Department of Architecture and Civil Engineering Division of Construction Management CHALMERS UNIVERSITY OF TECHNOLOGY Master’s Thesis BOMX02-17-92 Gothenburg, Sweden 2017 Current Practices of Construction and Demolition Waste Management (CDWM): Based on Observations at Swedish Construction Site Master Thesis in the Master’s Programme Design and Construction Project Management MAHLET TESFAYE HAILE YUDHI DWI HARTONO MASTER’S THESIS BOMX02-17-92 Current Practices of Construction and Demolition Waste Management (CDWM): Based on Observations at Swedish Construction Site Master’s Thesis in the Master’s Programme Design and Construction Project Management MAHLET TESFAYE HAILE YUDHI DWI HARTONO Department of Architecture and Civil Engineering Division of Construction Management CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2017 Current Practices of Construction and Demolition Waste Management (CDWM): Based on Observations at Swedish Construction Site Master’s Thesis in the Master’s Programme Design and Construction Project Management MAHLET TESFAYE HAILE YUDHI DWI HARTONO © MAHLET TESFAYE HAILE -YUDHI DWI HARTONO, 2017 Examensarbete BOMX02-17-92/ Institutionen för Arkitektur och Samhällsbyggnadsteknik, Chalmers tekniska högskola 2017 Department of Architecture and Civil Engineering Division of Construction Management Chalmers University of Technology SE-412 96 Göteborg Sweden Telephone: + 46 (0)31-772 1000 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 I Current Practices of Construction and Demolition Waste Management (CDWM): Based on Observations at Swedish Construction Site Master’s Thesis in the Master’s Programme Design and Construction Project Management MAHLET TESFAYE HAILE YUDHI DWI HARTONO Department of Architecture and Civil Engineering Division of Construction Management Chalmers University of Technology ABSTRACT The purpose of this master thesis is to understand the current practice of Construction and Demolition Waste Management (CDWM) in the case area of a Swedish construction site. In addition, this paper aims to comprehend how Building Information Modelling (BIM) could support CDWM in the case area. This paper presents a case area of Swedish construction industry, and the results are based on observation, semi- structured interviews, and questionnaires. The current practice of case area’s CDWM includes on-site sorting, reuse, recycling, Just-in-time delivery (JIT), using prefabricated construction materials and color-coded waste containers. The practice of the CDWM mainly focused on sorting and recycling. The information regarding CDWM was shared among project stakeholders by using brochures, presentation, meeting, and information board. In addition, the contractor and subcontractors have a contract that stated who is responsible to take care of the waste on site. The use of BIM has been given attention in the current literature to support CDWM. BIM has not been used for CDWM in the case study. However, the case study’s company has an optimistic view about how BIM could support CDWM. Additionally, there is positive effort to implement BIM for CDWM for future projects at the company level. If BIM is used for case area’s CDWM, it could support the CDWM in many ways, such as minimizing CDW through design validation, providing material information regarding waste, and quantifying the generation of waste before construction or demolition. To bring change and improvement in the current practices of case area’s CDWM, there should be an education, workshop, and training regarding the concept of CDWM, waste management strategies and benefits of BIM in managing CDW to construction project participants. This, in turn, can help the case study’s firm and the general public to attain environmental, social and economic benefit from CDWM. Keywords: BIM, CDWM, CDW, Information flow, waste management strategies II CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 III Contents ABSTRACT …………………………………………………………………………...I CONTENTS …………………………………………………………………………III LIST OF FIGURES …………………………………………………………………VI LIST OF TABLES …………………………………………………………….…...VII PREFACE …………………………………………………………………………VIII 1 INTRODUCTION …………………………………………………………….1 1.1 Problem Statement ………………………………………………………….1 1.2 Relevance of the Study ……………………………………………………..1 1.3 Purpose ……………………………………………………………………..2 1.4 Research Questions ……………………………………...…………………2 1.5 Scope of The Study ……………………………………………………...…2 1.6 Structure of the Report ……………………………………………..………2 2 THEORETICAL FRAMEWORK ……………………………………………5 2.1 Construction and Demolition Waste Management (CDWM) ………………5 2.1.1 Concept of Construction and Demolition Waste Management (CDWM) …………………………………………………………………..………5 2.1.2 Generation of Wastes in Construction Industry ………………………6 2.1.3 Management of Construction and Demolition Waste (CDW) in Construction Industry …………………………………………………………..7 2.1.4 Challenges in Managing waste of Construction Project ……………..15 2.1.5 Communication and Information Flow ……………………………....16 2.2 Building Information Modelling (BIM) and CDWM……………………....16 2.2.1 Building Information Modelling (BIM): Concept and Definition…....17 2.2.2 Benefits and Challenges of BIM Implementation …………………...18 2.2.3 BIM Use for CDWM …………………………………………………20 2.2.4 BIM as a Communication and Collaboration Hub …………………...22 3 METHODOLOGY …………………………………………………………..23 3.1 Research Approach ……………………………………..………………….23 3.2 Research Design ………………………………………………..………….24 3.2.1 Case Study Design ……………………………………..……………24 IV CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 3.3 Data Collection Methods ……………………………………………………24 3.3.1 Observational Method ……………………………………..…………25 3.3.2 Interview Method ………………………………………….…………26 3.3.3 Questionnaires ……………………………………………….………26 3.4 Data Analysis ………………………………………………………………27 3.5 Research Quality …………………………………………………..….……27 3.5.1 Reliability ……………………………………………………………28 3.5.2 Validity ………………………………………………………………28 3.6 Research Ethics …………………………………………………..………28 4 CONTEXTUAL REVIEW AND CASE STUDY ……………………..……31 4.1 Current Practice of CDWM in Swedish AEC Industry ……………………31 4.2 Case Study ……………………………………………………………...… 32 4.2.1 Company’s Profile ………..……………………………………….…32 4.2.2 Project Description ……………………….………………………….32 5 FINDINGS AND RESULT …………………………………………………35 5.1 Current Practices of CDWM ………………………………………...…… 35 5.1.1 Current Practices of the Case area’s CDWM ……….……………… 35 5.1.2 Current Practices of CDWM at Company Level …………………….42 5.1.3 Current Practices at Multi-Project Level …………………………….44 5.1.4 Challenges in Managing Construction Wastes ………………………45 5.1.4.1 Challenges at Case Area’s Construction Site ……………………45 5.1.4.2 Challenges at Company Level …………………………………...45 5.1.5 Information Flow and Communication …………………………...….47 5.1.5.1 Information Flow and Communication at Case Area’s Construction Site ………………………………………………………………………… 47 5.1.5.2 Information Flow and Communication at Company Level ……...49 5.1.5.3 Information Flow and Communication at Multi-project …….…..49 5.2 BIM …………………………………………………………………………50 5.2.1 BIM at Case Area’s Construction Site ………………………………50 5.2.2 BIM at Company Level ……………………………………………...50 5.2.3 BIM at Multi Project Level ………………………………………….51 5.3 Summarized Findings ………………………………………………………52 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 V 6 DISCUSSION ………………………………………………………………...…..57 6.1 Current Practices of CDWM ……………………………………………….57 6.1.1 Challenges in Managing CDW ………………………………………59 6.1.2 Information Flow and Communication ………………………………59 6. 2 BIM ………………………………………………………………………...60 7 RECOMMENDATION ……………………………………………...………63 7.1 Current Practices of CDWM ……………………………………………….63 7.1.2 Information Flow and Communication ………………………………65 7.2 BIM and CDWM ……………………………………………………………65 8 CONCLUSION ……………………………………………………………...67 REFERENCES ………………………………………………………………………69 APPENDIX ………………………………………………………………………….75 Appendix 1 Interview Questions ……………………………………………….77 Appendix 2 Questionnaires …………………………………………………….79 Appendix 3 Checklist for Observation …………………………………………80 Appendix 4 Questionnaire Result ………………………………………………82 Appendix 5 Components for Designing Out Waste in Construction Projects ….83 VI CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 List of Figures Figure 2.1 The C&D waste management method hierarchy (Yuan and Shen, 2011: 672)…………………………………………………………..8 Figure 2.2 Waste management hierarchy (Bell and McWhinney 2000) (Li, 2012: 2)..8 Figure 2.3 Summary of existing waste management strategies (Ajayi et al., 2015: 103) ……………………………………………………………...11 Figure 2.4 Attitudes of construction project participants towards waste management (Udawatta et al., 2015: 143) …………………………………………………………12 Figure 2.5: BIM Fields. Source: Kalinichuk (2015: page 25) ……………………….18 Figure 2.6 Return on Investment on BIM. Source: Shin (2017: Pg. 206) …………...19 Figure 4.1 Location map of the project ………………………………………………32 Figure 5.1 Room to sort hazardous wastes such as chemicals, electronics ………….36 Figure 5.2 Room/container to sort gases …………………………………………….36 Figure 5.3 The location of waste containers …………………………………………37 Figure 5.4 containers with orange and red colour tag for combustible and landfill wastes ………………………………………………………………………………..37 Figure 5.5 Waste Container is signed with red colour for hazardous wastes ………..38 Figure 5.6 Waste container with yellow tag for wood ………………………………38 Figure 5.7 Waste containers with light brown tag for cardboard ……………………38 Figure 5.8 Waste container for foam (‘cellplast’) …………………………………...39 Figure 5.9 Mixed wastes: foam, plastics, carton, etc…………………………………39 Figure 5.10 Combustible Waste materials: plastic carton, paper, etc. ………………39 Figure 5.11 Earth that is disposed on the construction site ………………………….40 Figure 5.12 Concrete waste ………………………………………………………….40 Figure 5.13 Tent-1 …………………………………………………………………...41 Figure 5.14 Tent-2 …………………………………………………………………...41 Figure 5.15 Temporary storage ……………………………………………………...41 Figure 5.16 LP 1 (A sign for smaller delivery) ……………………………………...42 Figure 5.17 Brochure that is distributed to the workers ……………………………..47 Figure 5.18 Waste sorting guidelines attached on the information board …………...48 Figure 5.19 Place for meeting and presentation ……………………………………..48 Figure 5.20 Existing waste management strategies ………………………………….53 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 VII List of Table Table 3.1: Elements of good scientific observing. Source: Farenga et al. (2003: p.57) ……………………………………………………………25 Table 5.1: Summary of current practices of CDWM ………………………………..53 Table 5.2: Summary of challenges..………………………………………………….54 Table 5.3: Summary of information flow and Communication ……………………..54 Table 5.4: Summary of BIM ………………………………………………………...54 VIII CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 Preface This master’s thesis is a final project of MSc program in Design and Construction Project Management, at the Department of Architecture and Civil Engineering, Division of Construction Management at Chalmers University of Technology. The thesis was carried out by Mahlet Tesfaye Haile and Yudhi Dwi Hartono from January to August 2017. This thesis involved many activities and individuals from academia to practitioners from the construction industry in Sweden. First of all, we would like to thank our supervisor, Petra Bosch Sijtsema, for her guidance from the beginning to the end of our master thesis. She is consistent in reading, correcting and giving valuable suggestions to our thesis work. We could not have imagined having a better supervisor for our research paper. Secondly, we would like to extend our great thanks to our mentor from NCC company, Fredrik Johansson, who help us to conduct the interview with the practitioners of the company. We would also like to acknowledge all interviewees who gave a valuable information during the interview time: the researcher from Chalmers, project members from case’s area of Children's Hospital (Östra Barnsjukhuset), the environmentalist from the company and the market manager from NCC recycling company. Thirdly, we would like to express our gratitude to Indonesia Endowment Fund for Education (LPDP) and William Chalmers Scholarship for giving us a full scholarship to study in Sweden. At last but not the least, our great thanks go to our family, friends, the company and university for providing their support to accomplish our thesis. Gothenburg, August 2017 Mahlet Tesfaye Haile and Yudhi Dwi Hartono CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 1 1 Introduction 1.1 Problem Statement Construction and Demolition Waste Management (CDWM) is a waste management practice in the construction industry and comprises the minimizing and management of Construction and Demolition Waste (CDW); reusing, recycling and disposal (Teo and Loosemore, 2001). CDWM is considered to be a vital issue for sustainable development, which deals with environmental, social and economic development (Lu and Yuan, 2011). Richardson and Springer (2013) mentioned that economic and social benefits are also acquired by planning construction waste precisely and managing the waste properly. Additionally, CDWM in a construction industry can achieve environmental and economic benefits (Bon‐Gang and Zong, 2011). However, CDW may prevent the construction industry from achieving such benefits. This is because; the output of CDW has increasingly resulted in serious problems in environmental, social and economic realms. The harm to the environment includes the depletion of limited landfill resources and an increase in energy consumption. (Marzouk and Azab, 2014). Furthermore, globally, construction activities contribute a lot to waste generation (Chinda, 2016; Teo and Loosemore, 2001; Yuan and Shen, 2011). Waste can be generated at any phase of the construction process from design to the operation and maintenance phase. It seems difficult to manage waste at the entire phase of construction due to the unique and temporal nature of construction projects as well as the fact that less priority is given to waste management in the construction industry. In addition, site managers and other construction project stakeholders (such as clients, designers, builders, and subcontractors) in the construction industry seem to pay less attention to CDWM (Udawatta et al., 2015). Furthermore, it seems also that there is lack of information about CDWM and poor communication among site workers, subcontractor and this might result in mismanagement of construction waste (Li, 2012). To solve the aforementioned problem, this study tries to understand the present practices of CDWM and how information regarding CDWM is shared among the aforementioned stakeholders in the case area of a Swedish construction site. This study attempts to provide solutions by understanding how BIM could support CDWM in the case area. This, in turn, might help contractor firms and the general public to acquire economic, social and environmental benefit from CDWM. 1.2 Relevance of the Study It is undoubtedly that the construction industry contributes to the biggest percentage of waste generation in most countries. However, waste management is not perceived as a project priority in the construction industry (Kareem et al., 2015; Teo and Loosemore, 2001). Therefore, this study can assist the case study’s firm to improve their practice by using waste management strategies as well as by applying BIM. This, in turn, helps 2 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 the firm to obtain environmental, social and economic benefits from CDWM. Furthermore, in the future, the case study and other construction industries can use the study as a possible solution to improve practices of CDWM. This is because; the study will provide recommendation regarding different strategies of waste management and BIM. 1.3 Purpose The purpose of the study is to understand the current practice of CDWM in a case study area. As well as to comprehend how new technology (such as BIM) could support CDWM is also the objective of the study. The specific objectives of the study are stated as follows: - To understand the current practices of case area’s CDWM - To understand the information flow concerning the CDWM - To understands what aspects of current CDWM could be supported/improved with the help of BIM 1.4 Research Questions - What are the current practices of case area’s CDWM? - How is the information regarding CDWM shared with site workers, subcontractors and contractor in the case study? - What aspects of current CDWM could be supported/improved with the help of BIM? 1.5 Scope and Limitations of the study The thematic scope of this research is limited to CDWM in the construction industry and BIM on the construction site. CDWM is also considered within the scope range of the research as the study focuses on waste management effort in the construction industry. For this specific study, the chosen construction site is Östra Barnsjukhuset, which is a new big construction project located at Mölndal, Västra Götaland County, Sweden. Due to time constraints, only one case study area was selected from construction companies of Gothenburg. Existence of few literatures about how information regarding CDWM should be shared was also limitation of the study. 1.6 Structure of the Report The research paper is composed of eight chapters and is organized in the following manner. The first chapter gives a brief introduction to the research problem, purposes, research question, significance/relevance and scope of the study. The second chapter CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 3 reviews the literature regarding the concept of CDW, and its management effort, challenges, information flow and communication as well as the potential of BIM as its, provide future solutions for managing CDW. The third chapter elaborates on the type of research approach selected for this study. Additionally, this chapter explains, the various techniques and tools adapted and used to collect the necessary information and data for the study. This section also described reliability and validity of the selected method. The fourth chapter focuses on the current practice of CDWM in Swedish Construction site as well as the description of the case study. The fifth chapter presents the results and findings of different type of data collected. The sixth chapter includes discussion in which the empirical data is related to theory. The seventh chapter includes recommendations regarding CDWM and BIM. The eighth includes the concluding remarks of the report. 4 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 5 2 Theoretical Framework The theoretical framework is formed by reviewing the literature regarding waste management in the construction industry and other related literatures associated with the thesis topic. The first section includes the concept of CDWM, challenges in Managing waste of Construction Project, and information flow and communication regarding CDWM. The second section discusses the concept of BIM, Benefits of BIM in managing construction wastes and the method how BIM can benefit the current practices of CDWM. 2.1 Construction and Demolition Waste Management (CDWM) 2.1.1 Concept of Construction and Demolition Waste Management (CDWM) During the past decades, practitioners and researchers have paid more attention to Construction and Demolition waste (CDW) issues, and an excessive number of researches have published about CDW (Lu and Yuan, 2011). It is vital to define the notion of Construction and Demolition waste (CDW) in order to understand waste in construction industry more deeply (Kareem et al., 2015). Before defining CDW, the term waste is defined: Waste is unusable and unwanted material, and it is also called rubbish, trash, garbage (Kareem et al., 2015). Ortiz et al. (2010), as cited in Bakshan et al. (2015: 70), defined waste as “a material by-product of human or industrial activity that has no residual value.” Waste is any material which is no longer used in a normal commercial cycle or chain of utility as the holder has a plan to throw away materials (Sertyesilisik et al., 2012). CDW has no single and agreed definition, and different countries perceive CDW in different ways. The Hong Kong Polytechnic (1993) as cited in Kareem et al. (2015: 21) defined construction waste as follows: “Construction waste as the bye-products generated and removed from construction, renovation and demolition sites of building and civil engineering structures.” Bakshan et al. (2015) argued that construction waste is an element or subset of CDW and contains wastes that are produced during new construction. On the contrary, Chen and Lu (2016) argued that the term and CW and CDW are utilized interchangeably when the waste sources are not the centre of attention. The existence of different perspectives on CDW has resulted in different waste management philosophies. For example, in Japan, CDW is not considered as waste 6 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 rather it is a construction by-product. As a result, waste management efforts focused on recycle and reuse programs. In Hong Kong, CDW is classified into two, and these are inert materials (such as earth, concrete, debris, etc.) and non-inert waste (such as bamboo, timber, vegetation. etc.) (Lu and Yuan, 2011). Chinda (2016); Yuan and Shen (2011); Zhao et al. (2010); Udawatta et al. (2015) as well as Roche and Hegraty (2006) as cited in Chen and Lu (2016), defined Construction and demolition waste (CDW) as waste that is generated from construction, renovation and demolition activities. Roche and Hegarty (2006) as cited in Lu and Yuan (2011) mentioned that CDW may include hazardous materials and surplus that is generated during the construction work. The disposal of construction waste has a negative impact on the environment as it has resulted in air pollution (CO2 emission) water pollution, soil pollution, etc. (Wu et al., 2016; Ajayi et al., 2015 and Vivian et al., 2014). Construction Waste has also socio- economic impact (Wu et al., 2016). Udawatta et al. (2015) argued that construction waste has not only economic impact but also it has negative environmental impact. Bakshan et al. (2015) stated that construction and demolition waste has environmental impact and risks to human health. 2.1.2. Generation of Wastes in Construction Industry The construction industry is one of the industries that contributes to the overall socio- economic development of any country. However, the construction industry is the main contributor to environmental degradation as the industry is exploiting natural non- renewable resources and pollutes the environment (Kareem et al., 2015). In addition, Lu and Yuan (2011); Mendis (2011); Marzouk and Azab (2014); Udawatta et al. (2015) discussed that the construction industry contributes to land depletion and deterioration, energy consumption, dust and gas emission, noise pollution, and solid waste generation. Chinda (2016); Teo and Loosemore (2001); Yuan and Shen (2011) discussed that enormous amounts of waste have been generated from construction activity. The amount and type of wastes that are generated from construction work differ from country to country. For instance, in Germany, the amount of construction and demolition waste is about 30 and 14 million tons respectively. In Hong Kong, according to the Environmental Protection Department (EPD), the construction waste accounts for 25% of total municipal solid waste (Ajayi et al., 2015). Won et al. (2016) noted that waste generated in C&D processes comprised around 50% of the solid waste in South Korea in 2013. Moreover, Bon‐Gang and Zong (2011) mentioned that the amount of waste produced from construction industry is about four times of the household waste. Waste can be generated at any phase of the construction process. That means waste can be produced from inception, design, construction, and operation of the built facility/ civil engineering structure (Richardson and Springer, 2013; Teo and Loosemore, 2001). CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 7 Bakshan et al. (2015) discussed that building construction projects produce various type of waste materials at shoring, excavation, foundation, structural concrete, masonry and finishing stages. The waste materials in building construction project can be classified into three main categories: inert, non-inert and hazardous (Bakshan et al.,2015). An extensive amount of waste can be produced from construction project if the project does not consider constructability in the design process (Saheed et al., 2016). Wu et al., 2014 as cited in Wu et al. (2016) mentioned that the construction industry has carried out immense resource consuming activities which contribute to the production of construction waste. Additionally, Bakshan et al. (2015) described that the growth in construction activities contribute to construction waste generation. Li (2012) argued that potential of a project team in management can be a factor for construction waste generation. Waste generation can be influenced by project size, duration, and worker numbers as well as activities during project delivery processes. For instance, if project size is bigger, the amount of waste is likely to be increased (Li, 2012). Saheed et al. (2016) argued that extensive amount of waste can be produced from construction project if the project does not consider about constructability in the design process. On the contrary, Ajayi et al. (2015) argued that the existence of ineffective strategies for managing construction waste has contributed to the generation of C & D waste intensively. 2.1.3 Management of CDW in Construction Industry To solve Construction and Demolition waste problems, many strategies, methods, techniques, principles, and models regarding waste management have been devised by different scholars. Sertyesilisik et al. (2012) discussed waste management methods. These methods include a well-structured waste management plan; use colour coded waste containers in order to sort waste for recycling, agreement between contractors and subcontractors to determine who is responsible for waste on-site. The other method includes appointing a waste manager that works on delivery and materials storage to address the problem of damaged material due to improper handling, delivery, climate and insufficient storage (Sertyesilisik et al., 2012). Richardson and Springer (2013) argued that there are two methods to address construction waste. The first method deals with the minimisation of waste by applying source reduction techniques at design and procurement phases of a project. The second method is to manage inevitable waste materials that are already produced through three hierarchical methods (reuse, recycling, and disposal). A waste management method hierarchy has been developed by different scholars, and the hierarchical model consists of strategies that range from 4 to 7. For instance, Yuan and Shen (2011) discussed that waste management method hierarchy contains four strategies. These strategies are reduction, reuse, recycling and disposal, and arranged in ascending order from low to highs based on its environmental impact (see figure 1). Additionally, the hierarchy that is proposed by Bell and McWhinney (2000) as cited in 8 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 Li, (2012) contain 7 strategies. i.e., avoid, reduce, reuse, reprocess, reclaim, treat and dispose of (see figure 2). Fig 2.1 The C&D waste management method hierarchy (Yuan and Shen, 2011: 672) Fig 2.2. Waste management hierarchy (Bell and McWhinney 2000) (Li, 2012: 2) Moreover, Kareem et al. (2015) and Yuan (2011) discussed principles of waste management, i.e. the ‘3Rs’ principle (reduce, reuse and recycling) that can guide waste management plans as well as practice and research of construction and demolition management. The principle has been arranged in ascending order based on their impact on the environment. A reduction is a more effective and efficient waste management CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 9 method than reuse and recycling. This is because reduction can minimize CDW generation and transportation costs for waste disposal and recycling. Next, to reduction, reuse is a more effective method for managing waste than recycling (Kareem et al., 2015; Lu and Yuan, 2011). In addition to the above waste management methods and hierarchical models, Ajayi et al. (2015) discussed different waste management strategies. These are sorting and recycling, material re-use, use of waste prediction tools, site waste management planning (SWMP), design for flexibility and deconstruction, waste efficient procurement, offsite construction as well as legislative and tax measures, and each of the strategies is described as follows: Sorting and recycling is a strategy that can be adopted after waste has existed. Barros et al. (1998) as cited in Ajayi et al. (2015: 102) stated that: “Recycling contains sorting of waste materials into recyclable and non- recyclables during construction activities or at the recycling site”. Such a strategy has the potential to divert waste from landfill sites as well as prevent the use of raw materials for material production. Construction waste recycling operations have assisted communities to have free space in their landfill site. Recycling operations are relevant to reduce CO2 emission and save energy as well as create job opportunities. For successful recycling operations, the existence of committed construction professionals to sort the waste materials are vital. Material re-use: like recycling, material reuse is vital to divert waste from landfill sites. Unlike recycling, such waste management strategy makes possible the reuse of materials without any change to its physical and chemical state. For example, construction demolition material has been used again for land reclamation, concrete aggregates, and road surfacing. “Reuse” principle is more preferable than recycle. The objective of the principle is to extend lifetime of existing structures or materials (Wu et al., 2016: 899). Use of waste prediction tools: are used as a means to measure and predict construction waste. Waste prediction tools are also vital for managing construction waste effectively. For instance, Net Waste is a tool used in the UK to estimate waste arising from the construction process. Different models have been used across the world to predict construction waste. Waste prediction tools should be implemented in the design phases of the construction process (Ajayi et al., 2015). Site waste management planning (SWMP): in many countries, SWMP is a legislative prerequisite. For example, in the UK, every project, which is above £ 300,000, has SWMP as a requirement in their legislation framework (Ajayi et al., 2015). 10 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 Design for flexibility and deconstruction: This happens when a design of a building is optimized to the standard of the industry so that it is removed materials perfectly fit into another optimized project. Waste efficient procurement: the procurement phase is a very important phase for waste management planning in a construction project. The reason for construction wastes are improper material storage, packaging material, and double handling are related/ associated with the procurement stage, For this reason, different strategies such as Just in time delivery (JIT), reduced packaging material and improved collaboration between the supply chains have to be applied to ensure waste efficient procurement. JIT is used to minimize waste (Ajayi et al., 2015). Offsite construction: it is waste management strategy in which building materials are produced offsite and assembled onsite. Prefabrication and offsite production are means for minimizing waste generation in the construction industry (Ajayi et al., 2015). Vivian et al. (2014) discussed that adoption of prefabrication can minimize construction wastes that are resulted because of poor workmanship, excess order, design alteration, damage during installation and cutting. Prefabrication can reduce construction cost through mechanization, standardization, and industrialization. Legislative and tax measures: the measures include a polluter pay principle such as “pay as You Throw” (PAYT), which is variable landfill tax. In the case of PAYT, charges are paid per unit volume or weight of all waste disposed on landfill site. The objectives of the principle are to discourage disposal of waste to the landfill site and encourage the 3R principles. Using the principle of PAYT, which is used in a number of EU countries (such as Greece, Sweden, Netherlands, Switzerland, and the UK) has enabled to minimize the amount of waste disposed on the landfill site. Before the adoption of PAYT, there was a fixed billing scheme in the US as landfill penalty. But the scheme has not shown any improvement in waste reduction on the landfill sites of US. In addition to the aforementioned tax measures, legislative measures also help to minimize C & D wastes. Legislative toolkits play a great role in increasing the awareness of the construction industry about waste management (Ajayi et al., 2015). Some of the above-mentioned waste management strategies are also discussed by other scholars. For example, Saheed et al. (2016) also discussed a design for flexibility and deconstruction. According to Saheed et al. (2016), construction waste intensiveness can also be reduced through the production of deconstruction plan and designing a building that is flexible and adaptable. Additionally, Li (2012) and Sertyesilisik et al. (2012) discussed SWMP. Sertyesilisik et al. (2012) explained that SWMP assists in managing waste on-site, and the plan has made possible the management and recycling of waste on-site in a structured way. It can also reduce/ decrease waste cost/expense and increase the profitability of the construction sector. SWMP can help to reduce risk that has happened due to waste related accidents. Additionally, Li (2012) discussed the need for on-site waste plan to manage/control waste in a construction supply chain. Lu and Yuan CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 11 (2012) and Wang et al. (2010) also explained about sorting of construction waste. sorting construction waste before disposal/dumped in landfill has perceived as good practice (Lu and Yuan, 2012). Moreover, to facilitate sorting, collaboration between site managers and waste contractors is crucial (Sezer, 2017). There are two types of sorting: i.e., on-site sorting and off-site sorting. The advantage of on-site waste sorting includes maximising reuse and recycling rate, mitigate the waste transportation cost and disposal, prolong life of landfills. (Wang et al., 2010). In addition, according to Wang et al. (2010) “manpower, recycled materials market, waste sortability, good management, site space and equipment for sorting of construction waste are critical success factors for on-site sorting of construction waste”. Off-site sorting can contribute to construction waste reduction (example: off-site construction waste sorting program at Hong Kong in 2006). sustainable policy support and implementation, encouraging off-site construction waste sorting through increased disposal cost lead to success of the off-site construction waste sorting program. This in turn can help the reduction of construction waste (Lu and Yuan, 2012). . Figure 2.3 Summary of existing waste management strategies (Ajayi et al., 2015: 103) Construction and demolition waste management strategies are relevant in order to achieve environmental and economic benefits (Richardson and Springer, 2013; Teo and Loosemore, 2001). According to Bon‐Gang and Zong (2011), different benefits such as cost saving and profit maximization; minimize demand for landfill spaces, improve resource management, company’s image improvement, as well as productivity and quality improvement, can be achieved through implementation of waste management strategies properly in the construction industry. Additionally, Richardson and Springer (2013) mentioned that economic and social benefits are also acquired by planning 12 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 construction waste precisely and managing the waste properly. However, there are factors and practices that contribute to the ineffectiveness of construction and demolition waste management strategies and this in turn results in immense amounts of construction waste as it is described by different scholars. According to Ajayi et al. (2015), The factors and practices are classified into five. These are “end of pipe treatment of waste”, eternality and incompatibility of waste management tools with design tools”, “perceived or unexpected high cost of waste management” and “culture of waste behaviour within the industry. Udawatta et al. (2015) discussed about factors that can influence effectiveness of CDWM and its strategies, and these practices include stakeholders’ attitude towards WM practices and cost-drive nature of a construction industry as it is explained as follows: Cost-drive nature of a construction industry: decisions to execute waste management practices in a construction industry depend on financial profit. Attitude towards WM practices: most construction project participants’ (such as clients, designers, builders, and subcontractors) attitudes do not support waste management practice since the aforementioned project participants are influenced by the profit driven nature and competitiveness of the construction industry (Udawatta et al., 2015). For instance, to execute waste management practices, there is no incentive for contractors, and subcontractors do not have that much concern for waste management as time has financial value for them (Udawatta et al., 2015). In addition, waste management practices are influenced by clients’ interests as the client is the investor to the construction project and play a key role in processes of decision making (Udawatta et al.,2015). It is crucial to enforce the regulation in order to improve waste management practices until such practices adopted /accepted culturally in a construction industry throughout the supply chain. (Udawatta et al., 2015). The following diagram Udawatta et al. (2015) has illustrated attitudes and behaviours of construction stakeholders towards waste management in the following diagram. Figure 2.4: Attitudes of construction project participants towards waste management (Udawatta et al., 2015: 143) CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 13 Site managers play an important role in waste management practice at the construction implementation phase (Sezer, 2017). However, site managers do not perceive waste management as a vital task (Udawatta et al., 2015). Saheed et al. (2016) and Udawatta et al. (2015) argued that architects take part in practices of waste management and minimisation to less extent. This is because; architects have no knowledge regarding causes of design waste generation, and they thought that contractors are responsible for waste minimization. In view of this, the profit-driven nature of the construction industry and the less positive attitude of the aforementioned stakeholders may lead to an intensive amount of CDW. To achieve reduction of an extensive amount of waste in the construction industry, and enhance the effectiveness of waste management strategies, the following six strategies are necessary “tackling of waste at design stage, whole life waste consideration, compliance of waste management solution with BIM, cheaper cost of waste management practice, increased stringency of waste management legislation and fiscal policies, and research and enlightenment” (Ajayi et al. pp 101, 2015). Saheed et al. (2016) also explained that Waste in the construction industry can be minimized by taking waste preventive measures during the design phase. This is because; design phase is a major phase that has implication on project result. Waste can also be reduced through design out construction waste. Saheed et al. (2016) discussed about five competency categories that are important and requisite to design out construction waste. The five competencies include design task proficiency, low waste design skills, behavioural competence construction-related knowledge, interprofessional collaborative competency (see appendix 5). The first four competencies are requisite for designing out waste, and inter-professional collaborative competency is required for design manager. This, in turn, contributes to effective waste minimization and management Competency for designing out waste can also be determined by incorporating design with site topography and considering reusable elements on site (Saheed et al., 2016). Understanding site topography also helps to minimize excavation waste. Furthermore, according to Teo and Loosemore (2001), to reduce the waste level in the construction industry, it is important to give priority to waste management in relation to other project goals, and managers should reveal commitment toward waste management activities and provide the necessary resources. Waste minimisation strategies Osmani (2012) as cited in Richardson and Springer (2013) defined waste minimization as mitigation of waste at source (i.e., designing out waste) through comprehending the main factor of waste and redesign present processes and practices to reduce waste generation. waste minimization includes any process, method or activity that minimizes or eliminates waste from its source or enable reuse by permitting recycling (Richardson and Springer, 2013). Li (2012) mentioned that waste minimisation should be considered 14 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 at first in waste management effort, and reuse and recycling can be used if the wastes are unavoidable. Different scholars discussed about waste minimisation strategies. For instance, Lu and Yuan (2011) discussed the five methods/strategies for waste minimization, and these are minimizing waste by government legislation; reducing waste through design; establishing an effective waste management system and use of low waste technologies and improving practitioner's’ viewpoint toward waste reduction. Mendis (2011) argued that planning and controlling are the two waste minimisation strategies. Planning strategies include procuring material, design, construction scheduling and site layout. Controlling strategies involve delivery and handling of materials, security, storage waste accounting, recordkeeping, safety, education and maintenance of machinery. Proper materials management plays a great role in reducing waste on-site (Mendis, 2011). Furthermore, different scholars explained about methods for waste minimisation. For example, Mendis (2011) argued that waste can be minimised by using durable, recyclable and used materials as well as materials with lower environmental impact. Li (2012) argued that cooperation/collaboration and effective management of project stakeholders (such as clients, designers, head contractors, and subcontractors) throughout the construction supply chain, as well as incentive measures, contribute to minimization of waste. Additionally, Sezer (2017) argued that collaboration between site managers and waste contractors is crucial to reduce waste. Moreover, in order to come up with practical waste minimization and management strategy, it is vital to understand the root causes of waste. Waste minimisation strategies require the concerted effort of all project participant such as client, government contractors, and the whole supply chain (Richardson and Springer, 2013). Beside the waste management and reduction strategies, Wang et al. (2014) discussed about three design strategies that can help the management of waste. The first design strategy focused on the use of prefabricated components in construction project mitigate different construction wastes (Wang et al., 2014). According to Wang et al. (2014), waste reduction investments, is the second design strategy, and deal with incentives (special motivational and reward programs) for participants of a construction project to execute construction waste management. The final strategy is design Modification: design change produces a large amount of waste if performed at the finishing stage of a building. Therefore, avoid design modification at the accomplish of a building is crucial to be able to manage construction waste effectively (Wang et al., 2014). On the contrary, Udawatta et al. (2015) argued that effective construction waste management can be achieved by changing attitude rather than changing techniques. Incentives to implement the practices, equity distribution of the benefits of waste management as well as education and raising social awareness on issue regarding waste management practices plays a crucial role in the process of changing attitudes and behaviours of construction practitioners towards waste management. This in turn contributes to the improvement of waste management practices in a construction industry (Udawatta CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 15 et al., 2015). In addition, having knowledge about the attitude and behaviours of construction project’s stakeholders towards waste management play a greater role in management of construction waste in a better way (Udawatta et al., 2015). Seneviratne et al. (2015) argued that identified the source of waste and proposing waste auditing system is essential for effective construction waste management. Effective waste management at each phase of a building material life cycle is vital to attain sustainability in construction (Richardson and Springer, 2013). 2.1.4. Challenges in Managing waste of Construction Project To improve waste management practices, construction clients and developers are increasingly attempting to set waste management requirements (Kareem et al., 2015). Udawatta et al. (2015) argued that clients and other construction project participants have a less positive attitude and behaviour toward waste management practices. There are different reasons that contribute to the difficulty of waste management practice in the construction industry. Some of the reasons are an inability to predict production environment; unique characteristics of each project; time pressure and cost limitation (Kareem et al., 2015; Teo and Loosemore, 2001). Additionally, building material can end up as waste due to improper handling and misuse as well as less management attention. For instance, if a building material has an impact on project cost, more management attention will be given to expensive building material, and less attention will be paid to wastage of other materials. Waste management activities were considered as unimportant to contractor work (Udawatta et al., 2015). Such negative thinking regarding waste management efforts has become a hindrance for the adoption of positive attitudes (Kareem et al., 2015). Additionally, Kareem et al. (2015) and Teo and Loosemore (2001) discussed major challenge/obstacle to waste reduction in a construction industry particularly in the developing world. One of the challenge is a lack of managerial commitment and support on an issue regarding waste reduction has affected operatives’ attitude toward reduction of waste and this contributes to the shortage of resource, manpower and time for waste management activities in relation to other project goals. The second challenge is that non-existence of performance standard for managing waste. The third challenge is that resistance to change the existing work trends in the construction industry. The fourth is waste reduction activities are predominantly profit motivated. In Canada, challenges for CDWM are that waste is bulky, difficult to compress and occupies more space in municipal landfills (Yeheyis et al., 2013). A positive attitude and perception regarding waste management activities can be attained through training and incentives to operatives in order to develop knowledge and participate in less wasteful practice respectively (Kareem et al., 2015). 16 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 2.1.5 Communication and Information Flow regarding Waste Management Communication is most often described along three dimensions: content, form and direction. Any of these dimensions can have some barriers which disturb the messages. These barriers vary from the language-barriers to lack of understanding the context (Sandhu and Ajmal, 2012). Sandhu and Ajmal (2012) argued that communication among different actors at the initial project phase is very crucial as there are lots of activities take place. Communication has various forms such as oral, written (e.g. textual, drawings, and graphics) and nonverbal communication. Effect of communication and information flow to waste management Terje and Morten (2007) as cited in Li (2012) mentioned that information flow is considered as crucial parts of construction supply chain that facilitates the united efforts of stakeholders in waste management. Having adequate knowledge and data on the occurrence of waste and its causes helps to understand and address the problems (Seneviratne et al., 2015). However, lack of data and poor communication have a negative effect on waste management. For instance, Li (2012) argued that lack of data is a barrier which prevents effective handling and management of construction waste. In addition, Gavilan and Bernold (1994) as cited in Li, (2012) noted that poor communication among project team members has resulted in craftsmen’s error and mishandling of materials at the construction phase. For this reason, policies should be developed to give emphasis on ‘stakeholders’ awareness of Demolition Waste Management (DWM)’, ‘developing and promoting knowledge and communication among stakeholders with issues regarding environment and waste management concepts and practices (Ding et al., 2016). Understanding about waste management can also be improved through training (Kareem et al., 2015). To prevent waste, design managers are expected to be skilled in both design coordination and ‘inter-professional collaborative competencies’ such as communication. (Saheed et al., 2016). 2.2. BIM and CDWM The Architecture, Engineering, and Construction (AEC) industry is in the middle age of a technology revival. As a part of this fast-growing innovation, Building Information Modelling (BIM) acts as the antecedent catalyst (Hardin & McCool, 2015) which has a promising advancement in this industry (Eastman et al., 2011; Rogers and Preece, 2015). This advancement leads the majority of world’s prominent AEC firms changing their preceding drawing-based CAD (Computer-Aided Design) technologies into BIM for almost all of their projects (Eastman et al., 2011). BIM has been widely used to minimize cost and time and enhance productivity within AEC industry in the last ten years (Won et al., 2015). In addition, current studies show that BIM has also been enthusiastically promoted as a solution to Construction and Demolition Waste Management (CDWM) (Lu et al., 2017; Won et al., 2015), and is potential to help CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 17 architects to reduce waste produced during the design phase (Akinade et al., 2016; Liu et al., 2015b). Hence, this section covers the BIM concept and definition, its benefit in the AEC industry as well as its potential to be applied in Construction and Demolition Waste Management (CDWM) practice. 2.2.1 Building Information Modelling (BIM): Concept and Definition Although BIM concept has existed from the 1970s (Eastman, 2011), the term “Building Information Model” appeared the first time on the paper written by van Nederveen and Tolman in 1992. Besides, the term “Building Information Model” or “Building Information Modelling” along with its acronym “BIM” was not popularly used until ten years later, in 2002, which was proposed by Autodesk (Zhou et al., 2015). Regardless its popularity for more than 15 years in today’s AEC industry, no single uniform definition of Building Information Modelling is widely accepted (Liu et al., 2015a). One of the most used definitions is from U.S. National BIM Standard (Version 2, page 21), which defines BIM as: “a digital representation of physical and functional characteristics of a facility. As such, it serves as a shared knowledge resource for information about a facility, forming a reliable basis for decisions during its life cycle from inception onward.” A simpler definition is proposed by Kensek and Noble (2014) who defined BIM as a fundamentally changing mode of design practice and standards of a building from design, delivery, to operation. Porwal and Hewage (2012) argued that BIM is a tool in the AEC industry that is utilized to design, document, and improve communication among all project stakeholders. BIM covers a variety of areas: from interacting policies, processes, and technologies applied to modelling, visualization, analyses, simulation, to documentation (Kalinichuk, 2015). According to Kalinichuk (2015), the entire concept of Building information modeling consists of three interlocking BIM Fields of activity: Process, Technology, and Policy fields along with each two sub-fields: players and deliverable. This concept, according to Kalinichuk (2015), was originally introduced by (Eastman, 2011; Succar, 2008) and illustrated in Figure. 1 18 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 Figure 2.5: BIM Fields. Source: Kalinichuk (2015: page 25) Eastman et al. (2011) emphasized that BIM does not only change the technology used in AEC industries but also change the process. It does not only change how visualizations and drawings of a building are created but also drastically transforms the entire key processes implicated in assembling a building. As mentioned by Kalinichuk (2015), current studies tried to examine how information is exchanged between different areas. 2.2.2 Benefits and Challenges of BIM Implementation AEC firms progressively implement BIM in the whole building’s lifecycle (Wong et al., 2015). The majority of the world’s prominent AEC firms have changed their preceding drawing-based, CAD technologies, into BIM for most of their projects (Eastman et al., 2011). To illustrate, the level of BIM adoption in North America has increased significantly from 28% in 2007 to 71% in 2012 (McGraw-Hill Construction, 2012). Besides, research conducted by Jung and Lee (2015) has found that its adoption in this country increased to 82.1% by 2015, which made North America in the top ranked, followed by Oceania, The Middle East/Africa, Europe, and Asia with 81.8%, 80.0%, 75.0% and 46.3% respectively. The significant interest in BIM use in the AEC industry seems to be the result of such early researches that prove obvious project benefits. According to the study conducted by Bryde et al. (2013), the most frequent project benefit of BIM reported was related to CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 19 cost reduction followed by time reduction, communication and collaboration improvement, and quality through the project lifecycle. Ghaffarianhoseini et al. (2017) have also highlighted additional advantages of BIM such as technical benefits, knowledge management benefits, standardization benefits, diversity management benefits, building LCA benefits, and decision support benefits. BIM benefits have also been presented in number. For example, Shin (2017) has outlined the Return on Investment (ROI) when utilizing BIM, as illustrated in the figure below: Figure 2.5. Return on Investment on BIM. Source: Shin (2017: pg. 206) BIM has also benefited in visualization and consistency of design, cost estimations, clash detection, lean construction implementation or enhancing stakeholder collaboration (Volk et al., 2014). It can also be used for monitoring construction progressively, building renovation, building system analysis, as well as energy system simulation (Wong et al., 2015). On the other hand, along with its inherent advantages, BIM has been indicated to have shortfalls. These negative benefits, however, are outweighed by its advantages (Bryde et al., 2013; Ghaffarianhoseini et al. 2017). The negative benefits are mostly associated with software and hardware issues, which are related to technical difficulty (Ghaffarianhoseini et al. 2017). For example, the employees are not trained well and are not used to a new way of working with this technology. This, in turn, causes to low return of investment faced by many BIM users worldwide (Ghaffarianhoseini et al. 2017). Therefore, to tackle these challenges, the AEC firms need to invest more significantly in software, hardware, or training for employees. The significant improvement of BIM implementation leads the researchers to expand the BIM use for further application, such as, constructing more sustainable building. 20 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 This seems to be the results of the awareness of the AEC stakeholders about the importance of sustainability in the construction for the past few decades (Akbarnezhad et al., 2014). One of many other possibilities of BIM implementation for sustainable building is for CDWM. 2.2.3 BIM Use for CDWM Besides its potential to improve performance on construction management (Bryde et al., 2013), BIM has also been enthusiastically promoted as a solution to CWDM (Lu et al., 2017). BIM has been studied extensively to CDWM in some industrialized countries like Hong Kong, the UK, the USA and South Korea. Recent studies have found its benefits in minimizing waste generation in the construction industry. For example, Won et al. (2016) proved that 4.3-15.2% waste generation in the construction phase in South Korea can be prevented by using BIM. There is a growing but limited body of literature researching how BIM can be implemented for CDWM (Lu et al., 2017). Therefore, the way how BIM is applied for construction and demolition waste management is still debatable. BIM utilization to support CDWM varies. It can be utilized as a modern design tool to help designers ponder various design options, prefabrication option for example, or to help contractors to evaluate different construction and demolition schemes (Lu et al., 2017; Won et al., 2016). Preventing the waste from the design phase seems to be the best solution in construction waste management. Some researchers claim that clash detection and design validation during design phase are potential to reduce the amount of waste generated during construction (Cheng et al., 2015; Liu et al., 2011). According to Won et al. (2016), improper design and unexpected changes in the design and construction stages are the main contributors of construction waste generation. This waste, therefore, can be reduced with BIM since, in many cases, BIM is effective to reduce the amount of construction waste during the design phase (Won et al., 2016). For instance, BIM is considered as an effective tool to detect errors and validate building designs. This ability, according to Won et al. (2016), was able to minimize the design mistake, rework and unplanned changes, therefore has been proved to prevent waste by 4.3-15.2% from the construction projects in South Korea. Similarly, Porwal and Hewage (2012) established a BIM-enabled analysis to reduce the rebar waste of structural reinforcement in the design phase. In their study, a BIM model, which contains project data from AEC disciplines, was used as a communication centre among various design teams, and then minimized the potential reinforcement waste by optimizing the algorithm. The design teams can make necessary changes to the designs so that the rebar waste can be reduced. Whilst the aforementioned studies are yet to convincingly link BIM to prevent the waste from the design phase, other studies have attempted to manage waste during demolition CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 21 since most construction waste is from this phase. Earliest study was conducted by The Associated General Contractor of America (AGC) which developed BIM as a digital visualization tool to estimate and identify construction and demolition waste materials. The practitioners could establish a material recycling plan more cooperatively and efficiently prior to actual demolition and renovation. Cheng and Ma (2013) have also established a model in BIM to estimate the waste material from the demolition by extracting the information on volume and materials from every selected building element in BIM. From this information, the practitioners can calculate how much waste generated after demolition, so that they can predict the number of trucks needed as well as the cost to deliver the waste. Similarly, Hamidi et al., (2014) introduced a BIM-based demolition waste management system. BIM was used to provide reliable material information prior to demolition by either reviewing material properties or taking off material quantities from schedule/quantity sections. In addition, Park et al. (2014) have also established a BIM-based database system for demolition waste (DW). Here, BIM material information libraries were used to analyse the construction material categories. The abovementioned studies have raised the benefits of BIM in preventing waste during construction as well as managing waste during demolition waste. Another study focused on benefiting BIM in favour of the waste at the end of building lifecycle, like deconstruction or renovation. Similar to demolition project, deconstruction and renovation also contribute to the huge amount of waste compared to new construction. According to Ding et al. (2016), BIM can be used as an application for deconstruction. For example, to examine the deconstruction scheme, the designers can integrate a “de- constructability assessment score” with a BIM model during the design phase. As many of the building components can be reused from the deconstruction or renovation project, the expected waste generated can be reduced. For example, to handle the deconstruction waste, Akbarnezhad et al. (2014) have developed a BIM-based model for assessing various options in deconstructing building in favour of the economic and environmental benefits. This model was intended to achieve a balance from such benefits because not all building components can be reused or recycled. By enhancing the BIM implementation in this way, renovation or deconstruction waste can be minimized (Akbarnezhad et al., 2014). Different from conventional architectural and structural drawings which often use only combination of lines, without any information attached, to show the visualization of a building, every component of a building in BIM model has its own information attached (Akbarnezhad et al., 2014; Eastman et al., 2011; Wang et al. 2012). This information is typically about building geometry and its relationships; geographic, quantity, the material used, and property information about the building components. In addition to this information, with current BIM software, any other new customized information or variables can be added to the objects/elements by designers, owners, and contractors. This information, which consists of various characteristics, may have an effect on reusability and recyclability of its components (Akbarnezhad et al., 2014). Therefore, in order to make a good recycling and reusing strategy at the end of the building life 22 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 cycle, it is important to add any information about this issue to the BIM model. Akbarnezhad et al. (2014) proposed some attributes based on previous studies that can be put in the BIM model so that it will be useful for the reusing and recycling strategy at the end of the building lifecycle. The first attribute that can be added is recyclability, which provides the information of whether the materials used for building are suitable for recycling or not. The second is the reusability attribute which determines whether the building component can be reused at the end of lifecycle based on components’ life service and disassemble-able connections availability. The third is the structural attribute which provides data of structural capacities, such as shear and moment, from various elements. The next is handling, installation, and disassembly attributes which can be used to provide information of the required procedures on how to handle, install and disassemble elements. The fifth is geographic coordinates attributes which give the information about the nearest recycling and reuse plants and its distance to the construction sites. The last attribute is condition-related attributes which may be applied to store the results of several condition assessment tests. 2.2.4 BIM as a Communication and Collaboration Hub According to Zurita et al. (2008) as cited in Park and Nagakura (2014), utilizing wireless and IT technology to improve communications is considered as necessary factor in maintaining the collaboration quality. “Communication tools have been revolutionised with the explosion in information technology, as a multitude of methods and software programs have become available for business” (Sandhu and Ajmal, 2012). Collaboration is necessary for saving the investments and enhancing the competitiveness of the AEC industry (Shin, 2017). In addition, information sharing can also enhance to efficiency of working. One of new technologies that can be utilized in collaboration and communication among project parties is Building Information Modelling (BIM). Although the main element of BIM is about data sharing in a single and distributed platform, it is usually presented as a platform of collaboration (Forgues, 2016). In addition, BIM is an efficient tool for asynchronous communication, such as modelling and drawings (Knotten et al., 2015). CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 23 3 Methodology This chapter discusses the reasoning behind selecting the methodology and delineates the stages taken to pursue the research questions. Several methods and approaches have been evaluated in regards to time, strength and practical consideration. The selected methods are observations, interviews, and questionnaires. Furthermore, the description of each selected method and tool are demonstrated. Research quality which is assessed by its reliability and validity is also outlined. In addition, to warrant respectable research practice, this chapter ends with a research ethics section. 3.1 Research Approach Before deciding what type of study that is going to be performed, quantitative or qualitative, it is important to select whether to use an inductive or deductive view. According to Saunders et al. (2016), an inductive approach is selected when the researchers aim at exploring a topic or developing a theory through collecting and analysing the data (data-driven), On the other hand, a deductive approach is used when the researchers aim to test a theory (theory-driven) through data collection. Different ways of data collection methods can be applied such as observations, interviews, and questionnaires. However, the core element is whether it is a quantitative or qualitative approach. According to Bryman and Bell (2015), a quantitative research is characterized as requiring the collection of numerical data which are evaluated in regard to statistical interpretation. On the other hand, qualitative research deals with qualities, meanings, and processes that are not tested through experimentation, or measured in terms of quantity (Hogan et al., 2009). In other words, a qualitative approach stresses the words instead of numbers in data collection and analysis (Bryman and Bell, 2015). Mixed-methods research which combines quantitative and qualitative approach may be used in the research strategy. According to Basu (2010), this approach is considered as an outstanding research strategy as it has an inherent self-correcting element which strengthens the credibility of the research in academia. However, combining these two approaches is not without controversy. Bryman and Bell (2015) discussed that practical difficulties associated with this combination approach may happen, and not all writers agree that this approach is feasible and desirable. For instance, it has a risk in data collection and is considered as time-consuming, which makes it not applicable option (Denzin, 2012; Ma & Norwich, 2007). In addition, Basu (2010) suggests that mixed- method approach can be a preferable solution if it is applied properly. From the description above, this study has decided to employ an inductive view which further performed qualitative approach. A qualitative emphasizes the generation and establishment of the theory. Furthermore, with an inductive view, the theory is the outcome of the research which is obtained from observations/findings (Bryman and Bell, 2015). From this theory approach, the data is usually analysed to generate theory. It breaks down the current practice of CDWM to offer areas of improvements. 24 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 3.2 Research Design Research designs are associated with the research method. It correlates with the criteria employed when evaluating business research and gives a framework for collecting and analysing the data. Some research designs that may be applied are experimental design, cross-sectional design, longitudinal design, case study design, and comparative design (Bryman and Bell, 2015). Case study design is chosen in this master thesis due to its ability to combine several qualitative methods. This enables the authors to observe the current situation, connecting theory to practice. 3.2.1 Case Study Design The case study encompasses the detailed and comprehensive analysis of a single case (Bryman and Bell, 2015). It enables the researcher to observe the current situation, connecting theory to practice (Levine, 1996). This approach is very prominent and widely applied in the business research. The cases used can be a single organization, a single event, a single location, or a single person (Bryman and Bell, 2015). The examples of a single location can be a factory, office building or even a construction site, which was used in this dissertation. A case study design enables the authors to combine several qualitative methods, therefore avoiding to rely greatly on a single approach (Bryman and Bell, 2015). It may involve either several cases or a single case. Although some writers prefer the generalization of some cases, some other researchers tend to use a single case. For instance, according to Lee, Collier, and Cullen (2007) as cited in Bryman and Bell (2015), particularization constitutes the main strength of the case studies than generalization. As Bryman and Bell (2015) said, it is suggested to select the cases based first and foremost on the anticipation of the opportunity to gain knowledge, so that the learning will be greatest. A construction site, which is a new children's hospital project (ÖstraBarnsjukhuset), has been chosen as a case area because the project site is quite big and has various construction activities that might have effects to CDWM. Furthermore, the site also has a huge ambition to achieve a sustainable goal through miljöbyggnad guld, which is the highest level of green building certification in Sweden, issued by Sweden Green Building Council. This ambition may affect how the CDW is treated. In addition, there are subcontractors, site workers and site manager with different cultural backgrounds. This, in turn, might have influence management of case area’s CDW. 3.3 Data Collection Methods This section describes the methods used to collect data during the case study. Primary and secondary data are collected qualitatively. The primary data included site observation of the study area as well as semi-structured interviews conducted with an environmentalist, researcher, recycling company as well as project member of studied project. In addition, a close-ended questionnaire was distributed to six site workers of the study area’s construction site. The secondary data included reports and a brochure which were collected from the study area. CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 25 3.3.1 Observational Method Different from interview and questionnaires, direct observations provide more clear information about what happens in the real-world situations (Ritchie et al., 2013). According to Farenga et al. (2003), observation is an effort to recognize the patterns by doing an empirical process directly based on the initial knowledge of the researchers. Furthermore, Farenga et al. (2003) argued that good scientific observing consists of these following components: as presented in table 3.1 below. Table 3.1: Elements of good scientific observing. Source: Farenga et al. (2003: p.57) Direct observation was done by investigating directly the construction and demolition waste management practice on the case area’s construction site. The open observation was used which means that the participants were aware that they were being studied (Bryman and Bell, 2015). These observations were carried out twice in the site office as well as on the construction site. In the site office, waste management plan along with its related information that could be seen directly was gathered. In addition, the process of how the waste handled on the construction site was observed. Since the information gathered by doing observation may be limited due to external factors, additional reports and documentations were used to build and strengthen research foundation. The work environment, as well as the process of waste handling of the construction site and site office, were captured by using a camera. It gave a clear picture of the real situation of waste management on sites as well as every component used to handle the waste. Moreover, a checklist was used to underpin the data collections. The checklist contains critical issues regarding CDWM that can facilitate the collection of data at the construction site and its office (site office) (see appendix 3). 26 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 3.3.2 Interview Method Several interview methods may be used for collecting data in both quantitative and qualitative research. However, the interviews employed in qualitative research are often far less structured compared to those in quantitative research (Bryman and Bill, 2015). One of the most popular interview methods applied in qualitative research is the semi- structured interview (Bryman and Bill, 2015; DiCicco and Crabtree, 2006), which was employed in this dissertation. This interview style has a flexible nature, so it is possible to raise new questions based on the dialogue between interviewer and interviewee (Duignan, 2016; Louise et al.,1994). DiCicco and Crabtree (2006) argued that besides emerging questions during the dialogue, the semi-structured interview also includes an open-ended questionnaire. In addition, a semi-structured interview is also used to explore opinions of interviewees regarding specific issues, which can be complex or sensitive (Louise et al., 1994). Semi-structured interviews were conducted with concerned bodies involved in CDWM in the study area. These consisted of an environmentalist and project members of the contractor company involved in the project, as well as the recycling company that handles the wastes in the case area. The interviewees were selected based on their expertise and responsibility. The environmentalist was chosen as she is responsible for environmental ambition including CDWM at the case company. The project members, including a logistic person, is selected due to his knowledge and responsibility for waste at the construction site. The market and sales manager from a recycling company was chosen as he is responsible for collecting and recycling the waste from the case areas of a construction site. In addition, to have a broader perspective and understanding of CDWM in the Swedish construction industry, the interview was also done with a research expert in this field. The current work process and practices of CDWM and its challenges as well as information flow and communication were discussed with the aforementioned actors. The possibility of BIM usage in CDM was also discussed. The questions raised were about what information would be needed to put in BIM model in order to support waste management issues in construction and demolition project. The interviews were conducted in English and took about 30 minutes to one hour per interview. These interviews were recorded and then transcribed to avoid misinterpretation or mixing of data from various interviews. 3.3.3 Questionnaires One of the main ways of collecting data is a questionnaire. Usually, questionnaires are self-completion questionnaires or self-administered questionnaires which mean the questions on the questionnaires are answered and completed by the respondents themselves (Bryman and Bell, 2015). As a method, it can come in different forms such as electronic or postal mail. In the business method, questionnaires are very similar to a structured interview. The clear difference is that in the self-completed questionnaires, the respondents need to read the questions themselves. Self-completion questionnaires have some weaknesses and strengths compared to structured interviews. According to Bryman and Bell (2015), self-completion questionnaires are cheaper and quicker to administer, the absence of the interviewer CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 27 (which can usually affect the answer of the interviewees), no interviewer variability, and convenience for respondents. On the other hand, self-completed questionnaires also have some disadvantages such as the interviewer cannot help the respondents to answer the question, or even ask the respondents to elaborate more, etc. (Bryman and Bell, 2015). In addition to the aforementioned data collection methods, this dissertation employs a questionnaire. The purpose of distributing this questionnaire is to give additional information about CDWM at the study area based on site workers’ perspective. Site workers were chosen because they are directly involved in managing waste on site. By doing a questionnaire, it is also possible to understand how information about CDWM is practiced by the site workers as the recipients. The questionnaire was randomly distributed to some site workers in the study area. The questions were designed to be simple and were translated to the Swedish language in order to be easily understood by the respondents. The questions types were not multiple choice but rather multiple answers which allow the respondents to choose more than one answer and/or add more answer based on their experience. The questionnaire covered five big questions related to the thesis topic, including waste sorting, information flow, and challenges of waste management practice. These topics were carefully chosen in regards to the research questions. 3.4 Data Analysis Although there are various methods of analysing qualitative in the scope of academia, only a few acknowledged and established guidelines exist (Bryman & Bell, 2015). The traditional method of analysing the data consists of collecting, evaluating, and structuring the data iteratively. This method is able to tailor the interviews and incorporate important factors found during the observations. The data gathered from both primary and secondary sources were analysed qualitatively. In general, qualitative analysis will also be obtained by interpretation of data obtained from interviews, observations and questionnaires. The observations, interviews, questionnaires and documentation were reviewed to assist creating an understanding of current situation of CDW practice in order to accurately identify possible area of improvements. 3.5 Research Quality Assessing and establishing the quality of the study are important in the business research. Most prominent criteria for evaluating the business and management research are Reliability and Validity (Saunders et al., 2016). In qualitative research, the meaning of reliability and validity needs to be adapted from its meaning in quantitative. For example, validity seems always to have a connotation of measurement which is not a big issue in qualitative research. Therefore, in qualitative research, as cited in Bryman and Bell (2015), Mason (1996) argues that the term validity refers to ‘whether you are observing, identifying, or “measuring” what you say you are’. On the other hand, Saunders et al. (2016) have a somewhat different meaning of reliability and validity, which were used in this study. They divided into external and internal of either 28 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 reliability or validity. While external reliability measures the degree to which the research can be replicated, the internal is more about how much agree the observers hear and see something and has the same perceptions. Internal Validity means that how correlated between the researchers’ theoretical ideas which they developed with the observations they do. Whilst the external validity refers to the degree of generalizing findings across social settings. 3.5.1 Reliability This study had chosen specific case area which applied construction and demolition waste management. To avoid bias and errors either from researchers or the site workers, collecting data was carefully done. For example, when observing, note taking and capturing pictures were done carefully. Interviews were taped and transcribed to avoid misinterpretation. In order to improve current practices of CDWM, this study tries to come up with waste strategies as well as integrate BIM in CDWM by considering perceptions of different scholars. Therefore, if other researchers would like to do the same method, the same answers will be derived if the research objects are the same. However, since the authors only used single case study, the findings cannot be generalized with other cases. 3.5.2 Validity As indicated earlier, research quality does not only depend on its reliability but also its validity. In this study, several data collection methods were carefully selected to enable the researchers to answer the research questions. The interviewees were selected in accordance with their expertise and knowledge. On the other hand, since the questionnaires were distributed randomly, the findings might be slightly affected since the participants were from various background, which leads to different answers on questionnaires. However, since there were still other data collecting methods employed, which had a bigger influence in this study, the findings are believed to be valid and are possible to be applied in other similar projects. 3.6 Research Ethics The interviewees such as researcher, environmentalist and project members as well as the respondents of the questionnaires are only anonymous with name but not with their role. If the interviewees and respondents explicitly agree to be listed with name in this dissertation, written request will need to be filed, which is reviewed in regards of applicable rules and regulations from Chalmers University of Technology. Confidential information may be encountered due to the nature of a case studies. However, it will not be included in the final dissertation and observational notes. Therefore, all primary and secondary data written in this dissertation were reviewed by the company, interviewees and respondent involved by sending them the copy of dissertation ahead of deadline. If any important information that needs to be included in this dissertation but is confidential, an open dialog between the researchers and the involved parties are done. As the primary data collected may be sensitive to the individual or organizations involved, storing this information have to be carefully done to reflect the importance. CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 29 All the data gathered including interview records and transcribe, and documentations are kept by the researchers, and supplied to Chalmers University of Technology. If this data is considered to be obsolete in terms of research validity, it may be removed in the future. 30 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 31 4 Contextual Review and Case Study This chapter is divided into two sections. The first section provides the information about current practice of CDWM in Swedish AEC Industry, including regulations and current state of Sweden’s waste. The second section describes the case study used in this master thesis. 4.1 Current Practice of CDWM in Swedish AEC Industry In Sweden, CDWM represents the largest waste stream, mining waste excluded, with a volume of 8 million tons generated annually (SEPA, 2014). In waste prevention program, Sweden has pointed out that CDWM are priority areas. It is also emphasized that it is important not only to dispose of the waste in an environmentally friendly manner, but also to reduce the waste quantity and its hazardousness. According to the official statistics, the recycling rate in Sweden range between 50-60 %, (SEPA, 2015). It indicates that more effort is needed in order to reach the recycling target and move beyond this level. Therefore, in 2020, it is targeted by EU’s member states including Sweden, to fulfil the directive regarding waste which states that non- hazardous construction and demolition waste will be recycled for a minimum of 70%. To reach the target, The Swedish Government has published “Resource and Waste Guidelines during Construction and Demolition”, which purpose is to increase resource management towards the construction and demolition industries. These guidelines are a tool intended to fulfil the requirements of the Swedish Environmental Code (Kretsloppsrådet's guidelines, 2015). According to Resource and Waste Guidelines During Construction and Demolition, the containers of waste should be signed with different colours: a. Hazardous waste (Sign colour red) b. Electrical waste (Sign for colour red/white) c. Wood (Sign colour yellow) d. Plastic for recycling (Sign colour purple) e. Combustible materials (Sign colour orange) f. Scrap metal (Sign colour grey/white) g. Aggregates (Sign colour brown) h. Landfill after sorted (Sign colour black) i. Mixes for post-sorting as alternative fraction to landfill (Sign colour yellow/black) 32 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 4.2. Case Study 4.2.1. Company’s Profile The company that has responsibility as the main contractor for our study case is NCC. With turnover of SEK 53 billion and 17000 workers in 2016, this company has become one of the prominent construction and property development companies in Northern Europe (NCC 2016, ‘About NCC’). As a construction and property development company, NCC is also active around the value chain - building and developing residential and commercial properties, constructing public building, industrial facilities, roads civil engineering structures and other kinds of infrastructure. Furthermore, materials used for paving and road services are also offered by NCC as one of its projects (NCC, 2016). 4.2.2 Project Description One of the biggest ongoing projects constructed by this contractor company is a new children’s hospital, the extension of Queen Silvia’s Children’s Hospital, which is located in the city of Gothenburg, Västra Götaland County, Sweden. The company is also commissioned to make connections to the existing hospital nearby as well as to build an attractive site environment (NCC 2015, ‘NCC to construct a new children’s hospital in Gothenburg’). This project, which is under the Design Bid Build Contract, was started in 2015 and is targeted to complete in 2020. Situated in the west of the old building, this new hospital is estimated to have value of SEK 850 million with construction costs around SEK 1.6 billion. Figure 4.1 Location map of the project CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 33 This hospital will be one of the world’s foremost children’s hospitals with high standard of facilities such as children care, clinical research and education. Moreover, it will also be equipped with places for operation, intensive care, rehabilitation, nursing wards and administration. This nursing wards will offer improved care environment for patients and their close relations (NCC 2015, ‘NCC to construct a new children’s hospital in Gothenburg’). Business Area Manager for NCC Construction Sweden, said “NCC strives to achieve a Gold environmental rating from Sweden Green Building Council, which is the highest classification and demonstrates the building’s environmental performance with respect to energy, indoor environment and material,” (NCC 2015, ‘NCC to construct a new children’s hospital in Gothenburg’). 34 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 35 5 Findings and Result In this section, results and findings were discussed based on observation, semi- structured interviews, and questionnaires of the case area. The results were explained at case area, company and multi-project level. 5.1 Current Practices of CDWM 5.1.1 Current Practices of the Case Area’s CDWM The case area’s construction site was big in size. It was paved with asphalt in order to keep the site clean as mentioned by a logistic person. In addition, in the case area’s construction site, different types of construction wastes were generated. The logistic person who was in charge of waste management on site said that at least there were eight different fractions for wastes on site. These wastes were earth, concrete, foams, plastics, cardboards, wood, papers as well as hazardous wastes. In addition, most site workers who responded to the questionnaires considered earth/soil as the main waste generated during construction, followed by wood/timber and scrap metal. Waste sorting was carried out on site. There were rooms/containers to sort waste materials such as electric, gases, chemicals and hazardous wastes (see figure 5.1 and 5.2). These rooms/containers were labelled based on waste types. Suppliers were responsible for taking care of the toxic/hazardous wastes as described by the logistic person. The logistic person also mentioned that the recycling company took the waste material to their station and the recycling company’s chemist analysed everything. In addition, the interviewee, who works in the recycling company, discussed that the recycling company is responsible for collecting and recycling the waste from the construction site. The interviewee mentioned that the recycling company has attempted to provide waste containers as many as possible and the construction company decides where to locate the waste containers based on waste management plan of the construction site. The waste materials that are brought to the recycling company were still sorted a little more to have clear fractions. The mixed and combustible wastes were sorted carefully using waste sorting vehicle. Any wastes that were suspected to be harmful were tested before treated for further process. Some wastes were treated differently. For example, wood was crushed into small pieces and then sold to the energy recovery plant to produce heat. More than 95% of the waste went to energy recovery. On the other hand, metal was sent to other recycling company which took care of metal. This metal was melted and moulded to make a new metal and used in the industry. Plastic was also recycled and exported to other country like China and Indonesia for other purposes. In other words, the recycling company sold these wastes as raw material for further purpose. 36 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 Figure 5.1 Room to sort hazardous wastes such as chemicals, electronics Figure 5.2 Room/container to sort gases The waste containers were put in a row, and clustered in the same place (see figure 5.3). In addition, the waste containers were near to one side of the building, which was under construction but the containers were far from the other side of the building. The other side of the building, which was under construction, had only one or two waste containers. CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 37 Figure 5.3 The location of waste containers On the construction site, the waste containers were signed with different colours in order to easily distinguish the various types of construction wastes as well as to avoid mixing of the wastes. For instance, orange colour was used as a sign for combustible materials; black colour was used as a sign for landfill; red colour for hazardous wastes and yellow for wood. However, some of waste containers contained mixed waste (see figure 5.4, 5.5, 5.6, 5.7, 5.8 ,5.9 and 5.10). The colour codings are the same with those shown on the brochure. Figure 5.4 containers with orange and red colour tag for combustible and landfill wastes 38 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 Figure 5.5 Waste Container is signed with red colour for hazardous wastes Figure 5.6 Waste container with yellow tag for wood Figure 5.7 Waste containers with light brown tag for cardboard CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 39 Figure 5.8 Waste container for foam (‘cellplast’) Figure 5.9 Mixed wastes: foam, plastics, carton, etc. Figure 5.10 Combustible Waste materials: plastic carton, paper, etc. 40 CHALMERS Architecture and Civil Engineering, Master’s Thesis BOMX02-17-92 As it is mentioned above, the construction wastes were disposed in containers.