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In recent years, human activities especially in construction industry are causing negative impacts towards the environment. Construction industry currently faces challenges towards the implementation of sustainable development worldwide where we need to enhance and protect our natural environment without damage and destruction. Hence, the responsibilities of construction industry towards sustainable development are vital to be taken by implementing green technology into their project. Applications of green technology have been implemented internationally in order to reduce negative impacts to the environment. However, the use of green technology in Malaysian construction industry especially in Sarawak is one of the crucial issues since it is still at the low level of application. Hence, the aim of this research paper is to identify the adoption of green technology among the contractor in Central Region of Sarawak, Malaysia. This paper presents the result by using distribution of questionnaire as a main research method. About 200 respondents of construction player in Sarawak has been participated with have a strong experienced in the said issues highlighted. The survey however, has identified that most of construction player in Sarawak were refuse to use the existing green technology and choose to stick with the conventional types of projects due to their limited knowledge and expertise. [ABSTRACT FROM AUTHOR]

Abstract Attitudes in the construction industry towards emissions and cleaner production are mixed. Many in the industry do not measure their emissions, or show awareness or progress towards minimizing emissions, but rather focus on more traditional matters of time, cost and production. Some writers suggest cost, or an industry perception of extra cost, as a main barrier to implementing more sustainable practices. There has been a slow shift to a sustainability mindset, but commonly this shift is only embarked upon if there are parallel cost savings. A realistic business view is that sustainability in the construction industry will only be achieved if parallel cost reductions occur. Within this debate, the paper puts forward the proposition and shows that, for a defined type of construction operation, performing at minimum unit cost (cost per production) also leads to minimizing unit emissions (emissions per production). The implication of this is that, within an existing operation, least unit emissions can be achieved without an increase in unit cost; alternatively, traditionally efficient ways of undertaking construction have the least environmental impact. Conversely, not operating at minimum unit cost leads to unnecessary emissions. The paper demonstrates this on an array of construction practices, and opines that similar results will hold for related construction operations. Graphical abstract Image 1 Highlights • Unit cost and unit emissions performances coincide for many construction operations. • Cleaner production need not lead to increased cost. • Not operating cost efficiently leads to unnecessary emissions. [ABSTRACT FROM AUTHOR]

The present paper details about the application of high volume copper slag in concrete. The study leads towards cleaner production by, utilizing the land-filled or stockpiled industrial by-product copper slag as an alternative to natural river sand in concrete. The current global production of copper slag is about 40 million tonnes which if utilized properly will be a sustainable substitute for tremendous demand of natural aggregate, worldwide. In literature, several studies have highlighted promising aspects of copper slag in developing it as a valuable resource. However, there are very limited studies available on the performance of copper slag in concrete at the structural level and its possible life cycle effects in concrete construction. The present research is aimed to bridge the aforementioned gap. The contributions from the paper are a comparative evaluation on the effect of substituting 100% natural sand with copper slag in terms of (i) load capacity, ductility and failure behavior in all failure modes such as shear, flexure and mixed (ii) total embodied energy and the global warming potential. From the overall studies, it is concluded that high volume copper slag with 100% replacement as fine aggregate in concrete structures is technically viable. [ABSTRACT FROM AUTHOR]

In the face of a changing climate, a growing number of construction firms are adopting carbon reduction targets on individual projects and across their portfolios. In the wake of the Paris Agreement, some firms are seeking a means of aligning their targets with sectoral, national and international mitigation commitments. There are numerous ways by which such an alignment can be achieved, each requiring different assumptions. Using data from the UK construction industry, this paper reviews current company commitments and progress in carbon mitigation; analyses the unique challenges in aligning construction targets, and presents a series of possible sectoral decarbonisation trajectories. The results highlight the disparity between current company targets and the range of possible trajectories. It is clear that a cross-industry dialogue is urgently required to establish an appropriate response that delivers both a widely-accepted target trajectory and a plan for its delivery. This paper is intended to stimulate and support this necessary debate by illustrating the impact of different methodological assumptions and highlighting the critical features of an appropriate response. [ABSTRACT FROM AUTHOR]

Global warming is one of the global major issues owing to excessive emission of greenhouse gases (GHGs). Construction industry accounts for about 40% of the total emissions and conventional building materials are believed to be the major contributors. This paper attributes to the potential of manufacturing environmental friendly building material namely EnO-Roofing tiles by utilizing only catalyzed waste engine oil (WEO) as a binder together with coal-fired ash (CFA). It was discovered that waste engine oil under specific temperature and condition would induce its chemical transformation from liquid to solid state via complex oxy-polymerization reaction. The functional groups of waste oil which initiated the chemical reactions and led to the stiffening of tiles were analyzed by using Fourier Transform Infrared Spectroscopy (FTIR). In addition, a series of manufacturing processes were carried out to determine the optimized condition for the production of catalyzed EnO-Roofing tiles. Standard specification tests for EnO-roofing tiles were conducted in terms of flexural strength, water absorption and permeability as per requirement of American Society for Testing and Materials (ASTM C 67–07a, C 1167–03, and C 1492–03). Moreover, the embodied carbon (EC) and embodied energy (EE) of the novel tiles were found at 0.4178 kgCO 2 /kg and 1.27 MJ/kg respectively, which is relatively lower with respect to the conventional roofing tiles. Conclusively, conversion of existing resources, recycled and reused waste materials, manufacture of environmental friendly roofing tiles are the prominent outcome of this paper. [ABSTRACT FROM AUTHOR]

The construction sites are prone to environmental incidents. In this paper, the root causes of incidents and immediate actions taken after events are identified through qualitative analysis, while the environmental impacts, the cost of mitigation, time of incident occurrence, as well as the relationship between the causes of incidents and immediate actions and the causes and environmental impacts were quantitatively analysed. In total, 499 environment incidents occurred over an 8-year period on the construction sites in Australia was examined in this study. The results show that the most common causes of incidents were equipment and plant failure, oil spillage, and fuel spillage, while the most expensive incidents in terms of mitigation were flooding, poor weather, and process failures. Further, the most common actions taken immediately after incidents were cleaning and clearing, shut down of operation, plant and equipment and notifications. More than 50% of incidents resulted in the contamination of land and groundwater, while the majority of incidents occurred between 10:00 am and 12:00 am. We propose strategies for project managers and environmental managers to better understand potential environmental hazards. [ABSTRACT FROM AUTHOR]

The environmental effects of construction equipment emissions have been studied in previous research. Total emissions for construction activities and projects were previously calculated for various transportation projects as well as for other project types. This paper focuses on how contractors can use different equipment combinations and make project schedule adjustments to reduce total emissions from construction projects. It presents a newly developed optimization model that companies can use to select a fleet for a particular project to achieve the reductions. The model can be used to minimize total equipment cost and total emissions, or to minimize total equipment cost while limiting (capping) emissions for one or more of six pollutants. When the model was applied to example construction projects, the predicted reductions in emissions were significant, ranging from 25 to 85% depending on the pollutant. When the model was used to minimize cost, a reduction of 63% of the total equipment cost was achieved from the minimum-emissions solution. The lower-cost solution also resulted in a 43% reduction in project duration from the minimum-emission solution. The major contribution of this paper is the development of a decision model that can be used to select construction equipment fleets to reduce emissions production or equipment cost. The model can be customized to take into consideration the equipment fleet available for each activity and can be developed in concert with preliminary activity scheduling to look at daily emissions. [ABSTRACT FROM AUTHOR]

Abstract The Australian construction industry's resource use and emissions' production—particularly in the building sector—has a significant effect on the environment, thus, highlighting the growing importance for increasing sustainability in the sector. To achieve this within the industry and ensure the uptake of better design and construction practices across Australia, it is necessary to educate building professionals about sustainability. The residential construction industry has a poor record of implementing innovation and transferring information to homebuyers. This has necessitated a need to understand how residential building professionals can be educated to enact change and empower themselves (and others) through knowledge to strive towards more sustainable outcomes. Using a leading program in Australia, presented by one of the main industry associations' courses as a case study, this paper investigates the efficacy of the sustainability education program in teaching and motivating residential construction sector participants to make their day-to-day business operations and products more sustainable. This research is the first to analyse the benefits and outcomes of sustainability education program outcomes for residential construction professionals in Australia. This article will examine how motivation and perception, as well as the value of education, affects practice. A myriad of course-specific factors can be attributed to the poor implementation of sustainable practices, such as the limitations of course structure, format and content. Further, the contemporary industry landscape depicts a sector in decline, which is plagued by a challenge to remain competitive with volume builders. Consequently, this sector fundamentally lacks genuine value for large-scale sustainability adoption in the residential sector, which has bearing on the underwhelming implementation rates in the Australian housing industry. [ABSTRACT FROM AUTHOR]

Abstract China has about 60 billion m2 of existing buildings, with approximately 2 billion m2 newly constructed each year. This accounts for half of all new buildings globally. A large number of buildings were demolished during the urban renewal process in China, significantly reducing the average lifespan of buildings and wasting vast amounts of energy and resources. However, the corresponding environmental impacts of reduced building lifespans have not been studied. Moreover, how to accurately evaluate future environmental impacts of construction projects is still a difficult problem, since in some cases the environmental impacts may not be realized for many years. In order to investigate the relationship between building lifespans and the corresponding environmental impacts, this paper first estimated the average lifespan of buildings in China through literature review, field investigation and calculation (using survival rate and demolition rate, respectively), revealing that the average building lifespan in China is from 25 to 35 years which is far shorter than the designed lifespans of buildings in China. It is also much shorter compared to the building lifespans in ten developed countries. Six buildings in Hebei Province in China were selected as case studies to conduct life cycle environmental (LCE) impact assessment. The results of the case studies indicate that (1) extending the building's lifespan from 30 to 50 years would reduce 40% of its total LCE impacts; (2) the environmental impacts caused by buildings (per area per year) in China is 2.3 times than that in the UK; (3) when environmental impacts are considered over time, they would decrease dramatically with the increase of discount rate, indicating that the buildings in developed cities in China with higher discount rates are more sensitive to environmental degradation. Highlights • The average lifespan of buildings caused by over demolition in China was estimated. • The building environmental impacts in different countries were examined. • Both life cycle embodied and operational environmental impacts were considered. • Time value of environmental impacts was also considered. [ABSTRACT FROM AUTHOR]

Abstract Subway construction in China has experienced a surge during the past decade. Though subway is often viewed as a clean commute mode, the construction of its stations and tunnel sections requires large quantities of energy consumption, generating multiple pollutants, among which the Green-house gas (GHG) emissions would be a major issue in the context of a worldwide plea for carbon reduction, and it has to be quantified for the interest of a comprehensive assessment with regard to the GHG emissions of subway system. This paper proposed a GHG emissions quantification model for the construction of the subway stations based on a quota. A quota-based GHG emissions quantification model is able to estimate GHG emissions during the planning stage of subway projects, providing designers with the environmental consciousness on their design choices, as well as a reference for reduction potential of GHG emissions within or among schemes. Specifically, GHG emissions in the construction of subway stations are attributed to the contribution of each sub-project, a database for the GHG emissions of those sub projects is established through their construction quota. Case study for an open-excavation station shows 69% of the GHG emissions come from the construction of main structures. In terms of emission sources, embodied emissions account for 90.72% of the totality, of which concrete and steel components are the two major contributors. Besides, parameter on the buried depth of top slab shows that GHG emissions from each sub-projects increase with buried depth. [ABSTRACT FROM AUTHOR]

This paper presents practical guidance and resources for use during the construction phase developed by the Construction Industry Institute (CII) Research Team (RT) 304, Sustainability Practices and Metrics for the Construction Phase of Capital Projects. It introduces 54 construction phase sustainability actions (CPSAs) that project teams can use during project execution to prioritize and carry out sustainability solutions. Further, it discusses the results of the sustainability survey on current and future capital project implementation of CPSAs, with a focus on frequency of use and barriers to deployment. By following the guidance provided here for adopting these CPSAs, owners and contractors will be better prepared to implement sustainability actions during the construction phase of their capital projects. This paper's primary contributions are the identification of construction-related decisions and actions to advance sustainability implementation, the provision of detailed practical guidance for effective application, and the validation of the 54 CPSAs in the catalog based on the frequency of current and likely future application. [ABSTRACT FROM AUTHOR]

The building sector is one of the key consumers of energy worldwide. Thus, the retrofitting of existing buildings provides excellent opportunities for reducing energy consumption and greenhouse gas emissions. This paper presents a critical review of the research undertaken on housing retrofits and discusses the approaches driving the assessment of energy-efficiency measures. It is clear from the existing literature that many retrofitting strategies are quite similar in their approaches, the most common of these being passive strategies such as insulation of the envelope, replacement of windows, and air sealing. However, the assessment methodologies differ broadly and widely, which restricts a comparison of the results across various studies. This current state of the art review highlights the need to apply a life cycle approach in order to find the optimal retrofitting solutions, and to identify the real improvement potential of housing renovation. Life cycle assessment and life cycle cost methodologies have been analyzed by discussing the existing limitations, which can be mitigated by sensitivity analysis. Finally, whilst social impacts were addressed in a few studies, life cycle social assessment was not conducted in any of the papers reviewed. [ABSTRACT FROM AUTHOR]

Despite a great deal of research into precast production scheduling published in academic journals worldwide, little attention has been given to environmental performance related to precast construction transportation and assembly scheduling problems. To address this issue, this paper studies the Just-in-Time (JIT) strategy for supply chain management of precast construction while considering time-dependent transportation time and on-site assembly time. There are two main contributions of our work. First, our analysis expands the current batch-scheduling model of minimizing earliness/tardiness penalties, by incorporating environmental impact considering the time-dependent transportation time and economic impact of resources wasted by waiting for on-site assembly. Second, we quantify the economic and environmental performance using our research objective, consisting of earliness/tardiness penalties, an additional transportation time penalty, and a resource waste penalty. The optimal results show that, compared with the supplier's intuitive minimax optimization with deliveries on the earliest due date, there is an average 10.7% reduction of the objective value of a one-day assembly task by our proposed method. The results also show that the objective of achieving additional environmental performance conflicts with that of obtaining economic performance. However, sensitivity analysis further shows it is not always true to consider only additional environmental performance for the suppliers to achieve ‘green’ value. For a sustainable business, the customer's service-JIT delivery should also be considered. Thus, when the policy makers assign importance weights to different objectives, they should fully consider both the economic and environmental impacts. The research contributes to batch delivery theory by expanding the approach to a time-dependent delivery model by considering both the economic and environmental effects. The method developed is of practical value for precast building projects to help in the successful implementation of sustainable development. [ABSTRACT FROM AUTHOR]

Background Children's pneumonia is a heavy health burden. Few studies have been carried out on residential risk factors for pneumonia in children. Potential risks associated with dwelling characteristics are still unknown. Methods A cross-sectional study was conducted among children in 8 cities in China during 2010–2011 and 41,176 valid data on children aged 3–8 years old were used in this analysis. To obtain the lifetime-ever incidence of pneumonia in children and identify associations between pneumonia and residential risk factors, chi -square analysis and logistic regression methods were employed. Adjusted odds ratios were used as measures of effect with a 95% confidence interval. Confounding variables in the regression model include children's gender, birthweight, breastfeeding duration, parental smoking and family history of atopy. Results The average lifetime-ever incidence of childhood pneumonia was 32.3%. Urban children (33.6%) had more pneumonia than suburban (29.9%) and rural children (24.9%). More residential risk factors were found in urban-dwellings. Boys, low birthweight (<2500 g), breastfeeding duration <6 months, family allergic history, and exposure to parental smoking were found to be associated with higher pneumonia lifetime-ever incidences. Various indicators of dampness, including visible mold spots, damp stains, water damage, water condensation, damp clothing or bedding and mold odor, were also positively associated with pneumonia. Pneumonia incidence increased as the number of dampness indicators increased. Both natural gas and solid cooking fuels were positively associated with pneumonia compared with electricity. Compared with cement, construction materials including synthetic fiber, laminated wood, real wood, paint, emulsion paint and wall paper were positively associated with pneumonia. Daily living habits such as putting bedding to sunshine frequently and cleaning the child's bedroom every day could be effective preventive strategies. A dose-response relationship between the number of residential risk factors and pneumonia was observed when the risk factors number ranged from 7 to 11. Residences with more risk factors had higher lifetime-ever pneumonia odds ratios. Conclusions Indoor environmental factors including dampness, use of solid fuels or natural gas for cooking and use of new construction materials are risk factors for childhood pneumonia. This study gives evidence for the importance of home environment exposures in the occurrence of childhood pneumonia. Actions against the residential risk factors described in this study may help to prevent pneumonia in children. [ABSTRACT FROM AUTHOR]

This paper addresses the detailed characterization of coal fly ashes with respect to their utilization in alkali-activated cement systems, thus maximizing the use of fly ashes in the construction industry. A technique was developed to estimate the reactivity of low calcium fly ashes in alkali-activated systems. The technique is based on a K-value which combines three characteristics of a fly ash. Two characteristics – amorphous phase percentage and specific surface area determined through Blaine measurement – are observed quantities. The third characteristic – degree of polymerization of silica in the amorphous phase of fly ash – is a calculated parameter. To take into account the water demand of fly ashes, which will influence the amount of water needed to get a workable mix, the shape factor was used to adjust the Blaine specific surface area. The relationship between the proposed K-value and compressive strength of alkali-activated fly ash pastes is approximated by a linear function. The correlation coefficient of the relationship varied from 0.961 to 0.833 for 1 and 91 days compressive strength respectively. The proposed K-value can firstly be used to rank fly ashes for their suitability to produce high strength alkali-activated materials and secondly when calibrated for a specific activator and curing conditions, to predict the compressive strength of alkali-activated fly ash binders. [ABSTRACT FROM AUTHOR]

The construction industry is one of the most important actors in the global sustainability act, seeing as it is responsible for a significant negative load over the natural environment. In the journey towards minimising these damaging effects, the first key step is understanding the environmental performances of the materials used in this sector. Taking into account that forests have a crucial role in sustaining life, analysing the environmental impact of wood as a construction material represents a necessary task for civil engineers. The present paper aims at evaluating and comparing the environmental performances of three timber structures for pitched roofs: the trestle frame roof structure, the roof structure with collars, and the trussed rafter roof structure. The environmental burdens have been determined by using the cradle-to-cradle Life Cycle Assessment methodology and the GaBi ts software. Upon analysing the results, the authors have concluded that the roof structure with collars has the lowest impact over the Earth's ecosystem. The study also shows that even if the trestle frame is the leading environmentally friendly solution over the pre- and post-operation phases, this structural system is responsible for the highest unfavourable effects over its entire life cycle. The authors argue that by using the roof structure with collars, the damaging load of the construction sector over the natural environment is one step closer to being minimised. [ABSTRACT FROM AUTHOR]

To date, many tools and guidelines to reduce environmental impacts from a life cycle perspective are available concerning the construction sector. However, basically all of them are modelled according to an attributional approach and there is a lack of studies that develop strategies for improvement based on a consequential LCA. The goal of this paper is to analyze to what extent the results differ when both models are applied on the same case, a representative dwelling located in Niel, Belgium. A conceptual optimization scenario for insulated exterior cladding has been added as well to examine to what extent different models affect the ranking of improvement strategies. For both approaches, the same foreground data and energy calculations are used, but the underlying structure of the models is different. The starting point is an attributional scenario, based on a Belgian guidance document ‘Environmental profile of building elements’ (EPBE) published by the Public Waste Agency of Flanders. The results of the entire life cycle indicate differences between the approaches, in direct relationship to the underlying modelling assumptions. The discrepancy becomes more pronounced when looking at the separate materials so the effect is not damped as a consequence of the aggregation in life cycle phases. Especially the three most contributing materials (steel, concrete and brick) show clear differences. The optimization scenarios underline previous statement, since the ranking of the different solutions is not equal according to both approaches. This research points out the emergence of a discrepancy between results when different modelling approaches are applied. The consequential model that complements the attributional EPBE study is therefore a useful addition to provide information for decision-makers. This way, the right information is available for all type of decisions. [ABSTRACT FROM AUTHOR]

The construction industry is adopting off-site construction for its superior quality, short cycle time, and minimal environmental impact. Among the different off-site construction methods, panelized construction follows a manufacturing approach where houses are built in smaller panels in an assembly line. Due to the complex and unique nature of the home building process, existing manufacturing concepts such as automated production planning and control system are not applicable to the panelized home production facility. This paper utilizes radio frequency identification (RFID) technology, data mining, and simulation-based optimization to develop a production planning and control system for a panelized home production facility. The RFID system is used to automatically collect the production data; however, the RFID data in this study contains considerable noise. Thus, it is crucial to extract the relevant data from the raw data. A RANSAC model is developed for this purpose to automatically clean the RFID data and then use it to build the simulation model, which is then integrated with an optimization algorithm to generate the production schedule and real-time performance monitoring. The proposed framework cleans the noisy RFID data to extract records that represent a steady flow of assembly line. These clean records are then used to build PDFs that are required to develop discrete event simulation model that can help managers to capture an almost real-time snapshot of the production of the assembly line as well as automatically optimize the production schedule. The proposed system is implemented and validated in a panelized wall production facility operated by ACQBUILT Inc., a prefabricated home builder in Edmonton, Canada. [ABSTRACT FROM AUTHOR]

In this paper, the feasibility of using two solid wastes in alkali activated slag composites as construction and building materials is evaluated. One waste is the municipal solid waste incineration (MSWI) bottom ash, and the other one is fine granite powder from aggregate manufacturing. These two solid wastes are thoroughly characterized, and their effects on reaction process, gel composition, microstructure are investigated by isothermal calorimeter, TG/DSC, FTIR and SEM. Leaching properties and CO 2 footprint of some typical mixes are evaluated. The results indicate that both bottom ash and granite addition can be regarded as non-reactive phases. Micro scale analyses show no evident chemical involvement of both wastes on the gel structure of the reaction products. Bottom ash addition reduces the compressive strength, and granite powder presents a lower influence; 28 d strengths of around 20–70 MPa can be achieved depending on the replacement levels. Most of the mixtures pass the Dutch regulation for heavy metal leaching, while the excessive chlorides and sulfates contents can be easily treated by methods such as washing. The carbon emission is significantly reduced due to the negative impact of the waste solids, and this value can be further lower if bottom ash with larger sizes is used to replace coarse aggregates. Therefore, these two solid wastes present promising application potential based on the identified performances and sustainability. [ABSTRACT FROM AUTHOR]

Life-Cycle Assessment has been used extensively in the construction industry to assess the environmental impacts of building materials. Attributional LCA considers processes in a supply chain which allows users to identify a process to improve to minimize the environmental impacts. However, the level of detail adopted in traditional attributional LCA is aggregate, not appropriate for process improvement efforts in the construction project context which is characterized as a complex system. This paper proposes Activity-based LCA (ABLCA) which adopts the methodology of the activity-based costing system to carry out the assessment and analysis of environmental impacts for the life cycle. The research carried out a case study on the curtain wall supply chain. The outcome of inventory analysis for each activity and environmental impact assessment showed the curtain wall supply chain process made an impact on five environmental impact categories: global warming air, acidification air, HH criteria air; eutrophication air, and photochemical smog air. With comparison to the outcome of environmental impact assessment from existing LCA, the proposed management system to investigate environmental impacts was addressed. The proposed ABLCA enables management to develop an environmental-impacts-reduction plan focusing on critical activities. [ABSTRACT FROM AUTHOR]

Abstract: Construction has been accused of causing environmental problems ranging from excessive consumption of global resources both in terms of construction and building operation to the pollution of the surrounding environment, and research on green building design and using building materials to minimise environmental impact is already underway. However, relying on the design of a project to achieve the goal of sustainable development, or to minimise impacts through appropriate management on site, is not sufficient to handle the current problem. The aim for sustainability assessment goes even further than at the design stage of a project to consider its importance at an early stage, before any detailed design or even before a commitment is made to go ahead with a development. However, little or no concern has been given to the importance of selecting more environmentally friendly designs during the project appraisal stage; the stage when environmental matters are best incorporated. The main objectives of this paper are to examine the development, role and limitations of current environmental building assessment methods in ascertaining building sustainability used in different countries which leads to discuss the concept of developing a sustainability model for project appraisal based on a multi-dimensional approach, that will allow alternatives to be ranked is discussed in detail in the paper. [Copyright &y& Elsevier]

To improve the accuracy and achieve a good level of detail, a process-based method was adopted in this paper to conduct a life-cycle CO 2 emission analysis of China's construction sector from 2005 to 2012 by quantifying the CO 2 emission during the six life-cycle stages, including building materials manufacturing, building materials transportation, building construction, building operation, building demolition as well as construction and demolition (C&D) waste disposal. The results indicate that the CO 2 emission of China's construction sector rose moderately from 2005, and has increased considerably since 2010. The total CO 2 emission mainly stems from building materials manufacturing stage (73%) and building operation stage (24%). The CO 2 emission from steel and cement account for the most of the CO 2 emission at building materials manufacturing stage (87%). The CO 2 emission of road transportation with 83% shares the highest proportion at building materials transportation stage. The CO 2 emission of centralized heating with 49% is the dominant source of CO 2 emission during building operation stage. The CO 2 emission at construction and demolition (C&D) waste disposal stage is mainly generated from demolition waste with 86%. These findings could provide references for measures to take targeted at various life cycle stages. [ABSTRACT FROM AUTHOR]

Along with China's modern industrialization, challenges on smog crisis are raising dramatically in the past decade. The sources of municipal smog are multiple and complex, one of which is construction dust emission due to the rapid urbanization. In literature, there are studies focusing on the end-pipe treatment of construction dust; however, very little research has been conducted from the perspective of dust mitigation in developing countries. To fill in this research gap, this paper investigates the current situation of construction dust prevention and control in China, with the aim of providing insights for mitigating dust pollution caused by the construction industry. Through a combination of the content analysis, on-site observation, questionnaire survey and interviews with experienced professionals, a total of 11 related regulations are thoroughly reviewed, and the main sources of construction dust production are identified. A case study is further presented to demonstrate the prevailing dust control measures on site. Recommendations are proposed in order to increase the awareness of related stakeholders, including formulation of targeted regulations, establishment of an appropriate charging scheme, development of a feasible monitoring system, and enhancement of training and dissemination. [ABSTRACT FROM AUTHOR]

The construction industry already recognises the strong business case for improving resource productivity. It is associated with circular economy system (CE), propagated by the European Union. Circular economy systems keep the added value in products for as long as possible and virtually eliminate waste. Transition to a more circular economy requires changes throughout value chains, from product design to new business and market models, from new ways of turning waste into a resource to new modes of consumer behaviour. These actions relate to all industries, including the construction industry. Nowdays, the increase in demand for construction materials as a result of development has called for an alternative way to develop or derive construction materials from different sources, including sewage sludge ash (SSA). SSA is produced after the firing process of sewage sludge, and it must be disposed by other means. Researches were already accomplished investigating the use of sewage sludge ash for the building materials manufacturing, such as produce bricks and tiles, as a raw materials for cement production, as aggregates for concrete and mortar, as a component of the synthesis of lightweight materials and as substitute for sand and/or cement in cement stabilized bases, subbases and embankments in road constuctions. A detailed description of each application as a way towards a circular economy is presented in this paper. [ABSTRACT FROM AUTHOR]

Environmental Management System (EMS) has been one of the important tools for sustainable construction for around two decades. However, many issues concerning sustainable development have not been properly addressed, and there is a need for the introduction of green specifications to advance green performance in construction through contract management. This paper defines green specifications, identifies the reasons for adopting green specifications and highlights the environmental issues that may not be addressed by solely adopting EMS. It also presents the results of a recent survey of practitioners concerning their opinions towards green specifications and possible impacts arising from their adoption. From the results of the survey, a framework for developing green specifications is deemed valuable for the cities striving for sustainability. Interestingly, the level of acceptable changes brought about by green specifications as perceived by different industry stakeholders is found to be unrelated to whether they were from organizations implementing EMS or not. [Copyright &y& Elsevier]

Sustainable development is forward-looking; it is a continuous mission for future developments of human society. A genuinely sustainable society is one that initiates developments in sustainable ways. The development of a genuinely sustainable society is supported by its citizens who think and act according to a recognized code of conduct - the sustainable culture. Similar to other forms of culture, sustainable culture of a society is not static, but changes over time. The changes found in a sustainable culture are reflections of the status of sustainability in a society and these changes should be measured from time to time. The resulting measurement gives very important information for decision-makers, in the government and in the private sector, to examine the magnitude of changes that have taken place in a given period of time. The results will also enable them to review and adjust policies in order to better accommodate changes according to the trends of society. This paper provides a method – the T-model, to investigate and measure the extent of change of sustainable culture through two extensive surveys among participants of the construction industry of Hong Kong. The change in sustainable culture is reflected by the change in attitude and practice among construction participants, this can be found in their performance in project development, design and construction operations. The data of these changes are collected and converted to numerical scores. The T-model synthesized these scores and revealed the change of sustainable culture within the specific study time frame. [Copyright &y& Elsevier]

Abstract: Environmental problems have been considered to be serious in the construction industry. Waste management pressures are pressing very hard with alarming industrial warming signals. Among the different types of construction and demolition wastes, concrete is about 81 percent of the volume of construction and demolition waste in Australia. To minimize the concrete waste generated from construction activities, recycling of concrete waste is one of the best methods to improve the environment. However, situations of concrete recycling in different countries vary considerably. Japan is a leading country in recycling concrete waste, with 100 percent recycling of the wastes that are used for new structural applications. This paper investigates the current concrete recycling situations in Australian and Japanese construction industries. A questionnaire survey and structured interviews were conducted. In comparing the current concrete recycling situations between Australia and Japan, it should be noted that major difficulties found from Australian and Japanese construction industries are on different phases of the transition to recycling of construction wastes. Therefore, it is suggested that the Australian construction industry should be: i) developing a unified policy in concrete recycling; ii) providing financial governmental support; iii) developing clear technical specifications or standards on the use of recycled aggregate for structural applications. [Copyright &y& Elsevier]

This paper describes the process of urbanization and land use change in the urban ecosystems of the National Capital Region (NCR) of Delhi, India. Two types of land use change are considered--from natural to urban and from agricultural to urban. Both types are explained in terms of economic variables known to be drivers of change. A panel data method was used, and economic variables were combined with GIS-based information on land use change during 1986-2004 for 11 administrative units of the NCR. The results suggest that investment in the construction sector plays a major role in converting the land from natural to urban areas, while differences in land productivity seems to be the major driver for change from agricultural to urban uses. [ABSTRACT FROM AUTHOR]

Recycled concrete use is necessary in order to decrease the environmental impact of the construction industry. Coarse aggregates from crushed concrete may lead to relatively high porosity in the resultant concrete. For this reason, recycled concrete may seem detrimental to the durability of reinforced concrete structures, particularly when they are exposed to marine environments. The objective of this paper is to analyze the influence of coarse aggregates from concrete on the chloride penetration rate and binding capacity of concrete under marine exposure. Concrete specimens were molded and exposed to a natural marine atmosphere. After exposure periods of 6, 12, and 18 months, ingress profiles of total and water soluble chlorides were measured. Results indicate that recycled aggregate incorporation causes two opposed effects on concrete: It increases its chloride penetration rate and chloride binding capacity. Therefore, water soluble chloride contents in conventional and recycled concrete series have similar values. [ABSTRACT FROM AUTHOR]

Although the construction pollution index has been put forward and proved to be an efficient approach to reducing or mitigating pollution level during the construction planning stage, the problem of how to select the best construction plan based on distinguishing the degree of its potential adverse environmental impacts is still a research task. This paper first reviews environmental issues and their characteristics in construction, which are critical factors in evaluating potential adverse impacts of a construction plan. These environmental characteristics are then used to structure two decision models for environmental-conscious construction planning by using an analytic network process (ANP), including a complicated model and a simplified model. The two ANP models are combined and called the EnvironalPlanning system, which is applied to evaluate potential adverse environmental impacts of alternative construction plans. [ABSTRACT FROM AUTHOR]

Early hydration of tricalcium silicate (C3S) has received great attention over the years due to the increased use of composite cement with a reduced number of clinker phases, especially the addition of what should be very reactive C3S to guarantee early strength. Although many mechanisms have been proposed, the dissolution of polygonal C3S at the material interface is not yet fully understood. Over the last decade, computational methods have been developed to describe the reaction in the cementitious system. This paper proposes an atomistic insight into the early hydration and the dissolution mechanism of calcium from different crystalline planes of C3S using reactive force field (ReaxFF) combined with metadynamics (metaD). The reactivity and thermodynamic stability of different crystal planes were calculated from the dissolution profile of calcium during hydration at 298 K. The simulation results, clearly describe the higher reactivity of ( 0 1 ¯ 1 ¯ ), (011), (100), and (1 ¯ 00) surfaces of C3S due to the strong interaction with the water, whereas, the dissolution profile explains the lower reactivity of ( 1 ¯ 1 ¯ 0 ), (110), ( 0 1 ¯ 0 ) and the effect of water tessellation on the (001), (010) planes. [ABSTRACT FROM AUTHOR]

Construction operations are highly energy-intensive and account for significant environmental impacts, including greenhouse gases (GHG) and other engine exhaust associated with material procurement/delivery and on-site construction activities. The opportunities for mitigating air pollutant emissions from construction operations can be captured by estimating and benchmarking during the preconstruction phase and then monitoring during the construction phase. However, a formal process model to manage the environmental aspects of on-site construction activities has yet to be clearly delineated, although recently several research efforts have appeared in relevant areas such as the development of in-use emission factors of construction equipment, methods for reliably estimating emissions at the project level, embodied carbon footprint benchmarking methods, and practical monitoring tools. Such a lack of a formal process model causes the misinterpretation of the benefits from recent research efforts in each area and hinders their implementation in practice. In this context, this paper aims to establish a framework model that could be a systematic and generic reference to the management of pollutant emissions from construction operations with state-of-the-art methods and tools. To do so, the paper identifies a generic process to be supported by research efforts in each area and presents an integrated framework based on the analysis of data connectivity between processes. An example of the indirect emission measurement is presented to demonstrate how data connectivity can be ensured between processes within the framework. [ABSTRACT FROM AUTHOR]

Asbestos cement (AC) pipe accounts for approximately 15% of the total length of water distribution system piping in North America. Pipe renewal activities are needed to maintain these pipes as they deteriorate, but concerns over the environmental impact and regulations associated with these construction methods are largely misunderstood. Confusion around these issues led this study to determine (1) what the regulations allow, (2) which renewal methods are applicable, and (3) the critical data needs associated with these methods when used for AC pipe renewal. This paper describes current AC pipe renewal regulations and practices (e.g., pipe bursting, cured-in-place pipe lining, etc.) and the critical data needs relating to AC pipe renewal (e.g., study of the asbestos fibers released in air, water, and soil during construction). These findings are valuable for water utilities in need of solutions for renewing their aging AC pipes and in understanding regulations. The recommendations highlight the needed investigation into the environmental impact of AC pipe renewal construction, which when completed will help clarify future regulations. [ABSTRACT FROM AUTHOR]

The importance of green buildings has been frequently highlighted. However, barriers such as greater complexity, lack of understanding of sustainability, and the perception of a greater possibility of cost overrun have hindered the dissemination of green buildings. More planning efforts for green buildings can presumably help mitigate these barriers. This paper investigates preproject planning efforts for green and conventional building projects. Project-level data were collected (124 in total, 71 from conventional building projects and 53 from green building projects), with project data consisting of general information about the project, a Project Definition Rate Index (PDRI) survey, and cost performance. The project data were categorized into four groups based on their project type (green and conventional) and cost performance (actual cost on/under budget and over budget). For the four groups, a two-way analysis of variance test was used to compare the degree of preproject planning efforts measured by PDRI. The analysis indicated that green projects tend to have more investment in preproject planning efforts than conventional projects, and the difference was marginally statistically significant at the level of . In addition, a comparison of the mean PDRI values of the four groups revealed that green projects with a superior cost performance invest more in preproject planning efforts than other groups, and the difference was statistically meaningful. From the interaction effect, we also found that the impact of preproject planning on cost performance is more critical for green projects than for conventional projects. Regarding the preproject planning category, we found that green projects with superior cost performance tend to involve more planning with regard to business strategy, project requirements, site information, building programming, and building/project design parameters. These findings make two contributions. First, the findings help practitioners justify additional preproject planning efforts for green projects. Second, some of the results of this study will be useful to practitioners initiating sustainable projects by helping with the determination of which aspects of green buildings should involve more extensive planning. These findings will help reduce the possibility of cost overruns and allow more green projects to be deployed in order to address the need for sustainability. [ABSTRACT FROM AUTHOR]