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The validation of a feasible application for the production of sustainable bricks with local materials in humid and hot climates, which would allow the current housing needs of a constantly growing population with scarce economic resources to be met while also reducing energy inputs for climate control, is a current challenge without a definitive solution. Therefore, this research studied the incorporation of local aggregates and two second-generation materials to produce lime-stabilized Compressed Earth Blocks (CSEBs) using a semi-automatic machine for their manufacture. An initial matrix was designed as a baseline, and three more were developed with variations to incorporate second-generation materials individually and as mixtures. The stabilizer was added in concentrations of 5, 10, and 15%, resulting in a total of 12 batches of CSEBs. Eleven of the studied batches exceed the normative limits for simple compressive strength and initial water absorption coefficient. The best result of simple compressive strength was obtained in two batches of the same matrix that used construction demolition waste (CDW), reaching 4.3 MPa (43% above the minimum limit established by the most restrictive regulations and 115% above the least restrictive). It was possible to produce sustainable bricks in situ with average ambient temperatures of 32 °C and relative humidity of 91%. [ABSTRACT FROM AUTHOR]

The validation of a feasible application for the production of sustainable bricks with local materials in humid and hot climates, which would allow the current housing needs of a constantly growing population with scarce economic resources to be met while also reducing energy inputs for climate control, is a current challenge without a definitive solution. Therefore, this research studied the incorporation of local aggregates and two second-generation materials to produce lime-stabilized Compressed Earth Blocks (CSEBs) using a semi-automatic machine for their manufacture. An initial matrix was designed as a baseline, and three more were developed with variations to incorporate second-generation materials individually and as mixtures. The stabilizer was added in concentrations of 5, 10, and 15%, resulting in a total of 12 batches of CSEBs. Eleven of the studied batches exceed the normative limits for simple compressive strength and initial water absorption coefficient. The best result of simple compressive strength was obtained in two batches of the same matrix that used construction demolition waste (CDW), reaching 4.3 MPa (43% above the minimum limit established by the most restrictive regulations and 115% above the least restrictive). It was possible to produce sustainable bricks in situ with average ambient temperatures of 32 °C and relative humidity of 91%.

As the demand for materials continues to increase and building lifespans shorten, the construction industry faces mounting pressure to reduce its material and environmental impacts. Mismanagement of construction and demolition waste (CDW) can have severe environmental consequences. To address this, material recovery and circular economy approaches offer significant potential for reducing construction waste through the sustainable use of resources. Existing circular economy and material recovery models that prioritize recycling and reuse efforts demonstrate a sustained commitment to supporting circular practices in the construction and demolition sector. The goal is to minimize waste production, which poses environmental challenges such as raw material shortages and sustainability concerns. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement for recruiting relevant literature, this mini review aims to identify the obstacles to implementing circular economy practices in the construction industry, while exploring opportunities for material recovery and circularity. The ultimate aim is to facilitate a fair and smooth transition towards sustainable development, while addressing environmental, social and economic barriers. A more sustainable and circular approach to building construction and management can be attained by considering all the aspects of the CDW cycle, resulting in significant benefits for the environment and society as a whole. [ABSTRACT FROM AUTHOR]

Günümüzde, inşaat ve yıkım atıklarının artan miktarı nedeniyle ülke ekonomileri birçok zorlukla karşı karşıya gelmektedir. Döngüsel ekonomilerde inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerinin daha önemli rol oynaması beklenmektedir. Buna paralel olarak inşaat ve yıkım atıklarının geri dönüşümü ülkelerin rekabet gücünü doğrudan etkilemektedir. Bu çalışma inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerini gerçekleştiren işletmelerin performanslarını değerlendirmeyi amaçlamaktadır. İşletmelerin performanslarını değerlendirmek için kullanılan kriterler detaylı bir literatür taraması yapılarak belirlenmiştir. Çalışmanın alternatiflerini ise inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerini gerçekleştiren işletmeler oluşturmaktadır. Belirlenen kriterlerin ağırlıklandırılmasında Step-Wise Weight Assesment Ratio Analysis (SWARA) kullanılmıştır. Kriter ağırlıklarının belirlenmesinin ardından inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerini gerçekleştiren işletmelerin performansı Evaluation Based on Distance from Average Solution (EDAS) ile değerlendirilmiştir. Çalışmanın sonuçlarına dayalı olarak, inşaat ve yıkım atıklarının geri dönüşümünde en önemli kriter Sürdürülebilirlik olarak belirlenmiştir. Ayrıca çalışma çevresel etkiler ile inşaat ve yıkım atıklarının taşınması kriterlerinin sırasıyla diğer önemli kriterler olduğunu göstermektedir. EDAS yönteminin sonucu ise Alternatif 5 işletmesinin inşaat ve yıkım atıklarının geri dönüştürülmesi açısından en iyi performansa sahip olduğunu göstermektedir.

Smart management of construction and demolition (C&D) waste is imperative, and researchers have implemented machine learning for estimating waste generation. In Korea, the management of demolition waste (DW) is important due to old buildings, and it is necessary to predict the amount of DW to manage it. Thus, this study employed decision tree (DT)-based ensemble models (i.e., random forest—RF, extremely randomized trees—ET, gradient boosting machine—GBM), and extreme gradient boost—XGboost) based on data characteristics (i.e., small datasets with categorical inputs) to predict the demolition waste generation rate (DWGR) of buildings in urban redevelopment areas. As a result of the study, the RF and GBM algorithms showed better prediction performance than the ET and XGboost algorithms. Especially, RF (6 features, 450 estimators; mean, 1169.94 kg·m−2) and GBM (4 features, 300 estimators; mean, 1166.25 kg·m−2) yielded the top predictive performances. In addition, feature importance affecting DWGR was found to have a significant impact on the order of gross floor area (GFA) > location > roof material > wall material. The straightforward collection of features used here can facilitate benchmarking as a decision-making tool in demolition waste management plans for industry stakeholders and policy makers. Therefore, in the future, it is required to improve the predictive performance of the model by updating additional data and building a reliable dataset. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study is performed to identify environmental aspects that can be improved during the derivation of recycled aggregates (RAs) from construction and demolition waste (CDW). The Life Cycle Inventory of RAs is established by considering the "gate to gate" scope. Primary data acquired by a Brazilian CDW processing company are used. The result shows that, to derive 1 m3 of RAs, the amount of raw material (i.e., CDW) required is 1.01 to 1.67 m3. The output includes embodied energy and water measuring 2.22–4.35 MJ/m3 and 15.38–30.30 L/m3, respectively; meanwhile, the CO2 emission from the beneficiation process is 5.07–6.20 kg·CO2/m3. Transport emissions are also significant in the environmental impact of recycled aggregates. CO2 emission associated with the transport of CDW and RAs is investigated, in which transport is optimized and non-optimized when the CO2 emission is 0.27–7.68 and 0.53–15.35 kgCO2/m3, respectively. This study is relevant to the circular economy and corroborates the closure of the life cycle of materials used in the civil construction sector by identifying the effects of CDW recycling and RA derivation, as well as their application in civil construction. [ABSTRACT FROM AUTHOR]

At the present time, national economies encounter many challenges by the reason of the increasing amount of construction and demolition waste. Recycling activities of construction and demolition wastes have been anticipated to play an important role in the circular economies. Parallel to this, the recycling of construction and demolition wastes directly affects the competitiveness of countries. This study objectives to evaluate the performances of the enterprises which carry out recycling activities of the construction and demolition wastes. The criteria which are used in the evaluation of the enterprises' performances are specified with an elaborative literature search. Enterprises which are executer of the recycling activities of construction and demolition wastes form the alternatives of the study. Step-Wise Weight Assessment Ratio Analysis (SWARA) is used to weight the determined criteria. In the wake of the weighting of the criteria, performances of the enterprises, which executer of the recycling activities of construction and demolition wastes were evaluated by way of Evaluation Based on Distance from Average Solution (EDAS). Based on the consequences of the study, the most weighty criterion from the point of recycling of the construction and demolition wastes was specified to the sustainability. The study also indicates that the environmental effects and the transportation of construction and demolition wastes are specified as the other important criteria, respectively. As to EDAS method, consequences show that the Alternative 5 is the best firm in terms of recycling of the construction and demolition wastes performance. [ABSTRACT FROM AUTHOR]

One-third of the total waste generated in the world is construction and demolition waste. Reducing the life cycle of building materials includes increasing their recycling and reuse by using recycled aggregates. By preventing, the need to open new aggregate quarries and reducing the amount of construction waste dumped into landfills, the use of recycled concrete aggregate in drum compacted concrete protects the environment. Four samples of PRCC were prepared for testing (compressive strength, tensile strength, flexural strength, density, water absorption, porosity) as the reference mix and (10, 15, and 20%) of fine recycled concrete aggregate as a partial replacement for fine natural aggregate by volume. The mix is designed according to (ACI 327-15) with the specified cylinder compressive strength (28 MPa). The results showed a decrease in mechanical properties with an increase in partial replacement compared to the reference mixture and an increase in water absorption and porosity at 28 days. This is because old cement mortar on the surfaces of fine recycled concrete aggregates leads to higher porosity and water absorption than fine natural aggregates. At 90 days, results improved slightly. This is due to the non-aqueous cement in the recycled fine concrete aggregate.

This research will make an analysis of the material stock in Tungurahua-Ecuador from 2013 to 2019 using the general purpose of six "s" of Brand (1994) for site, structure, skin and space plan layers, data was taken from the Instituto Nacional de Estadisticas y Censos (INEC), from 2013 to 2019; and for the stuff layer the research applied online forms, the results show that reinforced concrete is the predominantly material used in foundation, structure and skin layers, then bricks and blocks are most common used in space plan layer and timber elements are the most used in the stuff layer, finally the paper proposes some ways to deal with this type of materials and future information to be addressed in new research. [ABSTRACT FROM AUTHOR]

The environmental conditions of sustainable improvement in manufacturing consist of the application of secondary raw materials in the design and structure of new structures. Presently, the demand to construct new structures is growing rapidly, especially in the developed world. All of the construction and demolition (C&D) waste is deposited in open landfills in easily reachable spaces, which leads to numerous environmental problems. The utilization of this waste in concrete will help in sustainable and greener development. The main goals of using waste, by-products, and recycled materials to develop sustainable concrete are to reduce carbon dioxide emissions, which are a cause of environmental pollution and climate change, and to enhance exploitation of waste, which creates problems of disposal that can be solved by completely or partially replacing concrete components. This paper aims to provide a comprehensive overview of the published literature on the replacement of cement in concrete such as rice husk ash (RHA), olive stone biomass ash (OBA), recycled coal bottom ash (CBA), and recycled palm oil fuel ash (POFA), and its effects on the characteristics of concrete like workability, density, compressive strength, splitting tensile strength, flexural strength, shrinkage, and durability. Also, this paper aims to review the impact of the replacement of cement on sustainability. The author has also included recommendations for future research. [ABSTRACT FROM AUTHOR]

This paper presents the results of research into construction and demolition (C&D) waste in Colombia. The data and analyses are shown in a local and Latin American context. As the situation in Colombia is quite similar to that in many developing countries worldwide, this research and its findings are potentially applicable to similar economies. Several factors were calculated and compared in order to evaluate which best fit the data from Colombia. We also included an experimental characterization and analysis of several key types of C&D waste from important infrastructure projects in Colombia, specifically by using the X-ray diffraction and scanning electron microscopy techniques. For the quantification of CDW, a calculation was performed based on the area and four factors of volume and density, followed by an econometric analysis of the detailed information using the Hodrick–Prescott filter, which revealed the CDW trends. Our results revealed that there are limitations regarding the availability of information and effective treatments for this waste, as well as shortcomings in education and other issues, not only for Colombia but also for other countries in Latin America. [ABSTRACT FROM AUTHOR]

Renovation is a crucial part on the urbanization drive in China. Despite it being a common practice in the country today, there is a lack on the available studies regarding the subject. Renovation itself is discussed on various architectural and engineering websites as well as the urbanization drive in China that is pushing renovation. On the other hand, the sub-practice of waste management which is crucial on the process of renovation or construction and demolition in general is not provided with much attention. Currently, there is a high percentage of construction and demolition waste all over the country which is a issue that has been neglected by researchers. This study aims to fill that gap through the use of groundedtheory and secondary data gathering. The study concluded that there are existing sustainable renovation waste management practices that could be applied to the country as a response to the lack of studies and attention to the issue of renovation waste management in the country. [ABSTRACT FROM AUTHOR]

• Construction and demolition waste is either landfilled or used for roadworks. • Recycled concrete aggregates can be reused for the construction of new buildings. • Optimisation model minimises the total costs and the mining of natural aggregates. • Concrete with recycled aggregates is viable without natural aggregates supply. • Minimum quota of recycled concrete allows to strengthen closed loop material cycle. In Germany, construction and demolition waste is either landfilled or used for roadworks after being treated in recycling plants. However, recycled concrete aggregates from building demolition can be reused for the construction of new buildings, which allows to close the material loop of concrete. The aim of this study is to develop a decision support system (DSS) in order to investigate the economic impacts and consequences of recycling concrete from building demolition in a closed loop material cycle. To do so, we propose a bi-objective mixed-integer linear optimisation model that provides information on the number and location of installed sorting screens and defines the material flows within a comprehensive regional recycling network covering all processes from building demolition to construction of new buildings. While the economic objective function minimises the total costs of the recycling network, the circularity objective function minimises the amount of primary natural aggregates required for concrete manufacturing. We apply our optimisation model to the German federal state of North Rhine-Westphalia. Results show that under current conditions the manufacturing of concrete with recycled concrete aggregates is economically viable predominantly in areas without local supplies of natural aggregates. In addition, analysis of the trade-offs between the two objectives as well as recommendations on the design of political regulations and economic instruments to foster such recycling networks are presented. [ABSTRACT FROM AUTHOR]

Construction and Demolition ( C&D ) waste constitutes a major portion of total solid waste production in the world. The main purpose of this research is to study the effect of addition of waste Yellow Clay brick powder (CBP) on the behavior of cement mortar and concrete of Grade (C25) at both conditions; fresh and hardened on the mechanical properties of concrete through by using of different partial replacement of powdered brick with cement until 100 percent by weight (0% , 5% , 10% , 15% , 20% , 25% , 50% and 100% ) to produce concrete and to reduce the impact on environment by consuming the material generally considered as waste product. The yellow clay brick was crushed and grinded manually and also sieve through 75µm sieve size in order to be fineness as cement. Cubes of size 150mm x 150mm x 150mm, Cylinders of size 300mm x 150mm and prisms of size 100mm x 100mm x 500mm were casted and tested, different ratios of waste CBP have been used to study its effect on the workability (slump flow), compressive strength and splitting tensile strength for 7, 14 and 28 days; and the modulus of rupture for 28 days. The results compared with the reference specimens and study the relationship between the mechanical properties of concrete.

The construction and public work sectors are faced with a series of challenges that will need to be addressed in moving towards an effective circular economy model. The aim of this work was to develop a simple but holistic approach to the management of construction projects in order to ensure compliance with technical standards and environmental criteria right from the set-up phase and to foster an increased use of recycled materials and saving of natural resources. To achieve this goal, a multi-user platform was designed and developed to manage and control all stages and procedures of public work and provide support to all those involved throughout the various stages of implementation. The platform included (1) technical standards; (2) environmental law; (3) databases; (4) technical specifications for public tenders; (5) a tool to assess environmental impacts and circularity; (6) a marketplace to facilitate and transparently manage trading of natural, artificial, and recycled aggregates; (7) interactive catalogues with declarations of building products; and (8) interactive maps for the geolocation of treatment plants, producers, and construction sites. The platform, currently undergoing validation by public administrations, will represent a valuable tool for use in enabling public work contractors to reduce environmental impacts, promote an informed and transparent use of recycled products, and to encourage a more sustainable use of natural resources. The platform will facilitate the application of green public procurement (GPP) which, although mandatory in several countries (e.g., in Italy), continues to encounter a series of problems in implementation. The platform will also enhance compliance with technical standards and minimum environmental criteria (MEC), as recently defined for buildings and road construction and maintenance, thus expanding the market for artificial and recycled aggregates with certified products and guaranteed quality. [ABSTRACT FROM AUTHOR]

Construction materials are considerable forces of global environmental impacts, but their dynamics vis‐à‐vis urban development are poorly documented, in part because their long lifespans require elusive and sometimes nonexistent decade‐long high‐resolution data. This study analyzes the construction material flow and stock trends that shaped and were shaped by the development, decline, and renewal of the Tiexi district of Shenyang, a microcosm of China's urban transformations since the early 20th century. Chronicling building‐by‐building the material flows and stock accumulations involved in the buildup of this area, we shed light on the physical resource context of its socioeconomic history. We find that 42 million tonnes of construction materials were needed to develop the Tiexi district from 1910 to 2018, and 18 million tonnes of material outflows were generated by end‐of‐life building demolition. However, over 55% of inflows and 93% of outflows occurred since 2002 during a complete redevelopment of the district. Only small portions of end‐of‐life materials could have been reused or recycled because of temporal and typological mismatches of supply and demand and technical limitations. Our analysis reveals a dramatic decrease in median building lifetimes to as low as 6 years in the early 21st century. These findings contribute to the discussion of long‐term environmental efficiency and sustainability of societal development through construction and reflect on the challenges of urban renewal processes not only in China but also in other developing and developed countries that lost (or may lose) their traditional economic base and restructure their urban forms. This article met the requirements for a Silver/Silver JIE data openness badge described at http://jie.click/badges. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to identify and evaluate the advantages and the obstacles of C&D (Construction and Demolition) waste management in UAE (United Arab Emirates). A mixed research methodology was used to identify and evaluate the advantages and barriers facing C&D waste management in the UAE. The qualitative method reflects collecting a review of published literature from peer-reviewed journals on C&D waste as well as from the conducted unstructured interview. The quantitative portion of the study was a questionnaire using a multiple-choice questionnaire and a five scale Likert-style ratings for quantifying the results. The adoption of sustainable methods for waste minimisation on construction sites in the UAE looks positive. The profile of the UAE construction sector has radically changed during the last two decades. The sharing of knowledge and a culture of cooperation on construction sites are highly needed currently. The research could be presented in much stronger base analysis if it was based on a case study with the UAE local market. However, organizations are very much reluctant to offer such data due to the sensitivity of the matter. [ABSTRACT FROM AUTHOR]

• Eleven PFAS species were measured in landfill leachates along with pH and COD. • Leachates from ash landfills had lower levels of PFAS relative to MSW/C&D landfills. • PFAS from ash landfills was correlated with temperatures used to generate the ash. • Treatment of MSW leachate at 1 site resulted in increased levels of carboxylated PFAS. Per- and polyfluoroalkyl substances (PFAS) are found in many consumer products which will be ultimately disposed in landfills. Limiting environmental contamination and future exposures will require managing leachates from different types of landfills, each with different PFAS levels depending upon the source of the waste. The objective of this study was to evaluate the influence of waste type and on-site treatment on PFAS levels in landfill leachates. Eleven PFAS species (7 carboxylic acids, 3 sulfonic acids, and 5:3 fluorotelomer carboxylic acid) were evaluated in leachates from municipal solid waste (MSW), construction and demolition (C&D), MSW ash (MSWA), and a mixture of MSWA and MSW with landfill gas condensate (MSWA/MSW-GC). Leachates were also analyzed before and after on-site treatment at two of these facilities. Results indicate that MSWA leachate had significantly lower PFAS levels relative to other leachate types. Lower total PFAS concentrations in MSWA leachates were correlated with an increase in incineration temperature (R2 = 0.92, p = 0.008). The levels of PFAS in untreated C&D and untreated MSW leachate were similar. The levels of targeted PFAS species in MSW leachate for one of the facilities evaluated increased after on-site landfill treatment presumably due to the conversion of PFAS precursors in the untreated leachate sample. [ABSTRACT FROM AUTHOR]

The Sudokwon landfill site in Korea, is one of the largest landfill sites in the world, and consists of a first landfill site and second landfill site. The second landfill site generates 3–30 times more H2S than that of the first landfill site. However, the cause of the increase in H2S has not been identified. In this study, the main causes of H2S concentration increase were investigated in the second landfill site in the Sudokwon landfill site. We classified wastes at the Sudokwon landfill site into seven types including Construction and demolition (C&D) debris waste. A lysimeter reactor was designed as a similar environment to the Sudokwon landfill site for simulation. In addition, the experiment was conducted under the same conditions. Three components and elements were analyzed to identify the composition of waste in the landfill site. Leachate was analyzed through a chemical oxygen demand and SO42− standard method. For landfill gas, a gas analyzer was used. The trend in the generation of leachate and landfill gas depending on waste composition at the landfill site was observed and the cause of the increase in H2S was examined. As a result, landfilling of C&D debris waste is recommended as a single landfill. [ABSTRACT FROM AUTHOR]

In Sri Lanka, the management of Construction & Demolition (C&D) waste poses a major problem, leading to environmental degradation and depletion of resources. This study aims to tackle these issues by examining the implementation of Circular Economy (CE) strategies within the construction industry of Sri Lanka. The focus is on reducing waste generation and maximizing resource utilization during the demolitions and repurpose, as well as material recovery and production stages of the building project life cycle. These stages are crucial in terms of waste generation and resource consumption. A qualitative approach was employed in this research, utilizing the Delphi technique to gather insights through a series of three rounds of expert interviews. In the first round, 17 experts were involved, followed by 15 in the second round, and 12 in the final round. The data collected from these interviews were analysed using manual content analysis methods. Based on the research findings, a total of 14 C&D Waste Management (WM) issues were identified specifically in the Demolitions and Repurpose Stage in Sri Lanka. For each issue, suitable strategies were proposed to overcome them effectively. Furthermore, the study examined the impact of CE strategies on minimizing these issues within the context of the project management iron triangle. Similarly, the Material Recovery and Production Stage of the building presented eight C&D WM issues, each accompanied by corresponding strategies to address them. The research also explored the influence of CE strategies in mitigating these issues, considering the project management iron triangle. During the demolitions and repurpose stage, CE strategies focus on reducing waste generation and optimizing resource utilization. This involves carefully deconstructing buildings to salvage and recover materials that can be reused or repurposed., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract The Kingdom of Saudi Arabia's (KSA) population growth has demanded that the country expand its housing and infrastructure inventory inevitably resulting in an accumulation of construction and demolition waste (C&D) that has the potential for the promotion of environmentally sound waste management practices. Prior to implementing best practices in the region, there is an impending need to first understand C&D generation in the KSA. This study investigated the current challenges for managing C&D debris in the Eastern Province region in Saudi Arabia. Likewise, it provided a roadmap and solution to manage C&D debris in relation to existing legislations and generation of C&D debris. A review of existing regulations governing C&D was conducted through the use of interviews held with relevant governmental and technical officials, over 200 surveys were administered to academic, governmental and industrial stakeholders. Data was collected from a landfill to help quantify the amount of C&D flowing through the Kingdom's Eastern Province and construction sites were observed to better understand how waste generators were disposing of C&D. Based on assessment of C&D waste generation, regulation and management policies, major issues were revealed that included: (i) lack of institution collaboration (academic, governmental and private sectors), (ii) immature strategic policies for effective C&D management and recycling, (iii) limited coordination among C&D regulators and generators, (iv) lack of motives, awareness and incentives to manage C&D, (v) lacking enforceable law for debris generators (vi) improper infrastructure for disposal of landfills and absence of treatment facilities and (vii) no suitable plan of sustainable management of landfills. C&D management can be effectively grouped by considering three major factors, mainly: (i) economic, (ii) regulatory, and (iii) technical factors. The key points include "promoting C&D waste recycling", "encouraging adoption of recycled materials to construction industry", "enforcing regulations to prohibit illegal dumping", and "landfill disposal and recycling fees for debris generators". Several other factors are also proposed and discussed within the framework of this research. Finally, potential avenues by which environmentally sound construction and demolition waste management practices can be imported for use within Saudi Arabia's unique geographical and cultural climate were introduced as a roadmap containing alternative solutions for C&D management. Highlights • Identifying challenges, roadmap and solutions for managing C&D debris in eastern province, Saudi Arabia. • Review of legislation and administered interviews, emails, surveys with C&D waste management stakeholders. • Major issues including but not limited to: lack of institution collaboration, effective policies, recycling systems. • Key solution includes: enforcement of C&D waste recycling, adoption of recycled materials, prohibit illegal dumping. [ABSTRACT FROM AUTHOR]

This paper investigates using recycling and demolition waste from the Euphrates Basin in eastern Syria as concrete aggregate. The recycled aggregate samples were tested in comparison to natural river ones. Samples from governmental buildings and normal housing units (including lean concrete, white and black brick, and mixed brick with ceramic) were selected and tested individually in order to determine their properties. Normal Portland cement was used (350 kg/m3, watercement ratio 0.5 and tap water). The recycled building material was ground into various combinations of coarse and fine recycled aggregates. Natural aggregates were also used for comparison. The concrete was casted into cubes for up to 28 days and monitored under continuous curing in tap water. The cube compressive strength of the concrete made from recycled aggregate types ranged from 24 to 30 MPa. Comparing natural and recycled aggregate values showed similar results, except for the sample obtained from reinforced concrete taken from normal housing buildings, where the cube compressive strength value exceeded 6%. The compressive strength of concrete that made from other recycled aggregate types reached 90% of the natural one, which was 28.49 MPa in the natural samples. In addition, abrasion test values varied between 29.55% to 44.36%. Results showed that recycled concrete aggregates produced from construction and demolition waste in Euphrates Basin, Syria can be used in concrete works. [ABSTRACT FROM AUTHOR]

The Sudokwon landfill site in Korea, is one of the largest landfill sites in the world, and consists of a first landfill site and second landfill site. The second landfill site generates 3−30 times more H2S than that of the first landfill site. However, the cause of the increase in H2S has not been identified. In this study, the main causes of H2S concentration increase were investigated in the second landfill site in the Sudokwon landfill site. We classified wastes at the Sudokwon landfill site into seven types including Construction and demolition (C&D) debris waste. A lysimeter reactor was designed as a similar environment to the Sudokwon landfill site for simulation. In addition, the experiment was conducted under the same conditions. Three components and elements were analyzed to identify the composition of waste in the landfill site. Leachate was analyzed through a chemical oxygen demand and SO42− standard method. For landfill gas, a gas analyzer was used. The trend in the generation of leachate and landfill gas depending on waste composition at the landfill site was observed and the cause of the increase in H2S was examined. As a result, landfilling of C&D debris waste is recommended as a single landfill.

Naturally-occurring uranium can be found at elevated concentrations in groundwater throughout the world, with the potential to cause kidney damage in chronically exposed individuals. Empirical evidence shows that uranium mobilization can be enhanced in the presence of ions that are associated with leachate from construction and demolition (C&D) disposal sites. There is need for a simple and effective procedure to evaluate soil and rock formations for uranium mobility prior to the permitting of waste disposal facilities which could alter groundwater chemistry. A series of leachate extractions were performed to represent the impact of C&D leachate on uranium-bearing rocks, focusing on the impact of calcium, sodium, chloride, sulphate, and bicarbonate concentrations on uranium mobilization. Based on these observations a uranium leaching procedure (ULP) was developed and compared to the synthetic precipitation leaching procedure (SPLP). The ULP was capable of mobilizing an order of magnitude more uranium than the SPLP from six rock samples and shows promise as a tool for assessing the risk of groundwater contamination by C&D waste through uranium mobilization. [ABSTRACT FROM AUTHOR]

Promoting recycled aggregates from construction and demolition (C&D) waste for producing concrete will reduce the demand on conventional aggregates and it is an alternative to effectively manage C&D waste. Application of recycled C&D aggregates as a substitute to conventional aggregates in low strength concretes is the best way to initiate this in the industry. Therefore, this study focused on investigating the strength properties and the influence of time on the behaviour of strength gaining of concrete elements made by mixing the conventional aggregates and recycled C&D aggregates. The grade of the concrete was 25. The research methodology involved replacing the conventional coarse aggregates partially with 0 %, 20 %, 40 % and 60 % recycled C&D aggregates in concrete mixtures. Test cubes were cast for each percentage of the materials and other conditions were kept as constants. The test cubes were then subjected to compressive strength test under three test series. The test series were focused on different curing periods of the specimens as 7, 28 and 90 days to determine the behaviour of strength gaining with time. The conclusion drawn from the study is that it is feasible to substitute up to 40 % of coarse aggregates by recycled C&D aggregates in conventional low-intermediate strength concrete applications with the specified mix design. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering & Sustainable Development is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As construction increases through a rise in development in Vietnam, the environmental performance of recycling construction and demolition waste is not well documented. This paper addresses this lack of knowledge, by mapping the current recycling system and estimating recycling performance of a key component in construction and demolition waste in Vietnam, concrete. Primary data were collected directly from six Vietnamese construction enterprises involved in the life cycle of construction and demolition waste management. The results indicated that potential net environmental benefits exist for all impact categories examined if a mechanised plant were considered. Moreover, construction demolition waste may then be used for more permanent applications such as building foundations and in new building materials. The results confirm benefits to technological advancements in concrete recycling in the construction demolition waste sector. Fostering investment and interest in such strategies could be achieved by imposing clear and consistent construction demolition waste classifications, establishing clear lines of responsibility, and coordinating activities amongst key stakeholders to promote the benefits of concrete recycling. These findings consolidate the need of further research in Vietnam and other developing nations, where more detailed life cycle inventory development and stakeholder engagement could help. Then better environmental outcomes through the concrete recycling management may be delivered. [ABSTRACT FROM AUTHOR]

In this paper, a circular-economy framework is applied to the prefabricated building sector to explore the environmental advantages of prefabrication in terms of reduction, reusability, adaptability, and recyclability of its components. A qualitative approach is used to revisit the design, construction, and demolition stages of prefabricated buildings; in so doing, the circular-economy framework is applied to foster circular prefabricated modi operandi. Prefabrication of buildings can be divided into four entities: elements and components, panels (or non-volumetric elements), volumetric, and entire modules. Through an analysis of published research on how the circular economy can be applied to different industry sectors and production processes, seven strategies emerged, each of which revealed the potential of improving the circular economy of buildings. The first strategy is reduction of waste through a lean production chain. By reusing the waste, the second strategy investigates the use of by-products in the production of new components. The third strategy focuses on the reuse of replacement parts and components. The fourth strategy is based on design toward adaptability, respectively focusing on reusability of components and adapting components for a second use with a different purpose. Similarly, the fifth strategy considers the implications of designing for disassembly with Building Information Modeling so as to improve the end-of-life deconstruction phase. The sixth strategy focuses on design with attention to recyclability of used material. Finally, the seventh strategy considers the use of tracking technologies with embedded information on components’ geometric and mechanic characteristics as well as their location and life cycle to enable second use after deconstruction. It is demonstrated that prefabricated buildings are key to material savings, waste reduction, reuse of components, and various other forms of optimization for the construction sector. By adopting the identified strategies in prefabricated buildings, a circular economy could be implemented within the construction industry. Finally, seven guidelines were distilled from the review and linked to the identified strategies. Owing to their degree of adaptability and capacity of being disassembled, prefabricated buildings would allow waste reduction and facilitate a second life of components.

The main objective of this research is to investigate the utilization criteria of the recycled aggregates gained from construction and demolition wastes, in the production of various ready-mixed and precast concrete elements. Within this scope, construction and demolition waste materials were selectively separated to have homogeneous concrete wastes in the recycling plant. Then, fine and coarse aggregates were achieved from concrete wastes. Recycled concrete aggregates were than crushed to specific sizes; physical properties were determined and compared with those of normal aggregates. Finally, these recycled aggregates were investigated about their utility in the industrial production of various concrete products like ready-mixed concrete, concrete pipe, paving stone and kerbs. Also some studies were done to determine durability and permeability properties of these products. It can be concluded that the use of recycled aggregates in the production of various concrete elements is possible with proper separation and classification. Moreover, lower replacement rates should be applied to obtain sufficient conditions which are specified in related product standards. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to focus on the identification of the existing capacities of post disaster C & D waste management in developing countries, with a special emphasis on Sri Lanka to determine the capacity gaps and related influencing factors. Design/methodology/approach – Multiple case studies and expert interviews were conducted to gather primary information on the existing capacities of disaster C & D waste management. Three case studies, including 15 individuals and six experts representing government, non-government institutions and others, were selected. Findings – The results revealed the existing capacities, capacity gaps and influencing factors for post disaster C & D waste management in the areas of skills and confidence building, links and collaborations, continuity and sustainability, research and development, communication and coordination, organisational implementation and investment in infrastructure. Research limitations/implications – This study limited disaster C & D waste to debris generated from totally or partially damaged buildings and infrastructure as a direct impact of natural disasters or from demolished buildings and infrastructure at rehabilitation or at early recovery stages. Originality/value – The research enabled an analysis of existing capacities and identified capacity gaps in post disaster C & D waste management with influencing factors developing countries. [ABSTRACT FROM AUTHOR]

Abstract: While concrete recycling is practiced worldwide, there are many unanswered questions in relation to ultrafine particle (UFP; D p < 100 nm) emissions and exposure around recycling sites. In particular: (i) Does recycling produce UFPs and in what quantities? (ii) How do they disperse around the source? (iii) What impact does recycling have on ambient particle number concentrations (PNCs) and exposure? (iv) How effective are commonly used dust respirators to limit exposure? We measured size-resolved particles in the 5–560 nm range at five distances between 0.15 and 15.15 m that were generated by an experimentally simulated concrete recycling source and found that: (i) the size distributions were multimodal, with up to ∼93% of total PNC in the UFP size range; and (ii) dilution was a key particle transformation mechanism. UFPs showed a much slower decay rate, requiring ∼62% more distance to reach 10% of their initial concentration compared with their larger counterparts in the 100–560 nm size range. Compared with typical urban exposure during car journeys, exposure decay profiles showed up to ∼5 times higher respiratory deposition within 10 m of the source. Dust respirators were found to remove half of total PNC; however the removal factor for UFPs was only ∼57% of that observed in the 100–560 nm size range. These findings highlight a need for developing an understanding of the nature of the particles as well as for better control measures to limit UFP exposure. [Copyright &y& Elsevier]