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Abstract

Substitution between energy and CO2 intensive materials is a potentially important climate mitigation strategy. We compare buildings with concrete frames and wooden frames concerning their life-time carbon dioxide emissions as well as their total material, energy and carbon dioxide costs. By using consistent energy systems scenarios meeting stringent targets for atmospheric CO2 concentrations we investigate the impact of higher energy and carbon dioxide prices as well as of the availability of carbon capture and storage (CCS) technologies. We find that wooden frames cause lower carbon dioxide emissions given the prevailing energy system, but concrete frames obtain about the same emissions as the wood frame in a system where CCS is not used for wood incineration in the demolishing phase. The net present costs for the different buildings are also affected by the future energy supply system, even though the impact is small, especially compared to the total construction cost. We conclude that it is unclear whether wood framed buildings will be a cost-effective carbon mitigation option and that further analyses of costs should be performed before prescriptive materials policies are enforced in the buildings sector.

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... They came to the conclusion that the timber building had a lower impact overall. Nässén et al. (2012) considered that the case for favouring timber over concrete as a construction material was more ambiguous. The methodology that they chose involved the evaluation of net present costs and carbon balances over the whole life of building structures with different material compositions. ...
... The energy costs for erecting and operating the buildings were not included since they were assumed to be independent of building type. In the study of Dodoo et al. (2009), recycling rates for timber and steel were assumed to be 90%, which was considered optimistic by Nässén et al. (2012) who assumed 80%. Building lifetimes were assumed to be 100 years and two scenarios were considered with construction years of 2010 and 2050. ...
... The associated GHG emissions (CO2 equivalents) of the concrete structure were 49% higher than those attributable to the wooden frame equivalent. Nässén et al. (2012) compared the whole life carbon emissions associated with buildings constructed using concrete or timber frames. The model assumed that the land used for providing timber for the timber framed house was replaced with new long-rotation forest for the future production of wood materials. ...
Technical Report
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The Norwegian Government has set ambitious goals for the fossil carbon intensiveness of the Norwegian economy. The built environment can make an important contribution towards achievingthose goals by:  Building energy efficient buildings;  Using low embodied energy materials;  Using construction materials as stores of atmospheric carbon dioxide. An analysis of life cycle assessment (LCA) studies published in the scientific literature has been undertaken. The use of timber in construction has an important role to play as part of an energy reduction and carbon storage strategy for the built environment. In the majority of studies analysed there is agreement that there are environmental advantages associated with the use of timber in construction from a climate change mitigation perspective. At the time of writing this report there is no LCA-based tool that is sophisticated enough to be used at the whole building level to assist in decision-making processes for materials to minimise environmental impacts. This can only be determined on a case-by-case basis. However, LCA can be used to inform policy decisions regarding the use of materials to minimise the climate change impacts of the built environment in Norway, if the GWP (global warming potential) impact category is used in combination with the embodied energy data. But the methodology does have inherent uncertainties. The original terms of reference for the report, were as follows:  General considerations on the different methods of environmental impact analysis and evaluations (LCA, EPD, HWP, BREEAM….) and what the differences are between these systems;  Conduct an analysis on wood LCAs that have been done in Norway and comparable countries, anda compilation of these data. Which factors influence the analysis and how much do single factors affect the result?  Conduct a similar analysis on competing materials like concrete and steel;  Conduct an analysis comparing the environmental impacts of wood and other materials. What is actually being compared and what does it imply for the real climate footprint?  Summarise the results, evaluation of their importance and the use such findings can have for political decisions in the future. The report begins with a description of the Norwegian built environment and forest products’ sectors and then gives an overview of the methodologies used in LCA and the strengths and weaknesses of the technique. LCA is a complex subject and there is still debate about the methodologies and impact categories. LCA does not have the level of accuracy needed in many impact categories in order to make comparative assessments and only the impact categories global warming potential and ozone layer depletion potential are considered to be sufficiently robust to give accurate and reliable data. A review of building assessment schemes has also been undertaken. LCA comprises only a minor part of building assessment schemes, such as the Building Research Establishment Environmental Assessment Method (BREEAM) and Leadership in Energy and Environmental Design (LEED) and these have little to say about the choice of materials for construction. These schemes have some value in promoting more environmentally-conscious designs, but they are not sufficiently robust to be used as tools to inform policy-making, or building material choices. The report focuses on issues surrounding carbon sequestration in forests and how atmospheric carbon can be stored in long-life products in the built environment. One of the advantages of using timber in construction is the potential for the storage of biogenic carbon (derived from atmospheric carbon dioxide) in long-life structures. Although this does have a role to play in climate change mitigation, this literature review has revealed that most studies show that the effects of substitution for high embodied energy materials and for fossil fuels for energy production are much more significant. The overwhelming majority of LCAs of timber products have shown that the amount of atmospheric carbon stored in the wood (measured as CO2 equivalents) is always larger than the GHG (greenhouse gas) emissions associated with the processing of the material. Additional benefits arise when the wood is incinerated at the end of the life cycle, with substitution of fossil fuels. The highest fossil fuel substitution benefits arise when coal is replaced with timber wastes/by-products. In a Norwegian context, the highest benefits will arise if wood is used as a fuel for cement kilns, or as a carbon-source for aluminium anodes, followed by a replacement of oil for heating then natural gas for heating or electricity production. This report also reviews the scientific literature of published LCA studies of commonly-used building materials (timber, cement/concrete, aluminium, steel, poly(vinyl chloride)). It is shown that the outcomes of the LCAs are very heavily dependent upon the assumptions made and the system boundaries used. It is not possible to arrive at definitive a value of (for example, global warming potential, GWP) that is characteristic for a material, but there is a range of values. The methodology used to determine the environmental impacts is complex and many studies are not readily amenable to comparative studies. This is because of differences in functional unit, supporting databases, assumptions regarding material life, maintenance, end-of-life scenarios, etc. In addition, most studies lack sufficient transparency to allow for proper verification of the results obtained. LCAs also inevitably contain simplifications, which may affect the accuracy of the data. Most studies do not employ a sensitivity analysis to show how the assumptions and variabilities affect the results. It is necessary to consider the whole life cycle when making materials choices and the only way to do this is at the whole building level. However, this increases the degree of uncertainty in the calculations and involves assumptions and the introduction of scenarios which may not be realistic or reasonable. A variety of factors can affect the LCA of building materials over their lifetime, which can be divided into uncertainties and variabilities. Uncertainties arise from lack of precise knowledge regarding processes or the use of assumptions. Variabilities can arise due to different choices regarding the use of materials, such as frequency and type of maintenance, different disposal methods, transport distances, etc. Combinations of uncertainty and variability can be difficult to separate. There is considerable scope for uncertainty to affect the data, especially when the in-service and end-of-life stages of the life cycle are included. Consequently, there is considerable variability in the methodology applied for LCAs, which has a significant influence on the output and hence the task of making comparative assertions is extremely difficult. However, there has been some degree of consensus reached with the introduction of environmental product declarations (EPDs) and standardisation of procedures; known as product category rules (PCRs). Nonetheless, there is still concern that inter-product comparisons are not reliable, due to uncertainties and variations in the assumptions made, the use of different databases, etc. The main advantage with EPDs which are produced in conformity with the European standard EN 15804, is that the impacts have to be reported separately for different life cycle stages. Of these, the cradle to factory gate life cycle stage (modules A1-A3) is likely to be the most reliable, since this part of the life cycle involves the least assumptions and the most accurate data. This study has largely focussed on data concerned with the embodied energy associated with materials and the global warming potential (GWP) environmental impact category, because these have the lowest uncertainties. GWP data is strongly influenced by the time-frames of the study and by a range of different factors that have to be taken into account when making comparative studies:  Greenhouse gas (GHG) emissions associated with the manufacture of construction materials, maintenance, replacement and disposal;  GHG emissions associated with operational energy requirements, if these are relevant and realistic and have not been introduced to favour one material over another;  Carbon emissions and storage from forestry operations and sequestration by growing biomass;  Substitution effects associated with the use of timber in comparison to other building materials;  End-of-life scenarios, such as recycling, or incineration with energy recovery. The embodied energy used to produce construction materials is an important consideration when analysing the environmental impacts. This initial embodied energy is to be distinguished from the recurring embodied energy which arises due to maintenance of the materials and the operating energy, which is energy consumed due to the operational requirements (e.g., heating) of the building. As the operating efficiency of buildings improves, the embodied energy will be a larger proportion of the overall energy requirements. The embodied energy also represents a greater proportion of the overall energy consumption of the sector in a growing market. Sawn timber products are lower embodied energy materials when compared, on a functional unit basis, with non-renewable construction products. The increased use of timber in construction will result in more carbon storage in the harvested wood products carbon pool at a critical time. This can form part of a wider strategy to move to a low fossil carbon economy. Although timber is the dominant material used in single-family dwellings, it is little used in multipleoccupancy buildings. The Norwegian forests are currently absorbing levels of carbon dioxide which are equivalent to about 40% of the annual emissions, but this will fall as the age structure of the forests matures. In order to maintain these high levels of sequestration it is necessary to increase the harvesting intensity of Norwegian forests. The carbon in the HWPs produced should be stored in long life products in the built environment for the maximum climate change mitigation effect. The use of timber in high-rise non-residential and multiple-occupancy residential construction would give benefits from a climate change mitigation perspective. The Norwegian forest products sector should use the opportunity provided by the increased use of timber in multi-occupancy and multi-storey buildings to develop an export industry in pre-fabricated structures. Adding value to the forest products sector is essential. By encouraging a cross laminated timber industry in Norway, there will be potential for export of multi-occupancy buildings using modular construction methods to exterior markets, such as the UK.
... Meanwhile, building energy consumption is projected to rise steadily as a result of the increasing population and people's increasing demand for household appliances and indoor comfort [5]. Thus, the evaluation in the current study of buildings' energy consumption is of vital importance [32]. The focus on green construction, alongside its energy conservation implications has drawn more and more attention worldwide [33]. ...
... Using bio-based building materials including straw bales can be an efficient method to achieve a low carbon footprint for buildings [58]. Compared with concrete and other conventional building materials, straw bales are fully renewable and sequester carbon throughout their life cycle, effectively locking carbon within the plant-based building materials [32,59]. The proper treatment of bio-carbon storage is critical to quantifying greenhouse gas emissions from bio-based materials. ...
Article
Full-text available
Over the past decade, the concept of a circular economy has increasingly gained attention as a framework for guiding businesses and policymakers. Given its significant environmental impact, the building industry plays a pivotal role in the transition toward a circular economy. To address this, our review proposes a bio-based building material, specifically straw bale, which elaborates on the circularity of bio-based buildings based on the 3R principles of a circular economy: reduce, reuse, and recycle. In terms of the “reduce” principle, straw-bale buildings can reduce construction waste, the environmental impact, energy requirements, and carbon emissions. Regarding the “reuse” principle, straw-bale buildings utilize agricultural waste resources and are easily disassembled due to their prefabrication. As for the “recycle” principle, straw-bale buildings can undergo physical, biological, and biochemical conversion processes (thermochemical conversion), yielding both wooden composite boards and potential biogas and biomass fuels for electricity and heating. This study evaluates the contribution of straw packaging construction and the use of straw as a raw material, using the 3R principles to determine future research opportunities for the construction industry to achieve a circular economy. The results of this study offer circular economy solutions and interdisciplinary research insights for researchers and practitioners interested in the building environment.
... More specifically, Saade et al. [35] presented the results of a systematic literature review of eleven case studies that ranked wood and concrete or steel framed buildings based on their sustainability performance; the study concluded that, in terms of climate change mitigation potential, wood-framed buildings performed better than concrete-framed buildings in all comparisons. However, Nässén et al. [36] highlighted the uncertainty of whether wood-framed buildings would be a cost-effective carbon mitigation option. Further, Cabeza et al. [37] came to the conclusion that most Life cycle assessments LCAs are performed in "exemplary buildings" that have been designed and constructed as low-energy buildings. ...
... In addition, the life cycle emission difference ranges from 30 to 130 kgC/m 2 of floor area [60]. The results of Dodoo et al. [61], Nässén et al. [36] and Yadav et al. [62] also confirmed that a wood-framed building has remarkably lower life-cycle carbon emissions than a concrete-framed building. The use of wood-based building materials can be of benefit to resource-efficient systems with a low environmental impact [31]. ...
Article
Full-text available
The European Commission adopted a long-term strategic vision aiming for climate neutrality by 2050. Lithuania ratified the Paris agreement, making a binding commitment to cut its 1990 baseline GHG emissions by 40% in all sectors of its economy by 2030. In Lithuania, the main construction material is cement, even though Lithuania has a strong wood-based industry and abundant timber resources. Despite this, approximately twenty percent of the annual roundwood production from Lithuanian forests is exported, as well as other final wood products that could be used in the local construction sector. To highlight the potential that timber frame construction holds for carbon sequestration efforts, timber and concrete buildings were directly compared and quantified in terms of sustainability across their production value chains. Here the concept of “exemplary buildings” was avoided, instead a “traditional building” design was opted for, and two- and five-floor public buildings were selected. In this study, eleven indicators were selected to compare the sustainability impacts of wood-based and concrete-based construction materials, using a decision support tool ToSIA (a tool for sustainability impact assessment). Findings revealed the potential of glue-laminated timber (GLT) frames as a more sustainable alternative to precast reinforced concrete (PRC) in the construction of public low-rise buildings in Lithuania, and they showed great promise in reducing emissions and increasing the sequestration of CO2. An analysis of environmental and social indicators shows that the replacement of PRC frames with GLT frames in the construction of low-rise public buildings would lead to reduced environmental impacts, alongside a range of positive social impacts.
... The choice of construction materials affects the building's environmental impact within the whole life cycle [14]. Studies from several countries show that wood materials used in building frames usually release less CO2 than other materials throughout the life cycle [15][16][17]. This is due to the relatively small amount of energy needed to manufacture wood products compared to other materials and the opportunity to replace fossil fuels with wood byproducts during the manufacturing process. ...
... Several methods of specifying the environmental impact exist. Generally, GWP is the main impact category assessed by many authors [2,[14][15][16][17][18][19][20]25,[27][28][29]33,35,36,42,[44][45][46][47][48][49][50]. Other environmental impacts are rarely discussed [16,27,33,35,46]. ...
Article
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The aim of the study is to point out the burden of passive wood-based buildings throughout the life cycle from the environmental point of view to better understand the consequences and importance of building design in Slovakia. The analysis was carried out according to the Life Cycle Assessment methodology. The results were calculated by the CML-IA baseline method. The impacts of the product stage and operational energy use were the highest throughout the considered life cycle. Substances contributing to eleven impact categories were identified. Foundations, especially foam glass, were found to bear the majority of the impact of the overall construction materials. The normalization category showed considerable impact on marine aquatic ecotoxicity mainly due to building energy consumption over the course of 50 years. Loads connected to the replacement stage were the third highest. The study also proved high demand on elements of photovoltaics.
... Several studies have shown that timber-based buildings generally have lower carbon footprint and lower energy consumption during their life cycle (i.e. lower embodied energy) than concrete buildings with comparable heating and cooling requirements [23]. Research on cradle-to-gate environmental performance has also confirmed very low values of carbon footprint and embodied energy for prefabricated TCC wall element [3]. ...
... • Timber part of TCC element represents storage for carbon, which was captured there during tree growth. In order to avoid release of the captured carbon in the atmosphere and consequential increase of carbon footprint it is important to apply available carbon capture and storage (CCS) technologies for timber incineration at the end of its lifetime [23]. ...
Chapter
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Timber-concrete composites are interesting engineered wood products usually used for structural elements, which are mainly subjected to bending load; from simple floor systems to long-span bridges. This way, the advantage can be taken of timber tensile strength and concrete compression strength. The chapter begins with an introduction of various types of timber-concrete composite structural elements regarding type of the element, connection type and types of timber and concrete. Next, specific characteristics and advantages of timber-concrete composite structural elements are thoroughly discussed from viewpoints of engineering, architecture, builders and ecology. Furthermore, basic mechanical principles of timber-concrete composite structural elements are presented and some design methods are briefly described. Finally, worldwide inclusion of timber-concrete composite structures in currently applicable standards is discussed.
... They provide quantitative data for a better comparison in the way of EC per functional unit of building materials or products [26]. Accordingly, suitable materials with lower EC impacts can be identified by analyzing the LCA information of alternative materials during material selection [22,27,28]. Table 1 summarizes EC reduction options associated with the selection of materials, followed by a brief description of each strategy. ...
... Previous studies have revealed that the use of natural and bio-based materials has a high EC reduction potential, mainly due to their simple and low energy production methods [27,28,30]. Natural products, such as wood, natural wool, bamboo, water-based paints, and hemp and straw-based products, have relatively low EC contents compared to other traditional materials [22]. ...
Article
Full-text available
The choice of materials is crucial in responding to the increasing embodied carbon (EC) impacts of buildings. Building professionals involved in material selection for construction projects have a vital role to play in this regard. This paper aimed to explore the extent to which building professionals in Sri Lanka considered EC as a material selection criterion. A questionnaire survey was conducted among a sample of building professionals in Sri Lanka. The results indicated that the consideration of EC as a material selection criterion remained low among key professionals, such as architects, engineers, and sustainability managers, despite their reasonable influencing powers and knowledge of EC. Those respondents who had considered EC as a selection criterion said they had been primarily driven by green building rating systems and previous experience. Those respondents who had not considered EC during material selection commonly reported that they had been prevented from doing so by the lack of regulations and the lack of alternative low carbon materials. Respondents believed that the involvement of actors, such as the government, professional bodies, environmental organizations, activist groups, and the public, may be significant in promoting the greater consideration of EC during material selection.
... One significant milestone in the global effort to combat climate change is the widespread declaration of carbon neutrality, or net-zero emissions, by around 130 countries, including the EU, the United States, and Japan, with some nations already enacting legislation to achieve this goal by 2050 [2,3]. Central to these initiatives is the promotion of green building materials, particularly wood, which is recognized for its renewability and environmental benefits [4,5]. However, the inherent combustibility of wood poses significant challenges in ensuring the safety and resilience of structures against fire hazards [6]. ...
Article
Full-text available
The increasing global commitment to carbon neutrality has propelled a heightened focus on sustainable construction materials, with wood emerging as pivotal due to its environmental benefits. This review explores the development and application of eco-friendly polymer nanocomposite coatings to enhance wood’s fire resistance, addressing a critical limitation in its widespread adoption. These nanocomposites demonstrate improved thermal stability and char formation properties by integrating nanoparticles, such as nano-clays, graphene oxide, and metal oxides, into biopolymer matrices. This significantly mitigates the flammability of wood substrates, creating a robust barrier against heat and oxygen. The review provides a comprehensive examination of these advanced coatings’ synthesis, characterization, and performance. By emphasizing recent innovations and outlining future research directions, this review underscores the potential of eco-friendly polymer nanocomposite coatings as next-generation fire retardants. This advancement supports the expanded utilization of wood in sustainable construction practices and aligns with global initiatives toward achieving carbon neutrality.
... Mass-timber building is constructed mainly of engineered wood, a composite wood product made by bonding layers or strands of wood fibers. A mass-timber building can reduce emissions from the construction sector because wood has a lower carbon footprint than steel and concrete (Nässén et al. 2012;Ryberg et al. 2021;Konnerth et al. 2016). ...
Preprint
Full-text available
The construction sector can significantly reduce carbon emissions by decreasing cement usage, which accounts for 9-10% of global energy related CO2 emissions. To address this, this study explores alternative materials: mass-timber and low-carbon cement due to expected urbanization with increasing cement demand. However, the potential emission reduction and cost-saving prospects at the city scale remain uncertain. Here, this paper creates future scenarios and compares mass-timber and low-carbon cement in terms of carbon mitigation and cost savings. Results indicate that mass-timber buildings offer net-negative emissions and cost savings compared to conventional concrete-frame buildings. While low-carbon concrete buildings can achieve net-negative emissions, they require a cost increase. Both alternative building materials reduce emissions by ~80.4% at a city-wide scale, with mass-timber buildings emerging as the superior choice due to environmental and economic factors.
... In addition, note that many elements can be reused for engineering, architecture, or other elements, which would bring significant savings in energy and CO 2 emissions (Bergman et al., 2014). Compared to traditional construction, timber construction is not only limited to being a natural carbon reservoir, but timber buildings are also less polluted (Nässén et al., 2012). In addition, studies also indicate that wood-based wall systems account for 10-20% less embodied energy than traditional concrete systems (Santi et al., 2016). ...
Preprint
Full-text available
In recent years, wood has gained important significance in construction, with several developments and research conducted. Despite this, some species show scarce dedicated research on the mechanical behavior and data about material parameters is limited. Timber exhibits variable mechanical properties influenced by several factors. Particularly, when subjected to certain stress states, wood tends to display a quasi-brittle behavior, which is noticeable in structural elements like trusses or beams. Identifying fracture strength parameters then becomes crucial for accurately predicting structural behavior. This paper introduces the application of a methodology to characterize fracture strength in Chilean radiata pine by finite element simulations. Utilizing phenomenolog-ical models developed for composite materials and implemented in the commercial finite element software Ansys, a methodology to fit strength parameters based on techniques such as Design of Experiments and Optimization algorithms is applied. Subsequently, and to validate the methodology , numerical predictions are compared with experimental results from tensile, three-point, and four-point bending tests. In the simulations, the finite element is deactivated after reaching the failure criterion, reducing the overall stiffness of the structure. The results, employing the obtained parameters, align closely with experimental findings, demonstrating the adequacy of the proposed framework. This methodology offers a robust approach to accurately determine material parameters, even in scenarios with incomplete or scattered material data, ensuring reliable characterization.
... This is due to timber's appreciable mechanical strength both in compression and in tension, which makes it an excellent competitor even for modern steel or reinforced concrete structures. Timber is also characterized by natural hygroscopicity, high thermal inertia, and low conductivity, therefore contributing to environmental comfort [8,9]. Owing to these positive issues, the wood industry is constantly expanding in Europe. ...
Article
Full-text available
The construction sector is currently responsible for over 30% of the consumption of natural resources and the release of solid waste and pollution into the environment. This situation is even more serious in closed communities such as islands, economically highly dependent on the outside world. One of the possible interventions to reverse this trend is the use of eco-sustainable construction materials such as wood, produced through supply chains with a low environmental impact. This paper reports on a research activity that analyzed the feasibility of implementing a sustainable local supply chain in Sardinia to produce Cross-Laminated Timber (CLT) panels made of locally grown wood. This research has experimentally carried out the entire supply chain process: (i) choice and collection of the raw material in the forest for producing strength-graded boards to manufacture laminated timber, (ii) manufacturing of CLT panel prototypes, and (iii) determination of CLT panels’ mechanical performance through laboratory tests. This experimentation allowed, on the one hand, to evaluate the performance and competitiveness of CLT panels made of local wood, and on the other hand, to identify the criticalities that currently hinder the implementation of this supply chain in Sardinia, and to propose possible actions to solve them.
... Therefore, the use of naturally occurring materials such as wood and bamboo looks promising in designing climate-smart houses. Several comparative studies between wood-frame, concrete, and steel frame buildings in different parts of the world have reported that wood-frame buildings have much lower energy use and carbon emission than the other building materials 26,27 . Similarly, another study in different climatic zones of India revealed that vernacular dwellings exhibit higher resilience in response to climate change compared to modernized dwellings 28 . ...
Article
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The present study describes the ethnobotanical knowledge and socio-ecological significance of the vernacular architecture of local house construction styles of Adi, one of the major ethnic communities inhabiting Upper Siang district of Arunachal Pradesh. The community uses 21 plant species belonging to 15 genera and 12 families in vernacular architecture constructed as per local needs and traditions, exhibiting native designs. The community possesses significant traditional knowledge and skills regarding the utilization of species in vernacular architecture. The houses capitalize on the availability of resources close to the construction site and fulfill basic community needs, values, economies, and ways of life as per local cultures. The study recommends that the vernacular architecture of Adi community is best suited to the local environment, climate, and culture; and therefore, needs to be preserved along with sustainable management and conservation of the plant resources used. Further multidisciplinary research is required to capture the overall significance of these vernacular architectures in terms of raw materials, structural designs, and environmental suitability and sustainability.
... In addition, most methods still exhibit shortcomings in terms of application convenience and cost. The cement-based materials can capture CO 2 from the atmosphere during the hydration reaction [9,10], and thus their application potentials in CO 2 sequestration have gradually attracted great attention [11][12][13]. Pure cement materials, such as cement and concrete, can sequester CO 2 but not cost-efficiently. ...
Article
Full-text available
Using solid waste to sequester carbon dioxide not only reduces the greenhouse effect but also reuses resources. However, the existing solidified carbon dioxide storage materials are expensive and have poor storage effect. Therefore, in this study, cement, solid waste base material, and 30% hydrogen peroxide were used to make foamed concrete materials through chemical foaming, and XRD, BET, SEM, and thermogravimetric techniques were used to explore the amount of carbon dioxide adsorbed by foamed concrete materials under different ratio conditions. The results show that (1) the hydration products of the cementified materials mainly include C-S-H, Ht and Ca(OH)2, which are important factors for the storage of CO2. (2) A water–cement ratio of 0.7 and a foaming agent dosage of 10% are the best ratios for foamed concrete materials. With the increase of the water–cement ratio and the dosage of the foaming agent, the amount of CO2-sealed stock first increases and then decreases. (3) The maximum carbon dioxide sealing capacity of foamed concrete material is 66.35 kg/m3.
... There are few materials that can match wood in terms of environmental benefits [2]. Thus, wood plays an important role in future buildings to reduce global energy-related CO 2 emissions from the building industry by replacing steel and concrete [3][4][5][6][7][8]. Cross-laminated timber is a sustainable product made with several layers of lumber boards stacked in alternating directions, most often with an odd number of layers and usually between three to seven layers [1,9]. ...
Article
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Buildings constructed with cross-laminated timber (CLT) are increasing in interest in several countries. Since CLT is a sustainable product, it can help the building industry to reduce greenhouse gas emissions. Furthermore, buildings constructed with CLT are increasing in building height, thereby increasing the load on the junctions and structural building elements further down in the building. Several studies have investigated how the load impacts the sound transmission between apartments. The majority found that an increasing load could have a negative effect on the vertical sound insulation. However, the findings are limited to a few measurements or building elements, and the studies only investigate junctions with resilient interlayers. This article aims to investigate if the building height, and thereby the load, affect the vertical airborne sound insulation between apartments on different stories in different cross-laminated timber buildings, with or without the presence of viscoelastic interlayers, and to quantify the effect. Four CLT buildings with different building systems, building heights, and the presence of viscoelastic interlayers in the junctions were measured. The airborne sound insulation between different apartment rooms was measured vertically for stories on the lower and higher levels. The difference in airborne sound insulation was calculated separately for each building, and the measurements indicate that the vertical airborne sound insulation reduces further down in the buildings. Therefore, results show that increasing load, by an increasing number of stories, has a negative effect on the vertical airborne sound insulation.
... From a purely energy-centric point of view, many authors criticized the feasibility of using biomass in general as a source of energy [74], touted to be CO 2 -neutral and renewable, but also suffering from limitations that restrict its potential in supplanting the role currently fulfilled by crude oil and natural gas. Because of this, authors point to the fact that the usage of lignocellulosic biomass as building materials may be a more sustainable and less CO 2 -intense [75] application. From this perspective, lignin derived from pulping streams occupies a specially interesting spot due to its unique structure composed of aromatic units and the fact that it is potentially available in large quantities as side-streams of already economically feasible processes. ...
Article
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The consumption of fossil fuels is one of the main drivers of climate change. Lignin derived from biomass is a carbon-neutral raw feedstock, and its conversion into fuels is gaining much attention. The gasification of biomass aims to transform heterogeneous feedstocks into syngas and heat that could be used for various purposes. Lignin is a biomass feedstock of special interest due to its particular properties and its ability to be obtained in abundant quantities as a side product from the paper pulp industry as well as the growing cellulosic ethanol industry. This review explores the existing works regarding lignin gasification from different perspectives and compares the results obtained with other existing thermochemical processes, in addition to providing a perspective on the long-term fate of gasification as a technology compared to other emerging technologies. The analysis indicates that while lignin gasification may grow in importance in the near future due to increased interest in hydrogen production, its potential in emerging applications indicates that lignin may be too valuable to be used purely for energy generation purposes, and applications that take advantage of its inherent chemical compounds are expected to take priority in the long-term.
... In response to the environmental problems of global warming, the need to save energy and carbon emissions, the energy usage in the building sector accounts for 40% of global energy consumption, and its greenhouse gas emissions account for more than three-thirds of its global emissions. In this study, the energy consumption differences between building material used were examined, and the method follow the previous researches which indicated the benefit of applying wood as building materials [1,2,3,4]. A typical research building located in Taipei, Taiwan as an example for many similar cases was selected for simulation. ...
Conference Paper
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In response to the environmental problems of global warming, the need to save energy and carbon emissions, the energy usage in the building sector accounts for 40% of global energy consumption, and its greenhouse gas emissions account for more than three-thirds of its global emissions. In this study, the energy consumption differences between building material used were examined. A typical research building located in Taipei, Taiwan as an example for many similar cases was selected for simulation. Through building a simulating model in MIDAS and replacing partials of reinforced concrete with wood, it was able to compare the difference of energy consumption between wood and reinforced concrete. Considering Taiwan is an island located at the Pacific Rim Seismic Belt with frequent earthquakes, our project not only aims to reduce energy consumption, but also the building weight. Simulation method was used to compare the energy efficiency between the existing building and three other variations including: A. Drywall partitions replaced with wood, B. All levels of reinforced concrete floor slabs replaced with wood, and C. The upper four levels of structure completely replaced with wood. And two major study objectives were focused in this study, the difference of building weight by replacing original concrete building into partial wood building, and the difference of the energy consumption un these buildings. The simulation results showed that by replacing all non-structural walls with wood can help reduce the building's weight, Co2 emission without a drastic increase in budget and therefore would be preferable as a common methodology in Taiwan's future.
... The materials selected are mainly used as prefabricated wall panels and do not function as columns or beams. There is widespread agreement in literature that wood and mass timber have lower environmental emissions than steel and concrete (Nässén et al., 2012;Balasbaneh et al., 2018;Walbech et al., 2021;Konnerth et al., 2016). Therefore, this study focuses on evaluating three different engineering wood products to reveal which is the most sustainable choice. ...
Article
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The construction industry is one of the largest consumers of energy and materials, which leads to it being one of the highest sources of environmental emissions. Quantifying the impact of building materials is critical if strategies for mitigating environmental deterioration are to be developed. The lifecycle assessment (LCA) consequential methodology has been applied to evaluate different methods of constructing residential double-story buildings. The ReCiPe methodology has been used for life cycle inventory. Three different forms of mass timber construction have been considered including cross-laminated timber (CLT), nail-laminated timber (NLT), and dowel-laminated timber (DLT). These have been assessed as load-bearing panels or wood frame construction. We evaluated the global warming potential (GWP), embodied energy, and cost to identify the building type with the lowest impacts. The results revealed that total CO2 emissions for mass timbers for the construction stage are 130 CO2/M², 118 CO2/M², and 132 CO2/M² of the panel for CLT, DLT, and NLT, respectively. The embodied energy emission is 1921 MJ/M², 1902 MJ/M², and 2130 MJ/M² related to the CLT, DLT, and NLT, respectively, for this stage. The results also indicated that the carbon emission of DLT is lowest compared to the other two alternatives in the manufacturing and construction stages. However, when the entire life cycle is considered, NLT is the most favorable material. However, based on the life cycle cost (LCC), DLT has a lower cost. Finally, multiple-criteria decision-making (MCDM) was used to normalize the results and compare the alternatives. This showed DLT to be the best alternative, followed by CLT and NLT. In conclusion, the selection of building materials needs to prioritize regulations to reduce environmental and economic impacts.
... This reinforced concrete material is one of a large share of global emissions [1]. The process of wood processing from raw materials to production or the cradle-to-gate process produces lower CO2 emissions compared to concrete, steel, or brick constructions [2][3][4][5]. Therefore, building structural materials with wood materials should be introduced in Indonesia to overcome these CO2 emission issue. ...
Article
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Laminated Veneer Lumber (LVL) is one of the engineered wood products consisting of wood veneers that are glued and pressed together. In this study, the behavior of LVL Sengon slender beam is numerically investigated by means of nonlinear finite element analysis (FEA), where only half of the experimental beam was modeled due to symmetry of the load configuration. The LVL Sengon wood material used Hill failure criterion with isotropic hardening rules, and its mechanical properties in both tension and compression are modelled according to its mechanical properties in tension obtained from the clear specimen test. The contact analysis is defined for each contacting and contacted elements. The FEA results well agreed with the experimental results in term of the load-deflection curve and failure mode of the beam. It is found that the lateral support has no effect on the stiffness of the beam. The beam stiffness and ultimate load increase by the increase of beam height-to-width ratio (𝑑/𝑏).
... These limitations cause uncertainty about the embodied carbon results for the roofing. They also lead to uncertainty about the reliability of comparative assessments of the embodied carbon effects of different design options [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. ...
... Considerable previous research indicates that wood is an ideal choice for building construction compared to steel or concrete. This is because of its lower carbon and environmental emissions (Glover et al. 2002;Hill and Dibdiakova 2016;Nässén et al. 2012b). Some research emphasizes the importance of increasing the quota of wood in a building. ...
Article
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Purpose The construction sector is interested in considering environmental implications as necessary criteria for sustainability. In this regard, wood materials, especially engineering wood, are a promising choice for sustainable buildings. In some countries such as Malaysia, timber is rarely considered in the construction sector despite there being abundant access to wood. This is because of the scarcity of timber structures and the dominance of alternative materials such as steel and concrete. The cross-laminated timber-steel composite introduced in this research benefits both the wood and the steel markets leading to standardization and a more extensive market. At the same time, it contributes to environmentally friendly requirements. The main objective was to investigate timber applications in local construction and make proposals for its promotion. The new specimen described here could potentially enhance the strength of timber beams using steel plates. Four current structural methods have been chosen based on environmental and economic comparisons with a new composite structure. Methods The life cycle assessment (LCA) and life cycle cost (LCC) have been used to compare the performance of four current conventional structures. Results and discussion The results showed that the new proposed structure has lower emissions in all environmental categories, namely, Global Warming Potential (GWP), Human Carcinogenic Toxicity (HCT), Fossil Depletion Potential (FDP), Ozone Layer Depletion (OLD), Terrestrial Acidification (TA) and embodied energy. The results of the LCC are consistent with the environmental issue as the new composite has a lower cost over its entire life span. Conclusions The new structure provides a novel and sustainable alternative for the construction industry.
... Historically, wood has performed well in a wide range of climate conditions. Moreover, comparing to most other construction materials (e.g., concrete and steel), wood is more environmental friendly because of its less CO 2 emission (Nässén et al. 2012) and less embodied energy (Glover et al. 2002). Due to the need in the prefabrication process, offsite construction has more rigorous requirements in terms of design and planning (Alwisy et al. 2019) than those of onsite construction. ...
... Furthermore, CO 2 emissions can be significantly reduced by replacing Portland cement with geopolymers such as slag and fly ash [7,20]. The production of traditional concrete and particularly Portland cement is a significant contributor to global greenhouse gas emissions [59,60]. Considering current global climate debates and continuing population growth related to an inevitable increase in demand for concrete [20,61], it is of global significance to find a more sustainable alternative to replace traditional concrete in the building and construction sector. ...
Article
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Using fibre-reinforced polymers (FRP) in construction avoids corrosion issues associated with the use of traditional steel reinforcement, while seawater and sea sand concrete (SWSSC) reduces environmental issues and resource shortages caused by the production of traditional concrete. The paper gives an overview of the current research on the bond performance between FRP tube and concrete with particular focus on SWSSC. The review follows a thematic broad-to-narrow approach. It reflects on the current research around the significance and application of FRP and SWSSC and discusses important issues around the bond strength and cyclic behaviour of tubular composites. A review of recent studies of bond strength between FRP and concrete and steel and concrete under static or cyclic loading using pushout tests is presented. In addition, the influence of different parameters on the pushout test results are summarised. Finally, recommendations for future studies are proposed.
... Therefore, a life cycle approach is important to assess the environmental performance of buildings. Studies from several countries have shown that wood materials used in building frames usually use less energy and release less CO2 than other materials throughout the life cycle (Gustavsson, et al., 2006;Gerilla, et al., 2007;Upton, et al., 2008;Dodoo, et al., 2009;Blengini and Di Carlo, 2010;Bribián, et al., 2011;Nässén, et al., 2012;Tettey, et al., 2014;Peñaloza, et al., 2016;Kovacic, et al., 2018;Pittau, et al., 2018). This is due to the relatively small amount of energy needed to manufacture wood products compared to other materials and the opportunity to replace fossil fuels with wood by-products during the manufacturing process. ...
Article
The building sector has a significant impact on the environment, accounting for 36% of CO2 emissions and about half of material consumption in Europe. Residential buildings dominate the European building stock. In Finland, residential buildings account for up to 80% of the existing buildings and the rate of construction is higher compared to other building types. Therefore, residential buildings play an important role in the transition to a sustainable built environment. A number of studies show that increasing the use of wood can lower the life cycle environmental impacts of buildings. In Scandinavia, the use of wood in small houses is well established, used in 90% of cases. Furthermore, the increasing number of high-rise wooden buildings suggests a growing interest in the potential of wood in large-scale buildings. Green building certification provides criteria to assess the sustainability level of buildings and is expected to influence the building sector in the near future, by promoting the use of sustainable technologies. The aim of this study was to investigate how green building certification schemes assess wood materials and how wood materials can help fulfil sustainability criteria for green buildings. We analyse the sustainability criteria adopted by the most common certification schemes in Finland, BREEAM, LEED and the Nordic Swan Ecolabel, as well as the upcoming Level(s) certification promoted by the European Commission. The analysis shows that the contribution of wood materials to the overall score of green building certifications accounts for between 10 and 36%. Wood is advantageous as a renewable and low-carbon material. Furthermore, wood can offer indirect benefits due to its recycling potential and to water saving in the construction stage. However, wood materials have to comply with some requirements, such as sustainable forest management and low volatile organic compound content. The new European certification suggests a comprehensive assessment including circular material life cycles.
... Buildings using steel and concrete contain and consume 12-and 20% more energy, respectively than wooden buildings [27]. Moreover, products made from sustainably sourced wood replace other fossil-intensive substitutes, like concrete and steel [54][55][56][57][58][59]. ...
Chapter
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This chapter examined the various stages and benefits of wooden extra stories from the perspective of Finnish housing and real estate companies through interviews with professionals involved in these projects. Key findings highlighted are as follows: (1) in the feasibility study, project planning primarily focuses on property condition and potential improvement targets as well as other considerations, for example, compliance with current regulations and parking arrangements; (2) in the project planning, application of extra stories is thoroughly examined, and construction costs, profits, and the sale of building rights are discussed; (3) in implementation planning, issues related to building rights, city plan change, and conditions of the company that manages the property play an important role; and (4) during construction, frequent information updates are made to residents regarding the site arrangements and the construction program. Wooden extra floor construction, which requires commitment, investment, and cooperation among the interested parties, has great potential in construction technology, contracting mechanisms, and ecological engineering solutions. It is believed that this chapter will increase the dissemination of wooden extra stories, thus contributing to the greater use of more sustainable materials in renovation projects and the ecologically sensitive engineering approaches to meet the challenges arising from climate change.
... 46). This suggestion is supported by findings in the literature [13][14][15][16]. ...
Article
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The concept of the bioeconomy is associated with sustainable development changes and involves transitions in both production and consumption within systems. Many of these transitions relate to using renewable resources, like forest biomass, to meet basic needs, such as food, energy and housing. However, consumers must become aware of the forest-based bioeconomy so that they can contribute to the transition. This study aims to contribute to an understanding of this matter that may lead to social acceptance of the forest-based bioeconomy and, in particular, to Swedish consumer awareness of the concept and of a particular product (wooden multi-story buildings) representing the forest-based bioeconomy. The results show consumer awareness of forest sequestration capacity but less awareness of the connection to the forest-based bioeconomy and the role of wooden multi-story buildings. The results indicate a slow transition that is hindered by path dependence and limited comprehension among consumers of the effects of their choices for a forest-based bioeconomy. This study provides valuable insights for future studies of how consumer awareness and social acceptance of the forest-based bioeconomy are interconnected.
... Dimoudia and Tompa [88] stated that the highest EE values belong to concrete and reinforcing steel, representing about 59% to 66% of the total EE of a studied building. Wood-based materials have much lower EE values compared to conventional materials, such as concrete and steel, making them a more sustainable and low-carbon construction alternative [89][90][91]. According to Buchanan and Levine, this is due to the fact that the manufacturing process for wood-based materials is much less energy-intensive than that for other construction materials. ...
Article
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The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future.
... Greater losses of carbohydrates were observed with birch than with pine even at a slightly lower temperature during thermal modification in open systems (Zaman et al., 2000). The formation of soluble xylose-rich carbohydrates during thermal modification was greater in closed systems saturated with steam than in an open system (Karlsson et al., 2012). The degradation of wood polymers leads to shrinkage of the wood cell wall and, thus, to the dimensions of the wood and a small reduction in wood density occurs when degraded materials are removed during the heating. ...
... Further, at the end of their lifetime, wood building products generally need to be used to create bioenergy that displaces fossil-fuel energy sources, which provides a further impetus to their displacement benefit [45]. A study by Nässén et al. [46] even suggested that wood-based buildings would only be of benefit when the bioenergy produced from the endof-life products was generated with carbon capture and storage technology capabilities. ...
Article
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Background There are high estimates of the potential climate change mitigation opportunity of using wood products. A significant part of those estimates depends on long-lived wood products in the construction sector replacing concrete, steel, and other non-renewable goods. Often the climate change mitigation benefits of this substitution are presented and quantified in the form of displacement factors. A displacement factor is numerically quantified as the reduction in emissions achieved per unit of wood used, representing the efficiency of biomass in decreasing greenhouse gas emissions. The substitution benefit for a given wood use scenario is then represented as the estimated change in emissions from baseline in a study’s modelling framework. The purpose of this review is to identify and assess the central economic and technical assumptions underlying forest carbon accounting and life cycle assessments that use displacement factors or similar simple methods. Main text Four assumptions in the way displacement factors are employed are analyzed: (1) changes in harvest or production rates will lead to a corresponding change in consumption of wood products, (2) wood building products are substitutable for concrete and steel, (3) the same mix of products could be produced from increased harvest rates, and (4) there are no market responses to increased wood use. Conclusions After outlining these assumptions, we conclude suggesting that many studies assessing forest management or products for climate change mitigation depend on a suite of assumptions that the literature either does not support or only partially supports. Therefore, we encourage the research community to develop a more sophisticated model of the building sectors and their products. In the meantime, recognizing these assumptions has allowed us to identify some structural, production, and policy-based changes to the construction industry that could help realize the climate change mitigation potential of wood products.
... This solution uses a dry technique to form composite cross-sections, which is preferred for timber floors of historical or cultural interest [2,4]. Furthermore, it is also recognized in the scientific community that structures constructed from renewable bio-based construction materials such as timber have lower GHG emissions compared to structures made of concrete, steel or bricks [5][6][7][8][9]. Renewable bio-based construction materials have the potential to act as carbon sinks in the renovation of existing buildings [10]. ...
Article
A common occurrence in building renovation is the modification in the usage category that can lead to higher imposed loads, and consequently the need for structural improvements to the existing structure or to a structural element, such as timber floors. Strengthening practices oftentimes affect the originality of the building or a structural element under consideration. However, the preservation of the originality of timber floors having historical, architectural and cultural interest can be of high importance. This article provides insight into the field of timber floor strengthening techniques with regards to the requirements for conservation of the wooden built heritage. Moreover, a new strengthening technique using structural glass as a strengthening element for timber floors is presented, as reinforcing the bottom side of timber floors without compromising the appearance of the floor is an important objective of a successful intervention. In order to evaluate the performance of the newly proposed strengthening technique from a structural and environmental point of view, structural analysis and a life cycle assessment on a timber floor strengthened with cross-laminated timber panels and structural glass strips are performed. The structural analysis shows the possibility to use structural glass and still achieve a significant increase in the load-carrying capacity of the timber floor. Furthermore, the proposed strengthening technique has a lower global warming potential (GWP) and non-renewable cumulative energy demand compared to renovation and replacement with a cross-laminated timber panel, and a lower GWP compared to replacement with a reinforced concrete slab. This study not only represents the first holistic approach to evaluate the structural and environmental performance of the proposed strengthening technique, but it also addresses the aesthetically-aware design and technical limitations in the utilization of glass for the renovation of timber floors and thoroughly presents the possibilities to overcome these limitations.
... The advantages of wood in construction are various [2,3]. Wood is a material characterized by good mechanical strength both in tension and in compression, so it can be used for the manufacturing of elements prone to bending such as beams, compressed like the pillars, stretched like tie rods, without the need to combine it with other materials, unlike for example concrete and masonry. ...
Book
The construction sector alone accounts for 40 percent of resource consumption and environmental pollution. In line with the current considerations on environmental sustainability, particular attention is paid to eco-sustainable building materials such as timber. Timber is able to perform both load-bearing and comfort constructive functions. It is also a natural, renewable and recyclable material. However, its use as an engineering material calls for constant development and research. This book provides insight into the spread of the use of timber in the construction industry, presenting some thoughts on important aspects related to production, design and responsible use.
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This study addresses the acceptance of timber in building design and construction within Enugu state. The research aims to evaluate the current level of acceptability and identify factors influencing perceptions towards timber usage. Objectives include assessing prevailing attitudes, examining structural considerations, and proposing strategies to enhance the integration of timber in construction, ensuring safety, sustainability, and regulatory compliance. To achieve the aim and objectives, the study adopted a descriptive survey where the opinions of 982 respondents comprising the clients, consultants and end users were sought. The study found that timber is not a well-accepted material in the design and construction of buildings in Enugu State. The reason for the non-acceptance of timber as a sustainable material in the building delivery process in Enugu State are due to the lack of government and non-governmental programmes promoting the use of wooden construction among others in Enugu. The study concludes by stating that timber as a building material possesses qualities and performs better when compared with most other common building materials. The study recommends that there should be proper government and non-governmental programmes promoting the use of timber construction in Enugu State. This will grow the confidence of people and encourage them to invest in its usage.
Chapter
In China’s construction market, most existing buildings have high energy consumption and significant carbon emissions. This paper selects an office building in hot summer and cold winter areas for energy-saving transformation from high energy consumption to an ultra-low energy consumption building. By calculating carbon emissions in the transformation process stage by Yike Efootprint software, the building life cycle model is divided into an envelope Air tightness system, fresh air system, energy system, and door and window system. The five primary methods are described, energy input, energy consumption, pollutant output, process boundary, quantity used, upstream process traceability, sensitivity analysis. The materials and data are collected, analyzed, and calculated. The CLCD database is mainly used as the database, and some data are obtained from Ecoinvent. The CUT-OFF principle shall be used to reserve the materials with a significant weight proportion and high importance, and the materials with a weight less than 1% or with low significance and low material consumption shall be ignored. So we can get the critical influencing factors of carbon emissions in the transformation stage. By analyzing the influencing factors, we can provide some perfect suggestions for the energy-saving reconstruction of buildings. This paper uses LCA for modeling, calculation and analysis, data quality evaluation, and result output. So as to calculate the carbon emissions and effective recovery period of energy consumption from an ultra-low energy consumption building to a zero energy consumption building, it is proved that the carbon emissions in the transformation process can be recovered quickly through the energy-saving transformation of ultra-low energy consumption buildings. Ultra-low energy consumption buildings and zero energy consumption buildings will play a significant role in the development of China’s construction industry. It also provides more theoretical, and data support for developing zero-energy consumption buildings in China.
Conference Paper
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In response to the environmental problems of global warming, the need to save energy and carbon emissions, the energy usage in building sector accounts for 40% of global energy consumption, and its greenhouse gas emissions account for more than three-thirds of its global emissions. It is the largest source of emissions in most countries. However, previous research has mostly focused on comparing the energy-saving efficiency between wooden and RC structures in high-latitude regions, energy-saving efficiency between wooden and RC structures in low-latitude regions, especially in subtropical or tropical area in Asia, has not been focused. In this study, in order to examine the energy consumption differences in sub-tropic and tropic area, the energy consumptions in Taipei, Kaohsiung, Hochimin City and Singapore were compared. Moreover, considering the common-used construction materials in buildings in the selected Asian cities, hybrid structure system comprises RC beams/columns and various floors and walls system such as brick, wood and so on was used for the comparison. Simulation method was used to compare the energy efficiency of the four-story and ten-story wooden structures, RC structures, and other types of hybrid system focusing on the usage phase of the building in this study. The research method is to establish a simulation model based on the literature review to set the basic building parameters for analysis. The software called Green Building Studio in Revit was used to simulate the energy consumption in different types of buildings. The carbon emission was calculated to compare the difference in energy efficiency between different structures. Moreover, the combination of different wooden based structural system which was influenced by the energy consumption was evaluated as well, in order to understand the advantage of applying wooden components. The results of the study show that, the use of CLT in four-story and ten-story buildings has a common energy-saving trend in the energy consumption. For the hybrid structural system, the average energy saving are up to 7.49% to 8.12%, depending on the different types of wooden based hybrid system, when the numbers of the original RC buildings were replaced by wooden buildings.
Technical Report
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Gesamtziel des Verbundprojektes war es, für das mehrgeschossige Bauen im urbanen Raum den Nachweis zu liefern, dass zukunftsorientiert für Neubauten bis zur Hochhausgrenze (Gebäudeklasse 5) mit der Holzbauweise kreislaufeffektive Konstruktionen und Architekturen möglich sind. Der Nachweis wurde bis in die Detailtiefe im Maßstab 1:1 geführt: architektonisch, (bau)konstruktiv, brand- und wärmeschutztechnisch sowie ökobilanziell. Kreislaufeffektives Bauen bestimmt unsere Zukunft, weil es klimaschonend ist, den Ressourcenverbrauch reduziert und Abfall vermeidet. Ressourcen sind in biologischen und technischen Kreisläufen einzubinden. Das lineare Wirtschaften muss der Kreislaufwirtschaft weichen. Das Bauwesen hat dazu einen maßgeblichen Teil beizutragen. Im Rahmen des Forschungsprojektes wurde erarbeitet, dass sich die Kreislauffähigkeit von Neubauten in fünf (baukonstruktive) Hierarchieebnen gliedern lässt: Gebäude, Bauteil, Bauelement, Komponente und Material. Wirtschaften in Kreisläufen setzt im Bauwesen in erster Linie eine robuste Gebäudestruktur voraus, die nutzungsflexible Geschossebenen zulässt. Das betrifft vor allem das starr im Gebäude verankerte Tragwerk und erfordert die leichte Rückbaubarkeit nichttragender Bauteile, wie Innen- und Außenwände. Da die Rohholzernte von Laubholz bisher zu 70% direkt als Brennholz verarbeitet wird, steckt vor allem in der Entwicklung von Baustoffen aus Laubholz ein hohes Wertschöpfungspotential. Im Forschungsprojekt wurde zur Steigerung der Laubholzverwendung und Kreislauffähigkeit ein mehrgeschossiger Holzbau aus Buchenfurnierschichtholz so entwickelt, dass die Nutzungen Parken, Wohnen und Arbeiten möglich sind, ohne in die Tragstruktur eingreifen zu müssen. Bauen mit Holz verlangt grundsätzlich aufgrund der mäßigen Materialsteifigkeit konstruktive Disziplin beim Entwerfen. Stützen stehen über Stützen, tragende und aussteifende Wände stehen ebenfalls übereinander. Dadurch wird die Elementierung und Standardisierung ermöglicht. Werden Baukomponenten, Bauelemente und Bauteile zusätzlich durch lösbare, reversible Verbindungen gefügt, ist in Zukunft selbst beim Rückbau eines solchen mehrgeschossigen Holzbaus eine Wieder- und Weiterverwendbarkeit im Sinne eines Materiallagers gewährleistet. Auch die Nachweise reversibler Verbindungen wurden im Forschungsprojekt erbracht.
Conference Paper
The aim of our work was to study the mechanical characteristics in conditions of flat stress state and widen the current knowledge of construction plywood appliance. It was decided that the best method for this investigation was to examine randomly selected plywood batches and analyse the results with the use of mathematical methods of statistics. The specimens were made up of plywood that was typified by different veneer grades. The main two groups of the specimens were manufactured with PF and UF resin. The conducted tests under the main types of flat stress in material (linear tension, compression and transverse bending) showed the strengths and their correlation between theoretical and obtained values. Based on the carried on plywood research the linear correlation dependence of veneer thickness on strength limit was obtained along and across fibres of external layers under compressive stress. Our experiments prove that veneer grade does not affect the tensile strength independent of the applied load direction regarding the fibre of external layers. This means that veneer grade defines only the quality of appearance. The mentioned above accessed results could be used for practical calculations during the design and manufacturing.
Article
This research uses uncertainty analysis to determine and compare the range of embodied carbon outcomes of mid-rise mass timber and concrete buildings in Australia. In doing so, it measures the variability in inventory databases, transportation distance, lifetime of building components, biogenic carbon emissions, carbonation of concrete materials and end-of-life scenarios. Through the use of Monte Carlo analysis, the research found that the embodied carbon of a mass timber building ranged from 196 kgCO2-e/m² to 590 kgCO2-e/m² with a mean of 417 kgCO2-e/m². For a post-tensioned concrete building the range was 307 kgCO2-e/m² to 618 kgCO2-e/m² with a mean of 465 kgCO2-e/m². This equates to a 48 kgCO2-e/m² reduction in mean embodied carbon for the mass timber building. Using deterministic analysis, previous research suggested a more substantive 129 kgCO2-e/m² reduction. These results demonstrate that mass timber buildings do typically have a lower embodied carbon, compared to concrete buildings, however the significance of this depends on the assumptions made, and the input data used. For the concrete building, the variation in embodied carbon is primarily influenced by the inventory data and building products' lifetime. The greater range of embodied carbon in the mass timber building is due to variations associated with the inventory data, allocation of biogenic carbon emissions (sequestration, and forest management losses) and, different end-of-life scenarios associated with timber products. Despite this, the research suggests that with a carefully planned end-of-life strategy, mass timber mid-rise buildings have the potential to benefit from lower embodied carbon emissions, as compared to concrete buildings, across their full lifecycle.
Article
In this paper, it is attempted to study possible sustainability solutions for building structures. In this context, comparisons are made between two load-bearing columns with different building materials – glued laminated timber and concrete – with regard to structural design, economic consequences and the emission of greenhouse gases. In terms of structural design, the results show that with small axial forces, glulam columns will result in smaller cross-sectional areas compared to concrete columns. However, at larger axial forces, concrete columns will result in smaller cross-sectional areas than glulam columns. An increased column length also means larger dimensions for glulam columns, but this does not always apply to concrete columns. With respect to environmental impact, it is shown that using glulam columns is the more environmentally friendly option. From an economic point of view, the cost estimates for glulam and concrete columns may vary depending on the country and the abundance of the construction material. In Sweden, a forest-rich country, it is shown that the costs for both column types are quite similar considering small axial loads. At higher axial loading, concrete is generally the cheaper alternative.
Article
The recent energy and environmental crises and corresponding regulations have increased interest in replacing conventional materials with sustainable materials in construction. Due to the outstanding properties of wood, such as recyclability, reusability and natural renewability, it is considered a sustainable material. In addition, wood has a high strength-to-weight ratio and outstanding acoustic and thermal insulation properties, which make it an appropriate construction material in numerous applications, including in main structural members such as beams, columns and flooring systems as well as in non-structural members, such as windows, doorframes and insulating envelopes. Recent advancements in the production of engineering wood and efficient adhesives have made the fabrication of structural members with large cross sections, long spans and structural properties comparable to steel and reinforced concrete feasible and cost-effective. As a result, interest in long-span timber buildings has increased greatly. In this paper, a comprehensive review of research studies investigating various aspects of long-span timber structures, including material properties, structural performance and sustainability, are presented. In particular, over 100 research papers were systematically reviewed to study the constructability of long-span flooring systems. The techniques and methodologies available for the fabrication, analysis and experimental investigations of structural flooring systems are also reviewed in detail. Overall, this comprehensive review helps to achieve a greater understanding of structural static and dynamic responses of long-span timber flooring systems, and undertaking the challenges and opportunities presented in this paper could significantly contribute to the improvement of the structural design to reach optimised, sustainable, and constructible systems.
Article
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Natural frequency of any natural or artificial material play a role in selection it for industrial and manufacturing applications. Natural frequency for material meaning its ability to absorb external vibration for avoiding resonance. In the presented paper wood and steel will used as a type of natural materials, concrete also will used but as an artificial material. Calculation of natural frequency for each material will done with same volume of structure. Natural properties of wood show superiority for many mechanical applications. The aim of this study is to investigate the effects of various factors including characteristics of wood, steel and concrete on their natural frequencies with the aim of producing recommendations to promote sustainability. Fuzzy logic control system also implemented for optimizing the impacts of these characteristics on the structure' vibration. In addition, the natural frequencies of structures have been assessed against the wind, earthquakes, and traffic vibrations. The results reveal that for the same dimensions of the structure, wood shows the highest natural frequency, steel followed by concrete. Results indicate that wood can complement natural properties of a range of industrial manufacturing materials to promote sustainability and improve performance. This can have implications for heavy machines laboratories (like foundation for that machines) and other engineering applications.
Article
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From the environmental perspective, wooden structures are favorable insulators that are suitable for carbon fixation and wooden-related products are considered the most sustainable material. Research has indicated that wooden structures have superior energy-saving performance compared to reinforced concrete (RC) structures. In this study, a CLT-based hybrid structure system that potentially improves the efficiency of energy consumption is proposed. The proposed hybrid structure system, which preserved original RC beams, columns and replaced CLT floors and walls, has less building weight compared to the original RC building. Additionally, less energy required for the manufacturing of building materials in the renovation of the aged building is achieved, compared to building a new CLT building. The energy consumptions for buildings with heights of 10 stories were compared. CLT and RC were selected as benchmark building materials to compare the energy-saving efficiencies with the proposed hybrid structure system. In addition, to examine the energy consumption differences at different latitudes, the energy consumptions in Taipei, Tokyo, Harbin, and Singapore were compared as well. The simulation results indicate the proposed hybrid structure system, which comprises RC beams and columns and CLT floors and walls, and has an energy-saving efficiency close to that of a CLT structure, by approximately 3–5% higher, however, had a superior energy consumption performance to the RC structure. In general, the proposed hybrid structure system can be effectively used for old building renewal in the selected Asian cities.
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This paper investigates the amount of energy required to construct buildings, and the resulting carbon dioxide emissions to the atmosphere from the fossil fuel components of that energy. Energy requirements and carbon dioxide emissions are compared for typical commercial, industrial and residential buildings, using New Zealand as an example. A modest change from concrete and steel to more wood construction could lead to a substantial reduction in energy requirements and carbon dioxide emissions, but the sustainability of such a change has significant forestry implications.
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In this study we examine the use of wood products as a means to mitigate climate change. We describe the life cycle of wood products including forest growth, wood harvest and processing, and product use and disposal, focusing on the multiple roles of wood as both material and fuel. We present a comparative case study of a building constructed with either a wood or a reinforced concrete frame. We find that the production of wood building material uses less energy and emits less carbon than the production of reinforced concrete material. We compare the relative cost of the two building methods without environmental taxation, under the current Swedish industrial energy taxation regime, and in scenarios that incorporate estimates of the full social cost of carbon emission. We find that the inclusion of climate-related external costs improves the economic standing of wood construction vis-à-vis concrete construction. We conclude that policy instruments that internalise the external costs of carbon emission should encourage a structural change toward the increased use of sustainably produced wood products.
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Total energy use during the life cycle of a building is a growing research field. The embodied energy makes up a considerable part of the total energy use in low energy buildings. Recycling provides the opportunity to reduce the embodied energy by using recycled materials and reusable/recyclable materials/components. This paper presents values on embodied energy, energy needed for operation and the recycling potential of the most energy efficient apartment housing in Sweden (). In a life span of 50 years, embodied energy accounted for 45% of the total energy need. The recycling potential was between 35% and 40% of the embodied energy.
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This paper assesses a construction and demonstration (C&D) waste recycling program in relation to technical, institutional, and economic considerations. The focus is primarily placed on a feasibility study for a new mechanical sorting process that was installed with several unit operations, including bar screening, trommel screening, air classifier, disk screening, and final manual sorting. Lab analyses, consisting of sieve analysis, LA abrasion test, friability test, organic content test, and fineness test, with respect to three types of product streams (A, B, and C) were conducted in accordance with selected physical and chemical properties. Findings clearly indicate that the reuse of fine particle generated in product stream A as construction materials in roadbed is highly recommended if the impurities can be removed beforehand. The product stream B could be suitable for reusing as the covering materials in daily operation of sanitary landfills. Yet it could also be used as backfill materials in the construction projects if the impurities can be removed in advance. Only does the LA abrasion test support the reuse of product stream C as coarse aggregate or pavement subbase for those new structures. Once the secondary materials market is stable and the institution settings are sufficient, it is worthwhile addressing that the associated cost-benefit analysis does confirm the economic potential for such a management practice.
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In this paper, primary energy use and carbon dioxide (CO2) and methane (CH4) emissions from the construction of a multi-storey building, with either a wood or a concrete frame, were calculated from life-cycle and forest land-use perspectives. The primary energy input (mainly fossil fuels) in the production of building materials was found to be about 60–80% higher when concrete frames were considered instead of wood frames. The net greenhouse gas (GHG) balance for wood materials will depend strongly on how the wood is handled after demolition of the building. The nrt GHG balance will be slightly positive if all the demolition wood is used to replace fossil fuels, slightly negative if part of the demolition wood is re-used, and clearly positive if all wood is deposited in landfills, due to the production of CH4. However, if the biogas produced is collected and used to replace fossil fuels, the net GHG emissions will be insignificant. If concrete frames are used, the net GHG emissions will be about those when demolition wood from the wood-framed building is deposited in landfills and no biogas is collected. We have considered that the CO2 released from the chemical processes in the production of cement will be re-bound to the concrete by the carbonisation process. Otherwise, the net GHG emission would be more than twice as high when concrete frames are used. If forest biomass is used instead of fossil fuels, the net area of forest land required to supply both raw material and energy for the production of building materials, will be about twice as high when wood frames are used instead of concrete frames. However, the GHG mitigation efficiency, expressed as CO2 equivalents per unit area of forest land, will be 2–3 times higher when wood frames are used if excess wood waste and logging residues are used to replace fossil fuels. The excess forest in the concrete frame alternative is used to replace fossil fuels, but if this forest is used for carbon storage, the mitigation efficiency will be higher for the first forest rotation period (100 yr), but lower for the following rotation periods. Some of the data used in the analyses are uncertain, but an understanding of the complexity in comparing different alternatives for utilising forest for GHG mitigation, and of the fact that the time perspective applied affects the results markedly, is more important for the results than the precise figures in the input data.
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Data developed by the Consortium for Research on Renewable Industrial Materials were used to estimate savings of greenhouse gas emissions and energy consumption associated with use of wood-based building materials in residential construction in the United States. Results indicate that houses with wood-based wall systems require 15–16% less total energy for non-heating/cooling purposes than thermally comparable houses employing alternative steel- or concrete-based building systems. Results for non-renewable energy consumption are essentially the same as those for total energy, reflecting the fact that most of the displaced energy is in fossil fuels. Over a 100-year period, net greenhouse gas emissions associated with wood-based houses are 20–50% lower than emissions associated with thermally comparable houses employing steel- or concrete-based building systems. Assuming 1.5 million single-family housing starts per year, the difference between wood and non-wood building systems represents about 9.6 Mt of CO2 equivalents per year. The corresponding energy benefit associated with wood-based building materials is approximately 132 PJ year−1. These estimates represent about 22% of embodied energy and 27% of embodied greenhouse gas emissions in the residential sector of the US economy. The results of the analysis are very sensitive to assumptions and uncertainties regarding the fate of forestland that is taken out of wood production due to reduced demand for wood, the continued production of co-products where demand for wood products is reduced, and the rate at which carbon accumulates in forests.
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This study investigates the global impact of wood as a building material by considering emissions of carbon dioxide to the atmosphere. Wood is compared with other materials in terms of stored carbon and emissions of carbon dioxide from fossil fuel energy used in manufacturing. An analysis of typical forms of building construction shows that wood buildings require much lower process energy and result in lower carbon emissions than buildings of other materials such as brick, aluminium, steel and concrete. If a shift is made towards greater use of wood in buildings, the low fossil fuel requirement for manufacturing wood compared with other materials is much more significant in the long term than the carbon stored in the wood building products.As a corollary, a shift from wood to non-wood materials would result in an increase in energy requirements and carbon emissions.The results presented in this paper show that a 17% increase in wood usage in the New Zealand building industry could result in a 20% reduction in carbon emissions from the manufacture of all building materials, being a reduction of about 1.5% of New Zealand’s total emissions. The reduction in emissions is mainly a result of using wood in place of brick and aluminium, and to a lesser extent steel and concrete, all of which require much more process energy than wood. There would be a corresponding decrease of about 1.5% in total national fossil fuel consumption. These figures have implications for the global forestry and building industries. Any increases in wood use must be accompanied by corresponding increases in areas of forest being managed for long term sustained yield production.
Article
Establishing a successful construction/demolition (C&D) waste recyling operation in the USA is a challenge today, especially because secondary materials markets have not yet matured. Increasingly, municipal solid waste (MSW) landfill operations refuse to accept C&D waste. Skyrocketing tipping fees due to the scarcity of landfill sites, and growing concerns from regulatory agencies and the public, have placed C&D waste recycling operations under intense scrutiny. The experiences of regional C&D recyclers indicate that successful recycling operations require a minimum of 0.8 ha of clear space for processing equipment, incoming waste stockpiles, recycled materials, and manoeuvring room for mobile equipment and operations. Reasonable quality, reliable equipment suitable for these operations generally costs between 300000and300 000 and 750 000 for a 400-500 tonne/day operation. At present, operators of these facilities make a profit almost solely on tipping fees, with the recycling operation functioning mainly to maintain materials throughput. Different categories of C&D recycling machinery and waste processing strategies are presented. Strategies for converting C&D landfills into successful C&D recycling operations are also examined. C&D waste recycling economics are presented to demonstrate the essential ingredients for successful operations.
Environmental impacts of the New Zealand building industry, Research Rep. 92-2
  • Honey Bg Buchanan
Honey BG, Buchanan AH. Environmental impacts of the New Zealand building industry, Research Rep. 92-2. New Zealand: Department of Civil Engineering, University of Canterbury; 1992.
Energy use and environmental impact of new residential buildings
  • K Adalberth
Adalberth K. Energy use and environmental impact of new residential buildings. PhD dissertation. Department of Building Physics, Lund University, Sweden; 2000.
Wâlludden trâhus i fem våningar e Erfarenheter och lârdomar. Rapport TVBK-3032. Lund: Tekniska Hàgskolan i Lund
  • S Persson
Persson S. Wâlludden trâhus i fem våningar e Erfarenheter och lârdomar. Rapport TVBK-3032. Lund: Tekniska Hàgskolan i Lund; 1998.
LCA of building frame structures: environmental impact over the life cycle of wooden and concrete frames
  • T Björklund
  • A M Tillman
Björklund T, Tillman AM. LCA of building frame structures: environmental impact over the life cycle of wooden and concrete frames. Technical Environmental Planning Report 1997:2. Gothenburg, Sweden: Chalmers University of Technology; 1997.
Energi-och miljøanalyser af bygninger. SBI-meddelelse 108. Denmark: Statens Byggeforskningsinstitut
  • P Nielsen
Nielsen P. Energi-och miljøanalyser af bygninger. SBI-meddelelse 108. Denmark: Statens Byggeforskningsinstitut; 1995.
Emerging scarcities Scarcity and growth revisited. Natural resources and the environment in the new millennium
  • C Azar
  • Simpson Rd
  • Ma Toman
  • Ayres
Azar C. Emerging scarcities. In: Simpson RD, Toman MA, Ayres RU, editors. Scarcity and growth revisited. Natural resources and the environment in the new millennium; 2005.
Opportunities of using sawmill residues in Australia. Forest and Wood Products in Australia Limited
  • D Goble
  • C Jarvis
Goble D, Jarvis C. Opportunities of using sawmill residues in Australia. Forest and Wood Products in Australia Limited; 2007.
Building materials and CO 2 . Western European emission reduction strategies. ECN-C-97e065
  • D J Gielen
Gielen DJ. Building materials and CO 2. Western European emission reduction strategies. ECN-C-97e065. Petten, The Netherlands: Energy research Centre of the Netherlands (ECN); 1997.
Energy and communications. Mer trä i byggandet e Underlag för en nationell strategi att främja användningen av trä i byggandet
  • Ministry
  • Enterprise
Ministry of Enterprise. Energy and communications. Mer trä i byggandet e Underlag för en nationell strategi att främja användningen av trä i byggandet, vol. 1. Stockholm: Regeringskansliet, Näringsdepartementet; 2004.
Construction: construction costs for new residential buildings
Statistics Sweden. Construction: construction costs for new residential buildings 2007, BO 26 SM 00802; 2009.
Environmental impacts of the New Zealand building industry
  • B G Honey
  • A H Buchanan
Honey BG, Buchanan AH. Environmental impacts of the New Zealand building industry, Research Rep. 92-2. New Zealand: Department of Civil Engineering, University of Canterbury; 1992.
Scarcity and growth revisited. Natural resources and the environment in the new millennium
  • C Azar
Azar C. Emerging scarcities. In: Simpson RD, Toman MA, Ayres RU, editors. Scarcity and growth revisited. Natural resources and the environment in the new millennium; 2005.