed by the construction sector (Almasai et al., 2019). Of the total waste sent to incineration almost half of the waste was from packaging plastic (Almasai et al., 2019). The aim of the project was to develop circular strategies that promote efficient plastic packaging usage at construction sites. The first step was to identify the total quantity and type of packaging plastic used and to quantify its presence in waste containers at the construction sites by using Material Flow Analysis (MFA). From the results, it was observed that Polyethylene (PE) was the major plastic type present at construction sites and the combustible containers had the highest quantities of plastic. Due to unreliable data, a worst case and a best case scenario were made with total recyclability of 5.8% and 40% respectively. An Life Cycle Analysis (LCA) was performed with the results obtained from MFA to create a baseline scenario that was used for formulating circular strategies. A total of 25 circular strategies were developed from seven design principles adapted to circular economy. The suitable circular strategies were selected by a two step screening process which included environmental impacts and relevant framework. From the results, it could be observed that circular strategies with an emphasis on improving sorting and recycling, lowers the environmental impacts more than other strategies i.e transportation strategies. The circular strategy Less plastic types had the least amount of environmental impacts. This was due to the increased recyclability to 90%, which was achieved through improved sorting. This was accomplished by switching all hard plastic to the same type of Polypropylene (PP). An additional recycling scenario of 50% was considered because achieving a 90% recycling target might be difficult in the real world, given different working conditions at different construction sites. The results showed that even reaching a 50% recycling rate has significantly lesser impacts than the current scenario. Since PE was the major plastic type observed at the construction sites, it could be easier for suppliers to shift all hard plastic to PE instead of PP. Therefore the recycling scenarios were tested with PE and the results showed that the environmental impacts were close to PP.
- PostClimate impact from HVAC systems in the production and construction phase: A case study of two university buildings in Sweden(2023) Frendberg, Tobias; Wiksten, Kajsa; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Hollberg, AlexanderAs of today, the magnitude of the climate impact of the HVAC systems is currently uncertain as few detailed studies have been made on the subject. This study therefore intends to increase the knowledge regarding the climate impact of HVAC systems by calculating the climate impact of two university buildings in Sweden for life cycle phases A1-A5.1 and comparing the results to existing reference values. The results of the climate impact calculations are that the climate impact of Umeå Building is 30 kgCO2e/m2 Atemp, and Nya Konst is 31 kgCO2e/m2 Atemp. The result of the calculation of Umeå Building is based on Construction documents which makes for a sturdier foundation of the results while the result of Nya Konst is based on Project planning documents, that had less information available in them which makes the result more uncertain. The results also show that without a reference building to draw assumptions from when calculating the HVAC system with Project planning documents, it can be hard to achieve a high enough coverage rate to have a solid result. A hotspot analysis shows that by only calculating the six product groups with the largest climate impact for Umeå Building it would correspond to 81% of the total impact from the HVAC system and the calculations would be much quicker. The product groups not calculated could for example be accounted for with an add-on or by coverage rate. Several issues with performing this type of calculations are identified, such as the current lack of EPD´s, difficulties in processing the data provided through BIM-models and the time-consuming work of locating weights and material content for the products. It is therefore suggested that it would be preferable to update the BIM-models to include weight and material content of the HVAC products. This would make the calculations easier and faster to carry out. If also the availability of EPD´s increased, it would also be possible to increase the certainty of the results.
- PostComparison of the processes in Sweden and Demark for remediation of contaminated sites(2010) ROSÉN, STINA; Chalmers tekniska högskola / Institutionen för bygg- och miljöteknik; Chalmers University of Technology / Department of Civil and Environmental Engineering
- PostCONSTANT CHANGE - Exploring on site circulation of material through new building design(2017) Wilder, Ylva; Chalmers tekniska högskola / Institutionen för arkitektur; Chalmers University of Technology / Department of Architecture
- PostEnvironmental impact from space efficient dwellings - Can space efficient multi-family dwellings be beneficial to reduce the environmental impact from housing?(2017) BERGLUND, ASTRID; Cederbom, David; Chalmers tekniska högskola / Institutionen för bygg- och miljöteknik; Chalmers University of Technology / Department of Civil and Environmental EngineeringToday Sweden has a great housing shortage leading to a demand of 710 000 new dwellings until the year 2025. At the same time the Swedish climate targets is to reduce the greenhouse gas emissions with 40 percent until the year 2020 and with 85 % until the year 2050 compared to the emissions the year 1990. The aim of this study is to examine if space efficient dwellings can be a beneficial option for housing when aiming to reach Sweden's climate goal. The purpose of the study is to define space efficient housing and to investigate the environmental impact from space efficient multi-family dwellings in relation to average size multi-family dwellings. To do this a study investigating the size of newly built dwellings has ben made and a life cycle assessment of two conceptual dwellings has ben performed. Space efficiency can be defined as a ratio of square meters per resident. With this definition, space efficiency can be calculated with the measure total floor area (BTA) per resident. From this study the recommendation is that space efficient dwellings have total floor area per resident lower than 41,5 square meters. According to this study the average size dwelling had 23-109 percent higher emissions per resident compared to the space efficient dwelling depending on impact category. This is partly due to the more residents per heated area, the lower the emissions from energy use per resident. It can also be explained with the fact that more residents per total floor area leads to lower emissions per resident from construction materials due to lower material use per resident. The greenhouse gas emissions per resident is 18,3 percent lower for space efficient multi-family dwellings in comparison to average size multi-family dwellings. Space efficient dwellings can hence be one part of the solution to lower the emissions from housing in the aim to reach Sweden’s climate target.
- PostEnvironmental impact of retrofitting second homes: A case-study of the net global warming potential of different retrofit measures in a Swedish context(2023) Gutke, Julia; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Mjörnell, KristinaThe building and construction sector is responsible for a fifth of the greenhouse gases released by human activities, and retrofits are promoted by the IPCC as an effective way to reduce the energy consumption and hence environmental impact of buildings. Retrofits initially implies an increased environmental footprint associated to the addition of materials and activities that are then successively compensated by the expected savings in operational energy. For permanent housing this trade-off normally implies a decreased life cycle environmental impact, however this study focuses on second homes. What separates second homes from permanent housing is that they are used intermittently, typically during weekends or vacations, hence suggesting that the compensation for a footprint caused by a retrofit takes longer. This thesis compares the added environmental impact of three common retrofit measures to the reduced impact from the lower operational energy following each retrofit respectively. The analysis is performed on three different case houses in southern Sweden, and the studied measures are changing windows, addition of roofinsulation and installation of an air-sourced heat pump. The difference between the impact embodied in a retrofit measure and the reduced impact from operational savings is referred to as the net environmental impact. The findings suggest that it is not environmentally preferable to retrofit second homes, but rather to keep a low indoor temperature while not using the house if it can can be assured that this does not cause any risks or damages to the house.
- PostEnvironmental impacts of alternative water treatment strategies of process water from a herring processing plant(2020) Huyunh, Caroline; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Modin, OskarThroughout human existence, the oceans have been used as recipient for residues of man’s activities, which is still causing great environmental damages on the marine environment. Today, eutrophication of coastal areas is one of the most difficult environmental challenges humans are facing and the gradual increase of eutrophying emissions to the oceans shows the importance of creating and using sustainable solutions in order to mitigate as much emissions as possible. Hence, stricter legislations and requirements regarding wastewater treatment have been implemented as a strategy to reduce eutrophication. In Sweden, the Swedish herring company Scandic Pelagic AB (owned by the Danish company Skagen FF) have since the 1990’s rented part of the WWTP of the municipality in Orust, north of Göteborg for treatment of industrial wastewater. However, due to new emission requirements they are only allowed to use this solution until the end of 2021, meaning that Scandic Pelagic needs to find another solution for their wastewater treatment. The goal of this work was to compare the environmental impacts of the current wastewater treatment with a number of proposed alternative solutions using a life cycle assessment (LCA). The environmental categories global warming (kg CO2-eq) and eutrophication (kg N-eq) were considered. The goal was also to compare the removal efficiencies of organic matter and nutrients (BOD, N and P). The assessed alternatives are: Scandic Plagics’ current WWTP; pretreatment plant + mussel farm, using boat for transporting process water to mussel farm; pretreatment plant + mussel farm, using pipelines for transporting process water to mussel farm; pre-treatment plant + MBBR technology; pre-treatment plant + SBR technology; and pretreatment plant + SBR technology + surge tank. The results showed that the alternative pre-treatment plant + mussel farm (boat) has the highest global warming and eutrophication impact (132kg CO2-eq and 0.013kg N-eq) and the lowest contributor is pre-treatment plant + SBR (61kg CO2-eq resp 0.0016kg N-eq). Pre-treatment plant + MBBR was the highest emission contributor (89kg CO2-eq resp 0.024kg N-eq) among the assessed WWTPs mainly operated on land but has the highest nutrient reduction capacity. A correlation of the nutrient and organic removal efficiency levels and the environmental impact of the assessed alternatives could be observed. Since this work indicated that an increase of chemical, energy and material use generate a greater reduction of organic matter and nutrients in CHALMERS Architecture and Civil Engineering, Master Thesis ACEX30 process water. Based on this LCA study, pre-treatment plant + SBR should be implemented as a future solution by Scandic Pelagic since this is the most environmentally friendly treatment method and at the same time has sufficient organics removal.
- PostEnvironmental Risk Assessment of Fire-Water Runoff from Vehicle Fire - Development of a predictive model intended for the fire-rescue service(2019) Vilic, Azra; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik; Chalmers University of Technology / Department of Architecture and Civil Engineering
- PostEvaluating the environmental efficiency of passive climate change adaptation measures in the built environment: Exploring synergies between cooling energy reduction and environmental impact of passive climate adaptation retrofit measures in Gothenburg(2022) Egerlid, Hedda; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Thuvander, Liane; Xinyue, WangIn an increasingly warming climate with higher frequencies of heat waves and extreme heat, literature indicates that cooling will have increased relevance even in the Nordic climate. To ensure thermal comfort during summers and limit the use of electricity for air conditioning, climate adaptation in the form of passive cooling measures can be implemented. This study aims at evaluating the environmental efficiency of passive cooling measures that could be implemented in future renovations of the Swedish building stock, to illustrate how interdisciplinary assessments could aid in greenhouse gas emission reductions when considering climate change adaptation. A multi-family residential building built in the 1970s is used as a case study and the assessed measures include added insulation, improved glazing, added solar shading, improved solar reflectivity of façade material, and natural ventilation. The measures were assessed on their ability to reduce peak cooling demand, annual cooling demand, overheating hours and maximum temperature during peak conditions using an hourly energy simulation model, and the environmental impact of the measures was calculated based on material use. The study concludes that using natural ventilation is the most environmentally efficient passive cooling measure due to the devoid of environmental impact. However, to sustain thermal comfort in a future climate it could be beneficial to include complementary passive measures. Changing to triple glazing is the second most efficient in all aspects of thermal performance and has a similar environmental impact to the other assessed measures, and the option is consequently the next recommended measure, followed by the less environmentally efficient solar shading option. A combination of all measures is associated with the greatest cooling reduction potential; however, it poses a large trade-off in terms of environmental impact. The study illustrates that the inclusion of environmental impact when assessing climate adaptation measures is useful to provide guidance on GHG reduction when implementing climate change adaptation measures.
- PostFrameworks for sustainable development in the city of Gothenburg - A case study of sustainability frameworks and indicators within the area of the built environment(2020) Dahlgren Camacho, Carolina; Simonsen, Frida; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Holger, Wallbaum; Palme, UlrikaThe aim of this thesis was to examine the perceptions of using frameworks and indicators, such as Agenda 2030, for sustainable development within the area of the built environment, in the City of Gothenburg. The opinions of the interviewed stakeholders varied with regards to the need of using Agenda 2030 and the Sustainable Development Goals (SDGs) locally. Several interviewees meant that the municipality has an extensive amount of programs, and that Agenda 2030 should not be handled in a separate program. Therefore, it seemed to be preferred that the SDGs should be integrated in existing programs, or in financial control documents. Further, findings from literature showed that there is a lack of knowledge regarding sustainable development indicators (SDIs), and their impact on policy-making and to have better outcomes. However, a local adoption of Agenda 2030 requires adaptation of the global targets and indicators, to increase the relevance of the targets in local sustainability reporting and policy-making. All private companies included in this study were seen to have adopted Agenda 2030 for their operations. One of the reasons was by the authors suggested to depend on that organizations less complex than the municipal organization, face minor difficulties in the implementation, since they in comparison are less obliged to adopt the whole set of goals. Considering that studies have shown that the municipality already has strong steering towards sustainability, another implemented sustainability framework may be perceived as needless by politicians in the City Council and Committees. Conclusion regarding the research question, about defining the sustainable city, was that especially concrete targets and indicators are needed, else various actors involved with the built environment, will not follow the same desired path towards the sustainably built city. Furthermore, we the authors argue that SDG 11, in comparison to the national environmental quality goal 15 - god bebyggd miljö (a good built environment), better answer the question regarding the ’sustainably built city’. Furthermore, SDIs are needed as they provide guidance. There are some important things to consider when using indicators, such as that they are reflections of human values and never purely objective, that not everything is meaningful to measure, and that indicators purposed to assess sustainable development must be followed for a long time.
- PostHow is the composition of wastewater affected by variations in the environment? - A characterisation of organic matter, nitrogen, and phosphorus in the influent wastewater at Rya wastewater treatment plant in Gothenburg(2021) Rehnberg, Frida; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Modin, Oskar; Neth, MariaMore stringent future demands on effluent wastewater quality, together with changes in precipitation patterns due to climate change, make it increasingly important to understand how the composition of wastewater can be affected by environmental parameters. Organic matter, nitrogen, and phosphorus are the main pollutants wastewater treatment plants are built to remove. To ensure efficient removal, it is essential to know more about the speciation of these compounds. This study characterised the influent wastewater at Rya wastewater treatment plant in Gothenburg, mainly focusing on organic matter, but also including nitrogen and phosphorus in the analysis. The aim was to identify how the composition of wastewater is affected by external factors such as precipitation, water temperature, infiltration and inflow, and design of the sewer system (i.e. combined or separate sewers). The total COD concentration in the influent wastewater ranged between 310 – 620 mg COD/L during the sampling period. Approximately 85% was particulate COD, where 45% was slowly degradable COD, 31% inert particulate COD and 9% heterotrophic biomass. The colloidal COD corresponded to around 6%. Approximately 15% was defined as soluble COD, with 8% inert soluble and 7% readily degradable COD. The readily degradable COD consisted of 2% acetate and 5% other readily degradable COD. The results were compared with previous characterisations and variations in the results were discussed. Precipitation diluted the wastewater and caused a decrease in the concentrations of soluble fractions of organic matter, nitrogen, and phosphorus in the water. However, the particulate fractions increased with increased precipitation, probably since particles were transported with the infiltration and inflow. Gothenburg has a large share of combined sewers, which carry both stormwater and wastewater to the wastewater treatment plant. The results were, therefore, compared to a previous wastewater characterisation conducted in Linköping, which has a large share of separate sewers, to identify the impact of infiltration and inflow on the composition of the influent wastewater. Low volumes of infiltration and inflow found in separate sewers seem to result in lower concentrations of soluble inert organic matter and increasing concentrations of slowly degradable organic matter. Results from this study show that there are soluble fractions of nitrogen and phosphorus that are not removed to the same extent as other fractions in the treatment process but could be important to look into further with the increasing demands on treatment in the future. Current CHALMERS Architecture and Civil Engineering, Master’s Thesis ACEX30 III characterisations focus on fractioning organic matter, but future studies should include nitrogen and phosphorus to increase the knowledge on how specific fractions of these pollutants can affect treatment processes.
- PostLife cycle assessment of multi-family housing designed for flexibility -A study on the climate impact of flexibility and how to account for it in a life cycle assessment(2021) Moberg, Sandra; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Wallbaum, HolgerThe Swedish society is facing a challenge of reaching important climate targets while dealing with a shortage of housing. The building sector therefore has an imperative role to play. LCA (life cycle assessment) is a valuable tool that can guide design towards sustainability. Simultaneously, housing that lasts over time and is used fully can reduce climate impacts, making design for flexibility an important strategy. However, there exists knowledge gaps on the environmental impact of flexibility along with lack of procedures to quantitatively assess architectural design strategies that are hard to measure. This thesis explores the environmental performance of design for flexibility in housing with a life cycle perspective and considers how LCA can be used to evaluate it. The process consists of; a literature review, a qualitative assessment and lastly a case study comprising an LCA of a multi-family residential building, where a flexible case enabling increased longevity and space efficiency is compared to a reference case. The findings suggest that design for flexibility can provide essential meaning for sustainable building practice but that many benefits are scenario based. The case study reveals that a climate impact saving of 21-49 % is possible, depending on the methodological choices; functional unit, reference study period and scenarios. It is shown that commonly applied calculation methods need to be adapted to account for design for flexibility and results vary depending on it. A flexible building enables prolonging, ease of adaptations and using the long-lived parts of a building more, thus it can serve its purpose now and for a long unpredictable future.
- PostOptimized early-stage life cycle assessment of buildings -Developing a tool enabling early-stage parametric life cycle assessment(2021) Tjäder, Maria; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Hollberg, AlexanderIn the early stages of a building project, there is low quantity and quality of data regarding building materials while the ability to influence the environmental impact is high. Easy ways of assessing environmental impact of materials in these stages can make a big difference and shift buildings’ contribution to global warming towards a more sustainable track. The aim of the thesis project was to develop a parametric tool enabling earlystage Life Cycle Assessment (LCA) of buildings. The tool focus at guiding the user in lowering the embodied carbon from buildings by assessing building materials and building shapes. The tool also seeks to be educational about the climate impact from the production phase of buildings, and the intended user group is architects. The method of the thesis followed three steps: requirement definitions based on interviews and a tool and literature review tool development case studies for validation The interviews were a crucial step to inform the later tool development and to make sure the tool is usable by the intended target group. From the interviews it was found that important features of an early-stage LCA tool are to use national, generic data, show the results in a visual way and make it fast and easy to use. Additional results from the interviews are identified industry needs and challenges. The case studies included user tests and numerical tests. The developed tool fills most criteria set by the interviewees; however, further validation of the loadbearing concepts is asked for. The tool manages to balance a high level of detail and a user-friendly interface, and the calculated results are within a 15% accuracy. The thesis project shows that the integration of the users' needs and expectations from the very beginning of the development of assessment tools will ensure the tools’ applicability in the design process.
- PostRecovery Potential of Cotton Fibers from the Textile Products Using Circular Economy Strategies in Sweden(2018) AZIZ, MD TAREQ; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik; Chalmers University of Technology / Department of Architecture and Civil Engineering
- PostReducing the carbon footprint through reusing building materials: A case study of the Framtiden Byggutveckling residential building project Selma 2 Block 10(2022) Israelsson, Elin; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Johannison, Cecilia; Stenholm, TeresThe world is facing large scale climate and environmental challenges where the building sector accounts for a large share of the environmental impacts caused by material extraction, production, and use. In spite the fact that the built environment has major climate impact, a growing society demands an even more extensive building industry which in turn requires a radical development of sustainable building processes. Reuse of building materials can contribute to lowering the carbon footprints from buildings by using products several times in a closed loop. This thesis explores the possibilities and climate benefits from reusing building materials. Furthermore, it identifies possible trade-offs and challenges connected to the practice. The research process consists of a literature review and a case study of the residential building project Selma 2 Block 10. The case study includes interviews on reusable materials in Selma 2 Block 10 and LCA calculations comparing the carbon footprint from a reference case with the carbon footprints from three types of reuse cases. The findings suggest that there are possibilities to reuse building materials but also that there are several trade-offs and challenges connected to the practice, such as traditions, quality, and logistics. Moreover, the results from the LCA calculations in the case study suggest that the carbon footprint of Selma 2 Block 10 can be reduced by 76%.
- PostReuse of structural CLT elements: Assessing the impact of inter-element joint solutions on the reuse potential and environmental impact of a load-bearing wall panel(2022) Ljunge, Jonna; Nerhed Silfverhjelm, Helena; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wallbaum, Holger; Goto, YutakaThe construction sector is a significant contributor to many of our current environmental challenges. To make the sector more sustainable, it is important to increase the use of renewable materials and implement circular strategies such as the reuse of building components. For reuse to become practically possible, the elements of a building must be easily removable without causing them damage. The joints connecting the building elements are thus vital for enabling reuse. The aim of this study is to assess how the choice of inter-element joint solution affects the reuse potential and environmental impact of reusing a load-bearing CLT wall panel. A literature review is performed to analyse how joint solutions impact the reuse potential of a structural element. The limited amount of existing research on the topic was found to be too general to be of sufficient relevance for CLT construction, in addition to being inconsistent in including important factors determining reuse potential. A new framework for analysing reuse potential is therefore developed in which joint solutions for a CLT wall panel are categorised according to the direction of removal they enable and whether their removal causes damage to a panel. The reuse potential framework is further used as a basis for developing scenarios for reusing a wall panel over multiple cycles. Two types of reuse are distinguished between in the scenarios: reuse between buildings (disassembly) and reuse within a building (adaption), forming the basis of an LCA of the environmental impact of multiple cycles. By analysing the direction of removal and potential damage caused to a panel, it is found that common joint solutions for CLT wall panels offer a range of reuse potential when assessed individually. However, there is currently a lack of joint combinations that fully enable reuse of a wall panel both through disassembly and adaption. To ensure more flexibility in how a panel can be reused, it is necessary to opt for other, or develop existing, solutions to increase the overall reuse potential. Additionally, the choice of joint solution affects the number of possible reuse iterations (use cycles) which is a key factor in determining the potential environmental impact reduction of a reused panel compared to the corresponding linear pathway. The largest impact reductions are found in the intermediate use cycles, suggesting that joint solutions enabling many intermediate cycles might create the largest reuse incentive.