Methodology for quantification of waste generated in Spanish railway construction works

In the last years, the European Union (EU) has been focused on the reduction of construction and demolition (C&D) waste. Specifically, in 2006, Spain generated roughly 47million tons of C&D waste, of which only 13.6% was recycled. This situation has lead to the drawing up of many regulations on C&D waste during the past years forcing EU countries to include new measures for waste prevention and recycling. Among these measures, the mandatory obligation to quantify the C&D waste expected to be originated during a construction project is mandated. However, limited data is available on civil engineering projects. Therefore, the aim of this research study is to improve C&D waste management in railway projects, by developing a model for C&D waste quantification. For this purpose, we develop two equations which estimate in advance the amount, both in weight and volume, of the C&D waste likely to be generated in railway construction projects, including the category of C&D waste generated for the entire project.     

A BIM-based system for demolition and renovation waste estimation and planning

Due to the rising worldwide awareness of green environment, both government and contractors have to consider effective construction and demolition (C&D) waste management practices. The last two decades have witnessed the growing importance of demolition and renovation (D&R) works and the growing amount of D&R waste disposed to landfills every day, especially in developed cities like Hong Kong. Quantitative waste prediction is crucial for waste management. It can enable contractors to pinpoint critical waste generation processes and to plan waste control strategies. In addition, waste estimation could also facilitate some government waste management policies, such as the waste disposal charging scheme in Hong Kong. Currently, tools that can accurately and conveniently estimate the amount of waste from construction, renovation, and demolition projects are lacking.In the light of this research gap, this paper presents a building information modeling (BIM) based system that we have developed for estimation and planning of D&R waste. BIM allows multi-disciplinary information to be superimposed within one digital building model. Our system can extract material and volume information through the BIM model and integrate the information for detailed waste estimation and planning. Waste recycling and reuse are also considered in our system. Extracted material information can be provided to recyclers before demolition or renovation to make recycling stage more cooperative and more efficient. Pick-up truck requirements and waste disposal charging fee for different waste facilities will also be predicted through our system. The results could provide alerts to contractors ahead of time at project planning stage. This paper also presents an example scenario with a 47-floor residential building in Hong Kong to demonstrate our D&R waste estimation and planning system. As the BIM technology has been increasingly adopted in the architectural, engineering and construction industry and digital building information models will likely to be available for most buildings (including historical buildings) in the future, our system can be used in various demolition and renovation projects and be extended to facilitate project control.     

Estimation of building-related construction and demolition waste in Shanghai

One methodology is proposed to estimate the quantification and composition of building-related construction and demolition (C&D) waste in a fast developing region like Shanghai, PR China. The varieties of structure types and building waste intensities due to the requirement of progressive building design and structure codes in different decades are considered in this regional C&D waste estimation study. It is concluded that approximately 13.71 million tons of C&D waste was generated in 2012 in Shanghai, of which more than 80% of this C&D waste was concrete, bricks and blocks. Analysis from this study can be applied to facilitate C&D waste governors and researchers the duty of formulating precise policies and specifications. As a matter of fact, at least a half of the enormous amount of C&D waste could be recycled if implementing proper recycling technologies and measures. The appropriate managements would be economically and environmentally beneficial to Shanghai where the per capita per year output of C&D waste has been as high as 842 kg in 2010.     

Impact of Construction Waste Disposal Charging Scheme on work practices at construction sites in Hong Kong

Waste management in the building industry in Hong Kong has become an important environmental issue. Particularly, an increasing amount of construction and demolition (C&D) waste is being disposed at landfill sites. In order to reduce waste generation and encourage reuse and recycling, the Hong Kong Government has implemented the Construction Waste Disposal Charging Scheme (CWDCS) to levy charges on C&D waste disposal to landfills. In order to provide information on the changes in reducing waste generation practice among construction participants in various work trades, a study was conducted after 3 years of implementation of the CWDCS via a structured questionnaire survey in the building industry in Hong Kong. The study result has revealed changes with work flows of the major trades as well as differentiating the levels of waste reduced. Three building projects in the public and private sectors were selected as case studies to demonstrate the changes in work flows and the reduction of waste achieved. The research findings reveal that a significant reduction of construction waste was achieved at the first 3 years (2006–2008) of CWDCS implementation. However, the reduction cannot be sustained. The major trades have been influenced to a certain extent by the implementation of the CWDCS. Slight improvement in waste management practices was observed, but reduction of construction waste in the wet-finishing and dry-finishing trades has undergone little improvement. Implementation of the CWDCS has not yet motivated subcontractors to change their methods of construction so as to reduce C&D waste.     

A dynamic model for assessing the effects of management strategies on the reduction of construction and demolition waste

During the past few decades, construction and demolition (C&D) waste has received increasing attention from construction practitioners and researchers worldwide. A plethora of research regarding C&D waste management has been published in various academic journals. However, it has been determined that existing studies with respect to C&D waste reduction are mainly carried out from a static perspective, without considering the dynamic and interdependent nature of the whole waste reduction system. This might lead to misunderstanding about the actual effect of implementing any waste reduction strategies. Therefore, this research proposes a model that can serve as a decision support tool for projecting C&D waste reduction in line with the waste management situation of a given construction project, and more importantly, as a platform for simulating effects of various management strategies on C&D waste reduction. The research is conducted using system dynamics methodology, which is a systematic approach that deals with the complexity - interrelationships and dynamics - of any social, economic and managerial system. The dynamic model integrates major variables that affect C&D waste reduction. In this paper, seven causal loop diagrams that can deepen understanding about the feedback relationships underlying C&D waste reduction system are firstly presented. Then a stock-flow diagram is formulated by using software for system dynamics modeling. Finally, a case study is used to illustrate the validation and application of the proposed model. Results of the case study not only built confidence in the model so that it can be used for quantitative analysis, but also assessed and compared the effect of three designed policy scenarios on C&D waste reduction. One major contribution of this study is the development of a dynamic model for evaluating C&D waste reduction strategies under various scenarios, so that best management strategies could be identified before being implemented in practice.     

Quantifying construction and demolition waste: An analytical review

Quantifying construction and demolition (C&D) waste generation is regarded as a prerequisite for the implementation of successful waste management. In literature, various methods have been employed to quantify the C&D waste generation at both regional and project levels. However, an integrated review that systemically describes and analyses all the existing methods has yet to be conducted. To bridge this research gap, an analytical review is conducted. Fifty-seven papers are retrieved based on a set of rigorous procedures. The characteristics of the selected papers are classified according to the following criteria - waste generation activity, estimation level and quantification methodology. Six categories of existing C&D waste quantification methodologies are identified, including site visit method, waste generation rate method, lifetime analysis method, classification system accumulation method, variables modelling method and other particular methods. A critical comparison of the identified methods is given according to their characteristics and implementation constraints. Moreover, a decision tree is proposed for aiding the selection of the most appropriate quantification method in different scenarios. Based on the analytical review, limitations of previous studies and recommendations of potential future research directions are further suggested.     

Investigating barriers to sustainable management of construction and demolition waste: the case of India

Journal of Material Cycles and Waste Management - The generation of construction and demolition (C&D) waste is increasing, while management of it is a major issue which has detrimental...     

Developing strategies for managing construction and demolition wastes in Malaysia based on the concept of circular economy

Construction and demolition (C&D) waste is a pressing issue not only in Malaysia, but it is also a worldwide concern including the developed countries as well. C&D waste should be managed throughout the construction cycle. The concept of circular economy (CE) is an emerging notion that has the potential to be utilized as waste minimization approach. This paper aims to assess the potentials of incorporating the CE concept as an approach to minimizing C&D wastes, by developing a CE-based theoretical framework for C&D waste management in Malaysia. In line with this objective, a systematic review has been conducted to determine how CE can be operationalised as a strategy to minimize wastes, while considering it as a key factor for mitigating the environmental impacts. Based on the literature review, a CE-based theoretical framework has been proposed using Malaysia as a case study. The framework has been developed following a three-layer approach namely micro-, meso-, and macro-levels. Waste minimization strategies have been identified for each level taking into account the main stages in the construction industry, i.e., planning, designing, procurement, construction, and demolition. The different stakeholders involved at each stage and their interactions in the stages have also been identified.     

A framework for understanding waste management studies in construction

During the past decades, construction and demolition (C&D) waste issues have received increasing attention from both practitioners and researchers around the world. A plethora of research relating to C&D waste management (WM) has been published in scholarly journals. However, a comprehensive understanding of the C&D WM research is somehow absent in spite of its proliferation. The aim of this paper is to develop a framework that helps readers understand the C&D WM research as archived in selected journals. Papers under the topic of C&D WM are retrieved based on a set of rigorous procedures. The information of these papers is then analyzed with the assistance of the Qualitative Social Research (QSR) software package NVivo. A framework for understanding C&D WM research is created based on the analytic results. By following the framework, a bibliometric analysis of research in C&D WM is presented, followed by an in-depth literature analysis. It is found that C&D generation, reduction, and recycling are the three major topics in the discipline of C&D WM. Future research is recommended to (a) investigate C&D waste issues in wider scopes including design, maintenance and demolition, (b) develop a unified measurement for waste generation so that WM performance can be compared across various economies, and (c) enhance effectiveness of WM approaches (e.g. waste charging scheme) based on new WM concepts (e.g. Extended Producer Responsibility). In addition to the above research findings, the approach for producing the research framework can be useful references for other studies which attempt to understand the research of a given discipline.     

Estimating construction and demolition debris generation using a materials flow analysis approach

The magnitude and composition of a region’s construction and demolition (C&D) debris should be understood when developing rules, policies and strategies for managing this segment of the solid waste stream. In the US, several national estimates have been conducted using a weight-per-construction-area approximation; national estimates using alternative procedures such as those used for other segments of the solid waste stream have not been reported for C&D debris. This paper presents an evaluation of a materials flow analysis (MFA) approach for estimating C&D debris generation and composition for a large region (the US). The consumption of construction materials in the US and typical waste factors used for construction materials purchasing were used to estimate the mass of solid waste generated as a result of construction activities. Debris from demolition activities was predicted from various historical construction materials consumption data and estimates of average service lives of the materials. The MFA approach estimated that approximately 610–780 × 10⁶ Mg of C&D debris was generated in 2002. This predicted mass exceeds previous estimates using other C&D debris predictive methodologies and reflects the large waste stream that exists.     

Managing post-conflict demolition wastes in Gaza Strip: a case study on May 2021 conflict

Gaza Strip is considered as one of the armed conflicts prone areas in Middle East. Several intensive conflicts occurred in Gaza Strip in 2008, 2012, 2014 and 2021. These conflicts caused massive destroying the infrastructures, facilities, and buildings, which affected all services and activities in Gaza Strip. One of the major post-conflict issues in Gaza strip is the management of resulted demolition waste including its removal, sorting, recycling, and material recovery. In May 2021, over than 370,000 tons of demolition waste composed of rubbles and debris was generated during 11 days of armed conflict. The accumulated previous experience of rubbles and debris removal and recycling in Gaza Strip supported to perform a quick management approach for safe removal of the post-conflict demolition waste and reuse/recycle the resulted waste materials in various applications. The sorting and transporting process of concreate and non-concreate rubble elements of the waste were carried out in cooperation between local and international agencies as emergency recovery-funded projects. The most proportion of rubbles are concrete aggregates, thus, the material recovery was conducted through crushing process for concrete rubbles and then reusing it for road rehabilitation or producing concrete building blocks. The large concrete blocks reused to be placed for shoreline protection for specific area along Gaza beach. The recycling of post-conflict demolition waste management projects in Gaza Strip brought economic and social benefits through the reuse and recycle of resources and creation of job opportunities. In conclusion, although the post-conflict demolition waste management is quite different from municipal/industrial waste management in Gaza Strip, it is conducted through applying similar techniques of disaster waste management in waste removal, and those of construction and demolition (C&D) waste management in sorting, crushing, and sieving for recycling.

     

Construction and demolition waste management process modeling: a framework for the Brazilian context

Journal of Material Cycles and Waste Management - In Brazil, municipal public authorities are responsible for construction and demolition (C&D) waste management. However, there is a lack of...     

An empirical investigation of construction and demolition waste generation rates in Shenzhen city, South China

The construction and demolition waste generation rates (C&D WGRs) is an important factor in decision-making and management of material waste in any construction site. The present study investigated WGRs by conducting on-site waste sorting and weighing in four ongoing construction projects in Shenzhen city of South China. The results revealed that WGRs ranged from 3.275 to 8.791 kg/m² and miscellaneous waste, timber for formwork and falsework, and concrete were the three largest components amongst the generated waste. Based on the WGRs derived from the research, the paper also discussed the main causes of waste in the construction industry and attempted to connect waste generation with specific construction practices. It was recommended that measures mainly including performing waste sorting at source, employing skilful workers, uploading and storing materials properly, promoting waste management capacity, replacing current timber formwork with metal formwork and launching an incentive reward program to encourage waste reduction could be potential solutions to reducing current WGRs in Shenzhen. Although these results were derived from a relatively small sample and so cannot justifiably be generalized, they do however add to the body of knowledge that is currently available for understanding the status of the art of C&D waste management in China.     

Recycled blocks with improved sound and fire insulation containing construction and demolition waste

The environmental problem posed by construction and demolition waste (C&D waste) is derived not only from the high volume produced, but also from its treatment and disposal. Treatment plants receive C&D waste which is then transformed into a recycled mixed aggregate. The byproduct is mainly used for low-value-added applications such as land escape restoration, despite the high quality of the aggregate. In the present work, the chemical composition properties and grading curve properties of these aggregates are defined. Furthermore, the resulting recycled concrete with a high proportion of recycled composition, from 20% to 100% replacement of fine and coarse aggregate, is characterized physically and mechanically. An environmental study of the new construction material when all aggregates are substituted by C&D waste shows a low toxicity level, similar to that of other construction materials. The new material also has improved properties with respect to standard concrete such as high fire resistance, good heat insulation, and acoustic insulation.     

Evaluation of investments in recycling centres for construction and demolition wastes in Brazilian municipalities

There are very few construction and demolition (C&D) waste recycling centres in Brazil. To encourage the building and operation of new units, data were collected and analysed relating to C&D waste management and recycling in Brazil. Based on the results of this analysis, a conceptual model is presented for conducting viability studies of future C&D waste recycling centres. Applying this model to verify the viability of private recycling centres, the results show that under current market conditions in Brazil, C&D waste recycling centres are not financially feasible based solely on revenue from the sale of processed products. Nevertheless, under the same market conditions, the recycling centres could be economically viable for public authorities depending on the particular circumstances of each municipality. The feasibility, however, depends on continuity and the production volume reached. The conceptual model, the results of its applications and the discussions about the experiences of existing centres can strongly support public authorities and private initiatives in their decision-making about investments in Brazil and in other developing countries.     

A systems analysis tool for construction and demolition wastes management

Managing construction and demolition (C&D) wastes has challenged many municipalities with diminishing waste disposal capacity. Facing such challenges, the Massachusetts Department of Environmental Protection proposed a policy restricting the landfill disposal of certain C&D waste materials, if unprocessed. This research is to study the potential economic impact of such restriction on construction contractors and C&D waste processors. A spreadsheet-based systems analysis model has been developed to assist the cost-benefit evaluation for various C&D waste management scenarios. The model, developed based on the mass balance principle, is designed to track a C&D waste stream through the various stages of a waste management system, i.e. generation, source separation, processing, recycling, and final disposal. This model, by incorporating the material flow data with the cost/revenue data associated with each management activity, can then provide an economic analysis for a proposed C&D waste management scenario. A case study illustrating the application of this model for Massachusetts is also presented.     

A model for quantifying construction waste in projects according to the European waste list

The new EU challenge is to recover 70% by weight of C&D waste in 2020. Literature reveals that one major barrier is the lack of data. Therefore, this paper presents a model which allows technicians to estimate C&D waste during the design stage in order to promote prevention and recovery. The types and quantities of CW are estimated and managed according to EU guidelines, by building elements and specifically for each project. The model would allow detection of the source of the waste and to adopt other alternative procedures which delete hazardous waste and reduce CW. Likewise, it develops a systematic structure of the construction process, a waste classification system and some analytical expressions which are based on factors. These factors depend on technology and represent a standard on site. It would allow to develop a database of waste anywhere. A Spanish case study is covered. Factors were obtained by studying over 20 dwellings. The source and types of packaging waste, remains, soil and hazardous waste were estimated in detail and were compared with other studies. Results reveal that the model can be implemented in projects and the chances of reducing and recovery C&D waste could be increased, well above the EU challenge.     

Durability analysis and optimization of a binary system of waste cement concrete and glass-based geopolymer mortar

Journal of Material Cycles and Waste Management - Enormous generation of construction and demolition (C&D) waste along with municipal solid waste (MSW) is required to managed properly for...     

Preliminary study for the management of construction and demolition waste

This paper refers to the management of the construction and demolition (C&D) waste since, according to the EU Waste Strategy, C&D waste is considered to be one of the priority waste streams and appropriate actions need to be taken with respect to its effective management. Initially, the paper presents the state-of-the-art of the problem of C&D waste, including the amount and composition of C&D waste in EU countries, differences in the characteristics of this waste stream depending on its origin, as well as collection and management practices that are applied. A methodology is described for the estimation of the quantities of the waste stream under examination, since in most cases quantitative primary data is not available. Next, the fundamentals for the development of an integrated scheme for the management of C&D waste are presented and discussed, such as appropriate demolition procedures and location of waste management (off-site waste management, on-site waste management, direct on-site recovery, centralized on-site recovery). Finally, taking into consideration all relevant parameters, alternative systems that could be applied for the management of the C&D waste are suggested.