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The greenhouse gas emissions and mitigation options for materials used in UK construction
Abstract
The UK construction industry faces the daunting task of replacing and extending a significant proportion of UK infrastructure, meeting a growing housing shortage and retrofitting millions of homes whilst achieving greenhouse gas (GHG) emission reductions compatible with the UK's legally binding target of an 80% reduction by 2050. This paper presents a detailed time series of embodied GHG emissions from the construction sector for 1997–2011. This data is used to demonstrate that strategies which focus solely on improving operational performance of buildings and the production efficiencies of domestic material producers will be insufficient to meet sector emission reduction targets. Reductions in the order of 80% will require a substantial decline in the use of materials with carbon-intensive supply chains. A variety of alternative materials, technologies and practices are available and the common barriers to their use are presented based upon an extensive literature survey. Key gaps in qualitative research, data and modelling approaches are also identified. Subsequent discussion highlights the lack of client and regulatory drivers for uptake of alternatives and the ineffective allocation of responsibility for emissions reduction within the industry. Only by addressing and overcoming all these challenges in combination can the construction sector achieve drastic emissions reduction.
... The perception of the extra cost incurred ranks as the second most significant barrier to sustainable building materials in Australia (Gounder et al., 2021). Time and liability constraints further hinder the selection of non-conventional materials by architects and contractors (Giesekam et al., 2014;Giesekam et al., 2015;Krueger et al., 2019). Moreover, the adoption of non-conventional materials may bring risks and uncertainties regarding project cost and duration; hence, this is found to be a critical barrier to their use in both developed and developing countries (Akadiri, 2015;Giesekam et al., 2014;Giesekam et al., 2015). ...
... Time and liability constraints further hinder the selection of non-conventional materials by architects and contractors (Giesekam et al., 2014;Giesekam et al., 2015;Krueger et al., 2019). Moreover, the adoption of non-conventional materials may bring risks and uncertainties regarding project cost and duration; hence, this is found to be a critical barrier to their use in both developed and developing countries (Akadiri, 2015;Giesekam et al., 2014;Giesekam et al., 2015). ...
... Furthermore, this unwillingness to change can hinder stakeholders' motivation to prepare the technical resources necessary for adopting new materials, resulting in technical barriers. Examples of these barriers include designers lacking design knowledge and skills (Ameh et al., 2019;Franzini et al., 2018;Gounder et al., 2021) and contractors lacking the technical knowledge, experience, and skilled labourers needed for construction with these materials (Giesekam et al., 2014;Giesekam et al., 2015). ...
Circular bio-based building materials (CBBMs) provide a potential solution to reduce the climate impacts of buildings and offer opportunities to transition the construction industry to a circular model. Promoting the use of these materials can also bring economic, environmental, and social benefits from valorising biowaste and by-products from other sectors. Despite their potential, CBBMs have not received sufficient attention globally, and their adoption is hindered by various barriers. However, it is unclear what the CBBMs' use status is, what adoption barriers exist, how these barriers interact, and what should be done to address them. This study addresses these knowledge gaps through a systematic study using mixed methods to investigate the adoption status and barriers to these materials in developed economies by using a specific case analysis in Flanders. The data analysis results show that hemp-based, cork-based, and straw-based materials are the most used, while the market for CBBMs is very limited in the region. Twenty-three potential adoption barriers were identified and selected from the existing literature, then ranked based on their mean scores. The t-test analysis helps to identify 13 critical barriers, which are grouped into five categories, including cost and risk-related barriers, technical and cultural-related barriers, the government's role-related barriers, information and quality-related barriers, and market-related barriers. Among them, cost and risk-related barriers, including “concern about the high initial cost”, “risks and uncertainties involved in adopting new materials”, and “perception of the extra cost being incurred”, are the three most critical barriers to CBBM adoption in Flanders. Kendall's W test shows good consensus among the two expert groups—with and without hands-on experience in utilising CBBMs—in their rankings of the barriers. Meanwhile, the Mann-Whitney U test indicates no statistically significant differences in the ranks of barriers between the two expert groups. The interview results confirm almost all survey results and provide deeper insights into the status and barriers to adopting these materials. Practical and policy implications are discussed based on these findings to inform policy deliberations on promoting CBBMs. This study may also be a good reference for scholars and industry practitioners to better understand issues impacting decision-making towards the adoption of CBBMs in the construction industry.
... On one hand, there are operational emissions that occur while the building is operated, which include heating, cooling, and electrical applications [15]. On the other hand, there are embodied emissions, which occur during the building process and the production and transportation of the utilized building materials [16]. Most efforts in recent history have been directed at lowering operational emissions, with the result of switching from fossil to renewable energy sources and improving the insulation of buildings [14]. ...
... Most efforts in recent history have been directed at lowering operational emissions, with the result of switching from fossil to renewable energy sources and improving the insulation of buildings [14]. Reducing a building's embodied emissions is crucial for reducing its overall environmental impact [16], particularly given that the steel industry, which relies heavily on fossil fuels for the energy-intensive production and forming of construction-quality steel, contributes approximately 7-9% of global CO 2 emissions [17], with nearly 50% of produced steel globally being directed towards the construction sector [18]. ...
The ongoing effects of climate change have led to a rise in global temperature, significantly reducing snow cover and resulting in the abandonment of numerous ski areas across Switzerland. As a result, many ski lifts have been decommissioned and left to deteriorate due to lenient local regulations. To address this issue, this paper presents a case study approach to repurposing steel trusses from abandoned ski lifts for a new structural application within the building industry. The design, sourcing, and construction of a new load-supporting column are described, focusing on reusing the ski lift steel trusses as a whole, without dismantling them into their components. After collection, these elements are adapted to comply with current building standards. By pouring out the hollow structure with the recently developed building material Cleancrete ©, a new load-bearing structure is developed. A comprehensive life cycle assessment (LCA) demonstrates the environmental performance of the steel-Cleancrete hybrid construction, which achieves a global warming potential (GWP) of 536.58 kg CO 2-eq. In comparison, alternative designs using wood and concrete exhibited GWP values of 679.45 kg CO 2-eq, +26.6%, and 1593.72 kg CO 2-eq, +197.02%, respectively. These findings suggest that repurposing abandoned ski lift structures can significantly contribute to sustainable building practices, waste reduction, and the promotion of circular economy principles. The process outlined in this paper holds potential for future applications, particularly in the reuse of other steel components, ensuring continued circularity even as the supply of ski lift structures may dwindle.
... Since most SCMs are by-products of other processes, their quality has traditionally been secondary to the efficiency of the primary industrial activity. This has often resulted in suboptimal SCM quality and significant variability between sources over time [30,31], sometimes preventing the use of environmentally friendly materials due to their practical, technical, and economic impacts [32,33]. ...
The sudden increase in industrialization has reduced the availability of natural building materials and triggered the growing awareness of sustainable practices within the construction industry. The study presented here deals with marble powder, which is one of the by-products obtained from the marble industry, as a cement replacement in concrete mixtures. The main aims will be to investigate the impact of marble powder waste materials on the mechanical properties of concrete and to promote the recycling of various industrial wastes for environmental sustainability. Material testing was conducted with the levels of substitution of marble powder for cement ranging from 0% to 50%, and the resulting concrete was evaluated for compressive and tensile strength over different curing periods. The results show that concrete compressive strength and tensile strength are most efficiently improved when marble powder replacement is up to 10–15%, attaining its full potential after 28 days. Beyond this replacement level of 15%, the mechanical properties decrease, suggesting that higher substitution levels may not be effective. This paper consolidates findings, provides a novel comparative analysis, and addresses key challenges regarding the use of marble powder, providing room for the future industrial development of supplementary cementitious materials (SCMs), eventually leading to sustainability in the construction sector.
... Recycled steel and concrete, for example, have been shown to reduce the typically high greenhouse gas emissions (GHG) in conventional material production processes. Furthermore, recycled materials require less processing than newly manufactured components and thus consume less energy (Giesekam et al., 2014). From an economic perspective, recycled and upcycled materials are more affordable, notably if locally sourced, because of the lower processing and transportation costs. ...
This paper explores the increasingly popular practice of integrating recycled and upcycled materials in modern architecture and civil engineering and highlights their central role in promoting sustainability, energy efficiency, and environmental responsibility. Upcycling transforms discarded materials, such as reclaimed metal, wood, masonry, glass, concrete, and plastic, into valuable resources and offers a promising course for achieving sustainability. This research evaluates the performance, durability, and aesthetic potential of discarded materials through case studies of completed projects to illustrate their successful applications. It also addresses the challenges and opportunities associated with the widespread use of recycled and upcycled materials by focusing on technological advancements, lifecycle assessments, and economic feasibility. The findings underscore the significance of continued research and innovation in this field and the need for supportive government regulations and better public awareness. In summary, the study emphasizes the compelling need to integrate recycled and upcycled materials in construction to promote sustainable construction practices and develop a more resilient, resource-efficient built environment.
... La construcción genera un impacto ambiental considerable, principalmente en emisiones de CO 2 y consumo de materiales (Giesekam et al., 2014;Gómez, 2019). En este contexto, el marco metodológico propuesto en el Análisis de Ciclo de Vida (ACV) surge como una herramienta útil para evaluar el impacto ambiental de los proyectos de construcción. ...
En el desarrollo de proyectos de construcción, frecuentemente se seleccionan alternativas basadas en sus costos. Sin embargo, la presión que ejercemos sobre el planeta y sus recursos nos obliga a considerar como alternativas aquellas de menor impacto ambiental. Para obtener criterios que involucren el impacto ambiental, en este proyecto se llevó a cabo una revisión bibliográfica exhaustiva que permitió identificar la huella ecológica (HE) como un indicador de evaluación de impacto que integra el uso de fuentes primarias y secundarias centradas en la estructura de costos. La HE evalúa la demanda humana sobre los recursos, expresada en el área de tierra necesaria para producir los productos que consumimos y absorber los residuos, y se expresa en unidades de superficie globales (hectáreas globales, hag). Esta metodología se empleó en el presente trabajo para evaluar el impacto ambiental durante la fase de construcción de un proyecto de vivienda de interés social, ejecutado en la ciudad de San Andrés de Tumaco, en la costa nariñense, comparando dos alternativas constructivas: el sistema constructivo convencional de mampostería confinada y el sistema con formaleta tipo túnel Outinord. Los resultados mostraron que el sistema constructivo convencional produce un mayor impacto en comparación con el sistema Outinord, con índices de 0,0794 y 0,0617 hag/m² respectivamente, demostrando que este último es una alternativa apropiada en función de su huella ecológica total y la posible reducción en el tiempo de obra.
... Programmes aimed at reducing carbon emissions and waste from the building and construction sectors have existed for some time [8,9]; however, climate change, resource scarcity, and the demand for affordable housing has increased the demand for low-carbon "sustainable" buildings [10]. The EU mandates that new buildings are constructed to be "nearly-zero energy" [11] and the UK plans to implement an 80% reduction in CO 2 emissions by 2050; this will be partly supported by the substitution of carbon-intensive materials such as concrete with low-carbon materials, such as timber [12]. China has committed to a target of 30% of new buildings to be built using prefabricated techniques by 2025 [13,14]. ...
Prefabricated timber buildings offer a low-carbon approach that can help reduce the environmental impact of the building and construction sectors. However, construction materials such as manufactured timber products can emit a range volatile organic compounds (VOCs) that are potentially hazardous to human health. We evaluated 24 years (2000–2024) of peer-reviewed publications of VOCs within prefabricated timber buildings. Studies detected hazardous air pollutants such as formaldehyde, benzene, toluene, and acetaldehyde (indoor concentration ranges of 3.4–94.9 µg/m3, 1.2–19 µg/m3, 0.97–28 µg/m3, and 0.75–352 µg/m3, respectively), with benzene concentrations potentially exceeding World Health Organization indoor air quality guidelines for long/short term exposure. Most studies also detected terpenes (range of 1.8–232 µg/m3). The highest concentrations of formaldehyde and terpenes were in a prefabricated house, and the highest of benzene and toluene were in a prefabricated office building. Paradoxically, the features of prefabricated buildings that make them attractive for sustainability, such as incorporation of manufactured timber products, increased building air tightness, and rapid construction times, make them more prone to indoor air quality problems. Source reduction strategies, such as the use of low-VOC materials and emission barriers, were found to substantially reduce levels of certain indoor pollutants, including formaldehyde. Increasing building ventilation rate during occupancy is also an effective strategy for reducing indoor VOC concentrations, although with the repercussion of increased energy use. Overall, the review revealed a wide range of indoor VOC concentrations, with formaldehyde levels approaching and benzene concentrations potentially exceeding WHO indoor air quality guidelines. The paucity of evidence on indoor air quality in prefabricated timber buildings is notable given the growth in the sector, and points to the need for further evaluation to assess potential health impacts.
... Alongside travel sustainability, there are the energy impacts of new housing, including space and water heating, building energy efficiency and embedded emissions from materials and construction (Giesekam et al., 2014). Emissions from residences are the third largest sector of UK GHG emissions at 23 % (DESNZ, 2023). ...
Although London's high-density compact city planning has largely delivered sustainable development in the urban core, the wider regional challenge is that housing targets have been consistently missed for the last decade, and the lack of supply is exacerbating the housing affordability crisis. Releasing Green Belt land has been cited as a solution. This paper analyses new build development in the London region from 2011 to 2022, and confirms that Green Belt policy needs reform – local authorities in the Green Belt have the lowest housing delivery in the region, and car dependent ‘leap-frog’ development is occurring beyond the Green Belt boundary. The relaxation of Green Belt restrictions could greatly boost development, but would also risk producing car dependent housing. This research produces a new Travel Sustainability Index using census travel behaviour data, and analyses the travel patterns of residents in new build housing over the last decade. The conclusions are that more sustainable Green Belt development can be achieved by prioritising development in Outer London and through extending existing towns and cities in the Greater South East. Achieving this outcome will require improved regional planning coordination and infrastructure investment.
... Most existing research has overlooked variations in building types within cities, often neglecting the estimation and longitudinal mapping of building-specific ECE at the micro-unit scale. This oversight limits our ability to develop targeted sustainability strategies that consider the unique material compositions and associated carbon emissions of different building types, which are crucial for enhancing urban sustainability (Giesekam et al., 2014;Moncaster & Symons, 2013). Furthermore, detailed analyses comparing the ECE of metallic versus non-metallic materials are scarce. ...
... La implementación de materiales alternativos y sostenibles, como los reciclados o de bajo impacto ecológico, se ha convertido en una estrategia clave para disminuir la huella de carbono y el consumo energético asociado a la producción de materiales tradicionales como el cemento o el acero. Estudios recientes han demostrado que el uso de materiales locales y ecológicamente eficientes puede reducir hasta un 30% las emisiones de gases de efecto invernadero durante el ciclo de vida de una construcción (Giesekam et al., 2016). ...
Este artículo presenta un modelo de evaluación ambiental para la construcción de viviendas con materiales sostenibles en el sitio Joa, ubicado en el cantón Jipijapa, Ecuador. El objetivo del estudio es desarrollar un sistema de evaluación que considere los impactos ambientales de los materiales utilizados, promoviendo la sostenibilidad en la construcción local. Para ello, se utilizó una metodología basada en indicadores clave de sostenibilidad, como el consumo de energía, emisiones de carbono, reciclabilidad de materiales y generación de residuos. Los resultados muestran que la implementación de este modelo puede reducir el impacto ambiental de la construcción, fomentar el uso de recursos locales y mejorar la calidad de vida de los habitantes. Como conclusión, se propone la aplicación de este modelo en futuros proyectos de vivienda social en la región, con el fin de fortalecer las prácticas de construcción sostenible.
... Technological barriers also contribute to the shortage of skilled professionals in sustainable construction. Limited access to the latest sustainable construction technologies and materials presents a significant hurdle (Giesekam et al., 2014). Moreover, insufficient investment in research and development (R&D) within this sector hampers innovation and the creation of new sustainable practices and materials (Matar et al., 2008). ...
The sustainable construction industry is experiencing rapid growth, propelled by the urgent global need to reduce environmental impact and enhance resilience in the built environment. Nevertheless, this expansion is met with a significant deficit of skilled professionals equipped with the necessary knowledge and expertise in sustainable construction practices. This research explores the multifaceted approach required to rectify this shortage, with a primary focus on enhancing awareness and education, addressing training needs, and implementing effective policy interventions. This study begins with the examination of existing literature related to sustainable construction education, training, and current strategies to identify gaps and challenges. The research methodology entails a literature review to identify factors causing skilled professional shortages in construction. Semi-structured interviews with construction professionals follow this to confirm and explore underlying reasons. Transcripts are then analysed using content analysis to extract main themes and sub-themes. Gaining insight into the root causes of skilled shortages and the challenges within sustainable construction guides the development of targeted strategies aimed at attracting more professionals to the field. Proposed strategies for addressing shortages are validated with construction professionals, and conclusions are drawn. This approach not only helps alleviate professional shortages but also fosters sustainable growth within the sector. The findings of the study offer valuable insights for stakeholders, educational institutions, and policymakers, enabling them to enhance their approaches to sustainability in the construction industry.
... Accordingly, the objectives of sustainability are often ignored. Therefore, although many stakeholders are aware of the need for change, a few have the will to accept the financial and reputational risks associated with such adoption [131]. ...
Climate change is a significant challenge in today’s world. The construction industry is one of the most energy-intensive and raw material-depleting sectors worldwide. Legal regulations, such as laws, building codes, and alternative governance, are effective ways to help mitigate climate change risks. Most of the research focuses on either one country’s policies in the construction industry towards climate change or one type of regulation across various countries. Therefore, the objective of this study is to explore and compare various kinds of regulations, namely policies and laws, green codes, and green building rating systems, in three countries: Egypt, the UAE, and the United States, representing different country profiles from different continents. Sources from credible journal papers, conference proceedings, and theses dissertations were used to explore the most recent practices in these countries. It was found that Egypt is the least effective country in enforcing actions towards the climate crisis. There is a gap between the UAE’s actions and the nationally determined contribution target. Federal setbacks hinder the widespread adoption of green practices in the United States. Therefore, the key to effective approaches to combating climate change is enforcing inclusive laws, including all sustainability pillars, and having inclusive nationwide emissions targets in all sectors.
... Therefore, as Baeli (2019) identifies, there are a substantial number of the UK housing stock which can be considered less energy efficient than the newer built stock. As a result, to address and improve energy efficiency and reduce energy usage and CO 2 emissions, there is a substantial retrofitting programme required (Giesekam, et al., 2014). ...
Sustainability continues to be a key field of study, encapsulating three principle dimensions: social, economic and environmental, which are also found within the context of climate change. However, there appears to be limited literature drawing upon the between sustainability and climate change. relationship, particularly in connection to carbon emissions and energy management. These issues have already been the subject of legislation in different countries, though still, predominantly individually rather than from an integrated perspective. The Climate Change At (2008) provides a platform through which the relationship between sustainability and climate change can be considered. This paper establishes this relationship aspects of this relationship by employing the increased use of insulation within the UK housing stock to contribute to achieving the carbon reduction set by the Act. Taking a retrospective view through theoretical numerical modelling, this paper demonstrates that CO2 reductions were achievable. The results demonstrate that links can be drawn between sustainability and climate change and identifies that significant CO2 savings, through robust energy management of the UK housing stock, these results can be achieved. It is also suggested that the theoretical mole developed can be reproduced to consider climate change targets and provide benchmarks, not only in the UK but in other countries.
... Acquaye and Duffy (2010) explored the CO 2 emission intensity in the Irish construction sector through input-output analysis. Using multiregion environmentally extended input-output analysis, Giesekam et al. (2014) estimated CO 2 emissions and analyzed the pathway of emission reduction targets for the construction industry in UK. ...
China actively participates in global efforts to mitigate CO2 emissions, with a particular emphasis on the crucial role of the construction sector in achieving these objectives. This research endeavor commences by conducting an in-depth analysis of the maximum potential for reducing carbon intensity (CI) within China's construction sector from 2005 to 2019. The assessment is executed through the utilization of a non-radial directional function, with the total-factor CO2 emission performance index (TCPI) serving as the principal metric. Subsequently, this study employs network analysis, an extended decomposition technique, and scenario analysis to comprehensively investigate the evolving network trends, key determinants influencing TCPI, and potential pathways for further CI reduction. The findings of this investigation reveal the following critical insights: 1) The overall trajectory of TCPI exhibits an upward trend, characterized by dynamic shifts in its hierarchical structure over the specified time frame. 2) Several influential factors contribute positively to the observed TCPI increase, including investment-based energy intensity (the largest contributor), the potential carbon factor, technical efficiency in economic development, and carbon productivity. Conversely, the investment-output share exerts a negative influence on TCPI. 3) An alarming prospect emerges as the construction sectors in Tianjin, Heilongjiang, Anhui, Jiangxi, Henan, and Guizhou face potential challenges in achieving the 2030 targets, which aim for a 60%-65% reduction in CI compared to 2005 levels under a business-as-usual scenario. Consequently, a concerted effort to reduce carbon emission factors and energy intensity becomes imperative. This study underscores the critical need for the formulation and implementation of enhanced CI reduction policies within the construction sector, emphasizing the vital role of government intervention in achieving these objectives.
... In this research, the embodied energy consumption and the CO 2 gas emissions of the materials used in the building consolidation process in the existing reinforced concrete version and the metal frame version are highlighted, due to the fact that the production stage can account for up to 75% of the total energy consumption and carbon impact during the life cycle of a building [49][50][51]. ...
A very important problem encountered all over the world and increasingly widespread is represented by sustainability. The construction field is responsible for a high environmental impact, for the entire duration of a building’s operation, from the construction stage until its demolition. This paper presents a sustainability study, performed on an old historical building located in Romania—Arad County, which implied the consolidation of its resistance structure as a result of visible degradation. The study was performed using the Bob–Dencsak Calculation Model, which involved research into several specific parameters for each dimension separately (ecological, economic and social). Besides establishing the sustainability class for the consolidated building, an analysis was done on the impact that metal has as compared to reinforced concrete, thus resulting in the finding that metal is less sustainable than reinforced concrete, achieving growths of up to 42% for embodied energy and 28.50% of CO2 emissions in the atmosphere. Finally, the paper offers recommendations for future sustainability assessment research with the aim of increasing the quality of life and minimizing the negative impact on the environment with minimal costs.
... Sin embargo, alcanzar la sostenibilidad en la gestión de recursos implica evaluar la eficiencia en términos de ahorro de recursos naturales, disminuir la generación de residuos y su reutilización (4). Materiales sostenibles y respetuosos con el medio ambiente, elaborados a partir de materias primas secundarias y procesos de reciclaje sostenibles podrían contribuir a la reducción de las emisiones de CO2, y la reincorporación de residuos de otros sectores como el textil, en la elaboración de materiales y productos de la construcción (5). ...
La sostenibilidad en la construcción es clave en la reducción del consumo de recursos como materiales y energía, es fundamental adoptar acciones eficientes en procesos de construcción como la reutilización de residuos. Por ello, el presente trabajo analiza la influencia de la incorporación de residuos textiles posconsumo de algodón en las propiedades físico-mecánicas de compuestos de yeso. Se realizó un trabajo experimental en donde se ensayaron probetas de yeso adicionadas con fibras posconsumo de algodón en diferentes formatos, y longitudes (20 y 35mm), adiciones de 0,5% y fibras de 35mm de longitud incrementaron la resistencia a flexión y compresión en un 5,9% y 11% respectivamente, y la absorción de agua por capilaridad descendió un 26% con el 1% de adición. Finalmente se observó que las fibras reducen el desprendimiento de fragmentos de yeso al momento de alcanzar la carga de rotura, mejorando la tenacidad de los compuestos.
... Among the many construction materials, steel and cement are responsible for a large percentage of greenhouse gas emission (Allwood and Cullen 2012;Iuorio et al. 2023). For example, steel and cement contribute to 44% of industrial carbon emissions in the United Kingdom (Allwood and Cullen 2012;Giesekam et al. 2014). Recycling steel only saves approximately 50% of the energy and carbon compared with making new steel (Norgate et al. 2007) due to energy-intensive operations required for recycling steel (Burgan and Sansom 2006;Milford et al. 2013;Dunant et al. 2018). ...
Reducing carbon emissions in the construction sector is essential in a period of climate emergency. Disassembly and reuse of structural members are considered to reduce the carbon emissions from the construction and deconstruction of buildings. In this context, it is important to review the current state of the art to provide a framework for the development of future structural systems that can enable
the easy disassembly and reuse of steel-framed buildings. This paper (1) presents a review of more than 100 documents to discuss the feasibility of disassembly and reuse of structural members; (2) develops detailed schematic illustrations to explain the design concepts and the underlying mechanics governing the behavior of demountable connections; (3) sheds lights on the technical and design challenges to implement disassembly and reuse of the structural members; and (4) defines future research needs to facilitate the disassembly and reuse of the
structural members.
... Environment and occupants with strategies[6] ...
... This data is used to demonstrate that strategies which focus solely on improving operational performance of buildings and the production efficiencies of domestic material producers will be insufficient to meet sector emission reduction targets. Reductions in the order of 80% will require a substantial decline in the use of materials with carbon-intensive supply chains (Giesekam et al., 2014). ...
... Gypsum compounds with the addition of postconsumer textile fibres of cotton. Anabel Patricia Castillo-Rodríguez; Luz Alejandra Santander-Peralta; Justo García-Navarro Sustainable and environmentally friendly materials made from secondary raw materials and sustainable recycling processes could contribute to the reduction of CO2 emissions, and the reincorporation of waste from other sectors, such as textiles, in the production of building materials and products (Giesekam et al., 2014). In the European Union (EU), approximately 5.8 million tonnes of textiles are discarded every year, of which only 1.5 million tonnes (25%) are recycled by charities and industrial companies. ...
La sostenibilidad en el sector de la construcción es clave en la reducción del consumo de recursos como materiales y energía, es fundamental adoptar acciones más eficientes en procesos de construcción como la reutilización de residuos. Por ello el presente trabajo analiza la incorporación de residuos textiles posconsumo de algodón en las propiedades físico-mecánicas de compuestos de yeso. Se realizó un trabajo experimental en donde se ensayaron probetas de yeso de 4x4x16 cm adicionadas con fibras posconsumo de algodón en diferentes formatos, y longitudes (20 y 35mm), adiciones de 0,5% y fibras de 35mm de longitud incrementaron la resistencia a flexión y compresión en un 5,9% y 11% respectivamente, y la absorción de agua por capilaridad descendió un 26% con el 1% de adición. Finalmente se observó que las fibras reducen el desprendimiento de fragmentos de yeso al momento de alcanzar la carga de rotura, mejorando la tenacidad de los compuestos.AbstractSustainability in the construction sector is key in reducing the consumption of resources such as materials and energy, it is essential to adopt more efficient actions in construction processes such as the reuse of waste. For this reason, the present work analyses the incorporation of post-consumer cotton textile waste in the physical-mechanical properties of gypsum composites. An experimental work was carried out where gypsum specimens of 4x4x16 cm were tested with post-consumer cotton fibres in different formats and lengths (20 and 35mm), additions of 0.5% and fibres of 35mm in length increased the flexural and compressive strength by 5.9% and 11% respectively, and the capillary water absorption decreased by 26% with 1% of addition. Finally, it was observed that the fibres reduce the detachment of gypsum fragments at breaking load, improving the toughness of the composites.
... Upton et al. studied the impact of wood-based building materials on greenhouse gas emissions and energy consumption [75]. By applying input-output and LCA methods, the direct and implied carbon emissions of 238 cases have been studied, including the construction sector in Ireland and the United Kingdom [49,54,76]. Aye et al. found that steel structure prefabricated systems significantly reduce material consumption and carbon emissions compared with traditional concrete construction [77]. ...
The construction industry has great potential for carbon emission reduction, which strongly impacts the peak of carbon emissions and carbon neutrality. This paper compares foreign and Chinese articles on building carbon emissions from publication objects, journals, subject categories, authors, and institutions. It discusses the differences in research trends and hotspots from keywords, reference co-citation analysis, and historical citation analysis. The results show that the number of publications on building carbon emissions steadily increased. The research on building carbon emissions in foreign articles is earlier and more systematic than that in China, and the output and influence of foreign articles are generally more prominent than those of Chinese articles. However, the production and influence of articles by certain Chinese authors and institutions have been remarkable. The topics of ‘CO2 emission’, ‘life-cycle assessment’, ‘environmental impact’, ‘greenhouse gas emission’, and ‘renewable energy’ are essential subjects for foreign and Chinese articles in the research field of building carbon emissions and the development trend is similar. The thematic direction of Chinese articles is more divergent and lacks well-developed themes that greatly influence other research themes. Finally, based on the research results, this study puts forward the potential future research direction of building carbon emissions. The results of this study will provide a current and systematic overview of this field, which will be helpful for future researchers to promote the development of research on building carbon emissions.
... Pomponi and Moncaster [187] reviewed methods to minimise embodied carbon and identified 17 strategies, which include the use of low carbon materials, better design, reduction/reuse/recovery of carbon-intensive materials, use of local materials, efficient construction processes and off-site manufacturing. Giesekam et al. [85] reviewed different carbon optimisation strategies and proposed the use of alternative materials, substitution of production materials, minimising excess through improved design and manufacture, reuse and recycling of components, adaptive reuse and life extension of existing stocks as effective means. Therefore, the method of reducing embodied carbon covers an extensive scope that can be related to different phases of the life cycle of buildings. ...
Limiting global warming has become an internationally agreed target to stop the rapid and devasting consequences of climate change. Though reducing CO2 emissions is the path forward, a substantial component of the emissions stems from the processes related to the construction industry. The manufacture of cement alone accounts for 6% of global CO2 emissions. A significant challenge arises as CO2 reduction objectives must be achieved alongside the increasing demand for infrastructure caused by rapid urbanisation. This thesis explores how exploring different design solutions by varying design parameters, analysing alternative construction forms, and optimising shapes can reduce the embodied carbon of steel-reinforced concrete floors. Four interconnected optimisation studies are illustrated in this thesis: (1) shape optimisation of reinforced concrete beams using a parametric design approach to achieve practical and technically feasible solutions, considering deflection performance; (2) parametric optimisation for reinforced concrete flat slabs, coupled with a finite element model to estimate non-linear long-term deflections; (3) simultaneous optimisation of the cost and carbon emissions of concrete floors using different conventional slab designs; and (4) comparing the potential carbon savings of different optimisation strategies for concrete floors against the timeline for potential implementation. Possible variations of the optimisation outcomes depending on the selected embodied carbon coefficients and cost rates are also analysed. Shape optimised construction methods offer solutions with the minimum embodied carbon for a given set of design criteria in the long term. In the ascending order of possible reductions in embodied carbon, concrete floors can be optimised in the short term by: (1) minimising section depth to satisfy deflection limitations; (2) adopting low-strength concrete in flexural members; (3) analysing conventional alternative slab types; and (4) optimising column layouts. Nonlinear relationships observed in optimisation methods highlight key design aspects to target for maximum reductions in embodied carbon. The conclusions reached herein are presented as a set of guidelines for structural engineers to minimise the embodied carbon of concrete floor designs.
... The use of locally available materials reduces the need for transportation and intensive processing and wastage which contributes to lesser embodied energy [15][16][17]. Higher embodied energy in rapidly increases carbon footprint [19]. An increase in carbon dioxide in the atmosphere causes Global warming, a major threat to the ozone depletion and melting of Arctic and Antarctic glaciers. ...
Earth is the most primitive and traditional construction material which was used effectively with natural additives as admixtures from the ancient construction period. The zero-carbon footprint of this construction material makes it environment-friendly, economical, and sustainable. The overview on utilizing mud mortar in its best form is given by; the choice of local mud material and the role of fine aggregate to mud ratio to fulfill the strength & durability parameters. This research has been carried out by reviewing the past researchers throughout the world who have utilized mud mortar as a construction material with various natural admixtures were studied and it ensures a promising future to use these materials for sustainable construction for the people who would like to lead a life with nature without disturbing its ecological balance. A characterization case study on the Chakrapani temple compound wall made of mud mortar from an ancient site situated in Kaatumanarkoil (Komaratchi village), Kadalur district was studied with the samples collected to investigate the secret of their everlasting strength and durability properties that have withstood many man-made and natural disasters. The mineralogical characterization study on the mortar sample was performed with SEM-EDAX, FT-IR, and DSC-TGA to identify ingredients that made this construction material reach its stable form. From the SEM analysis, it is inferred that the samples have dense and minute pore structures and the presence of Calcium oxalate crystals, a stable form of calcium carbonate (lime) were present. It indicates the use of lime as a stabilizer in the mud mortar to improve its properties. The EDAX summarizes the
constituents of the mortar matrix with a major percentage of silica and secondly calcium, nitrogen, and alumina. The presence of oxygen confirms the breathable character of mud mortar. The sepiolite material formed by mud and air lime composition was profoundly found from the intense bands of FTIR analysis. The characterization study resulted in stable morphological details of the composition. These vernacular construction methods give way to the utilization of locally available materials that fulfill a comfort zone for the people living in it. Making use of local resources plays a vital role in preserving natural resources with numerous benefits in all aspects.
... As one of the main industries of the national economy, the construction industry has enormous carbon emissions. In addition, it has had a significant impact on the environment and consumes vast amounts of resources in the process of development [46,47]. The COVID-19 outbreak has had a severe impact on the global construction industry, with construction activity showing a 10-25% reduction compared to 2019. ...
With the increasingly serious global carbon emission problem, how to reduce carbon emissions has attracted a great deal of attention from academics and practitioners. Carbon emissions can be decreased more efficiently by coordinating the management of firms upstream and downstream in the supply chain, which has an increasingly important role in the low carbon process. Research on the low carbon supply chain (LCSC) has gradually evolved into important branches of global sustainable development. This paper aims to conduct a complete thematic analysis of 754 articles published between 2012 and 2021, identify the structural dimensions of evolution, and classify them according to systematic methodology. It provides a stage-by-stage summary of relevant research results from the past decade. At present, research in the LCSC field has resulted in a complete theoretical framework and research system and has formed the evolutionary path of method-policy-practice research. This study will help to promote further in-depth study of the LCSC and the fabrication and improvement of its theoretical system. It provides a valuable reference for researchers interested in LCSC, and points out the focus and direction of future research.
... This concern has forced the emergence of different types of tools to assess these impacts: through certification and standardisation, and the promotion of international standards to boost the use of the environmental labelling of construction products [71,73,74]; the development and application of life cycle assessment (LCA) in this sector [72,75,76] and the environmental management of buildings from a life cycle perspective [69,70]. However, the implementation of these standards is not always easy to achieve, due to economic, technical, practical and cultural barriers, which prevent professionals from selecting materials with a lower environmental impact [27,28]. ...
This publication presents a methodology for the evaluation of the carbon footprint of urban renewal projects. New models of architecture and urban environments that are replicated in many parts of the world are notable for the inclusion of plants and trees of all sizes and functions, which can absorb tons of CO2 and pollutants annually and produce oxygen. With the methodology developed in the present work, it is possible to analyse the amortisation period of these urban environments in terms of their carbon footprint by considering the reduction of the impact that is achieved with the increase of landscaped areas. Moreover, the carbon footprint of the construction process from the cradle to the grave can be determined as its indirect footprint. The street renewal has incorporated water-sensitive criteria, with the construction of five green areas, and of roads and pavements. The methodology identifies changes in garden designs, soil drainage, and rainwater-collection systems in terms of carbon footprint. The carbon footprint results from the execution of the work and the carbon sequestration by vegetation in a year, whereby differences are detected between scenarios. Materials and systems can be ranked according to their impact. The indirect footprint increases by a factor of 2.6 in comparison with that of a project without new green areas. However, in the long run, it is possible to triple the carbon capture capacity and halve the direct footprint during the use phase. This balance implies, at the end of the life cycle, that the carbon footprint has been reduced by 75%.
... Besides, the Architectural, Engineering and Construction (AEC) sector consumes a huge amount of raw materials (Hradil, 2012), which highlights the importance to move from a linear to a circular approach, the latter being addressed as a new strategy by the European Commission (European Commission, 2018). The use of alternative materials (Timber, hemp, bamboo, earth,...) has already been highlighted as a way to tackle the AEC environmental impact (Giesekam et al., 2014). Moreover, the material selection or substation strategy appears as one way to implement circular economy strategies (Eberhardt et al., 2020). ...
In this paper, the emphasis will be on the previous prototypes which laid the groundwork for this research project, and they will be evaluated in order to provide feedback to the design-fabrication system. These two instances, Common-action Walls in 2017, and Robotic Earth Crafts in 2018 attempted to integrate local earthen architectural knowledge with computational design and fabrication issues in order to broaden the architectural design medium. In both instances, the earth is stabilized with lime and gypsum called “Alker”, a building material that was founded by Kafescoglu and is also used in various RE buildings by Işık, both of whom are pioneers of contemporary earthen architecture research in Turkey. In these prototypes, the RE blocks made up of Alker had been supported by steel or wooden rods placed inside, because of the geometrical forms of the blocks, which go beyond the regular block shapes and exposed the need to improve new earthen mixes.
... Carbon emissions in the construction industry can be divided into operational and embodied carbon emissions, in which embodied carbon emissions include direct and indirect emissions (Giesekam et al., 2014). summarized it as ...
The carbon-intensive economy has dramatically caused global climate changes and profoundly impacted humankind. As one of the largest energy consumers, carbon emissions in the construction industry (CECI) play a crucial role in achieving the carbon neutrality goal. Government behaviors could significantly affect CECI. However, few studies have comprehensively reviewed existing literature regarding the effect of government instruments on triggering carbon reduction. A total of 1,082 papers about CECI from 51 countries/regions were retrieved in this study, while 296 relevant articles on the government behaviors in CECI were collected to conduct further analysis. Based on the bibliometric analysis with CiteSpace, the co-occurrence networks of countries/regions, institutions, keywords and cluster analysis are applied to illustrate the characteristics of previous studies. Furthermore, a research framework has been formulated to review the impact of government behaviors on CECI during the life cycle of buildings. The result indicated that government behaviors could affect CECI through three stages, i.e., material production, construction and operation, which is considered the transmission path of government behaviors towards CECI. Moreover, the findings revealed that government behaviors present the most significant impact on CECI in the following sectors: 1) the green supply chain management and waste recycling in the material production stage; 2) the green building decisions and the adoption of off-site construction in the construction stage; 3) energy conservation behaviors and green retrofit decisions in the operation stage. Finally, this study discusses prior study gaps and provides potential directions for future research.
The UK Supreme Court's ruling in "R (on the application of Finch on behalf of the Weald Action Group) (Appellant) v Surrey County Council and others (Respondents)" marks a pivotal moment in environmental law and greenhouse gas emission responsibility. The court's decision to include greenhouse gas emissions from the combustion of oil extracted from a project site within the Environmental Impact Assessment significantly broadens the scope of GHG assessments. This landmark ruling mandates a comprehensive examination of the entire project lifecycle and value chain actions, setting a precedent for more rigorous environmental accountability. The judgment emphasises causation and responsibility, underscoring the necessity for transparent and traceable environmental assessments. These are crucial for promoting best practices in sustainability and fostering innovation toward a lower-carbon economy. The article delves into the implications of this decision on the EIA process, focusing on GHG emissions and the importance of including downstream emissions in environmental assessments. It also explores the concepts of enabled emissions, control, influence, and responsibility within the value chain, highlighting the collective role of all stakeholders in mitigating environmental impacts. This collective responsibility is a call to action for everyone involved. The article references relevant judgment paragraphs (Para X) where appropriate.
The building and construction sector is one of the main sectors contributing to carbon emissions around the globe. Current emission reduction initiatives in the building and construction industry have largely lowered the share of operational carbon (OC) emissions in the project’s life cycle emissions. Achieving embodied carbon (EC) emission reductions is essential for decarbonising the sector. This study adopts a comprehensive literature review and expert interviews with key industry practitioners to identify the barriers to lowering EC emissions in the building and construction sector and to propose strategies and actions to overcome the identified barriers and further facilitate the uptake of EC considerations. The results show that the barriers fall under four categories, organisational, financial, regulatory and policy, and methodological and data availability. The study proposes the following strategies for lowering EC emissions: (1) embedding carbon reduction targets into an organisation’s strategy, (2) implementing regulations and policies, (3) integrating digital technologies for EC assessment, (4) encouraging cross-disciplinary coordination, (5) building capacity and capability, and (6) encouraging R&D initiatives. The study provides important insights into the strategies to be adopted to reduce EC emissions. Finally, an evidence-based framework is proposed to offer useful references for professionals and decision-makers in the building and construction sector when planning and implementing EC reduction strategies.
Graphical Abstract
Construction professionals and academicians/researchers are keen on sustainable solutions for buildings in a bid to reduce the increasing use of resources in the construction industry. A common mistaken belief is to consider sustainability as concerning environmental issues only, whereas “sustainability” is the triple bottom line framework, i.e., social, economic, and environmental factors of the building as a whole. Building life cycle consideration within sustainability should be considered majorly as Construction Material choice as the use of certain materials can dramatically alter the cost of construction and social hotspots. Whereas in India, there is no approach yet identified that concurrently includes all three aspects of sustainability for deciding on construction materials to adopt in residential buildings. So, there are environmental, social, and economic inferences, obstructing the sustainable performance of buildings. Sustainable performance is defined as the assessment of the sustainability level of a building and its components, as well as certifying the building based on a series of predefined sustainability parameters or categories (environmental, economic, and social). The study aims to assess parameters (sub-parameters), and their relative weights using relative importance index (RII) analysis. The results would help the development of a sustainability assessment index of residential building materials in India.
Purpose
Digital technology, which is regarded as a prominent and transformational force in modern society, encompasses a wide variety of technology that utilize digital data to process, store and transfer various types of information. Digital technologies have continually been introduced as cutting-edge information tools in order to achieve effective management of vast information that arises from the prefabrication supply chain. However, without a sufficient performance evaluation, drawbacks of technology investment, such as financial losses and ineffective resource allocation, keep occurring, which hinders the widespread implementation of digital technologies. This study demonstrates a comprehensive evaluation of digital technologies’ effects on the prefabrication supply chain based on multi-criteria decision analysis (MCDA) theory.
Design/methodology/approach
Specifically, the targeted digital technologies and project constraints were first identified through a systematic literature review. The effects of the digital technologies were then scored using a questionnaire survey. The TOPSIS model was established to quantitatively rank the effectiveness of selected digital technologies.
Findings
Overall, BIM technology shone out in the rankings and is regarded as the most beneficial digital solution by multi-stakeholders to the existing constraints, such as working efficiency. Collaboration patterns between different stakeholders and technology integration trend were also indicated.
Originality/value
Compared with existing outcomes, this study specifically focused on examining the effects of digital technologies on the prefabrication supply chain, the most significant link in the process for prefabricated structures. New findings indicate the overall performance that considered both multi-stakeholders’ preferences and project constraints. The quantitative evaluation presents a comprehensive understanding of digital technologies’ effects, enabling industrial participants to reach well-informed, strategic and profitable investment decisions.
Lap splices are the most commonly used method worldwide because they do not require specific equipment or skilled workers. However, lap splices incur high construction costs because of the long splice lengths required for large-diameter rebars in megastructures, as well as issues pertaining to material supply, labor costs, constructability, and project duration. Additionally, approximately 15% more rebar is required because of the overlap. Energy saving for a sustainable built environment is possible if the disadvantage of lap splices, which generate high CO2 emissions due to the excessive use of rebar, are resolved. Hence, mechanical rebar couplers (MRCs) have been developed. However, despite their advantages, they have not been widely applied in construction sites owing to concerns regarding safety, quality, and constructability. This is because data on MRC, including maintenance, and environmental impact, are not organized, making it difficult to select a coupler suitable for the environment during the construction stage. Therefore, a data-driven approach for selecting MRCs based on the reinforcing bar shape and structural characteristics is proposed in this study. The T-epoxy filled sleeve coupler was found to be the best in terms of seismic performance, durability, corrosion resistance, and long-term performance. In addition, using a data-driven MRC selection algorithm using the T-threaded coupler for one rebar over two floors resulted in 56% more efficient labor productivity, 15% shorter assembly time, 17% lower costs, and 26% lower CO2 emission. Using a developed algorithm, the appropriate MRC can easily and rapidly be selected for frequent design changes.
The impact of buildings on the environment is enormous. Buildings consume 40% of natural resources, use 70% of all electricity produced and their waste contributes 50% to all landfills. This situation has led to governments developing policy and regulations to mitigate the serious impacts on the planet. The emerging green building market is becoming part of the construction industry. Rapid demand for products present significant opportunities for products that can meet sustainability goals of building projects. The industry has low barriers to entry but the barriers to adoption and diffusion of new and innovative green building products are high. This is further compounded by the industries fragmented nature and its resistant to change. The research provides a comprehensive understanding of market conditions and clearly identifies factors that drive the market and those that influence the adoption and products. Research uncovered a specific set of factors that influence the development of strategies to commercialise new products into the market. Thorough analysis and understanding of these factors can be used to guide the development and advancement of hemp-lime composite products paving the way for broader adoption as a mainstream building material in the construction industry.
Achieving sustainability in building materials is a difficult task. In this research, the aim is to identify intellectual roots and to find an organized outcome of the status and trends analyzing the sustainability of Construction materials used in Building envelopes of group housing buildings and the construction industry. To provide support for the research, the PRISMA methodology is used for the extraction of related literature to identify articles for bibliometric analysis. The R-tool is then used to process the data extracted from the database in a graphical mapping analysis, which is used to evaluate the systematic literature review on this research domain. Using data from the Web of Science and Scopus databases, 50 papers were chosen for analysis. The study then extracts the annual publication on the topic, the authors' contributions, the articles' citation counts and conclusions, the contributions of various countries, enduring publications, and keywords. This study only discusses the elements that are now acknowledged in the literature to assess the sustainability of building materials, which are generally regarded as sustainable materials in India and throughout the world (environment, economics, and society). This study will help researchers and policy-makers working on the development of sustainability assessment decision-making frameworks for the selection of materials used in buildings worldwide, by providing a clear understanding of the actual work being done in this field, the necessary research gaps, and recommendations for future work.
The pervasive impact of industrialisation on our daily existence has precipitated carbon emissions that demand critical attention. Although international conventions and scholarly research have scrutinised carbon emission sources and reduction strategies, the integration of digital tools and databases for estimating embodied carbon emissions remains in an incipient phase. Consequently, this review study aims to seek to optimise opportunities for digital transformation and sustainable practices while addressing the digital carbon footprint in the building sector. Employing the PRISMA guidelines, we systematically analysed 59 publications amassed from Scopus and Web of Science databases. The study’s search parameters encompassed the analytical dimensions of “embodied carbon”, “emission data”, and “barriers to digital transformation”. Through this rigorous process, 32 salient challenges and barriers were synthesised, encapsulated within four overarching parameters: traceability, accuracy, auditability, and efficiency. At its core, this study’s primary objective resides in the evaluation of existing barriers and challenges within the realm of carbon emission estimation. By doing so, it aspires to proffer a cogent knowledge model capable of catalysing the development of digital methodologies and models that can, with a high degree of accuracy, assess the burgeoning digital carbon footprint within the expansive domain of the building sector.
The building sector, one of the most energy-consuming, is among the most current topics due to the maturing concerns about the anthropogenic factor’s impact on CO2 quantities in the atmosphere and its association with global temperature rise. Using sustainable building materials is a promising alternative in building envelope applications to improve in-use energy efficiency. These materials, having a low environmental impact, the advantage of being renewable, and low embodied energy, contribute to global sustainability. This comprehensive literature review presents a broad overview of these materials’ hygrothermal characteristics, thermal performance, and energy use. The main goal is to compile the most important research findings on these materials’ capabilities for building construction and their contributions and effects on energy performance and thermal insulation.
Using circular bio-based building materials (C3BMs) offers a viable solution to mitigate the building sector's climate and environmental impacts, yet they are still underused. The factors influencing, i.e., the barriers to and drivers for, the implementation of C3BMs need detailed investigation to boost their use. However, few studies have been done on the barriers to and drivers for C3BMs in developing countries such as Vietnam. This study explores perceived barriers and potential drivers for C3BMs with reference to the Vietnamese construction market. Firstly, a literature review is carried out to explore the existing barriers to and drivers for C3BMs both in developed and developing countries. Secondly, data collected from a questionnaire survey with building professionals in Vietnam, including architects, engineers, contractors, etc., were analysed using descriptive methods to identify the critical barriers to and drivers for C3BMs. The results indicate that "building code restriction" and "lack of design guides and tools for projects using C3BMs" are the key obstacles. Meanwhile, "government regulations and policies encouraging the use of C3BMs" and "public incentives and strategies for promoting the use of C3BMs are the most critical drivers. These findings may provide valuable information for scholars, businesses, and policymakers in promoting the utilisation of C3BMs in Vietnam.
The development of a circular economy seems more important than ever for cities. Due to urbanization and climate change, cities are forced to find new paths to a sustainable future. Climate change poses a significant threat to the environment in this regard, particularly in light of its impact on both natural and human systems. Humans are playing a vital role here. Approximately one billion tons of building debris is generated annually by the construction industry, which makes it one of the largest waste sources in the world. To mitigate climate change, we must be efficient with resources and reduce the consumption of materials and energy by delaying, shutting down, and shrinking the consumption cycle. Despite a recent spike in related literature, with 20 articles (83%) published in 2018–2019, this chapter shows that few studies have examined the connection between circular economy solutions and climate change mitigation. EVCIs (electric vehicle charging infrastructure) has been widely regarded as a strategic asset and a crucial public service for supporting the low-carbon transition in the transport sector since electrification became one of the most promising methods for a low-carbon transition. The deployment of EVCI requires massive investments, and the urgent need to combat climate change makes it important to maximize the environmental benefits of EVCI within limited resources. From a circular economy and energy transition perspective, this study proposes a set of targeted efficiency improvement strategies for provinces at various stages of development. Citizens’ multiple actions that are directed at addressing climate change demonstrate extra commitment, which leads to progress to a circular economy among waste reduction, environmentally friendly shopping, eco-friendly transportation, and reduction of domestic energy consumption. A paradigm shift in citizens’ attitudes toward climate change is necessary to combat climate change effectively, thus paving the way for a circular economy.
Emission of greenhouse gases and increasing global warming have posed serious threats to the environment and survival of mankind. Construction industry is amongst the leading polluters and currently traditional materials are being used at large scale to meet the increasing demand to construct new facilities. Concrete is a widely used material in construction industry and steel bars are often used as reinforcement. Cement being the main constituent of concrete and steel bars used in it require greater amount of energy. During the fabrication of concrete, an intensive amount of carbon dioxide (CO2) is emitted to the environment. The utilization of industrial waste (by-products) as a replacement of cement and textile waste as a reinforcement for cementitious composites represent one of the promising solutions. Use of industrial by-products not only address the waste disposal problem but also help in reducing energy demand for concrete production. This paper describes an over review on the efforts done in reducing dependence of traditional materials used in cementitious composites.
In-situ production of precast concrete (PC) members is affected by various factors, such as cost, time, quantity, lead time, number of molds, production cycle, number of cranes, and yard stock area. In particular, the yard stock area accounts for more than 84% of the total required area, which is considerably larger than the production area. This study proposes a novel scenario-based four-dimensional (4D) dynamic simulation model for sustainable in-situ production and yard stock of PC members. Using 4D simulation, this study confirms that the production and yard stock of 960 beams can be sufficiently produced on large sites of long-span and heavy-loaded buildings. Additionally, production and yard stock simulations can be quickly and easily performed according to quantity using the developed dynamic simulation algorithm. Lastly, the proposed algorithm can be used to conduct simulation studies applicable in various environments according to field conditions that change frequently.
The modern construction industry in Sri Lanka focuses on introducing environment friendly and long durable sustainable materials in constructions. Modern trend is producing different types of earth soil-based building blocks and innovating modified daub mixture-based structures. However, surface cracking and damage due to flood are the major issues that are faced in some soil-based structures. The use of cellulose fiber as a reinforcement material has many advantages such as providing adequate stiffness, strength, and bonding capacity to cement-based matrices for substantial enhancement of their flexural strength. The aim of present study was to find out the possibility of using Alkaline Hydrogen Peroxide (AHP)-pretreated cornhusk fibers as a reinforcement material to prepare soil and cement-based composite mixture for development of roofing sheets, ceiling sheets, and wall panels. The AHP pretreatment is an effective pretreatment that could be performed at room temperature and under atmospheric pressure for extracting cellulose from agro plant residue like cornhusks. Cornhusks is comparatively one of freely available agro plant residues in Sri Lanka and with required chemical composition, from which cellulose could be extracted easily from AHP pretreatment. The selected earth soil was laterite and has dark reddish color. The composite mixture was prepared by mixing of earth soil, cement, and AHP-pretreated cornhusks fibers in the weight ratios of 1:1:0.025 of, respectively, with a certain amount of water. Roofing sheets, ceiling sheets, and wall panels were prepared using the said composite mixture and were analyzed for morphological characteristics, water absorbency, flexural load, and durability. The developed composite samples have reddish to brownish color. The water absorbency, flexural load, and durability were of satisfactory level. These can be used in construction of low cost attractive and environment friendly architectural constructions especially in areas where tourists frequent in Sri Lanka.
In the absence of a benchmarking mechanism specifically designed for local requirements and characteristics, a carbon dioxide footprint assessment and labelling scheme for construction materials is urgently needed to promote carbon dioxide reduction in the construction industry. This paper reports on a recent interview survey of 18 senior industry practitioners in Hong Kong to elicit their knowledge and opinions concerning the potential of such a carbon dioxide labelling scheme. The results of this research indicate the following. A well-designed carbon dioxide label could stimulate demand for low carbon dioxide construction materials. The assessment of carbon dioxide emissions should be extended to different stages of material lifecycles. The benchmarks for low carbon dioxide construction materials should be based on international standards but without sacrificing local integrity. Administration and monitoring of the carbon dioxide labelling scheme could be entrusted to an impartial and independent certification body. The implementation of any carbon dioxide labelling schemes should be on a voluntary basis. Cost, functionality, quality and durability are unlikely to be replaced by environmental considerations in the absence of any compelling incentives or penalties. There are difficulties in developing and operating a suitable scheme, particularly in view of the large data demands involved, reluctance in using low carbon dioxide materials and limited environmental awareness.
The construction industry is known to be a major contributor to environmental pressures due to its high energy consumption and carbon dioxide generation. The growing amount of carbon dioxide emissions over buildings' life cycles has prompted academics and professionals to initiate various studies relating to this problem. Researchers have been exploring carbon dioxide reduction methods for each phase of the building life cycle - from planning and design, materials production, materials distribution and construction process, maintenance and renovation, deconstruction and disposal, to the material reuse and recycle phase. This paper aims to present the state of the art in carbon dioxide reduction studies relating to the construction industry. Studies of carbon dioxide reduction throughout the building life cycle are reviewed and discussed, including those relating to green building design, innovative low carbon dioxide materials, green construction methods, energy efficiency schemes, life cycle energy analysis, construction waste management, reuse and recycling of materials and the cradle-to-cradle concept. The review provides building practitioners and researchers with a better understanding of carbon dioxide reduction potential and approaches worldwide. Opportunities for carbon dioxide reduction can thereby be maximised over the building life cycle by creating environmentally benign designs and using low carbon dioxide materials.
The UK government has committed itself to demanding CO2 reduction targets. There is an expectation that significant carbon savings can be achieved in the construction and operation of buildings through the application of low carbon technologies. Current concentration on low carbon technologies to reduce operational energy requirements has overlooked the less significant gains possible in embodied energy. However, as gains in operational energy reduction are realised, embodied energy of the construction, maintenance, refurbishment and disposal cycle will become increasingly important in making further progress. In this position paper we suggest that the adaptable building agenda could complement the low carbon agenda by providing a vehicle for the reconciliation of the various facets of low carbon policy. This includes taking account of the need to reduce embodied energy, as buildings which are rendered obsolete significantly before their intended design life, or fail to adapt to increasing carbon reduction performance requirements, cannot be considered sustainable. There remains a need to explore to what extent these agendas, of adaptable, long life buildings and a low carbon society, are mutually beneficial and supporting, and the what extent they can be seen as competing and mutually exclusive.
Increasing the recovery of construction and demolition wastes, and the use of sustainable materials in construction is dependent on a range of drivers that influence design and project planning decisions, as well as mainstream practice on construction sites. In the absence of sustainable materials standards in UK Building Regulations, behaviour is influenced by a combination of sustainability assessment ratings (e.g. BREEAM and the Code for Sutainable Homes), waste regulations, landfill taxes and planning guidance. However, there is still a lot of work to be done to achieve consistent and widespread improved waste recovery performance and procurement of sustainable materials. This paper presents the authors' views on the efficacy of current drivers, supported by a case study analysis and pilot survey of industry views. Indicating gaps between rhetoric, aspiration and delivery, it compares UK policy, regulatory and voluntary drivers with approaches in the Netherlands and Germany.
Previous research has suggested that the major barriers to increasing market share of wood products in non-residential building applications in Australia are fire performance and overall designer confidence in commercial and industrial timber-based construction. While the issue of fire performance is being addressed both through design solutions and amendments to building codes and standards, the issue of overall confidence in the use of wood as a structural material in non-residential applications requires further exploration.
With the objective of determining the key reasons driving specifier confidence, focus groups and Interviews were held with 34 designers/ specifiers during March and April 2005. The issues deemed to be significant were similar to those found in previous studies. These issues were:
· a lack of available information and assistance with timber design;
· timber marketing that is targeted towards the residential sector and not segmented for specific building applications;
· lack of tertiary level training;
· lead times and cost;
· commercial risk;
· and the lack of connection detailing and timber fabricators to erect non-residential buildings
A range of strengths and weaknesses relating to the structural application of timber for non-residential purposes were highlighted, confirming that specifiers have reservations about its use as a viable product for certain high-performance applications. The more positive aspects related to:
· aesthetics,
· easy construction and adaptability of design;
· character;
· fire performance; and
· energy.
Negative structural aspects concerned:
· performance,
· cost, and
· speed of erection.
Specifiers indicated that timber would work better in buildings where there was a link to human growth and development, or community spirit, so that timber could be enjoyed. These building types included:
· residential care facilities;
· educational buildings;
· community and public buildings, and
· small stand-alone offices and clinics.
The architects also noted that the more promising building applications were smaller building types (eg. churches, clinics, community halls), and stated that this is where the industry should concentrate on expanding into initially, before targeting the larger storey buildings such as warehouses and multi-storey office blocks. It was noted that there is a large difference between type A and Type C buildings in the Building Code, especially regarding fire issues.
There are three recommended promotional strategies that the Australian industry should take to enhance specifier confidence in using timber in non-residential applications:
· Address negative perceptions of timber performance and appropriateness in non-residential applications, particularly focussing on issues with perceived commercial risk
· Use environmental assessment data to highlight the sustainable benefits of using timber in place of other competing materials, to gain a pull through from the market and increase the desire to specify with timber.
· Make timber design and technical information more readily available to specifiers in a format they find useful and useable.
Ensis recommends the following priority initiatives be employed to implement these strategies:
· Create a ‘one stop shop’ information centre for specifiers looking for timber design information.
· Develop a market for ‘green’ buildings using structural timber.
· Develop and provide design aids for timber building structural analysis.
· Provide and promote case study publications.
· Provide technical brochures and fact sheets to address negative perceptions, particularly relating to perceived commercial risks, and market to a wider specifier audience (developers, quantity surveyors and insurers also).
· Develop and support hybrid steel-timber components and enhanced connection details.
Geopolymers are a novel class of inorganic polymers, which have the potential to replace Portland cement in a number of different applications. Geopolymers can utilise a higher level of industrial by-products than Portland cement blends and numerous studies have concluded geopolymer concretes have significantly lower embodied carbon dioxide than Portland-cement-based concretes. This paper examines the potential for the use of geopolymer binders as a Portland cement replacement in the UK. The quantities of material required, the major sources of these materials, the environmental implications and the barriers to implementation are discussed.
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The latest carbon dioxide emissions continue to track the high end of
emission scenarios, making it even less likely global warming will stay
below 2 °C. A shift to a 2 °C pathway requires immediate
significant and sustained global mitigation, with a probable reliance on
net negative emissions in the longer term.
Geopolymer concrete is seen as a potential alternative to standard concrete, and an opportunity to convert a variety of waste streams into useful by-products. One key driver in geopolymer development is the desire to reduce greenhouse gas emissions from the production of concrete products. This paper presents an examination of the lifecycle cost and carbon impacts of Ordinary Portland Cement (OPC) and geopolymers in an Australian context, with an identification of some key challenges for geopolymer development. The results of the examination show that there is wide variation in the calculated financial and environmental “cost” of geopolymers, which can be beneficial or detrimental depending on the source location, the energy source and the mode of transport. Some case study geopolymer concrete mixes based on typical Australian feedstocks indicate potential for a 44–64% reduction in greenhouse gas emissions while the financial costs are 7% lower to 39% higher compared with OPC.
Fiber reinforcement can effectively improve the toughness, shrinkage, and durability characteristics of concrete. The use of recycled fibers from industrial or postconsumer waste offers additional advantages of waste reduction and resources conservation. This paper reviews some of the work on concrete reinforcement using recycled fibers, including tire cords/wires, carpet fibers, feather fibers, steel shavings, wood fibers from paper waste, and high density polyethylene. This paper also provides a summary of the properties and applications of concrete reinforced with these fibers.
Recital 16 of the Energy Performance of Buildings Directive (EPBD) requires the energy certificate to describe a building's actual energy-performance situation to the extent possible. If we wish to achieve the rapid reductions in energy use and CO 2 emissions that the EPBD anticipates, it is vital that this clause is taken seriously. It provides a fantastic opportunity to report actual energy use clearly, to grade it against a clear description of the building in use, and to relate it transparently to expectations at the design stage. This will at last begin to close the feedback loop, reduce the credibility gaps that so often occur between design expectations of energy efficiency and actual fuel consumption outcomes, and consequently lead to more rapid improvements in building energy performance. Credibility gaps arise not so much because predictive techniques are "wrong", but because the assumptions often used are not well enough informed by what really happens in practice, because few people who design buildings go on to monitor their performance. While some differences are legitimate (e.g. the building is used more, or has more things in it), surveys nearly always reveal avoidable waste - which can arise from poor briefing, design, construction and commissioning, and not just bad training, bad maintenance and bad management. A widespread problem is control systems which just do not work, or have poor management and user interfaces, resulting in equipment defaulting to ON unnecessarily. To achieve genuine step-change improvements, procuring clients, design and building teams, users and managers will all need to engage much more closely with achieved performance. Better transparency between intentions and outcomes will release drivers towards better assumptions, better predictions, better design, better implementation, and better management of both the procurement and the product. We discuss how certification might be developed to help identify and close the credibility gaps, and present an idea for an energy certificate which takes these issues into account.
Steel production is energy intensive so already has achieved impressive levels of energy efficiency. If the emissions associated with steel must be reduced in line with the requirements of the UK Climate Change Act, demand for new steel must be reduced. The strategies of 'material efficiency' aim to achieve such a reduction, while delivering the same final services. To meet the emissions targets set into UK law, UK consumption of steel must be reduced to 30 per cent of present levels by 2050. Previous work has revealed six strategies that could contribute to this target, and this paper presents an approximate analysis of the required transition. A macro-economic analysis of steel in the UK shows that while the steel industry is relatively small, the construction and manufacturing sectors are large, and it would be politically unacceptable to pursue options that lead to a major contraction in other sectors. Alternative business models are therefore required, and these are explored through four representative products-one for each final sector with particular emphasis given to options for reducing product weight, and extending product life. Preliminary evidence on the triggers that would lead to customers preferring these options is presented and organized in order to predict required policy measures. The estimated analysis of transitions explored in this paper is used to define target questions for future research in the area.
Oxidative stress can be a final common pathway for AED-induced teratogenesis.
To compare the oxidative stress of women with epilepsy (WWE) and unfavorable pregnancy outcome (fetal malformation or spontaneous abortion - group EM) with that of WWE with normal pregnancy outcome (group ENM) and healthy women with normal pregnancy outcome (group C).
We identified WWE under group EM (n = 43) and group ENM (n = 22) from the Kerala Registry of Epilepsy and Pregnancy (KREP). Group C was constituted of healthy volunteers (N = 20). Oxidative stress was assessed by estimating serum levels of malondialdehyde (MDA) and isoprostane (ISP). The antioxidant profile was evaluated as activity of superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT), total antioxidant status (TAO), and glutathione (GSH) content.
The MDA and ISP levels for group EM (3.46 + 0.82 and 17.77 + 3.0) were higher than that of group ENM (3.07 + 1.02 and 14.0 + 5.3), and both were significantly higher than that of group C (2.42 + 0.51 and 10.77 + 4.1). Their levels of SOD (146.82 + 42.64 vs. 175.81 + 42.61) and GSH (0.98 + 0.98 vs. 1.55 + 1.3) were significantly lower than those of controls. No significant changes were seen in TAO and GR. WWE on polytherapy showed significant increase in MDA when compared to monotherapy group.
WWE (group EM and ENM) had higher oxidative stress and reduced antioxidant activity. The subgroup of WWE with unfavorable pregnancy outcome (group EM) had higher oxidative stress. Excess oxidative stress can be a final common pathway, by which AEDs exert teratogenic effects.
In 2007, the UK Government announced an ambitious zero-carbon target for all new housing in England. This paper shows how the definition and its associated policies emerged from discourses of environmental policy innovation; how the problem subsequently became framed as one of mainstreaming, consequent upon the apparent success of experimental schemes and defined in more detail through the interaction between pressure group politics and the technical analyses that accompanied the government's consultation exercises. Finally, it shows how regional and local variations in housing and property markets are likely to influence the ease of zero carbon development. The analysis uses concepts drawn from both the science and technology literature and the literature on policy implementation.
The prospects of sustainable concrete construction in the developed world are discussed. The operation of buildings consumes more energy than any other activity, and consequently lifetime efficiency of buildings is a major determinant of the total energy demand. Extraction scars a lot amount of land, often near population centers and sensitive areas of landscape. Concrete has much potential for use in an environmentally beneficial ways, as its strengths include high thermal mass, good sound insulation, and flexibility of form.
It is widely acknowledged that the UK building sector is one of the key contributors to carbon emissions, as it is accountable for around 50% of carbon emissions, 27% of which are a product of domestic building construction and operation. As a result, the UK government announced that all new houses are to be zero carbon by 2016. However, the current recession has left the UK construction industry facing its toughest challenges for a generation with the housing sector among those to have sustained the worst damage. Indeed, recent figures reveal that housing orders in the UK were down 30%, amounting to an overall 18% yearly decrease. Hence, a quantitative methodology, consisting of a questionnaire survey sent to 100 UK architects specializing in residential design, was adopted in this research to investigate the effect of the current recession on zero carbon housing design practices in the UK. Results indicate that certain types of clients have been considerably affected more than others; with particular reference to large house builders, who appear to have suffered the most. Additionally, it appears that for many architectural practices, sustainability is no longer as important as making a profit; and for the majority of participants, the zero carbon housing agenda is not a design priority. However, a number of the problematic sustainable design issues identified during the course of the research were not exclusively as a result of the recession. Considerable difficulties had been experienced by the majority of architects concerning the lack of clarity and interpretation of the legislation surrounding low and zero carbon housing design. It is interesting to note, however, that the associated financial impact of zero carbon housing construction preceded the onset of the current recession; with particular challenges faced as a result of the legislative requirement to use onsite micro renewable energy solutions. The participating architects went further to argue that such strategies are generally considered to be too expensive, ineffective and under-developed to be the primary energy source for new housing developments.
Admixtures can reduce the embodied carbon content of concrete (ECO 2), despite having a relatively high ECO2 themselves when compared on a ton-for-ton basis. Admixtures are used in very small dosages compared to most other ingredients, and as such they typically contribute less than 1% to the total ECO2 of concrete, while allowing the overall cement content to be reduced. Under BS EN ISO 14044 constituents contributing less than 1% of the impacts can be ignored, and this would apply to most cases of admixture usage. Although admixtures are composed of a wide range of raw materials, they are not generally toxic and indeed most of them have been individually assessed for use in concrete in contact with drinking water by the UK's national water regulators. The assessment covers toxicology of the individual substances in the admixture and leaching tests from concrete.
The demand of traditional building materials such as straw, hemp, lime, and unfired clay for construction purposes have increased considerably in the UK because of their environment friendly properties. The development of these materials in modern construction processes is being led by the BRE Centre in Innovative Construction Materials at the University of Bath, the UK. Earth building methods such as cob and rammed earth involve low energy costs than wall construction, while straw bales are less expensive and provide high degree of thermal insulation through thick walls. Architects of White Design Associates and Integral Structural Design engineering consultancy have also developed the use of prefabricated modular straw bale (ModCell) panel construction in the UK, which maintains the benefits of straw bales while using the modern construction methods. The use of hemp and hydraulic lime in a composite light-weight material, hemcrete or hemp-lime, also is a unique innovation and has great future potential.
Cement is the second largest anthropogenic emission source, contributing approximately 7% of global CO2 emissions. Carbon dioxide capture and storage (CCS) technology is considered by the International Energy Agency (IEA) as an essential technology capable of reducing CO2 emissions in the cement sector by 56% by 2050. The study compares CO2 capture technologies for the cement manufacturing process and analyses the economic and financial issues in deploying CO2 capture in the cement industry. Post-combustion capture with chemical absorption is regarded as a proven technology to capture CO2 from the calcination process. Oxyfuel is less mature but Oxyfuel partial capture—which only recycles O2/CO2 gas in the precalciner—is estimated to be more economic than post-combustion capture. Carbonate looping technologies are not yet commercial, but they have theoretical advantages in terms of energy consumption. In contrast with coal-fired power plants, CO2 capture in the cement industry benefits from a higher concentration of CO2 in the flue gas, but the benefit is offset by higher SOx and NOx levels and the smaller scale of emissions from each plant. Concerning the prospects for financing cement plant CO2 capture, large cement manufacturers on average have a higher ROE (return on equity) and lower debt ratio, thus a higher discount rate should be considered for the cost analysis than in power plants. IEA estimates that the incremental cost for deploying CCS to decarbonise the global cement sector is in the range US60 to avoid each tonne of CO2 emissions. However, the expectation is that the current market can only provide a minority of financial support for CO2 capture in cement plants. Public financial support and/or CO2 utilisation will be essential to trigger large-scale CCS demonstration projects in the cement industry.
In this study a Building Information Model (BIM) tool is developed to simultaneously estimate embodied and operational carbon over a 60 year life span for a typical four bedroom detached house. Using the tool, four different construction scenarios are evaluated, representing a range of current construction methods used in present day UK house building. The results show that cradle-to-gate embodied carbon represents 20-26% of the total 60 year carbon emissions, with operational carbon representing 74-80% of total emissions. Construction scenarios that reduce operational carbon by improving the thermal envelope led to a 1-13% increase in embodied carbon but a 4-5% decrease in operational carbon compared to the basecase construction method. Approaches to reduce embodied carbon in new-build housing are also studied and a 24% reduction is demonstrated through building fabric changes. The study recommends that a universally robust methodology for measuring embodied carbon will enable design decisions to be taken to reduce whole life carbon emissions through improved choice of materials. Due to material changes impacting on the thermal characteristics of a dwelling, and to an extent the structural characteristics, an integrated BIM tool will be essential in quickly establishing whole life carbon impacts during the design stage.
The concepts of green building and sustainable construction have received tremendous interest in North America in the past decade, as shown by the growth in the numbers of L.E.E.D.™ certified projects (Kibert 2005). Parallel to this has been a growing interest in natural, vernacular, or traditional building materials and techniques. Examples of these include straw bale construction and rammed earth construction. From an environmental point of view, these materials offer a low embodied energy and low embodied carbon alternative to conventional building materials such as concrete and steel (Woolley 2006, Walker 2007). In the case of straw bale construction, use is made of a waste material with excellent insulation properties. Other benefits of many natural materials include their ability to passively regulate humidity in a building, reduced toxicity, high thermal mass, and biodegradability at the end of life (Walker 2007). There remain many barriers to the use of natural building materials in the mainstream construction industry, including a lack of scientific data to quantify their true performance (Woolley 2006) and lack of experience by the mainstream construction industry in using these materials. This leads to the perception that these materials are low-tech and have poor performance. This perception, however, is changing. There is a growing body of research that is quantifying the performance of natural building materials and showing that they can compete with conventional building materials. There are also some excellent recent examples of the integration of natural building materials in mainstream construction projects. This paper describes three natural building material products that have been successfully integrated into mainstream construction projects in the United Kingdom: straw bale panels by ModCell; a hemp-lime composite called hemcrete and marketed by Tradical; and, rammed earth and unfired clay bricks. The information in this paper is based on interviews and site inspections undertaken by the author during February 2008. Some of the research supporting the use of these products will be described. Finally, some lessons and cautions for the use of these products in North America will be discussed. A caveat regarding the limitations of this paper is in order. This paper does not claim to be an exhaustive review of natural building materials and their performance. Other references should be consulted for more details on thermal or fire performance, for example.
There has been growing interest in the use of non-conventional materials in the construction industry, and their introduction has presented both opportunities and challenges to researchers and engineers worldwide. This paper gives a brief overview of new and emerging materials in construction. The background to their introduction is introduced and discussed within the context of sustainable construction, with the significance of sustainable material selection highlighted. Attention is specifically drawn to the importance of considering both the cost and environmental implications when any new material is introduced into construction. The main barriers to application of new materials within the construction industry are discussed in detail with reference to the development of an advanced composite bridge decking system. Based on this, a successful model for conversion from academic excellence to commercial viability is suggested.
Fibre reinforced polymers (FRPs) are increasingly being used in construction due to their light weight, ease of installation, low maintenance, tailor made properties, and corrosion resistance. The UK FRP industry produces 240,000 tonnes of products a year with 11% of this being for the construction industry in a variety of structural and on-structural applications. Products made from FRP materials can offer significant environmental benefits, for example, FRPs used in bridges can reduce the overall weight of the structure and so offer reduced transport and installation impacts. However, although the in service environmental benefits of composites are known, there is far less understanding of the environmental and social implications associated with the manufacture of FRP materials and products.
Current and impending waste management legislation will put more pressure on the industry to address the options available for dealing with FRP waste. Such waste legislation focuses on dealing with waste through the w aste hierarchy and will therefore put more pressure on solving FRP waste management through recycling and reuse. At present the most common disposal method for UK FRP waste is landfill. To assist in the transition from disposal in landfill to recycling, the FRP industry needs to consider designing materials and components for easier deconstruction, reuse and recycling at the end of the product life.
This paper will highlight the key issues affecting the FRP industry, taking a cradle to grave approach and assessing the environmental impacts at each stage.
To achieve broader acceptance by the construction sector, novel and innovative materials and technologies often have to overcome a variety of market barriers. To evaluate attitudes to nonconventional materials and technologies in the UK, sixty-two construction professionals were surveyed on their opinions and views, how often these materials are used, and what influences their specification and use in building projects. Survey data have been analysed using qualitative techniques influenced by grounded theory to form an understanding of the construction industry and non-conventional building materials. Initial findings suggest that the most important barriers to market acceptance are high costs, lack of technical knowledge, and lack of client understanding. Proposed solutions suggested include increasing client and designer awareness through case studies, and knowledge sharing with professional with previous experience with non-conventional materials and legislative incentives.
Global awareness of environmental impacts such as climate change and depletion of ozone layer has increased significantly in the last few years and the implication for emissions reductions in buildings are widely acknowledged. The goal, therefore, is to design and construct buildings with minimum environmental impacts. Lifecycle emissions resulting from buildings consist of two components: operational and embodied emissions. A great deal of effort has been put into reducing the former as it is assumed that it is higher than the latter. However, studies have revealed the growing significance of embodied emissions in buildings but its importance is often underestimated in lifecycle emissions analysis. This paper takes a retrospective approach to critically review the relationship between embodied and operational emissions over the lifecycle of buildings. This is done to highlight and demonstrate the increasing proportion of embodied emissions that is one consequence of efforts to decrease operational emissions. The paper draws on a wide array of issues, including complications concerning embodied emissions computation and also discusses the benefits that come with its consideration. The implication of neglecting embodied emissions and the need for an urgent policy framework within the current climate of energy and climate change policies are also discussed.
The proper use of alternative fuels and materials in the cement industry is essential for the planning and promotion of different methods that can decrease the environmental impacts, lower the consumption of energy and material resources, and reduce the economic costs of this industry. Because of the great potential for the cement industry to save energy and reduce greenhouse gas emissions (GHG), many new research advances associated with the promising approach of introducing waste materials as alternative fuels or sustainable raw materials into the cement manufacturing process have been developed in recent years. Therefore, the main objective of this paper is to provide a literature review of these approaches based on previously published research studies. The analysis is specially focused on the technical, economic, and environmental effects of the uses of five solid wastes, namely, municipal solid waste (MSW), meat and bone animal meal (MBM), sewage sludge (SS), biomass, and end-of-life tyres (ELT), in the cement industry.
Bricks are a widely used construction and building material around the world. Conventional bricks are produced from clay with high temperature kiln firing or from ordinary Portland cement (OPC) concrete, and thus contain high embodied energy and have large carbon footprint. In many areas of the world, there is already a shortage of natural source material for production of the conventional bricks. For environmental protection and sustainable development, extensive research has been conducted on production of bricks from waste materials. This paper presents a state-of-the-art review of research on utilization of waste materials to produce bricks. A wide variety of waste materials have been studied to produce bricks with different methods. The research can be divided into three general categories based on the methods for producing bricks from waste materials: firing, cementing and geopolymerization. Although much research has been conducted, the commercial production of bricks from waste materials is still very limited. The possible reasons are related to the methods for producing bricks from waste materials, the potential contamination from the waste materials used, the absence of relevant standards, and the slow acceptance of waste materials-based bricks by industry and public. For wide production and application of bricks from waste materials, further research and development is needed, not only on the technical, economic and environmental aspects but also on standardization, government policy and public education related to waste recycling and sustainable development.
To meet targeted reductions in CO2 emissions by 2050, demand for metal must be cut, for example through the use of lightweight technologies. However, the efficient production of weight optimized components often requires new, more flexible forming processes. In this paper, a novel hot rolling process is presented for forming I-beams with variable cross-section, which are lighter than prismatic alternatives. First, the new process concept is presented and described. A detailed computational and experimental analysis is then conducted into the capabilities of the process. Results show that the process is capable of producing defect free I-beams with variations in web depth of 30–50%. A full analysis of the process then indicates the likely failure modes, and identifies a safe operating window. Finally, the implications of these results for producing lightweight beams are discussed.
Identifying strategies for reconciling human development and climate change mitigation requires an adequate understanding of how infrastructures contribute to well-being and greenhouse gas emissions. While direct emissions from infrastructure use are well known, information about indirect emissions from their construction is highly fragmented. Here, we estimated the carbon footprint of the existing global infrastructure stock in 2008, assuming current technologies, to be 122 (-20/+15) Gt CO2. The average per-capita carbon footprint of infrastructures in industrialized countries (53 (±6) t CO2) was approximately 5 times larger that that of developing countries (10 (±1) t CO2). A globalization of Western infrastructure stocks using current technologies would cause approximately 350 Gt CO2 from materials production, which corresponds to about 35-60% of the remaining carbon budget available until 2050 if the average temperature increase is to be limited to 2°C, and could thus compromise the 2°C target. A promising but poorly explored mitigation option is to build new settlements using less emissions-intensive materials, for example by urban design; however, this strategy is constrained by a lack of bottom-up data on material stocks in infrastructures. Infrastructure development must be considered in post-Kyoto climate change agreements if developing countries are to participate on a fair basis.
The transition towards a low-carbon infrastructure requires an understanding of the embodied carbon (eCO2) associated with concrete. However, much current work on eCO2 underestimates the complexity of its relationship with concrete mix design. This paper demonstrates how eCO2 of concrete is not a simple function of strength. Rather, for a given strength, considerable eCO2 savings can be made by careful attention to basic mix design. Replacement of cement with PFA (pulverised fuel ash) can achieve considerable savings; additionally, using a concrete of lower workability, employing a superplasticiser, using crushed rather than rounded aggregate and using a higher strength of cement can have comparably significant effects. The analysis is presented in terms of embodied carbon per unit strength; this shows that there is an optimum strength for all concretes (with regard to minimising eCO2 per unit of structural performance) of between 50 and 70 MPa.
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This briefing discusses the current challenges to the deployment of straw bale walling systems in the UK. A short historical context is described and the major areas of scientific interest are discussed. These areas include the environmental, thermal, acoustic, structural and durability performance of straw bale walling systems in relation to their properties. Current values and measurements of these properties are discussed along with a short introduction to the major researchers and institutions researching the design and attributes of straw bale walls. The briefing concludes that the evolution of straw bale walling systems is rapidly developing and can, when appropriate solutions to potential risk issues are used, provide the basis for comfortable and sustainable buildings
The North American nonresidential construction sector represents a substantial market for structural building materials, yet it is relatively untapped by wood. This study explored wood use and perceptions held by architects and engineers with respect to the structural use of wood in nonresidential buildings, using an extensive mail survey and a series of specifier focus groups in select geographic regions. Several clear barriers for wood emerged across code, technology transfer, and research and development cat- egories. Key problem areas identified were fire-related building code limitations, wood's cost-competitiveness with steel, wood's design difficulty, and poor training for designers and wood tradespeople. Recommendations for addressing these impedi- ments in both the short and long term are offered.
The environmental impact of Ordinary Portland Cement (OPC) is significant because its production emits large amounts of CO2. Further, OPC durability is limited largely due to inherent brittleness. This review examines the environmental and economic impacts of OPC. Using supplementary cementitious materials to enhance material greenness or produce alternative binders such as geopolymers is discussed. This is followed by a review of recent efforts to increase durability through fiber reinforcement. Finally, the current state of the art of geopolymer composites (with both high material greenness and high durability) is discussed along with opportunities and challenges for these promising materials.
If formulated optimally, geopolymer cement made from fly ash, metallurgical slags and natural pozzolans could reduce by 80% the CO2 emissions associated with the manufacturing of cement. However, almost all standards and design codes governing the use of cementitious binders and concrete in construction are based on the use of Portland cement. The 100+ year track record of in-service application of Portland cement is inherently assumed to validate the protocols used for accelerated durability testing. Moreover, the entire supply chain associated with cementitious materials is based on the production of Portland cement. The geopolymerisation of aluminosilicates constitutes a radical change in construction materials chemistry and synthesis pathways compared with the calcium silicate hydrate chemistry which underpins Portland cement. Consequently, there are regulatory, supply chain, product confidence and technical barriers which must be overcome before geopolymer cement could be widely adopted. High profile demonstration projects in Australia have highlighted the complex regulatory, asset management, liability and industry stakeholder engagement process required to commercialise geopolymer cement. While the scale-up from the laboratory to the real-world is technically challenging, the core challenge is the scale-up of industry participation and acceptance of geopolymer cement. Demand pull by a carbon conscious market continues to be the key driver for the short term adoption of geopolymer cement. In the absence of an in-service track record comparable in scale and longevity to Portland cement, research is essential to validate durability testing methodology and improve geopolymer cement technology. Colloid and interface science, gel chemistry, phase formation, reaction kinetics, transport phenomena, comminution, particle packing and rheology, which are familiar concepts to minerals engineers, are also key building blocks in the development of geopolymer knowledge. Analysis of the nanostructure of geopolymer gels has enabled the tailored selection of geopolymer precursors and the design of alkali activator composition, aiding in establishing the relationship between geopolymer gel microstructure and durability.
The growing demand for everything green to promote sustainability is being felt increasingly in the building and construction industry. The internationally recognised LEED initiative of the US Green Building Council promotes alternative, energy-efficient materials, which is good for composites. So are the building codes and standards being written for FRP materials. Richard Stewart reports on the latest R&D and innovative applications of composites in construction.
This paper describes various walling systems capable of providing an ultra low U-value wall construction for use in a domestic application. The target U-value is 0.11W/m2K - 36% less than the minimum requirement for the German 'Passivhaus' standard and some 60-70% more onerous than current UK building regulations; this value was chosen because of the high degree of challenge it presents whilst remaining technologically achievable. The paper briefly discusses whether static U-value is truly relevant to most domestic applications in the UK, or whether it is the less understood dynamic U-value that should be the focus of attention. The positive and negative characteristics, including wall thicknesses, embodied energy, toxicity, expected lifespan and ease of installation, of various systems are discussed. Test data provided by manufacturers to support U-value claims are carefully examined. The walling systems discussed cover a broad range of technologies, including structural insulated panels (SIPs), vacuum insulation panels (VIPs), insulating concrete formwork, traditional cavity wall masonry, external insulation of masonry and cellulose-based systems such as straw. The paper concludes by summarising the benefits of each system type and recommending applications that are particularly suitable for each type of wall.