Resource efficiency and circular economy (CE) has become increasingly relevant to the Swedish construction company NCC in connection to the plans of demolishing the current head office in Stockholm and building a new head office next to it. NCC wants to investigate how to minimize the negative sustainability implications of bringing down a commercial facility well before its life length has expired, through exploring the possibilities of integrating principles of CE in future planning‐and construction processes. This study seeks to understand how the Swedish construction company NCC could work with decision-making for CE in order to keep their materials in the loop. As the concept of CE is broad there are many options for working with its principles. However, the construction industry is relatively new to these and a list of priorities would therefore be helpful in such an initial phase, as focusing on all would be inefficient and rather daunting. Thus, this study suggests a multi-criteria decision analysis (MCDA) as a tool for decision-making and prioritizing between various approaches to CE. Together with NCC, an MCDA was performed where three different options for working with CE were analysed (Waste as Resource, Circular Design and Circular Business Models). In a focus group, 17 criteria that were relevant to NCC were developed as a basis for analysing the options. These were then defined, scored and weighted to reveal a most preferable option. The MCDA showed that the most preferable approach to CE for NCC is working with circular design, i.e. Design for Deconstruction (DfD), followed closely by measures to increase the rate of reuse and recycling of already existing construction- and demolition waste. However, the sensitivity analysis revealed that if economic criteria received a higher weight, increased reuse and recycling is the most preferable option. MCDA was deemed a helpful decision-making tool for CE principles. While the scoring and weighting is subjective and it is challenging to quantify the criteria, the strength lies in bringing a new and innovative topic on the agenda by gathering key decision-makers in focus groups to discuss and learn. A preliminary study to this thesis was conducted at NCC (Tabrizi, 2015) with the aim of conducting a survey of good examples with regard to development of commercial properties that are designed for flexibility and deconstruction during refurbishment and end‐of‐life. It showed that the challenges relate to the hesitant perception of secondary material, design and construction limitations, the need for material documentation, organization and logistics as well as creating sustainable business models. Key success factors for overcoming these challenges for NCC is working towards better communication and promotion of secondary material through information sharing, building up a knowledge base and internal targets, as well as establishing a consistent work methodology for DfD in order to move NCC towards a circular economy.

Efficient management of construction and demolition components is crucial for the sustainability of the environment, society, and economy. Reusing construction materials is an effective way to reduce construction debris. However, reuse is hurdled due to different factors, and one of the leading causes of these factors is improper information flow. The information flow is the transfer of relevant information within the network about construction materials such as quality, quantity and other specifications in the reuse aspect. The seamless flow of relevant information on the construction process and materials is crucial to facilitate reuse. Unfortunately, there are considerable obstacles to achieving a seamless information flow. By identifying and addressing the barriers that hinder the current information flow, we can thrive towards a seamless flow of information that facilitates reuse within the construction industry. This paper examines the challenges in the flow of information within the Swedish construction industry using a qualitative exploratory research design. The research also explores some strategies adopted by a few stakeholders to promote reuse. The study is performed using existing literature and interviews with various stakeholders mainly in the Swedish construction industry. The research identifies several barriers in information flow, including a lack of collaboration among stakeholders, fragmented information, no standardization, business models that do not support reuse, and low awareness of reuse prospects. To gain better insight into the flow of information, a five-component framework has been devised based on these challenges.

Yes / In this study, the main emphasis is placed on the development and characterization of alkali-activated binders completely produced by the use of mixed construction and demolition waste (CDW)-based masonry units as aluminosilicate precursors. Combined usage of precursors was aimed to better simulate the real-life cases since in the incident of construction and demolition, these wastes are anticipated to be generated collectively. As different masonry units, red clay brick (RCB), hollow brick (HB) and roof tile (RT) were used in binary combinations by 75-25%, 50-50% and 25-75% of the total weight of the binder. Mixtures were produced with different curing temperature/periods and molarities of NaOH solution as the alkaline activator. Characterization was made by the compressive strength measurements supported by microstructural investigations which included the analyses of X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). Results clearly showed that completely CDW-based masonry units can be effectively used collectively in producing alkali-activated binders having up to 80 MPa compressive strength provided that the mixture design parameters are optimized. Among different precursors utilized, HB seems to contribute more to the compressive strength. Irrespective of their composition, main reaction products of alkali-activated binders from CDW-based masonry units are sodium aluminosilicate hydrate (N-A-S-H) gels containing different zeolitic polytypes with structure ranging from amorphous to polycrystalline.

Yes / As a viable option to upcycle construction and demolition waste (CDW) into value-added materials, geopolymer technology is emerging. Most studies investigate CDWs in a separated form or in combination with mainstream pozzolanic/cementitious materials focusing only on fundamental properties of geopolymer pastes, not considering to scale such materials to the level of their application in the forms of structural mortars/concretes or to characterize long-term performance/durability. This study investigated the development and characterization of ambient-cured mortars with mixed CDW-based geopolymer binders and untreated fine recycled concrete aggregates (FRCA). Mixture of CDW-based roof tile (RT), red clay brick (RCB), hollow brick (HB), concrete (C), and glass (G) was used as the precursor, while ground granulated blast furnace slag (S) was used in some mixtures to partly replace CDW precursors. Compressive strength, durability-related parameters including drying shrinkage, water absorption, and efflorescence, microstructure and materials sustainability were evaluated. Results showed that 28 d compressive strength results above 30 and 50 MPa is achievable with the entirely CDW-based and slag-substituted mortars, which were found improvable to have entirely CDW-based structural concretes. Drying shrinkage of the mortars is slightly higher than that of conventional cementitious/geopolymeric systems although it can be minimized significantly through mixture optimization. Water absorption values remain comparable with the literature. CDW-based geopolymer mortars outperform Portland cement mortars in terms of CO2 emission and energy requirement. Our findings show that via utilizing CDW-based constituents in mixed form as precursor and waste aggregates, it is possible to develop greener construction materials with acceptable strength and long-term performance. / This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100. The authors also wish to acknowledge the support of the Scientific and Technical Research Council (TUBITAK) of Turkey provided under project: 117M447.

Yes / Construction and demolition waste (CDW) has reached severe environmental and economic dimensions due to its large volume among all solid waste, highlighting the importance of local actions to manage, recycle, and reuse CDW. Ductile demountable connections are necessary to disassemble and reuse the concrete structural members and fast assembly of precast structures in seismic regions without generating waste. In this study, the seismic performance of CDW-based reinforced geopolymer concrete columns has been investigated. Six ½ scaled columns (half of which were demountable and the other half monolithic) were experimentally tested under reversed cyclic lateral displacement excursions, considering three different levels of constant axial loading to determine failure mechanisms, load–displacement responses, ductilities, energy dissipation capacities, stiffness degradation relations, and curvature distributions. The obtained test results were used to determine the performance of CDWbased geopolymer concrete columns and compare the performances of the demountable connection with the monolithic connection. The test results showed that the novel demountable connection for precast concrete frames exhibited better seismic performance in terms of maximum lateral load capacity, initial stiffness, energy dissipation capacity, and maximum curvature than their monolithic counterparts. Besides, increasing the axial compression ratio on the columns caused an increase in lateral load capacity, energy dissipation capacity, energy dissipation ratio, and initial curvature stiffness; however, it decreased the ductility. Finally, the capacity predictions of current codes, i.e., TS500 and ACI318, were conservative when compared with experimental results. / This publication is a part of doctoral dissertation work by the first author in the Academic Program of Civil Engineering, Institute of Science, Hacettepe University. The authors gratefully acknowledge the financial assistance of the European Union’s Horizon 2020 research and innovation program under grant agreement No: 869336, ICEBERG (Innovative Circular Economy Based solutions demonstrating the Efficient recovery of valuable material Resources from the Generation of representative End-of-Life building material). This work was also supported by Newton Prize 2020. The fifth and seventh authors acknowledge the financial support received from the European Union’s Horizon 2020 research and innovation program under the Marie SkłodowskaCurie grant agreement No 894100. / The full-text of this article will be released for public view at the end of the publisher embargo on 4th Oct 2024.

Yes / CDW-based concrete requires alkali-activators to generate geopolymerization process. These alkali-activators are difficult to be handled at the construction site and one of the rational ways to built reinforced geopolymer structures is the prefabricated construction. The connection of the precast structures is the most vulnerable component under the effect of seismic actions. Proper detailing and design of connections are crucial for sufficiently-ductile performance under seismic loading. Additionally, to achieve the disassembling and reusing of structural members, a demountable connection, i.e., dry connection, should be used instead of a wet connection. In this study, four novel fully-demountable connections for reinforced construction and demolition waste-based (CDW) geopolymer concrete members are developed. Seismic performances of these different demountable connections and one reference monolithic connections are experimentally investigated. The connections are subjected to reversed cyclic lateral displacements under constant axial loading. Comparisons are made referring to observed damage patterns, connection strengths, moment–curvature relations, initial stiffnesses, plastic hinge lengths, and energy dissipation characteristics of the proposed demountable connections and the monolithic connection. The results of the experimental study indicate that one proposed demountable connection exhibited larger lateral capacity and better seismic performance than its monolithic counterpart, whereas the other three proposals showed less performance than the monolithic counterpart. / The authors gratefully acknowledge the financial assistance of the European Union’s Horizon 2020 research and innovation programme under grant agreement No: 869336, ICEBERG

Yes / Developing a fast, cost-effective, eco-friendly solution to recycle large amounts of construction and demolition waste (CDW) generated from construction industry-related activities and natural disasters is crucial. The present investigation aims to offer a solution for repurposing CDW into building materials suitable for accelerated construction and housing in developing countries and disaster-prone areas. Feasibility of recycled concrete aggregate (RCA) inclusion in geopolymer mortars constituted entirely from CDW (masonry elements) was investigated via an environmental impact-oriented approach by addressing the composition related key parameters. Mechanical performance was evaluated through compressive strength tests, and scanning electron microscope (SEM) imaging with line mapping analyses were carried out to monitor the interfacial transition zone (ITZ) properties. To investigate the environmental impacts of the geopolymer mortars and highlight the advantages over Portland cement-based mortars, a cradle-to-gate life cycle assessment (LCA) was performed. Findings revealed that roof tile (RT)-based geopolymer mortars mainly exhibited better strength performance due to their finer particle size. Mixtures activated with 15 M NaOH solution and cured at 105 °C achieved an average compressive strength above 55 MPa. RCA size was the most influential parameter on compressive strength, and a smaller maximum RCA size significantly increased the compressive strength. Microstructural analyses showed that the ITZ around smaller RCAs was relatively thinner, resulting in better compressive strength results. LCA proved that CDW-based geopolymer mortars provide the same compressive strength with around 60% less CO2 emissions and similar energy consumption compared to Portland cement-based mortars. / This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100. The authors also wish to acknowledge the support of the Scientific and Technical Research Council of Turkey (TUBITAK) provided under project: 117M447

This thesis explores the challenges and opportunities of reusing construction and demolition waste within Sweden's construction sector, employing a PEST-SWOT analytical framework. The focus is on three primary materials prevalent in residential single-family houses: brick, concrete, and timber. The study identifies key political, economic, social, and technological factors that influence material reuse practices. The analysis highlights substantial barriers including regulatory complexities, lack of incentives, and the tendency to often prioritize new over reused materials due to perceived risks and higher costs associated with reuse. Despite these challenges, the research identifies significant opportunities for advancing material reuse. These include the potential for implementation of technological advancements in material processing, and growing public and governmental support for sustainable construction practices. The thesis goes forward by proposing strategic recommendations aimed at enhancing the adoption of reuse practices, thereby contributing to a more sustainable and resource-efficient construction sector in Sweden. / Demand trust for circular building materials

A crescente quantidade de resíduos sólidos da construção civil gerada em cidades de médio e grande portes tem sido fonte de preocupação em todo o mundo em função de questões ambientais, econômicas e até sociais. Desta forma, a reciclagem dos resíduos de construção para a produção de agregados torna-se uma alternativa interessante, principalmente em função de normas e pesquisas já existentes que podem garantir sua aplicação. A pavimentação com agregados reciclados já vem sendo amplamente realizada em alguns países onde, inclusive, já existe conhecimento consolidado sobre o assunto. No Brasil, as primeiras experiências que remetem ao uso de agregados reciclados em pavimentação datam de meados da década de 80. Desde então, poucas pesquisas sobre o tema vem sendo realizadas, embora haja a necessidade de se procurar novas técnicas e materiais no setor de infra-estrutura rodoviária, uma vez que o país possui somente cerca de 10% de suas vias, muitas vezes urbanas, em condição pavimentada. Este trabalho analisa laboratorialmente aspectos físicos e de comportamento mecânico do agregado reciclado da cidade de São Paulo, a ser utilizado em camadas de base, sub-base ou reforço do subleito de pavimento, em substituição aos materiais convencionais, com enfoque em vias urbanas de baixo volume de tráfego. O estudo envolveu a análise do agregado reciclado in natura, além de sua mistura com 4% de cal ou 4% de cimento Portland, como forma de promover um aumento da resistência do material. Além disso, foram realizados alguns ensaios com brita graduada (material comumente empregado em pavimentos), a fim de comparar resultados. Concluiu-se que o agregado reciclado analisado é de uso promissor em pavimentação, dadas suas propriedades físicas e mecânicas satisfatórias, comparáveis a tradicionais materiais estabilizados granulometricamente ou mesmo a brita graduada simples. Ademais, a adição de cal ou cimento Portland apresenta-se como excelente alternativa quanto ao requisito de aumento de resistência do material reciclado. / The increasing amount of construction and demolition waste generated in medium-sized and large cities has become a source of concern all over the world due to environmental, economic and even social issues. Thus, the recycling of construction and demolition waste to produce aggregates becomes an interesting alternative mainly because of existing specifications and researches that can guarantee its application. Paving with recycled aggregates has already been largely done in some countries where there is even a consolidated knowledge about the subject. In Brazil, preliminary experiences that refer to the use of recycled aggregates in pavement layers date from the mid 80s. Since then, few researches on the subject have been conducted, although it is necessary to look for new techniques and materials in the road infra-structure sector, since the country has only about 10% of its roads, many times urban ones, in paved condition. This work analyses recycled aggregates from São Paulo City as a material to be used in base, subbase or subgrade reinforcement courses in urban roads of low-volume traffic, to replace conventional materials. So, physical and mechanical behaviour aspects of the material were observed by means of laboratory tests. This study involved the analysis of recycled aggregate in natura, as well as its mix with 4% of lime or 4% of Portland cement, to promote a gain in strength. Moreover, some tests were made using graded crushed rock (that is commonly used as a pavement material) so as to compare the results. It was concluded that recycled aggregate is promising for paving, given its satisfactory physical and mechanical properties, comparable to traditional granulometrically stabilized materials or even to simple graded crushed rock. The addition of lime or Portland cement is an excellent alternative concerning the increase in strength of those recycled materials.

Made available in DSpace on 2016-08-10T10:50:22Z (GMT). No. of bitstreams: 1 ROSANGELA MENDANHA DA VEIGA - PARTE 1.pdf: 15620641 bytes, checksum: 5d52ffa5ca3a1f10d3bd59d5c8266066 (MD5) Previous issue date: 2008-02-29 / The civil construction is one of the human activities that cause more impacts to the environment. It produces significant alterations in the environment along all its productive chain, especially in its principal chain where occurs the generation of construction and demolition waste, which contributes effectively to the aggravation of the questions related to the environment. The construction and demolition waste is produced in a great volume and generally does not receive appropriate destination. At the same time there is a lack of municipal policies and management plans for this kind of waste. In January 02nd 2003 came into force the CONAMA Resolution number 307 of July 5th 2002 that establishes directives, criteria and proceedings for the construction and demolition waste management. It was waited that the private sector, and mainly the public one, would take the necessary measurements to carry out the mentioned resolution, however very little or hardly anything was carried out by the social actors involved in the question and by the Brazilian cities. In most of them the corrective management prevails, and this kind of waste needs its own management. Due to this situation, it was tried to identify municipal experiences, in accordance with the legislation and standards referring to the construction and demolition waste, which could show possible solutions. There were carried out two case studies, whose focus was detained to a different management of construction and demolition waste in the cities of Belo Horizonte, the most important experience in Brazil, and São José do Rio Preto, which, in a short time, following the steps of Belo Horizonte, became also a model and a reference. The present research is a contribution to supply subsidies for the preparation of public policies and plans related to the introduction of a different management of construction and demolition waste in the Brazilian cities. / A construção civil é uma das atividades humanas mais impactantes do ponto de vista ambiental. Produz significativas alterações no meio ambiente ao longo de toda sua cadeia produtiva, sendo que na sua cadeia principal ou de processos ocorre a geração de Resíduos de Construção e Demolição (RCD), o que contribui efetivamente para o agravamento das questões relacionadas ao saneamento ambiental. Além de ser gerado em grande volume, o RCD, geralmente, não recebe destinação adequada. Concomitantemente existe uma carência de políticas e planos municipais de gerenciamento para este resíduo. Em 02 de Janeiro de 2003 entrou em vigor a Resolução CONAMA 307 de 5 de julho de 2002 que estabelece diretrizes, critérios e procedimentos para a gestão dos resíduos da construção civil. Esperava-se que o setor privado e, principalmente, o público, tomassem as providências necessárias para cumprir a referida resolução, porém muito pouco ou quase nada foi realizado por parte dos atores sociais envolvidos na questão e dos municípios brasileiros. Na maioria deles prevalece a Gestão Corretiva, sendo que esse resíduo necessita de gerenciamento próprio. Diante deste quadro, buscou-se identificar experiências municipais, em conformidade com a legislação e normas referentes ao RCD, que pudessem nortear possíveis soluções. Assim, foram realizados dois Estudos de Casos Observacionais, cujo foco deteve-se na Gestão Diferenciada do RCD nas cidades de Belo Horizonte, considerada a experiência mais importante em Gestão Diferenciada do RCD no Brasil, e São José do Rio Preto que, seguindo os passos de Belo Horizonte, em pouco tempo tornou-se também um modelo e uma referência. A presente pesquisa é uma contribuição para fornecer subsídios para a elaboração de políticas públicas e planos correlatos para a implantação da Gestão Diferenciada do RCD nos municípios brasileiros.