The construction industry is faced with many challenges, among which is waste management. Aside from the fact that wastage contributes to time and cost overrun, it also has environmental implications in the form of pollution. However, the industry has the capacity to effectively manage waste, from generation to disposal. All stages of the management process are important, but scholars and governments have provided the final step, being disposal, unabated attention in order to ensure effective management. Potential waste disposal methods, including incineration, burning, landfilling, recycling, reuse, open dumping, pyrolysis, and shredding have emerged from the literature around the globe. Despite various waste minimisation and sustainable disposal options that are available, construction material waste is still increasing in Nigeria, while disposal remains a major issue for firms and government. Therefore, this study assesses disposal methods among construction firms to determine whether there is a relationship between their practices towards waste disposal. The research followed a concurrent triangulation design in a cross sectional survey, while data were collected via a convergent parallel mixed methods. The quantitative phase employed a structured questionnaire to collect data from 243 building construction firms, while the qualitative phase involved semi-structured interviews with 65 professionals from 10 on-going construction projects in Lagos, Nigeria. The research revealed that landfilling is the most common method of waste disposal, which is closely followed by reuse as backfill and recycling. In addition, the study revealed no association between company’s ownership statuses, age, project specialisation, and disposal methods, except company’s size. In conclusion, the study establishes the need for regulatory policies, such as site waste management plan (SWMP), pay as you throw (PAYT), and landfill ban, which would minimise material waste and divert them from landfills. Recycling and reuse are recommended as sustainable approaches for waste disposal.

This study advances circular economy initiatives by advocating for the use of Multi-Criteria Decision-Making (MCDM). MCDM methods address the complex multi-faceted aspects of a product or process. They enable conflicting calculations of energy, cost, environmental criteria, and payback periods to be balanced. A systematic critical systematic review and bibliometric analysis were conducted to investigate the contribution of MCDM to the circular economy. The Scopus database was the primary data source reviewed. The geographical distribution, main research sources, and keyword co-occurrences were analyzed across 31 peer-reviewed book chapters, conference papers, and journal articles. The journal Sustainability (Switzerland) had the most publications (4), followed by the Journal of Business Strategy and the Environment and the Journal of Cleaner Production, each with two articles. Recently MCDM has gained popularity as a tool for evaluating the circular economy. This growing interest may be attributed to the complexity of the circular economy, as MCDM effectively balances multiple environmental criteria while integrating evaluations of economic cost and social impact. Criteria are incommensurable as each criterion has a distinct unit of measurement, making it impossible to compare outcomes across different indicators. MCDM is thus an ideal technique for assessing different options by integrating criteria within testable frameworks. However, no established patterns for selecting specific MCDM methods were identified. This is despite some options (e.g., combinations of AHP and TOPSIS) being used more frequently than others. In conclusion, all the studies identified financial factors as the most significant or highly sensitive issue in the transition toward a circular economy.

Purpose: Establishing a more sustainable built environment is an increasing global concern for the construction industry. Despite the intrinsic and extrinsic obstacles the stakeholders face, huge efforts are required to transition to a smooth, sustainable construction (SC) practice. This study identifies and discusses cogent obstacles to SC in developing nations.Design/methodology/approach: The Preferred Reporting Item for systematic reviews and Meta-Analysis (PRISMA) approach was employed to establish research work in SC for developing countries. The databases used were Scopus and Web of Science. Meta-analysis of keywords was analysed thematically. The initial broad search returned 8,420 publications which were filtered and reviewed in-depth to fit the aim of the study, produced only 21 relevant publications from the years 2000–2021.Findings: The four identified themes of obstacles to SC in developing countries are as follows: construction professional training and education, clients' attitudes and awareness, construction industries' culture and capacity and governments' regulation, policies and economy. The key barriers identified from the meta-analysis include inadequate training and education amongst construction professionals, poor execution of sustainability ethics, poor populace attitude towards sustainability, poor awareness and understanding, dearth of precise data and integrated study and inappropriate priorities about sustainability.Originality/value: The originality in this study are themes drawn from millennium development goals (MDGs) and sustainable development goals (SDGs) publications related to SC. Consequently, the final framework presented a holistic approach to surmounting the established limitations and aided recommendations for future studies. Thus, setting a background for developing strategies to overcome the limitations and further attain sustainable development (SD).

Successful subway construction projects involve many socio-economic, cultural and environmental challenges. These projects enhance public convenience, and are complex and uncertain, involving multiple governmental organizations. The critical success factors (CSFs) of these projects have been identified and prioritized from a main contractors’ perspective, to enable project managers to prioritize their efforts and concerns. This study sheds light on CSFs in subway construction projects and contributes to the project delivery success literature with an overarching focus on the contractors' perspectives. Our investigation revealed that, for subway construction projects in Iran, goal setting through clear and realistic project goals, project management competency, competent project team, good cultural fit, top management support and adequate funding throughout the project are the top-ranking CSFs. An extensive body of literature is reviewed, and 140 potential success factors are identified. Then, a focus group has been conducted in which the potential CSFs reduced to 39 success factors. The priorities and ranking of the success factors were evaluated according to the views of 63 project managers of subway projects. The correlation coefficients analysis was used to analyze the results, and it revealed that 23 success factors such as goal setting, top management support and PM competency were perceived to be critical by the respondents. No other research has, until now, found the critical factors leading to success in subway construction industry in Iran. The results have been verified against other research done in other countries.