Procurement innovation for a circular economy of construction and demolition waste: Lessons learnt from Suzhou, China

Trust (in)congruence, open innovation, and circular economy performance: Polynomial regression and response surface analyses

Engaging partner firms in open innovation is critical to overcoming internal resource/capability constraints to achieve firm and supply chain circular economy (CE) performance, yet scholars have not examined this link empirically. Further, while researchers have repeatedly emphasized trust as a key driver of open innovation performance, little is known from a dyadic trust perspective (e.g., congruence vs. incongruence, high-high congruence vs. low-low congruence). To fill these gaps, we propose a theoretical model based on the social exchange theory (SET) and test it using a dyadic dataset of listed Chinese manufacturing firms. The results suggest that 1) rather than unilateral trust from the focal firm or its partners, trust congruence is more predictive of successful open process and product innovations, 2) regarding congruence types (low-low vs. high-high), congruence at higher levels of trust facilitates open product innovation more than low-low trust congruence; interestingly, such an effect is not significant for open process innovation, 3) open process innovation has a positive influence on the focal firm's CE performance, but its impact on supply chain CE performance is not statistically significant, and 4) open product innovation has a significantly positive impact on the focal firm and supply chain CE performance. Our findings still hold after analyzing time-lagged models and alternative measurements as robustness checks. Our study provides meaningful theoretical contributions to the literature and useful, practical insights for managing inter-organizational relationships, open innovation, and CE performance.

A study on the waste generation rates and recycling potential for the construction and demolition waste in Dhaka, Bangladesh

Construction and demolition waste has a high environmental and socio-economic impact due to its poor management infrastructure. In recent years, Dhaka, the capital city of Bangladesh, experienced significant growth in the real estate sector, which demands substantial construction and demolition activities within the city. Most of the construction and demolition waste finds its way to landfills, roadsides, and unapproved locations with a 2% recycling rate through local scrap vendors and unregulated recyclers. In an effort to assess the waste generation rates from ongoing construction and demolition activities, the current study employed the Site Visit method along with direct and indirect waste quantification methodologies for the investigated demolition and construction projects, respectively. The findings indicate that for per unit area (m2) of demolition and construction, the average WGR was found to be approximately 575.0 kg and 73.9 kg, respectively. Projection reveals that by 2025 and 2030, within Dhaka City, construction and demolition activities will generate roughly 1.15 MT and 1.69 MT of construction and demolition waste if no recycling actions are considered. Additionally, the results highlight the recycling potential of construction and demolition waste with respect to economic benefits through the maximum recycling rates for the relevant materials. Furthermore, to address the future of sustainable construction and demolition waste management infrastructure, this paper presents a detailed overview of the current onsite construction and demolition waste management practices as well as safety protocols for demolition and construction activities.

Stakeholders' purchase intention of products with recycled content: a combination of SEM and BPNN approach

The rapid urban renewal progress has generated a large amount of construction and demolition (C&D) waste in China. According to the concept of circular economy (CE), producing products with recycled content (PwRC) is an effective solution to achieve sustainable C&D waste management. However, the low market acceptance of PwRC affects stakeholders' purchase intention, which hinders the development of the PwRC industry. In order to clarify the stakeholders' purchase intention and investigate the influencing mechanism of stakeholders' purchase intention, a novel method which combines structural equation modeling (SEM) with a back-propagation neural network (BPNN) is proposed. The method makes full use of the causal analysis ability of SEM and the nonlinear characteristics of BPNN to simulate and to verify the path of product cues, perceived value, and behavioral intention of stakeholders. The results reveal that the brand and materials of PwRC can affect stakeholders' perceived value, and in turn, affect their purchase intention. Focus on the brand and materials of PwRC will help recycled product manufacturers and governments to promote stakeholders' purchase intention and the development of the C&D waste recycled products market.

Urban mining from biomass, brine, sewage sludge, phosphogypsum and e-waste for reducing the environmental pollution: Current status of availability, potential, and technologies with a focus on LCA and TEA

Rapid industrialization, improved standards of living, growing economies and ever-increasing population has led to the unprecedented exploitation of the finite and non-renewable resources of minerals in past years. It was observed that out of 100 BMT of raw materials processed annually only 10% is recycled back. This has resulted in a strenuous burden on natural or primary resources of minerals (such as ores) having limited availability. Moreover, severe environmental concerns have been raised by the huge piles of waste generated at landfill sites. To resolve these issues, 'Urban Mining' from waste or secondary resources in a Circular Economy' concept is the only sustainable solution. The objective of this review is to critically examine the availability, elemental composition, and the market potential of the selected secondary resources such as lignocellulosic/algal biomass, desalination water, sewage sludge, phosphogypsum, and e-waste for minerals sequestration. This review showed that, secondary resources have potential to partially replace the minerals required in different sectors such as macro and microelements in agriculture, rare earth elements (REEs) in electrical and electronics industry, metals in manufacturing sector and precious elements such as gold and platinum in ornamental industry. Further, inputs from the selected life cycle analysis (LCA) & techno economic analysis (TEA) were discussed which showed that although, urban mining has a potential to reduce the greenhouse gaseous (GHG) emissions in a sustainable manner however, process improvements through innovative, novel and cost-effective pathways are essentially required for its large-scale deployment at industrial scale in future.

Identifying factors affecting the low uptake of reprocessed construction materials: A systematic literature review

The success of demolition waste reverse logistics supply chains (DWRLSCs) depend on the market uptake of reprocessed construction materials (RCMs) since resource recovery will not be viable without a well-developed consumption process. However, usage of RCMs is sparse while there is also limited focus in existing research on their market uptake. Therefore, this systematic literature review (SLR) attempts to discern trends in research on the use of RCMs and identify factors that limit their uptake. 52 articles from three databases published between 2000 and 2021 were selected for descriptive and content analyses. Descriptive analysis showed growing research interest in the area over the last 5 years. Content analysis was underpinned by Attitude-Behaviour-Context (ABC) Theory which focuses on pro-environmental consumer decisions. As predicted by the theory, a mix of personal and contextual factors affect the low uptake of RCMs. Negative attitudes, reluctance to change the status quo and limited decision-making capabilities were identified as personal factors that limit the use of RCMs. Similarly, contextual factors such as price, quality, information availability, market availability, sourcing lead times and lack of regulations, standards, and specifications inhibit the use of such materials. The review also proposes several future research directions to expand knowledge around this domain.

Characterization of Three Types of Recycled Aggregates from Different Construction and Demolition Waste: An Experimental Study for Waste Management

Achieving sustainable management and efficient use of natural resources stands out as one of the goals included in the Goals for Sustainable Development in the 2030 Agenda. The construction sector is currently far from presenting an efficient model in terms of treating waste generated by it. Variations in the physical and chemical properties of recycled aggregates coming from construction and demolition waste are one of the main reasons of their limited use in the production of construction materials. This research presents a physicochemical characterization of three different types of recycled aggregates coming from different types of waste: concrete, ceramic and mixed. Physical characterization shows that recycled concrete aggregate has better physical properties compared with mixed recycled aggregate and ceramic recycled aggregate, which makes it more suitable for use in masonry mortars and concrete, due to its higher dry density (2210.33 kg/m3), its lower content of fines (5.17%), its lower friability coefficient (24.60%), and its water absorption coefficient (6.70%). Chemical characterization shows that none of the tested recycled aggregates contains traces of harmful chemical agents that exceed the limits established by the reference regulations. Finally, the statistical analysis shows good homogeneity for these raw materials, obtaining low coefficients of variation and values within the recommended in each of the calculated confidence intervals.

The built environment impacts on route choice from home to school for rural students: A stated preference experiment

Introduction

Rural roads and built environment in China have been developed enormously, but it is not clear whether these roads fulfill the needs of school children as they need to travel long to school every day.

Objective

It is crucial to understand the influencing factors of their travel mode choices to better design future country roads and built environment, aiming to promote physical activities of school children in a safe built environment.

Method

This study thus attempts to explore the impacts of rural built environment attributes on children's school travel mode preferences. Eight rural built environment attributes are considered: distance from home to school; the number of intersections passed on the way to school; whether there are sidewalks/bicycle lanes; the traffic speed of school access routes; whether there are separation facilities between motor vehicles and non-motor vehicles; whether there are traffic lights and zebra crossings; availability of greenery such as lawns, flower ponds and street trees and whether there are shops on the way to school and at the school gate. Six hundred and thirty eight valid questionnaires were obtained through face-to-face interviews with school-age children in villages. A multinomial logit model was estimated to unravel the preferences and choices of rural school-age children in different models of school travel using the stated choice data.

Results

All the eight attributes have significant impacts on rural children's school travel choices on foot, bicycle, electric bicycle or motorbike. And four rural road design attributes have significant effects on rural children's school travel by private cars. A travel path with pavements or bike lanes, few intersections, low traffic speeds, greenery and shops can facilitate children's school travels on foot or by bike. The conclusions can provide reference for the further upgrading planning, designing and construction of rural roads, as well as enriching the theory and practice of child-friendly villages construction.

Improving Contractors' Participation of Resource Utilization in Construction and Demolition Waste through Government Incentives and Punishments

This paper develops a simulation model for analyzing how government incentives and punishments improve contractors' participation in resource utilization of construction and demolition waste (RUCDW) based on system dynamics theory. The construction industry's long-term objective is to become more sustainable and resource-effective, and as part of this objective, generated construction and demolition waste should be recycled and resource utilized. However, most contractors have little willingness to engage in RUCDW because it increases their costs. The government thus plays a vital role in improving their participation in RUCDW through a range of educational tools such as advertisements, professional training, incentives, and punishments. Among these approaches, incentives and punishments are considered the most effective because they directly change project costs. We use the Vensim software package for numerical simulation and data collected from Suzhou, China are used to demonstrate and validate the developed model. Simulation results show that the government can improve contractors' participation in RUCDW through three kinds of incentives and punishments: (1) subsidizing RUCDW; (2) increasing landfill fees; and 3) issuing fines for illegal dumping. Comprehensive application of multiple policies has a stronger effect than single policies. The established model is therefore a valuable tool for assessing the dynamic effects of government incentives and punishments on RUCDW ahead of implementation, which can provide guidance for policymakers.

Monitoring daily well-being and meaning-making tendencies among adult child working dementia caregivers: validating an experience sampling study protocol

BACKGROUND

Although the experience sampling method offers advantages for gerontological research, it has seldom been applied to examine well-being and meaning-making tendencies among adult children working caregivers of parents with dementia and thus lacks empirical support for such applications. In response, we aimed to validate the proposed protocol's participation status, feasibility, usability, and ecological validity.

METHODS

For 15 consecutive days, 100 adult child working dementia caregivers participated in our study via web-based assessments on their digital devices. The protocol was first adjusted based on a series of pilot interviews with eight volunteer dementia caregivers. Participants' compliance and preferred times for activities along with the protocol's feasibility, usability, and ecological validity were evaluated in a follow-up session with all participants.

RESULTS

The protocol was adjusted in light of recruitment details, user interfaces, the reminder mechanism, and reference time for assessments. The general compliance rate was 93.3%. Preference times for assessments of work (10 a.m. to 3 p.m.), care (6-8 p.m.), and personal activities (7-10 p.m.) were identified. The protocol was generally considered to be feasible and easy to use, and ecological validity analysis indicated that the collected data adequately represented real-world data.

CONCLUSIONS

Our study provides empirical evidence to support an innovative protocol and evaluate its implementation so that future studies using it can better investigate the relationship between meaning-making tendencies and well-being among adult child working caregivers for parents with dementia.

A Scoping Literature Review of Rural Institutional Elder Care

Under circumstances of pervasive global aging combined with weakened traditional family elder care, an incremental demand for institutional elder care is generated. This has led to a surge in research regarding institutional elder care. Rural residents' institutional elder care is receiving more attention as a major theme in social sciences and humanities research. Based on 94 articles related to rural institutional elder care, this study identified the most influential articles, journals and countries in rural institutional elder care research since 1995. This was done using science mapping methods through a three-step workflow consisting of bibliometric retrieval, scoping analysis and qualitative discussion. Keywords revealed five research mainstreams in this field: (1) the cognition and mental state of aged populations, (2) the nursing quality and service supply of aged care institutions, (3) the aged care management systems' establishment and improvements, (4) the risk factors of admission and discharge of aged care institutions, and (5) deathbed matters regarding the aged population. A qualitative discussion is also provided for 39 urban and rural comparative research papers and 55 pure rural research papers, summarizing the current research progress status regarding institutional elder care systems in rural areas. Gaps within existing research are also identified to indicate future research trends (such as the multi-dimensional and in-depth comparative research on institutional elder care, new rural institutional elder care model and technology, and correlative policy planning and development), which provides a multi-disciplinary guide for future research.

Circular economy in Brazilian construction industry: Current scenario, challenges and opportunities

The effective implantation of the circular economy (CE) presents a great challenge to the industrial sectors, mostly in those of greater environmental impact, such as construction industry. In Brazil, this industry has been growing over the last 20 years; however, such growth was based on an extractivist economy without any consideration to the end of its products lifespan. Only in 2017, 45 million tonnes of construction and demolition waste were generated in the country. This paper presents the current context of public policies in the Brazilian construction industry and proposes initiatives to introduce principles of CE. An exploratory study was developed, and all the 45 references presented in Appendix A of the review paper of Benachio et al. were considered to draw new ideas. These ideas are related and compared to key points in Brazilian regulations. Twelve opportunities for the improvement are listed and organized by construction stages (planning and design, materials manufacturing, construction processes, use and demolition). The ones related to design and planning using Green building information modelling, and materials manufacturing with recycled waste are highlighted due to the existing actions, standards, and Federal legislation. It was found that some sectors and the government already have actions related to CE (based on the 3R principle), but still there are several initiatives needed for its effective implementation in the Brazilian construction industry.

Tracing the Trends of General Construction and Demolition Waste Research Using LDA Modeling Combined With Topic Intensity

The study of construction and demolition waste (CDW) has attracted more and more attentions with the increasing CDW pollution caused by the large-scale infrastructure construction. This study used the Latent Dirichlet Allocation (LDA) combined with topic intensity to discover hot topics and development trends in the study area of CDW. First, the LDA was used for topic modeling to extract the existing topics from textual data. Second, the topic intensity was calculated for the extracted topics and the numerical values of the topic intensity represented the popularity of the topics. In this study, 4 topics were extracted from 1,849 relevant articles through the LDA modeling and topic intensity calculation. The results showed that the topic of “CDW management” had an upward trend. Topics such as “recycled aggregate,” “environmental impact,” and “study of CDW on soil” all showed a downward trend. The methods of this study can dig into the topics of CDW study and help scholars to engage in this field for better understanding the prevalence and evolution trends of these topics.

Information Processing for Quality Assurance in Reverse Logistics Supply Chains: An Organizational Information Processing Theory Perspective

Every year, the construction industry produces a large volume of demolition waste (DW) recovered through reverse logistics supply chains (RLSCs). Information-centric QA plays an important role in the RLSC, providing an excellent solution for inferior-quality reprocessed products. However, information deficiency creates epistemic uncertainties that lead to information-processing needs (IPNs) for QA, for which the internal stakeholders in the RLSC should respond by undertaking appropriate information-processing mechanisms (IPMs). Given this, the current study aims to explore how internal stakeholders process information for QA in RLSC of DW through the organizational information processing theory (OIPT) perspective. The study follows a qualitative approach encompassing 30 semi-structured interviews with internal and external stakeholders in the RLSC of DW. The study found eight uncertainties that stem from the internal organizational environment and two uncertainties caused by the interactions with stakeholders in the supply chain. In addition, 15 IPMs were identified, which the demolishers and waste processors could undertake in response to the epistemic uncertainties. The study developed an information-processing management framework that would serve practitioners and academics to understand how effectively process, people, policy and technology elements contribute to responding to the epistemic uncertainties for successful QA in RLSC of DW.

Investigating the Driving Factors of Public Participation in Public-Private Partnership (PPP) Projects-A Case Study of China

Public participation is an important procedure of the environmental impact assessment. Effective public participation is essential to the Public–Private Partnership (PPP) projects as such projects usually exert tremendous impacts on the environment and society. However, in literature, there are few studies investigating the driving factors of public participation in PPP projects, especially in the context of China. To bridge this research gap, this study proposed a theoretical model, which incorporates contextual factors (i.e., perceived benefit and perceived risk) into the classical Theory of Planned Behavior model, to explore the determinants. The initial proposed model was tested using structural equation modeling. Analysis results indicated that attitude towards behavior, subjective norm, perceived risk and perceived behavioral control were the four significant driving factors of public participation in PPP projects, whereas perceived benefit had limited impact. Furthermore, this study evaluated eight public participation approaches in PPP projects. Results revealed that the public were more willing to participate in public decisions through the internet platform, followed by the information disclosure or consultation provided by the government. The research findings derived in this study can provide valuable reference for the government to promulgate proper policies to attract more public participation in PPP projects. Moreover, the research idea and methods used in this study can be popularized in other countries to enhance the public participation in PPP projects.

Experimental Study on the Physical and Mechanical Characteristics of Roller Compacted Concrete Made with Recycled Aggregates

A huge volume of waste is generated by natural and human-made disasters and by rapid urbanization that leads to the demolition of structures reaching the end of their service life. Using recycled aggregates in concrete producing reduces environmental pollution by decreasing the disposal of this waste material in landfills and preserving unreasonable exploitation of natural resources. This manuscript presents the results of an experimental program aiming to study the effect of recycled aggregates on the physical and the mechanical properties of roller compacted concrete (RCC). A Dreux–Gorisse mix design method together with the modified proctor test were adopted to prepare a reference mixture with natural aggregates with three derived mixtures where coarse aggregates were replaced by 50%, 70%, and 100% of recycled aggregates. The physical properties of RCC were evaluated by means of water absorption and gas permeability tests while the mechanical properties were evaluated using compressive, tensile splitting and 3-point flexural tests. The results of physical tests showed that both water absorption ability and gas permeability increase proportionally with the replacement ratios. The results of the mechanical tests showed that the compressive strength class was approximately constant for all developed mixtures at the age of 28 days. For a substitution ratio of 100%, a drop in the compressive strength of only 6% was recorded. The reduction in the tensile and flexural strength was more pronounced than the compressive strength and was about 10% for the mixture of 100% recycled aggregates. It was found that the strength increases with time, and it can be estimated at any age using the analytical models adopted for conventional hydraulic concretes. Based on the obtained results, it was concluded that recycled aggregates up to 50% don’t negatively affect the physical and mechanical properties of RCC.

A Path Analysis of the Effect of Neighborhood Built Environment on Public Health of Older Adults: A Hong Kong Study

Introduction

Health deterioration among frail older adults is a public health concern. Among the multi-dimensional factors, the neighborhood built environment is crucial for one's health. Although the relationship between the built environment and health in the general population has been thoroughly investigated, it has been ignored in the case of frail older adults, who may have difficulties in their daily basic living skills. A path analysis is constructed to model the proposed theoretical framework involving the neighborhood built environment and health among frail older adults. This study thus aims to investigate the environmental influences on health, and to validate the theoretical framework proposed for health and social services.

Methods

This study used secondary data collected in Hong Kong. A sample of 969 older community dwellers aged 60 or above were frail with at least one activity of daily living. Demographic information, neighborhood built environment data, service utilization, and health conditions were collected from these participants and their caregivers. A path analysis was performed to examine the proposed theoretical framework.

Results

The health condition was of general concern, including frailty and incapacities in daily activities in frail older adults. Besides psychosocial factors, service use, and caregivers' care quality, the built environment had a significant impact on the health of older adults as well. Specifically, more facilities offering services and groceries, a shorter distance to the nearest metro station, and more greenery exposure are associated with a better-expected health condition among frail older adults.

Discussion

The proposed theoretical framework successfully supplements past negligence on the relationship between the built environment and the health of frail older adults. The findings further imply that policymakers should promote the usability of transit and greenery in neighborhoods and communities. In addition, service utilization should be improved to meet the basic needs of frail older adults in the communities.

Computer vision for solid waste sorting: A critical review of academic research

Waste sorting is highly recommended for municipal solid waste (MSW) management. Increasingly, computer vision (CV), robotics, and other smart technologies are used for MSW sorting. Particularly, the field of CV-enabled waste sorting is experiencing an unprecedented explosion of academic research. However, little attention has been paid to understanding its evolvement path, status quo, and prospects and challenges ahead. To address the knowledge gap, this paper provides a critical review of academic research that focuses on CV-enabled MSW sorting. Prevalent CV algorithms, in particular their technical rationales and prediction performance, are introduced and compared. The distribution of academic research outputs is also examined from the aspects of waste sources, task objectives, application domains, and dataset accessibility. The review discovers a trend of shifting from traditional machine learning to deep learning algorithms. The robustness of CV for waste sorting is increasingly enhanced owing to the improved computation powers and algorithms. Academic studies were unevenly distributed in different sectors such as household, commerce and institution, and construction. Too often, researchers reported some preliminary studies using simplified environments and artificially collected data. Future research efforts are encouraged to consider the complexities of real-world scenarios and implement CV in industrial waste sorting practice. This paper also calls for open sharing of waste image datasets for interested researchers to train and evaluate their CV algorithms.

A facilitating framework for a developing country to adopt smart waste management in the context of circular economy

To achieve higher standards of sustainability, the waste management sector now requires the incorporation of circular economy (CE) principles. However, an easy transition toward the particular goal would require the use of smart waste technologies. To achieve the aforementioned goal, this study aims to provide a facilitating framework for the adoption of smart waste management in the context of CE for Pakistan. To help Pakistan transition toward the new paradigm, a total of 16 critical facilitators are evaluated based on five distinctive criteria using a novel fuzzy hybrid multi-criteria decision-making (MCDM) approach. The hybrid MCDM approach includes fuzzy Stepwise Weight Assessment Ratio Analysis (SWARA) for allocating weights to the determined criteria; whereas, the fuzzy VIšekriterijumsko kompromisno rangiranje (VIKOR) approach is used to rank the critical facilitators adopted from the secondary literature. The fuzzy approach in both cases is to deal with any kind of uncertainty during the data collection process. Based on the achieved results, the study suggests that before the application of smart waste technologies in the country, Pakistan should first focus on devising regulations that effectively address the mismanagement of waste produced in the country. Also, the industries in the country need to become more responsible and should adopt environmental management systems that foster waste minimization. Lastly, the country in the third phase should focus on the wide application of digitalization both in the streams of ICT and IoT, for collecting, sharing, and receiving waste data. The study further provides policy recommendations to the respective stakeholders that will help the country achieve zero-waste CE.

How Different Tools Contribute to Climate Change Mitigation in a Circular Building Environment?—A Systematic Literature Review

The circular economy (CE) has become a trend because concern has arisen regarding the end of life of several products and the reduction of CO2 emissions in many processes. Since the architecture, engineering, and construction (AEC) industry is one of the biggest generators of environmental impacts, there is a need to apply the CE concept to the industry in order to reduce greenhouse gas (GHG) emissions. However, the role of different tools that are used to integrate CE strategies to reduce GHG emissions by the AEC industry is still unknown in the scientific literature. The purpose of this paper is to carry out a systematic literature review on the theme and analyze the following seven tools: (1) life cycle assessment—LCA; (2) building information modeling—BIM; (3) building environmental certifications—BEC; (4) building materials passports—BMP; (5) waste management plan—WMP; (6) augmented reality—AR; and (7) virtual reality—VR. A total of 30 papers were reviewed, and it was observed that, in terms of CE strategies and climate change mitigation, the vast majority can be classified as closing loops and are mainly related to recycling and reuse at the end of life and the use of recycled materials. Considering the building’s stakeholders, constructors, researchers, and designers can be the main users and, consequently, those that most benefit from the use of the evaluated tools. The integration between LCA, BIM, and BMP was also observed. Finally, as one of the main contributions of this research, other types of integration among the analyzed tools are proposed. These proposals seek to improve and update the tools and also address the need to reduce GHG emissions.

Diverting demolition waste toward secondary markets through integrated reverse logistics supply chains: A systematic literature review

Construction industry has adopted reverse logistics (RL) concept to manage high volumes of demolition waste (DW). However, DW RL supply chains (RLSCs) were found to be suffering from uncertainties, information deficiencies, and uncoordinated material flows. Improving supply chain integration (SCI), specifically external integration, across DW RLSCs was identified as a possible solution to overcome such problems. Despite this, studies that focus on external integration in DW RLSCs are limited. Using a systematic literature review (SLR), this study explores external integration in DW RLSCs. Sixty-six articles from three databases published between 2006 and 2020 were subjected to descriptive and content analysis. Arrangement of material, information, and financial flows across DW RLSCs, inhibitors of external integration, and potential measures for improving external integration were analyzed. Accordingly, material, information, and financial flows across DW RLSCs were mapped, and inhibitors of external integration, along with potential measures for improving external integration were identified. As the key outcome of this SLR, these findings were developed into a conceptual framework, which shows the main factors that inhibit and improve external integration in DW RLSCs. The framework will be useful in guiding further empirical research and informing industry practice. Several future research directions are also proposed to expand knowledge around the research domain.

Computer vision to recognize construction waste compositions: A novel boundary-aware transformer (BAT) model

Recognition of construction waste compositions using computer vision (CV) is increasingly explored to enable its subsequent management, e.g., determining chargeable levy at disposal facilities or waste sorting using robot arms. However, the applicability of existing CV-enabled construction waste recognition in real-life scenarios is limited by their relatively low accuracy, characterized by a failure to distinguish boundaries among different waste materials. This paper aims to propose a novel boundary-aware Transformer (BAT) model for fine-grained composition recognition of construction waste mixtures. First, a pre-processing workflow is devised to separate the hard-to-recognize edges from the background. Second, a Transformer structure with a self-designed cascade decoder is developed to segment different waste materials from construction waste mixtures. Finally, a learning-enabled edge refinement scheme is used to fine-tune the ignored boundaries, further boosting the segmentation precision. The performance of the BAT model was evaluated on a benchmark dataset comprising nine types of materials in a cluttered and mixture state. It recorded a 5.48% improvement of MIoU (mean intersection over union) and 3.65% of MAcc (Mean Accuracy) against the baseline. The research contributes to the body of interdisciplinary knowledge by presenting a novel deep learning model for construction waste material semantic segmentation. It can also expedite the applications of CV in construction waste management to achieve a circular economy.

The Mediating Role of Policy-Related Factors in the Relationship between Practice of Waste Generation and Sustainable Construction Waste Minimisation: PLS-SEM

As the construction industry grows, it produces large volumes of construction waste, which has a tremendous environmental impact and generates public concern in the neighbouring towns. The construction industry generates a significant volume of waste and faces a challenge with poor construction waste minimisation in order to prevent adverse environmental and dumping impacts worldwide. In developing countries, regional waste management systems have increased problems. Environmental pollution (air, water, and soil) and human health issues are caused by waste produced in a country as a result of different cultural, social, and religious activities. Prior studies were reviewed to choose dimensions and items for the data gathering instrument. A pilot test was conducted to identify potential questionnaire adjustments, and hypotheses were tested using structural equation modelling (SEM). A total of 220 Malaysian construction professionals answered the survey, which yielded the results. Five hypotheses have direct correlations based on the findings, three of which have a significant effect. Furthermore, the findings reveal that policy-related factors mediate the relationship between improving factors and sustainable construction waste minimisation. In contrast, they did not mediate the relationship between current practices/generation and sustainable construction waste management. The established framework can help improve construction waste management and help achieve global sustainable development goals. The data reveal that adopting preventive plans to reduce construction waste is one of the most important aspects of enhancing profitability. This study could aid construction industry players in evaluating waste management components during the construction and design stages of a building project.

A Synthesis of Express Analytic Hierarchy Process (EAHP) and Partial Least Squares-Structural Equations Modeling (PLS-SEM) for Sustainable Construction and Demolition Waste Management Assessment: The Case of Malaysia

Construction and demolition waste (CDW), as the main consequence of construction and demolition (C&D) activities, has severely affected our sustainability needs. However, construction and demolition waste management (CDWM) lacks the integration of sustainability concepts. Thus, there is a great need to include sustainability dimensions in CDWM to reach sustainable construction and demolition waste management (SCDWM). This study aims at empirically investigating SCDWM by analyzing the impacts of factors that contribute to sustainability aspects of CDWM on waste management hierarchy (WMH), including reduce, reuse, recycle, and disposal strategies. According to the literature, 26 factors were initially identified and grouped under four categories, namely environmental, economic, social, and administrative, that contribute to sustainability aspects of CDWM. Subsequently, a pilot test was performed to assess the significance and applicability of these factors in the Malaysian construction industry by implementing the express analytic hierarchy process (EAHP). Then, a questionnaire survey was performed to collect data from 132 construction companies involved in CDWM. Partial least squares-structural equation modeling (PLS-SEM) was used to test the hypothetical relationships by applying SmartPLS software. Results demonstrated that the economic aspect of CDWM (main category) and “public environment contamination due to illegal waste dumping” (sub-category) were the most influential factor in SCDWM in Malaysia.

A life cycle assessment framework for large-scale changes in material circularity

Increasing material circularity is high on the agenda of the European Union in order to decouple environmental impacts and economic growth. While life cycle assessment (LCA) is useful for quantifying the associated environmental impacts, consistent LCA modeling of the large-scale changes arising from policy targets addressing material circularity (i.e., recycled content and recycling rate) is challenging. In response to this, we propose an assessment framework addressing key steps in LCA, namely, goal definition, functional unit, baseline versus alternative scenario definition, and modeling of system responses. Regulatory and economic aspects (e.g., trends in consumption patterns, market responses, market saturation, and legislative side-policies affecting waste management) are emphasized as critical for the identification of potential system responses and for supporting regulatory interventions required to reach the intended environmental benefits. The framework is recommended for LCA studies focusing on system-wide consequences where allocation between product life cycles is not relevant; however, the framework can be adapted to include allocation. The application of the framework was illustrated by an example of implementing a policy target for 2025 of 70% recycled content in PET trays in EU27+1. It was demonstrated that neglecting large-scale market responses and saturation lead to an overestimation of the environmental benefits from the policy target and that supplementary initiatives are required to achieve the full benefits at system level.

Quality intervention, supplier performance and buyer–supplier relationships: evidence from the garment industry

Purpose

This study investigates the impact of a buyer-assisted quality intervention on suppliers' quality performance and buyer–supplier relational dynamics in the garment industry.

Design/methodology/approach

This study employed a multiple-embedded case study following a qualitative research approach. The study used data from buyer-assisted quality interventions in sewing lines of four garment supplier factories. Qualitative data were collected through semi-structured interviews of buyer's representatives at their office and senior managers, line inspectors, supervisors and workers in supplier factories. In addition, data related to product quality was obtained from quality check sheets and observations on the shop floor. Data were analysed using qualitative data analysis techniques.

Findings

This study demonstrates that a buyer-assisted quality intervention improves product quality performance by reducing quality defects in targeted garment products resulting in improved buyer–supplier relationships. Moreover, this study identifies the lack of a systematic approach in quality control as a key reason for poor product quality.

Research limitations/implications

The study adds knowledge to the literature on quality improvement and buyer–supplier relationships by analysing buyer-assisted quality interventions in the garment industry in Bangladesh. The study demonstrates that buyer's assistance and adopting a systematic approach in quality control can significantly improve product quality in the garment industry.

Practical implications

This research can help the quality assurance managers in buyer and supplier firms understand the significance of quality interventions and systematic quality control approach to decrease product quality defects and ensure smooth buyer–supplier relationships.

Originality/value

The study adds new knowledge on the link between buyer-assisted quality interventions, systematic quality control and product quality in garments factories in Bangladesh.

Circular Economy: Challenges and Opportunities in the Construction Sector of Kazakhstan

The circular economy in the construction sector in emerging economies is one of the most promising concepts that aims to keep the value of the construction materials and structures as long as possible. The construction industry is rapidly developing in Kazakhstan with a yearly increase in projects. This research paper investigates the construction sector in Kazakhstan in terms of the potential application of circular economy principles by local stakeholders—clients, contractors, designers, and manufacturers. As limited research has been conducted on the circularity within the construction environment, including construction parties, this paper aims to fill this research gap. It seeks to identify the construction trends and perform a barrier and opportunity analysis to develop circular economy principles in the construction sector. As a research method, PEST is used for the study of local construction trends. At the same time, stakeholders are interviewed using semi-structured surveys organized according to the ReSOLVE framework (regenerate, share, optimize, loop, virtualize, and exchange) to identify the barriers and opportunities for circular economy in the construction sector. As an outcome of this study, the most common barriers and opportunities were associated with the economic benefit factor, as this was the main motivation for the stakeholders to save construction materials for reuse or to refuse more eco-friendly technologies. Additionally, policy recommendations for companies involved in the construction ecosystem were provided according to the assessment of found barriers and opportunities in the context of the ReSOLVE framework. This analysis has shown that for most stakeholders of the Kazakhstani construction sector, virtualization is of the highest priority; therefore, opportunities for its development are recommended. Future research could focus on the development of economically feasible solutions for the circular economy in construction with the inclusion of virtualization technologies.

Tackling the "last mile" problem in renovation waste management: A case study in China

Solid waste generated from building renovation, called "renovation waste" in this study, represents a major waste management problem. A particular difficulty is sourcing renovation waste arising sporadically from discrete sites for central processing. This can be characterized as a "last mile" problem in renovation waste management (RWM). This study reports good practice for dealing with the RWM last mile problem in a city in China. We conduct qualitative research comprising site investigations and interviews, organized in an in-depth case study. We discover that the city effectively solved the last mile problem by developing a multi-layer, nested waste management system, empowered further by various smart technologies and concerted collaboration from multi-stakeholders coordinated by a determined government. Nevertheless, the longevity of the RWM is contingent on confronting several challenges, including (a) achieving cost and benefit balance, (b) defining clearer standards and policies, and (c) raising stakeholders' awareness of waste management. A general RWM strategy is recommended to establish fluent channels through which to source and qualify renovation waste for central treatment. The study delves into the much neglected world of RWM and provides a valuable reference for tackling similar problems.

Estimating construction waste generation in the Greater Bay Area, China using machine learning

Reliable construction waste generation data is a prerequisite for any evidence-based waste management effort, but such data remains scarce in many developing economies owing to their rudimentary recording systems. By referring to several models proposed for estimating waste generation, this study aims to develop a reliable and accessible method for estimating construction waste generation based on limited publicly available data. The study has two objectives. Firstly, it aims to estimate construction waste generation by focusing on the Greater Bay Area (GBA) in China, one of the world's most thriving regions in terms of construction activities. Secondly, it aims to compare the strengths and weaknesses of various waste quantification models. 43 sets of annual socio-economic, construction-related and C&D waste generation data ranging from 2005 to 2019 were collected from the local government authorities. By analyzing the data using four types of machine learning models, namely multiple linear regression, decision tree, grey models, and artificial neural network, it is found that all calibrated models, with their respective strengths and weaknesses, can produce acceptable results with the testing R² ranging from 0.756 to 0.977. This study also reveals that the 11 cities in the GBA produced a total of about 364 million m³ of construction waste in 2018. The result can be used for monitoring the urban metabolism, quantifying carbon emission, developing a circular economy, valorizing recycled materials, and strategic planning of waste management facilities in the GBA. The research findings also contribute to the methodologies for estimating waste generation using limited data.

Coupling Influence between Recycled Ceramics and Grazed Hollow Beads on Mechanical Properties and Thermal Conductivity of Recycled Thermal Insulation Concrete

This paper investigated the influence of recycled ceramics and grazed hollow beads on the mechanical, thermal conductivity and material properties of concrete. The results showed that the concentration of recycled ceramics and grazed hollow beads has significant optimization on the workability and thermal properties of the concrete. However, the superabundant concentration can reduce the hydration degree of the concrete, which results in the suppressed production of C-S-H gel and the increase of material defects. In summary, considering the coordinated development of key factors such as thermal insulation properties, mechanical properties and microstructure, 10% RCE and 60% GHB are the optimal material system design methods.

Decision-making interaction among stakeholders regarding construction and demolition waste recycling under different power structures

The market power and competition scenario of recycling enterprises and landfills may change in the future due to the environmental pressure caused by landfills and the environmental potential of construction and demolition waste (C&DW) recycling. In this context, how these changes will affect the economic performance of enterprises and the environmental performance of the whole society remains unclear, along with how the willingness to pay and the environmental awareness of contractors will affect the pricing decisions of recycling enterprises and landfills. This study investigates the charging and recycling problem under different power structures in the reverse supply chain of C&DW, which is composed of waste generators (construction contractors) and two disposers (recycling enterprises and landfills). The interactive decisions of three stakeholders are discussed and the optimal charge fee, profit, and recycling ratio are obtained. Results indicate the following (i) The environmental preference of contractors directly increases the charge fee of recycling enterprises, and indirectly increases the charge fee of landfills. (ii) An increase in contractors' environmental preference will reduce the recycling ratio of C&DW and increase landfill and illegal dumping ratios. (iii) From the perspective of environmental benefits, illegal dumping and recycling ratios experience the worst scenario in the Recycling-Stackelberg game model and the best scenario in Nash game model because recycling enterprises take advantage of their dominant market position and set higher charges than those that contractors can afford. This theoretical study bridges the research gap on the effects of the market power on the environmental and economic performance of stakeholders in the field of C&DW management. The findings also help policy makers understand the behavior of stakeholders under different power structures to formulate the most effective intervention strategies.

Influence of Recycled Aggregates on the Mechanical Properties of Synthetic Fibers-Reinforced Masonry Mortars

The construction sector is one of the main consumers of raw materials and generates a high volume of waste within the European Union. The search for new materials that are more sustainable and respectful of the environment has become a challenge for countries with a high degree of industrialization. In this work, a study of the most relevant properties of masonry mortars made with recycled aggregates and reinforced with synthetic fibers was carried out. Three types of aggregates were used—natural, concrete recycling and ceramic recycling—and two types of reinforcing fibers: polypropylene and polyolefin. In this way, various tests of physical-mechanical characterization and a statistical analysis of the results were carried out. It has been shown that the mortars made from aggregate recycled concrete and reinforced with polypropylene fiber are the ones with the best properties for application in the construction sector, although without improving the properties of traditional mortars made from natural aggregate and without fibers.

"Looking beneath the surface": A visual-physical feature hybrid approach for unattended gauging of construction waste composition

There are various scenarios challenging human experts to judge the interior of something based on limited surface information. Likewise, at waste disposal facilities around the world, human inspectors are often challenged to gauge the composition of waste bulks to determine admissibility and chargeable levy. Manual approaches are laborious, hazardous, and prone to carelessness and fatigue, making unattended gauging of construction waste composition using simple surface information highly desired. This research attempts to contribute to automated waste composition gauging by harnessing a valuable dataset from Hong Kong. Firstly, visual features, called visual inert probability (VIP), characterizing inert and non-inert materials are extracted from 1127 photos of waste bulks using a fine-tuned convolutional neural network (CNN). Then, these visual features together with easy-to-obtain physical features (e.g., weight and depth) are fed to a tailor-made support vector machine (SVM) model to determine waste composition as measured by the proportions of inert and non-inert materials. The visual-physical feature hybrid model achieved a waste composition gauging accuracy of 94% in the experiments. This high performance implies that the model, with proper adaption and integration, could replace human inspectors to smooth the operation of the waste disposal facilities.

Simulation analysis of implementation effects of construction and demolition waste disposal policies

Urban development generates large amounts of construction and demolition waste, and the enactment of various policies is an important way to increase resource efficiency. It is urgent to analyse the choices and effects of construction and demolition waste disposal policies around the world. This study analyses and compares the implementation effects of various construction and demolition waste disposal policies and provides suggestions on the selection and formulation of different disposal method policies. A BP neural network and an agent-based model are used to construct a simulation model for the implementation effects of construction and demolition waste disposal policies. The average acceptance willingness is analysed for the three disposal methods of reduction, reuse and recycling under the different policies based on questionnaire survey data. Simulation results show that the implementation effect of the incentive policy as a single policy is superior, and the comprehensive implementation effect of the guidance-incentive-mandatory policy as a combined policy is superior. The implementation effect of combined policies is better than that of single policies. The policies suitable for different disposal methods are inconsistent. Information interaction can effectively improve the implementation effects of different construction and demolition waste disposal policies, especially for single policies. This study innovatively compares the various construction and demolition waste disposal policies and explain the interaction during their implementation. The findings can help the government formulate policies at different stages of construction and demolition waste management and provide a new approach to policy simulation research.

An analytical framework of "zero waste construction site": Two case studies of Shenzhen, China

Around the global construction industry, there is an emerging trend to pursue a "zero-waste" goal at the site level, but little is known about it. This paper aims to shed insights on the waste management concept of "zero waste construction site" by delineating its meaning, system boundary, assessment period, and operation strategies, which are further formulated in an analytical framework. Owing to the nascent nature of the concept, we adopted a qualitative approach including archival study, a series of semi-structured interviews, and two in-depth case studies in Shenzhen, China to sketch the analytical framework. Meanwhile, an analogy between "zero waste construction site" and "net zero building" is continuously made to fine-tune and finalize the framework. This research demonstrates that the zero-waste goal is challenging but achievable on individual construction sites. The system boundary to examine the zero-waste goal is contingent on the project scope, be it a new construction, renovation, or demolition project. The assessment period is dependent on the duration of the construction project. However, it would be too costly, if not entirely impossible, to achieve a "zero waste construction site" by treating it as a closed system. Rather, one needs to consider open, off-site strategies, e.g., engaging third-party recycling services, reusing recycled materials in subsequent projects, or trading it in to a recycled material market. The analytical framework can be utilized to scrutinize existing construction waste management practices. In the long term, the research will contribute positively to a "zero waste" society.

A four-quadrant conceptual framework for analyzing extended producer responsibility in offshore prefabrication construction

Prefabrication has been widely advocated as a green production strategy to minimize the adverse environmental impacts of construction. Amid economic globalization, prefabricated construction materials are commonly sourced offsite and even offshore. As an issue emerging alongside offshore prefabrication, extended producer responsibility (EPR) is yet to be clearly identified, allocated, and implemented. This research develops a conceptual framework using a design thinking process, through which EPR associated with offshore prefabrication can be analyzed, agreed upon, and allocated. By considering the scope and scale of the responsibility and the procurement methods, the framework comprises four quadrants representing four typical scenarios for implementation of the EPR principle. It is applicable for both short-term and lifelong EPR analysis, in both traditional and integrated project delivery contexts. The framework will be particularly useful for devising public policies to achieve an onshore and offshore stakeholder win-win situation.

Implementing on-site construction waste recycling in Hong Kong: Barriers and facilitators

Construction and demolition (C&D) waste recycling constitutes an indispensable component in the overall waste management strategy. Unlike the traditional recycling approaches whereby C&D waste is transported to off-site facilities for treatment, construction managers are actively exploring the possibility of on-site recycling where C&D waste is treated directly at source. This study reports the barriers and facilitators of implementing on-site C&D waste recycling by contextualizing it in Hong Kong. It does so by adopting a mixed-method approach combining case study, site visits, and interviews. It is discovered that the barriers include (1) site space constraints, (2) narrow window of opportunity to trade recycled products, (3) vulnerable business case, (4) lack of support from off-site recycling, and (5) lack of government policy support. A series of facilitating measures are also proposed, including (1) developing customized on-site recycling equipment, (2) establishing a demand-supply information-sharing platform, (3) developing more thriving off-site recycling, and (4) providing more government support. This study probes into the real-life on- and off-site waste recycling practices in Hong Kong's prominent C&D management system. It can also provide useful references for others in developing their own C&D waste recycling strategies by rationally deploying on- and off-site recycling.

Challenges in current construction and demolition waste recycling: A China study

China produced a large amount of construction and demolition (C&D) waste, owing to the rapid development of construction industry. Although a set of policies and regulations are being drafted in China for promoting C&D waste recycling, execution of these policies in practice seems to be far from effective. Currently, approximately 75% of Chinese cities are still surrounded by large volumes of C&D waste. Therefore, identification of challenges in the development of C&D waste management, specially recycling, is essential. This paper employs site visits to 10 recycling plants in 10 Chinese cities (Shanghai, Hangzhou, Suzhou, Chongqing, Chengdu, Xi'an, Changsha, Shenzhen, Nanjing, and Zhoukou) and interviews with 25 industry practitioners for examining the challenges. Eight challenges are identified: (1) unstable source of C&D waste for recycling, (2) absence of subsidies for recycling activities and high cost for land use, (3) insufficient attention paid to design for waste minimisation, (4) absence of regulations on on-site sorting, (5) unregulated landfill activities, (6) a lack of coordination among different government administration departments, (7) a lack of accurate estimation of waste quantity and distribution, and (8) a lack of an effective waste tracing system. Recommendations to address these challenges are presented. The results of this study are expected to aid policy makers in formulation of proper C&D waste management in China and provide a useful reference for researchers who are interested in C&D waste recycling industry.

Enablers and Barriers for Creating a Marketplace for Construction and Demolition Waste: A Systematic Literature Review

Rapid population growth and urbanization have led to an increase in Construction and Demolition (C&D) waste, prompting government and industry bodies to develop better waste management practices. Waste trading has emerged as a targeted intervention to divert waste from landfill sites and create a second life for waste material. This paper examines key barriers and enablers influencing the creation of a marketplace for waste trading. A systematic literature review was undertaken to examine global efforts in creating a marketplace for C&D waste. A framework on enablers and barriers for developing a marketplace for C&D waste emerged from the review, based on market-based, operational, and governance factors. References demonstrated that markets for materials such as glass and metals have already been established, but there are increasing marketplace opportunities for other recycled materials. Technology-based market applications are emerging as targeted interventions to facilitate online trading, which will provide a more accessible and user-friendly marketplace for sellers and buyers. Further research should test the complex interactions between people and technology associated with online waste trading platforms, as well as help develop the business case for a C&D waste marketplace.

An environmental assessment model of construction and demolition waste based on system dynamics: a case study in Guangzhou

At present, China is in the rapid development stage of urbanization, and construction activities are becoming more frequent. This is accompanied by a large amount of construction and demolition waste (C&DW), which raises many problems with its governance, such as occupying valuable land resources, causing air pollution, and consuming raw materials. In this study, taking Guangzhou as an example, the system dynamics principle was used to establish an environmental assessment model of C&DW, and Vensim software was used to simulate and analyze the environmental, economic, and social impacts of various disposal methods of C&DW. The results showed that (1) among all waste disposal methods, landfill disposal had the highest greenhouse gas emissions. It was estimated that the greenhouse gas emissions from landfill disposal will account for 75% of the total emissions in 2030, while the greenhouse gas emissions from recycling disposal will only account for 0.5%. (2) The simulation results showed that, according to the current data, the land area occupied by waste landfills and illegal dumping in 2030 will be about 4.88 million m², and the economic loss caused by land loss and global warming will account for 9.1% of Guangzhou's GDP in 2030, which is equivalent to the national economy of a regional city with a less developed economy. (3) Enhanced supervision could significantly reduce the amount of illegal dumping, but its effect on landfill disposal and recycling would be very limited. According to the results of the simulation analysis, some suggestions were put forward to improve the environmental, economic, and social impact of C&DW disposal in Guangzhou.

University Students' Purchase Intention and Willingness to Pay for Carbon-Labeled Food Products: A Purchase Decision-Making Experiment

Carbon labeling describes carbon dioxide emissions across food lifecycles, contributing to enhancing consumers' low-carbon awareness and promoting low-carbon consumption behaviors. In a departure from the existing literature on carbon labeling that heavily relies on interviews or questionnaire surveys, this study forms a hybrid of an auction experiment and a consumption experiment to observe university students' purchase intention and willingness to pay for a carbon-labeled food product. In this study, students from a university in a city (Chengdu) of China, the largest carbon emitter, are taken as the experimental group, and cow's milk is selected as the experimental food product. The main findings of this study are summarized as follows: (1) the purchase of carbon-labeled milk products is primarily influenced by price; (2) the willingness to pay for carbon-labeled milk products primarily depends on the premium; and (3) the students are willing to accept a maximum price premium of 3.2%. This study further offers suggestions to promote the formation of China's carbon product-labeling system and the marketization of carbon-labeled products and consequently facilitate low-carbon consumption in China.

Developing efficient circularity for construction and demolition waste management in fast emerging economies: Lessons learned from Shenzhen, China

Proper management of construction and demolition (C&D) waste is a key challenge amid global advocacy of the circular economy. This is of particular urgency in fast-emerging economies, where economic development induces massive construction without the capacity to manage the associated waste. This paper reports lessons learned from Shenzhen, China, which has witnessed exciting economic growth in the past few decades but also been compelled to rapidly develop an effective C&D waste circular economy from a low base. The research adopts a mixed-method approach combining case study, site investigations, and interviews in Shenzhen. It is discovered that Shenzhen's success can be attributed to (a) implementing strong governmental interventions; (b) developing a thriving C&D waste recycling market; (c) introducing advanced recycling technologies; and (d) enacting responsive institutional arrangements. Further improvements related to (1) recycled product certification, (2) land use and economic subsidies, and (3) changing circular economy philosophies, inter alia, are desired to sustain the long-term prosperity of this circular economy. The research provides a reference which can be adapted to the unique context of other emerging economies in developing effective circularity.

Carbon emission reduction in prefabrication construction during materialization stage: A BIM-based life-cycle assessment approach

Prefabrication has gained its popularity in countries including China due to its various advantages such as quality control, waste reduction, onsite and offsite parallel coordination, and so on. It has also been recognized as a key strategy to reduce construction-induced carbon emissions. However, there is limited research to examine carbon emission reduction in prefabrication by using the advanced technological artefacts, e.g., building information modeling (BIM), emerging from the technology sphere. As a digital representation of a facility, BIM provides a cyber platform based on which many assessment and simulation works can be performed without having to construct the physical facility. This paper aims to develop a BIM-based approach to measuring carbon emission reduction during the materialization stage of a prefabricated building project. Findings from the study indicate that BIM is an efficient and effective method for measuring carbon emissions from the construction of new buildings and that prefabrication reduces carbon emissions when compared with conventional construction methods. The research contributes to the body of knowledge relating to the reduction of carbon emissions through prefabrication. This is pertinent to contractors, homebuyers and governments who are constantly seeking ways to achieve a circular economy.

Circular Economy Practices and Strategies in Public Sector Organizations: An Integrative Review

The concept of the Circular Economy (CE) is an increasingly attractive approach to tackling current sustainability challenges and facilitating a shift away from the linear “take-make-use-dispose” model of production and consumption. The public sector is a major contributor to the CE transition not only as a policy-maker but also as a significant purchaser, consumer, and user of goods and services. The circularization of the public sector itself, however, has received very little attention in CE research. In order to explore the current state of knowledge on the implementation of CE practices and strategies within Public Sector Organizations (PSOs), this research aims to develop an overview of the existing literature. The literature review was designed combining a systematic search with a complementary purposive sampling. Using organizational sustainability as a theoretical perspective, the main results showed a scattered landscape, indicating that the limited research on CE practices and strategies in PSOs has focused so far on the areas of public procurement, internal operations and processes, and public service delivery. As a result of this literature review, an organizational CE framework of a PSO is proposed providing a holistic view of a PSO as a system with organizational dimensions that are relevant for the examination and analysis of the integration process of CE practices and strategies. This innovative framework aims to help further CE research and practice to move beyond current sustainability efforts, highlighting that public procurement, strategy and management, internal processes and operations, assessment and communication, public service delivery, human resources dimensions, collaboration with other organizations, and various external contexts are important public sector areas where the implementation of CE has the potential to bring sustainability benefits.

Identification of critical factors in construction and demolition waste recycling by the grey-DEMATEL approach: a Chinese perspective

The extensive waste produced in construction and demolition activities affects the ecological environment, impeding green development in countries worldwide, including China. China has paid increasing attention to managing construction and demolition waste (CDW). However, most of the existing research only qualitatively studies the factors affecting the recycling of CDW and does not reveal the critical factors. Therefore, based on stakeholder theory and the grey-DEMATEL method, this paper aims to identify and quantitatively analyze the critical factors in CDW recycling from the perspective of China. This paper drew the following conclusions: (1) Stakeholders in China's CDW recycling mainly include the government, CDW production units, and CDW recycling units. (2) Public policy, government subsidies, media promotion, human resources, cost, environmental awareness, technological innovation, and supply chain management are the eight dimensions with 13 factors that constitute CDW recycling in China. (3) For the total relations between factors affecting the recycling of CDW in China, the most influential factor is specific legislation and regulations. The factor with the highest degree of prominence is environmental awareness. The factor with the largest net cause value is the rationality of disposal and landfill charges. The factor with the largest net effect value is experienced construction workers. (4) The critical factors in China's CDW recycling include specific legislation and regulations, mandatory degree of normative standards, environmental awareness, the supply of raw materials for CDW recycling units, and the sale of remanufactured products. Finally, this paper identifies the following management implications: (1) the government should prioritize the task of improving specific legislation and regulations, with a focus on a mandatory degree of normative standards. (2) CDW production units should put the task of improving environmental awareness high on their agenda, with a focus on the supply of raw materials for recycling units. (3) CDW recycling units should prioritize the issue of the sale of remanufactured products. This paper also provides a theoretical basis for revealing the critical factors of CDW recycling in other countries or regions.

Impacts of Tourism Demand on Retail Property Prices in a Shopping Destination

Understanding the relationship between tourism demand and retail property prices is of great significance to tourist destinations, especially shopping destinations. The increase in tourism demand may alter the implicit prices of certain retail property characteristics (e.g., age and accessibility to transit). This study examines how tourism demand (measured by tourist volume) affects retail property prices in the tourist precinct of a shopping destination, namely Hong Kong. The implementation of the policy Individual Visit Scheme (IVS) in 2003 in Hong Kong has substantially increased tourist shoppers from Mainland China, and it is used as a quasi-natural experiment of the increased tourist volume. Spatial and non-spatial hedonic pricing models are developed based on the ground-floor retail property transaction data of Causeway Bay, Hong Kong before and after the IVS (1993–2011). The findings of this study are as follows. (1) Accessibility to transit has a larger positive price effect after the implementation of the IVS. (2) The implicit price of accessibility to accommodation facilities is not significantly altered by the implementation of the IVS. (3) Age has a larger negative price effect after the implementation of the IVS. The first two outcomes are related to the economic concerns of tourist shoppers, while the last can be explained by their hometown experience. Finally, practical implications are discussed.

Waste Brick as Constructed Wetland Fillers to Treat the Tail Water of Sewage Treatment Plant

Adopting the concept of "using waste to treat waste", the waste bricks will be used for constructed wetland filling. Integrated vertical-flow constructed wetland (IVCW) studied on the purification effect in influent water under three hydraulic loads (0.15, 0.25, 0.35 m/day). The results show that the waste bricks can be used as the carrier for the growth of the system biofilm, and have positive effects on the removal of pollutants in the influent water. Under three different hydraulic load conditions, the vertical flow of CWs can significantly reduce the load of water intake. In the low hydraulic load condition of 0.15 m/day, the average removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH₃-N), total nitrogen (TN), and total phosphorus (TP) can reach 66.52%, 72.10%, 56.53% and 91.55% in this system, respectively. The influent pool on removal efficiency of pollutants was obviously higher than that of the upper pool, especially in the inlet surface 0-30 cm ranges. This research has achieved the effect of using "waste" to treat wastewater, which has strong practical significance and popularization value.