Life cycle assessment of the end-of-life phase of a residential building

Artificial intelligence and machine learning applications in the project lifecycle of the construction industry: A comprehensive review

The construction industry faces many challenges, including schedule and cost overruns, productivity constraints, and workforce shortages. Compared to other sectors, it lags in digitalization in every project phase. Artificial Intelligence (AI) and Machine Learning (ML) have emerged as transformative technologies revolutionizing the construction sector. However, a discernible gap persists in systematically categorizing the applications of these technologies throughout the various phases of the construction project life cycle. In response to this gap, this research aims to present a thorough assessment of the deployment of AI and ML across diverse phases in construction projects, with the ultimate goal of furnishing valuable insights for the effective integration of these intelligent systems within the construction sector. A thorough literature review was performed to identify AI and ML applications in the building sector. After scrutinizing the literature, the applications of AI and ML were presented based on a construction project life cycle. A critical review of existing literature on AI and ML applications in the building industry showed that AI and ML applications are more frequent in the planning and construction stages. Moreover, the opportunities for AI and ML applications in other stages were discussed based on the life cycle categorization and presented in this study. The practical contribution of the study lies in providing valuable insights for the effective integration of intelligent systems within the construction sector. Academically, the research contributes by conducting a thorough literature review, categorizing AI and ML applications based on the construction project life cycle, and identifying opportunities for their deployment in different stages.

From circular strategies to actions: 65 European circular building cases and their decarbonisation potential

The application of the circular economy (CE) in the building industry is critical for achieving the carbon reduction goals defined in the Paris Agreement and is increasingly promoted through European policies. In recent years, CE strategies have been applied and tested in numerous building projects in practice. However, insights into their application and decarbonisation potential are limited. This study analysed and visualised 65 novel real-world cases of new build, renovation, and demolition projects in Europe compiled from academic and grey literature. Cases were analysed regarding the circular solution applied, level of application in buildings, and decarbonisation potential reported, making this study one of the first comprehensive studies on the application and decarbonisation potential of circular strategies in the building industry in practice. The identified challenges of using LCA for CE assessment in buildings are discussed and methodological approaches for future research are suggested.

Physico-Mechanical Performances of Mortars Prepared with Sorted Earthquake Rubble: The Role of CDW Type and Contained Crystalline Phases

Construction and demolition waste (CDW) from earthquake rubbles was used here as recycled aggregates (RA) in cementitious binders. The materials were sorted in six groups: concrete (CO), natural stone (NS), tile (TI), brick (BR), perforated brick (PF) and roof tile (RT). The abundance (wt.%) of crystalline phases in each RA type was determined by X-ray Powder Diffraction (XRPD). Each group of RAs was used alone (100 wt.% of RA) and mixed with quartz-rich virgin aggregates (VA) to prepare 13 types of mortars (12 specimens per type): one reference mortar (RM) with only VA, six recycled aggregate mortars (RAM) and six recycled-plus-virgin aggregate mortars (RVAM). The physical and mechanical properties of aggregates and mortars reflect the type and abundance of crystalline phases in each CDW group. Recycled mortars rich in concrete, natural stones and tiles have better mechanical performance than mortars prepared with recycled bricks, perforated bricks and roof tiles. For each RA, RVAMs have superior mechanical characteristics than the corresponding RAM. Since the type and amount of phases contained in recycled aggregates strongly control the mechanical performance of new construction materials, they should be routinely quantified as reported here, in addition to other physical features (water absorption, density, etc.). The separation of heterogeneous CDW into homogeneous RA groups is necessary for the production of new construction materials with stable and predictable performances to ensure CDW recycling, especially in areas hit by major adverse events, where large amounts of still valuable materials could be used for reconstruction processes.

From prospecting to mining: A review of enabling technologies, LCAs, and LCCAs for improved construction and demolition waste management

Knowledge gained from anthropogenic resource prospecting can shed light on the theoretical potential of secondary resources stored in anthropogenic systems. Among others, secondary resources accumulated in the built environment account for a big fraction of anthropogenic resources, indicating great potential for urban mining. However, realizing these opportunities and developing urban mining strategies will require a comprehensive understanding of the technical viability of urban mining technologies, and how their implementation will affect the technical, economic, and environmental performance of a construction and demolition waste (C&DW) management system. To address these important issues, this review summarizes (1) current and emerging technologies that can enable the transition from anthropogenic resource prospecting to anthropogenic resource mining, (2) Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) results to date on various C&DW management systems, (3) key parameters that govern the technical, economic, and environmental performance of a C&DW management system, and (4) opportunities for improving the methodology of LCAs and LCCAs for future C&DW management. We find that enhancing the utility of extant LCAs and LCCAs in guiding technology deployment and policy decisions can be achieved by considering key parameters governing the techno-economic and environmental performance of C&DW management. In addition, it is critical to adopt and upscale emerging technologies to increase the added value of materials or products recovered from C&DW.

Life Cycle Assessment of Construction and Demolition Waste Management in Riyadh, Saudi Arabia

Extensive construction augmenting the infrastructure and real estate projects underpin Saudi Arabia’s Vision 2030 of sustainable cities. A part of this struggle involves the transformation of the existing infrastructure together with new construction, which generates a large amount of construction and demolition waste (CDW). In the absence of a structured life cycle assessment (LCA) framework, the waste management companies are planning future scenarios (phased expansions of material recovery facilities to improve the recycling rate) primarily on economic grounds. This study assesses the environmental impacts of the existing and planned CDW management practices of the Saudi Investment Recycling Company in Riyadh City by dint of LCA. Impact 2002+ performs life cycle impact assessment of the base case (45% recycling), four treatments (61, 76, 88, and 100% recycling), and zero waste scenarios. The study demonstrates the benefits of current CDW (mixed soil, concrete blocks, clay bricks, glazed tiles, and asphalt) recycling in terms of avoided impacts of non-renewable energy, global warming, carcinogens, non-carcinogens, and respiratory inorganics potentially generated by landfilling. For the treatment scenario of 100% recycling, CDW conversion into a wide range of aggregates (0–50 mm) can replace 10–100% virgin aggregates in backfilling, precast concrete manufacturing, encasements and beddings of water mains and sewers, manholes construction, non-load bearing walls, and farm-to-market roads. To achieve long-term economic and environmental sustainability, municipalities need to improve source segregation, handling, and storage practices to enhance the existing (45%) recycling rate to 100% in the next five years and approach the zero-waste scenario by 2030. The findings of the present study motivate the generators for source reduction as well as encourage the recycling companies and concerned organizations in the continuous performance improvement of the CDW management systems across Saudi Arabia on environmental grounds, as an addition to the perceived economic benefits.

Spatiotemporal evolution law and output prediction of construction waste in the People's Republic of China

Based on the relevant data of construction waste (CW) in the People's Republic of China (PRC) from 2010 to 2018, this study applied K-means clustering algorithm and grey prediction methods to systematically investigate the spatiotemporal characteristic distribution and provincial clustering of CW in the PRC, and predicted the annual output of CW in the next five years from the scientific perspective. Results showed that the annual output of CW in the PRC displayed an overall trend of "rising first and then falling" and "being high in the middle east and low in the northwest," and the areas with obvious agglomeration gradually spread from the west to the middle and eastern regions. The law of development was consistent with the goals of the Chinese government to promulgate urban agglomeration development policies, prefabricated building encouragement policies, and CW management regulations. In the next five years, the annual output of CW in the PRC will increase by a small margin. Thus, all aspects of CW resource management should be conducted in a planned and step-by-step manner.

Cost-benefit analysis of demolition waste management via agent-based modelling: A case study in Shenzhen

The economic instrument is an effective approach to encourage demolition contractors to conduct low-impact waste management. It is essential for project managers and decision-makers to better understand the cost-benefit of demolition waste (DW) management, to promote development of an effective waste management plan. This study explores the interactive dynamics and adaptive nature between stakeholders, where the cost-benefit of DW management is analysed through the agent-based modelling approach. Shenzhen, a leading city in China in the management of DW, was selected as the study area. It was revealed that if the traditional demolition method is adopted as the primary choice, the net benefit of demolition of buildings in the study case will reach -131.4 billion yuan, i.e. the cost will surpass the revenue. If the selective demolition method is widely used by demolition contractors, simulation results indicate that the net benefit will reach 33.3 billion yuan, an increase of 125.34%, compared to the situation in which the traditional demolition method is widely implemented. Based on the simulation, an optimal management framework for DW management stakeholders was constructed. The research results can provide a decision-making basis for the government and relevant departments to formulate DW management measures.

Petrography of construction and demolition waste (CDW) from Abruzzo region (Central Italy)

The density, colour and texture, plus mineral and chemical features of 18 ceramic-like CDW samples from the Abruzzo region (Central Italy) were characterised. The concretes, natural stones, tiles, roof-tiles, bricks and perforated bricks are either aphanitic to porphyric. Concretes and natural stones are grey to white and tend to be > 2.0 g/cm³; the masonries are brown to reddish and close to < 2.0 g/cm³. Concrete and natural stone are rich or even exclusively made up of calcite, with high amounts of CaO (>40 wt%) and LOI (volatiles, CO₂ + H₂O). The masonries are instead calcite-, CaO- (<25 wt%) and LOI-poor (<8 wt%) but enriched in SiO₂ (45 to 70 wt%) stabilised as quartz and/or cristobalite, with significant amount of Al₂O₃ (12 to 20 wt%). S and Cl contents are similar among concrete, bricks and perforated bricks. The petrography of CDW concretes is similar among geographical areas with abundance of limestones used as aggregates. However, in limestone-poor areas CDW are SiO₂- and Al₂O₃-rich, reflecting the prevalent use of masonry and/or silicate-rich construction materials, implying that each geographical area is characterised by peculiar CDW composition. Therefore, the knowledge of mesoscopic, physical and petrographic aspects has to be known for planning adequate sorting methods, promoting upcycling reusing applications. Some of the studied CDW samples are susceptible to release relative high Cr and As content.

Potential Energy Savings from Circular Economy Scenarios Based on Construction and Agri-Food Waste in Italy

In this study, our aim was to explore the potential energy savings obtainable from the recycling of 1 tonne of Construction and Demolition Waste (C&DW) generated in the Metropolitan City of Naples. The main fraction composing the functional unit are mixed C&DW, soil and stones, concrete, iron, steel and aluminium. The results evidence that the recycling option for the C&DW is better than landfilling as well as that the production of recycled aggregates is environmentally sustainable since the induced energy and environmental impacts are lower than the avoided energy and environmental impacts in the life cycle of recycled aggregates. This LCA study shows that the transition to the Circular Economy offers many opportunities for improving the energy and environmental performances of the construction sector in the life cycle of construction materials by means of internal recycling strategies (recycling C&DW into recycled aggregates, recycled steel, iron and aluminum) as well as external recycling by using input of other sectors (agri-food by-products) for the manufacturing of construction materials. In this way, the C&D sector also contributes to realizing the energy and bioeconomy transition by disentangling itself from fossil fuel dependence.

Environmental Impacts and Benefits of the End-of-Life of Building Materials: Database to Support Decision Making and Contribute to Circularity

This paper outlines a methodology for structuring a generic database of environmental impacts on the end-of-life phase of buildings, which can be used at the national level, in accordance with European standards. A number of different options are also considered for managing construction and demolition waste (CDW), as well as for promoting the circularity of materials in construction. The database structure has been developed for use by the main stakeholders who decide the disposal scenario for the main CDW flows, assess waste management plans, and identify the corresponding environmental aspects. The impact categories considered in this paper are global warming potential (GWP) and the abiotic depletion potential of fossil fuels (ADP (f.f.)). This lifecycle assessment (LCA) database further facilitates the identification of important information, such as possible treatments for CDW, or suppliers of recycled materials for use in new construction. Two demolition case studies were used to confirm the benefits of the proposed database. Two demolition scenarios are assessed—traditional and selective—in order to demonstrate the advantage of selective demolition in waste management. The results obtained from the environmental assessment of CDW flows demonstrate that the proposed database can be an important and useful tool for decision making about the end-of-life of construction materials, as it is designed to maximize their reuse and recycling. An innovative online platform can be created based on this database, contributing to the reduction of the environmental impacts associated with the end-of-life phase of buildings.

A building information modeling-based tool for estimating building demolition waste and evaluating its environmental impacts

The amount of building demolition waste produced in China is large, and waste treatment processes discharge many pollutants. Pre-evaluating waste's environmental damage at the design stage of building projects could provide an opportunity to understand and minimize potential environmental impacts. Tools that can conveniently estimate the amount of demolition waste and quantify its impacts are lacking. This study combines building information modeling (BIM), geographic information system (GIS), and life cycle assessment (LCA) to develop an estimation and evaluation system for building demolition waste. In this system, BIM digitizes the specific characteristics of the evaluated buildings and provides geometric and semantic information for waste estimation. GIS offers geographic information regarding waste treatment plants and landfill site, and is used to design waste transportation routes. LCA provides an environmental impact assessment framework and quantifies ecological damage impacts and resource depletion impacts due to demolition waste. The system includes five modules, which form the basis of an automated calculation tool. The evaluation tool can quickly quantify the amount of waste and assess its impacts, while achieving automated waste estimation and impact evaluation after a building is designed. A building in a middle school is taken as a case study to demonstrate and verify the system. This study provides an operable tool for waste evaluation and management at the design stage. With the increasing application of BIM technology in the construction industry, this tool is expected to gain popularity and promote efficient waste management.

Life Cycle Assessment on Construction and Demolition Waste: A Systematic Literature Review

Life Cycle Assessment (LCA) is considered an innovative tool to analyze environmental impacts to make decisions aimed at improving the environmental performance of building materials and construction processes throughout different life cycle stages, including design, construction, use, operation, and end-of-life (EOL). Therefore, during the last two decades, interest in applying this tool in the construction field has increased, and the number of articles and studies has risen exponentially. However, there is a lack of consolidated studies that provide insights into the implementation of LCA on construction and demolition waste (C&DW). To fill this research gap, this study presents a literature review analysis to consolidate the most relevant topics and issues in the research field of C&DW materials and how LCA has been implemented during the last two decades. A systematic literature search was performed following the PRISMA method: analysis of selected works is based on bibliometric and content-based approaches. As a result, the study characterized 150 selected works in terms of the evolution of articles per year, geographical distribution, most relevant research centers, and featured sources. In addition, this study highlights research gaps in terms of methodological and design tools to improve LCA analysis, indicators, and connection to new trending concepts, such as circular economy and industry 4.0.

An LCA-based model for assessing prevention versus non-prevention of construction waste in buildings

Waste generated by the Construction Sector represents an environmental problem in many countries. To achieve increasingly eco-efficient waste management, Life Cycle Assessment (LCA) provides an objective method for the quantification of the potential impact that waste management exerts on the environment. Traditionally, LCA has focused on the evaluation of non-prevention scenarios once the waste is generated, mainly by showing the benefits of recycling vs. disposal. Consequently, the literature has hardly addressed the positive environmental impacts caused by waste prevention, that is, the reduction at source, which constitutes the preferred option of any waste management hierarchy. Therefore, this study proposes a model to simulate the environmental performance of the prevention vs. the non-prevention of construction waste production. The model is applied to an urban system of residential buildings in Spain. The results provide evidence of the environmental benefits achieved with the prevention scenario. The prevention scenario reduces the construction waste generated in the non-prevention scenarios by up to 57%. Furthermore, it allows a potential reduction of up to 4.6 and 171.1 times the impact caused by the disposal scenario; and up to 1.7 and 8.3 times those of the recycling scenario. The model can be implemented in other contexts with other reference buildings, and enables the environmental benefits of reduction strategies to be studied, thereby providing a tool to guide and support decision-making during the building design stage. Moreover, the results obtained can help professionals and policymakers to incorporate effective construction waste prevention measures in waste prevention plans and programs.

Are LCA Studies on Bulk Mineral Waste Management Suitable for Decision Support? A Critical Review

Bulk mineral waste materials are one of the largest waste streams worldwide and their management systems can differ greatly depending on regional conditions. Due to this variation, the decision-making context is of particular importance when studying environmental impacts of mineral waste management systems with life cycle assessment (LCA). We follow the premise that LCA results—if applied in practice—are always used in an improvement (i.e., decision-making) context. But how suitable are existing LCA studies on bulk mineral waste management for decision support? To answer this question, we quantitatively and qualitatively assess 57 peer-reviewed bulk mineral waste management LCA studies against 47 criteria. The results show inadequacies regarding decision support along all LCA phases. Common shortcomings are insufficient attention to the specific decision-making context, lack of a consequential perspective, liberal use of allocation and limited justification thereof, missing justifications for excluded impact categories, inadequately discussed limitations, and incomplete documentation. We identified the following significant issues for bulk mineral waste management systems: transportation, the potential leaching of heavy metals, second-order substitution effects, and the choice to include or exclude avoided landfilling and embodied impacts. When applicable, we provide recommendations for improvement and point to best practice examples.

Possibilities of disposing silica fume and waste glass powder, which are environmental wastes, by using as a substitute for Portland cement

In this study, the possibilities of disposal of environmental waste, silica fume, and waste glass powder as substitutes in the mortar samples in Portland cement were investigated. For this purpose, Portland cement (CEM I), silica fume (SF), waste glass powder (WGP), CEN standard sand, and water were used in mortar production. Additive cements were obtained by using the SF, WGP, and SFWGP substitution methods in Portland cement at the rates of 10, 20, 30, and 40%. The flexural strength, compressive strength, radiation permeability (determination of linear absorption coefficient), high temperature, and alkali-silica reaction (ASR) effect on SF, WGP, and SFWGP were examined and compared with the control PC 42.5R samples. Mortar samples of 40 × 40 × 160 mm size were obtained with the grouts/mortars produced, and the samples were exposed to five temperature effects, namely, 20, 150, 300, 700, and 1000 ° C. Samples kept at 20 ° C are accepted as baseline. A total of 429 samples were studied, including the cooling process in the air (spontaneously in the laboratory, 20 ° C ± 2). After the samples achieved room temperature, flexural and compressive strength tests were carried out at 28 and 90 days. Test results demonstrate that SF, WGP, and SFWGP, which are environmental wastes, can be disposed both as a pozzolanic additive material both alone and together in cement mortars, can be utilized in buildings with high fire hazard, and the sample with the highest linear absorption coefficient is the sample obtained with SFWGP, and also, the expansion values ​​that occur in SF and WGP are less than the control sample.

Sustainability in Building and Construction within the Framework of Circular Cities and European New Green Deal. The Contribution of Concrete Recycling

Climate change and ecological crisis are a huge threat to Europe and the world. To overcome these challenges, Europe adopted the New Green Deal as a strategy transforming the Union into a competitive resource-efficient economy without greenhouse gas emissions and become carbon neutral in a few decades. The European Green Deal includes the new circular economy action plan, highlighting the importance of a products’ “green design”, saving raw materials, and waste prevention oriented along the entire life cycle of products. Construction and buildings represent one of the key topics for the green transition. In the European Union, buildings are responsible for 40% of our energy consumption and 36% of greenhouse gas emissions, which are mainly caused by construction, usage, renovation, and demolition. Improving environmental efficiency can play a key role in reaching the carbon neutrality of Europe that is expected to be achieved by 2050. In this research, it was explored how Eco-design, as an innovative approach in buildings and construction, Life Cycle Thinking and Life Cycle Assessment, as fundamental supporting tools in sustainability, and finally appropriate and effective Construction and Demolition Waste recycling processes, particularly oriented to concrete recycling according to the case studies analyzed, can promote a circular economy in buildings and construction.

Multi-stage network-based two-type cost minimization for the reverse logistics management of inert construction waste

The growing concerns for achieving sustainability has gained much attention from waste management experts with particular focus on reverse logistics, as it supports concepts like circular economy, material recovery, and improved environmental performances. This paper describes a multi-stage network-based model to minimize the overall cost for the reverse logistics management of inert construction waste across its entire life cycle. This model takes a unique two-type costing approach to overcome the ambiguities and deficiencies existing in previous models. Type-I cost refers to the facility-based costing (FBC) and Type-II cost refers to non-facility based costing (NFBC). The mixed-integer linear programming technique is applied using the LINGO software. A case study of construction waste management in Hong Kong is conducted to validate the developed model, which includes waste generation point as the starting node, public fill reception facility and recycling facility as an intermediate node, and landfill as an ending node. The result shows about 24% reduction in the total cost compared to the base case. Furthermore, to evaluate the impact of uncertainties on the cost parameters, a detailed scenario based sensitivity analysis is conducted. The optimal result shows that the larger portion of total cost come from the NFBC component. Therefore, NFBC is critical in defining the overall reverse logistics network and thus, should be given more emphasis in the design of an effective construction waste management system.

Transition to circular economy in the construction industry: Environmental aspects of waste brick recycling scenarios

The extensive exploitation of natural resources, together with an inefficient use of end-of-life materials, results in the generation of vast amounts of waste. The current material streams are to be reconsidered to mitigate the environmental burdens and achieve the sustainability goals. However, these intentions usually lead to material downcycling, which does not provide significant environmental benefits. In this paper, the potential of waste brick recycling is assessed from the environmental point of view as the recycling options of waste bricks attract an eminent attention due to rationalization and optimization of material streams, including transformation to the circular economy model according to the EU commitments. Three different scenarios are taken into account in that respect: replacement of natural aggregate, partial replacement of cement binder, and alkaline activation. The life cycle methodology is used at the assessment and the obtained results are presented on both midpoint and endpoint levels. The analysis of environmental impacts shows only minor improvements resulting from the replacement of natural aggregates by recycled waste bricks. The partial replacement of cement by waste bricks in powdered form can provide the most substantial benefits including decarbonization of the construction sector. The application of alkaline activators can harm the potential of alkali-activated materials considerably due to their negative effects on human health. A complex assessment of recycling scenarios is found to preferable to one-sided analyses aimed at carbon dioxide emission reduction only if a real sustainability without any hidden risks is to be achieved.

Review of construction and demolition waste management in China and USA

It has been observed that the massive urbanization has boosted up infinite construction in the developed as well as developing countries. The construction and demolition waste has been correspondingly increased enormously which results in nasty and fatal impacts on urban sustainability and survival in the term of economic values and environmental safety. Considering construction and demolition waste management (CDWM) in the USA and China and its comparison has not been discussed, this study explores some research questions to fill such gaps: What are the existing CDWM policies and regulations in these two countries? What is the market mode for CDWM? What are the key challenges of CDWM? What are the CDWM contribution and limitations toward circular economy? What are the lessons that must be exemplary for the two economies through mutual learning? Our results show that the CD waste generation and its management are influenced by several factors including population, urbanization, gross domestic product (GDP), and CDWM regulatory measures. The USA has more developed CDWM system. Whereas, China is a growing economy and it has some management deficiencies in the construction industry. Key suggestions for improving CDWM include: i. Government supervision along with an economic incentive approach, ii. Interaction between Stakeholders, iii. Mutual coordination among operational departments, iv. Audit and inspection setup, and v. Continuous development and integration of emerging technologies.

Strategies for enhancing the accuracy of evaluation and sustainability performance of building

In recent years, considerable efforts have been devoted to minimizing the environmental consequences from building industry globally, as the industry is notorious for its significant resource consumption and environmental emissions. However, due to a lack of data representativeness in many parts of the world, considerable variations were observed among studies, and thus makes life cycle assessment (LCA) results difficult for the decision-making purpose. In addition, the selection of low impact materials and the management of end-of-life building waste are the most important concern. By considering several strategies including data representativeness, low carbon material, and end-of-life building waste management, this study aimed to enhance the accuracy of such assessment and sustainability performance of building. An integrated LCA framework is proposed for implementing those strategies through a case specific high-rise residential building in Hong Kong. Based on case-specific/regional data, carbon emission of building was evaluated with a cradle-to-construction system boundary with the functional unit of 1 m² of gross floor area using the IMPACT 2002+ method, and then compared to that of selecting generic databases under different scenarios. The results demonstrate that the application of case-specific and generic data would significantly influence the outcomes of the case study, as the deviations of certain magnitudes were mostly derived from different building materials that it can lead to an underestimation of carbon emissions of up to 28%. Along with using alternative materials, the adoption of the proposed materials cycling and resource recovery approach at the end-of-life building could lead to a reduction of 14% of the total emissions (i.e. excluding the use and renovation of building). The results would support data selection for accuracy of evaluation which can be used as benchmark where recognized database is not available and promote sustainability performance of buildings locally, while the proposed framework could be adopted for comprehensive evaluation globally.

Is selective demolition always a sustainable choice?

Selective demolition is usually perceived as essential for a sustainable built environment since it aims to maximise the valorisation of constituent building materials and components giving them a new life. The successful diversion of construction materials from landfill and the extent of recovery of construction and demolition wastes as secondary raw materials depend on how the demolition work is executed, as well as on the logistic and economic aspects of the geographic context. The main goal of this study is to critically explore the sustainability of selective demolition practices versus traditional ones by addressing the environmental issues through the Life Cycle Assessment methodology. The key parameters that determine the environmental profile of a selective demolition project and their effects on the overall environmental balance were identified. Primary site-specific data supplied by the demolition companies involved in the demolition of a residential building located in Milan (Northern Italy) were used in the analysis. The results indicate that the environmental sustainability depends a lot on the characteristics of the building to be demolished as well as on the local markets for recycled materials. Moreover, the benefits from substituting primary raw materials can be overset by the increased impacts due to additional energy requirements of the selective demolition in comparison to the traditional one. Consequently, the environmental sustainability of selective demolition should be addressed on a case by case basis.

The Impact Assessment of Campus Buildings Based on a Life Cycle Assessment–Life Cycle Cost Integrated Model

The development of higher education has led to an increasing demand for campus buildings. To promote the sustainable development of campus buildings, this paper combines social willingness-to-pay (WTP) with the analytic hierarchy process (AHP) based on the characteristics of Chinese campus buildings to establish a life cycle assessment–life cycle cost (LCA–LCC) integrated model. Based on this model, this paper analyses the teaching building at a university in North China. The results show that the environmental impacts and economic costs are largest in the operation phase of the life cycle, mainly because of the use of electric energy. The environmental impacts and economic costs during the construction phase mainly come from the building material production process (BMPP); in this process, steel is the main source. Throughout the life cycle, abiotic depletion-fossil fuel potential (ADP fossil) and global warming potential (GWP) are the most prominent indexes. Further analysis shows that these two indexes should be the emphases of similar building assessments in the near future. Finally, this study offers suggestions for the proposed buildings and existing buildings based on the prominent problems found in the case study, with the aim to provide reference for the design, construction, and operation management of similar buildings.

Life cycle modeling for environmental management: a review of trends and linkages

With the dynamics in current industry-environment interaction, it has become essential to diagnose the impacts that one is leaving on the environment. The requirement of assessment has brought many changes in the analysis techniques and research methodologies. Life cycle assessment (LCA) is one such validated technique as a scientific tool in the diagnosis of environmental impacts with accuracy. Over the past few years, LCA has attracted more attention with different approaches and applications. But, there is a lack of efforts to review the LCA applications for environmental management. The aim of this study is to evaluate the trends and to address the evolution of linkages in the field of LCA modeling and environmental management. The review employs the PRISMA statement for systematic literature review amalgamated with a visualization technique using VoSviewer. The meta-analysis addressing the findings from the academic articles published until the end of May 2019 using the Scopus online database was considered. The study reveals a total of 23 eligible papers regarding LCA modeling and environmental management. Analysis of these articles and keyword visualization network depicts that most of the studies on LCA modeling application were based on waste management-related decision-making and construction sector focusing primarily on environmental impacts, environmental performance evaluations, and scenario modeling for decision support. This study not only contributes in summarizing the LCA research trends of the methods in the application areas but also attempts to identify the potential scope and research directions. LCA thus has proven to be an excellent evaluative tool for future analysis.

Multiobjective Mathematical Programming Model for the Optimization of End-of-Life Buildings’ Deconstruction and Demolition Processes

Nowadays, construction and demolition waste management has become a critical process for the construction industry, as the specific waste stream poses important environmental issues and challenges. In the case of dismantling end-of-life buildings, the selection of the appropriate technique between deconstruction and conventional demolition is a critical decision affecting the total volume and type of produced waste. Toward this effect, in this paper, a novel decision-making model for the optimization of end-of-life buildings’ deconstruction and demolition processes is proposed. The objective of the proposed model is the simultaneous and weighted optimization of the total cost and time for the completion of the deconstruction and demolition processes, taking into consideration economic, legislative, and environmental criteria. Finally, a demonstration of the application of the proposed model is presented via two specific case studies and by discussing a few interesting managerial insights.

Life cycle assessment of construction and demolition waste management in a large area of São Paulo State, Brazil

The study evaluated the environmental performance of the construction and demolition waste (C&DW) management in the area of PCJ Watershed, located in the São Paulo State, Brazil, by means of an attributional Life Cycle Assessment. The entire C&DW management under the responsibility of the municipal government was considered. The potential environmental impacts were assessed by using two specific life cycle impact assessment methodologies, CML baseline (v3.03) and Impact 2002+ (v2.12). The results obtained by both methodologies highlighted the importance of the avoided impacts from recovered materials, mainly those related to steel, glass and plastics recycling. In particular, the CML baseline indicated "Human Toxicity" as the most important category, mainly due to the avoided impacts from steel recycling and the generated impacts from transportation in all the C&DW management stages. The Impact 2002+ highlighted instead the role of the categories of "Respiratory Inorganics" and "Global Warming", in accordance with the results related again to steel recycling and transportation but also to landfilling of solid residues. The study considered some alternative scenarios of the mineral fraction management, which quantified the expected advantages of increasing C&DW recycling and improving the quality of recycled aggregates.

Impact of Service Life on the Environmental Performance of Buildings

The environmental performance assessment of the building and construction sector has been in discussion due to the increasing demand of facilities and its impact on the environment. The life cycle studies carried out over the last decade have mostly used an approximate life span of a building without considering the building component replacement requirements and their service life. This limitation results in unreliable outcomes and a huge volume of materials going to landfill. This study was performed to develop a relationship between the service life of a building and building components, and their impact on environmental performance. Twelve building combinations were modelled by considering two types of roof frames, two types of wall and three types of footings. A reference building of a 50-year service life was used in comparisons. Firstly, the service life of the building and building components and the replacement intervals of building components during active service life were estimated. The environmental life cycle assessment (ELCA) was carried out for all the buildings and results are presented on a yearly basis in order to study the impact of service life. The region-specific impact categories of cumulative energy demand, greenhouse gas emissions, water consumption and land use are used to assess the environmental performance of buildings. The analysis shows that the environmental performance of buildings is affected by the service life of a building and the replacement intervals of building components.

An attributional life cycle assessment for an Italian residential multifamily building

The study describes an attributional life cycle assessment carried out according to the ISO standards and focused on an Italian multifamily residential building. The aim was developing an exhaustive and reliable inventory of high-quality primary data, comparing the environmental impacts along the three stages of the building life cycle. The pre-use phase takes into account the production of all the construction materials, transportation, and on-site assembling. The use phase quantifies the resource consumptions for 50 years of the building utilization and ordinary maintenance. The end-of-life phase includes the building demolition and the management of generated wastes. The results quantify how the design criteria affect the environmental performances of the residential building along its life cycle. The role of the pre-use phase appears remarkable for global warming potential (GWP), due to the huge impacts of steel and concrete production processes. The use phase gives the largest contributions, which reach 77% and 84% of the total, for the categories of global warming and non-renewable energy. The end-of-life phase provides limited avoided impacts. A comparative analysis quantifies the improvements achievable with an alternative type of partitions and external walls. Acronyms: AC: air conditioning; C&DW: construction and demolition waste; CFL: compact fluorescent lamp; DHW: domestic hot water; EC: European Commission; EU: European Union; GDP: gross domestic product; GHG: greenhouse gases; GWP: global warming potential; LCA: life cycle assessment; LCI: life cycle inventory; LCIA: life cycle impact assessment; MFA: material flow analysis; NREP: non-renewable energy potential; RINP: respiratory inorganics potential; WFD: Waste Framework Directive.

Managerial Areas of Construction and Demolition Waste: A Scientometric Review

In past decades, the massive generation of construction and demolition waste (CDW) was increasingly threatening the public environment and humanity health worldwide. A large amount of research has been devoted to the CDW from difference perspectives. However, few scholars have attempted to summarize and review the extant studies, especially in the managerial areas of CDW (MA-CDW). This paper fills this gap via a systematic and quantitative review in the CDW management field. Employing the scientometric analysis method, a total of 261 articles published from 2006 to 2018 were collected to construct the knowledge map and comprehensive framework for MA-CDW. Results show that the overall evolutionary trend of MA-CDW was from basic management concepts to internal and external challenges analysis, to organizational strategy and innovative management practices. The major MA-CDW knowledge domains were identified and summarized into four pillars, namely: (1) factor and challenge; (2) composition and quantification; (3) assessment and comparison; and (4) technology and method. Based on the trend, knowledge gaps and future research directions were found out and discussed. This study contributes to the existing MA-CDW knowledge by presenting a comprehensive knowledge framework. Furthermore, these findings can provide the researchers and practitioners with an in-depth understanding for the sustainable governance of CDW.

Nutrient-derived environmental impacts in Chinese agriculture during 1978-2015

Nitrogen (N) and phosphorus (P) play a critical role in agricultural production and cause many environmental disturbances. By combing life cycle assessment (LCA) method with the mass balance principle of substance flow analysis (SFA), this study establishes a nutrient-derived environmental impact assessment (NEIA) model to analyze the environmental impacts caused by nutrient-containing substances of agricultural production in China during 1978-2015. The agricultural production system is composed of crop farming and livestock breeding, and the environmental impacts include energy consumption, global warming, acidification, and eutrophication. The results show all these environmental impacts had increased to 8.22*10⁹ GJ, 5.01*10⁸ t CO₂-eq, 2.41*10⁷ t SO₂-eq, and 7.18*10⁷ t PO₄^3--eq, respectively. It is noted the energy consumption and the climate change caused by the crop farming were always higher than those from livestock breeding, which were average 60 and two times, respectively. While the acidification and the eutrophication were opposite after 1995 and 2000, even they were similar. This was mainly due to the high N application including synthetic N fertilizer (from 1.33*10⁹ GJ to 2.08*10⁹ GJ), applied manure (from 4.94*10⁸ GJ to 5.65*10⁸ GJ) and applied crop residue (from 2.94*10⁸ GJ to 5.30*10⁹ GJ), while the synthetic N fertilizer was controlled and the livestock expanded rapidly after 1995. Among the sub-categories, the three staple crops (rice, wheat, and maize) contributed greater environmental impacts, which were about two to 10 times as other crops and livestock, due to their high fertilizer uses, sown areas and harvests. While the oil crops and fruit consumed the least energies because of their much lower fertilizer-use intensities. Pig and poultry especially pig also caused obvious effects on environment (even 20 times as other livestock) because of their large quantities and excretions, which emitted much higher N₂O and P loss resulting in much higher climate change, acidification and eutrophication than other livestock. Then the study proposes the nutrient management in agricultural production by considering crop production, livestock breeding and dietary adjustment, so that some valuable experiences can be shared by the stakeholders in other Chinese regions.

Environmental performances of different configurations of a material recovery facility in a life cycle perspective

The study evaluated the environmental performances of an integrated material recovery facility (MRF) able to treat 32kt/y of unsorted mixed waste, made of residuals from household source separation and separate collection. The facility includes a mechanical sorting platform for the production of a solid recovered fuel (SRF) utilized in an external waste-to-energy plant, bio-cells for tunnel composting of organic fraction, and a sanitary landfill for the safe disposal of ultimate waste. All the MRF sub-units have been analysed in depth in order to acquire reliable data for a life cycle assessment study, focused on the environmental performances of different configurations of the facility. The study investigated a "past" configuration, including just mechanical sorting, landfilling and biogas combustion in a gas engine, and the "present" one, which includes also a composting unit. Two possible "future" configurations, having a gasifier inside the MRF battery limits, have been also analysed, assessing the performances of two fluidized bed reactors of different size, able to gasify only the residues generated by the sorting platform or the whole amount of produced SRF, respectively. The analysis evaluated the contributions of each unit in the different configurations and allowed a reliable assessment of the technological evolution of the facility. The results quantified the positive effect of the inclusion of an aerobic treatment of the waste organic fraction. The SRF gasification in situ appears to improve the MRF environmental performances in all the impact categories, with the exclusion of that of global warming.