Demolition Phase Research Articles

Estimating construction and demolition waste in the building sector in China: Towards the end of the century

Amid China’s rapid urbanization and economic growth, increasing construction and demolition waste (CDW) has become a critical environmental and management challenge. In the present study, we introduce a dynamic recursive-based CDW assessment model designed to systematically track and analyze the origins, distribution, and composition of CDW across China. Our results show that China is projected to generate 224.08 billion tonnes (Bt) of CDW from 2000 to 2100, mostly gravel (34.15%), sand (30.08%), and brick/tile (14.37%). Additionally, the primary source of CDW generation will shift from rural to urban public and commercial (P&C) buildings. The proportion of metals such as steel in CDW is rapidly increasing, rising from 2.11% in 2000 to 17.66% in 2100. From 2020 to 2100, reducing material waste during the construction phase can decrease the amount of CDW by 6.88 Bt. Extending the building lifespan during the operation phase can further reduce the amount of CDW by 50.25 Bt. In comparison, implementing recycling strategies during the demolition phase can achieve the most significant reduction in the amount of CDW, with an estimated cumulative decrease of 151.25 Bt. The amounts of gravel, sand, and steel are anticipated to contribute the most to this reduction, accounting for 44.93%, 37.66%, and 8.8% of the total reduction in the amount of CDW, respectively.

A Study on Carbon Emission Reduction in the Entire Process of Retrofitting High-Rise Office Buildings Based on the Extraction of Typical Models

The building sector is one of the largest contributors to carbon emissions globally, with high-rise office buildings being a major source due to their energy-intensive operations. This study aims to address the critical issue of carbon emission reductions through the retrofitting of existing high-rise office buildings, focusing on the entire life cycle of these buildings, including the embodied, operational, and demolition phases. Existing research has primarily concentrated on energy consumption and carbon emissions during the operational phase, neglecting the carbon impact of the retrofitting process itself. This research seeks to fill that gap by quantifying the carbon reduction benefits of retrofitting across all life-cycle stages. Using data from 100 high-rise office buildings in Hangzhou’s Gongshu District, five typical models were extracted based on their construction eras and architectural features. Retrofitting strategies tailored to these models were developed, and the carbon reduction benefits were calculated using the carbon emission factor method. The primary findings indicated that the shape and orientation of buildings are crucial factors influencing the carbon reduction benefits of retrofitting. Buildings oriented east–west tend to exhibit greater carbon reductions after retrofitting. During the embodied and demolition phases, retrofitting emissions remain similar for models constructed in the same era due to consistent material inputs. However, emissions vary for models from different eras, primarily due to differences in envelope materials and subsequent material consumption. High-rise office buildings constructed between 2007 and 2021 demonstrate higher overall retrofit carbon reduction rates compared to those built before 2007, despite the latter achieving greater reductions during the operational phase. The shorter remaining lifespans of pre-2007 buildings diminish their life-cycle carbon reduction advantages. Notably, complex-shaped buildings from the same era do not necessarily exhibit lower overall retrofit carbon reduction rates compared with rectangular or L-shaped buildings, with comparable reductions per unit area. This suggests that complex-shaped buildings should not be disregarded for retrofitting based solely on shape considerations. Furthermore, the remaining lifespan of a building significantly impacts its post-retrofitting carbon reduction benefits; longer lifespans result in greater benefits, and vice versa. In practical engineering applications, structural reinforcement measures can be implemented prior to retrofitting to extend a building’s structural lifespan, ultimately enhancing its carbon reduction benefits.

Machine learning-based prediction of construction and demolition waste generation in developing countries: a case study.

Data is needed for making informed decisions regarding managing waste in the time of construction and demolition phases of buildings. However, data availability is very limited in most developing countries in the area of waste generation. The objective of this study is to employ an artificial intelligence (AI)-based approach to develop a reliable model for forecasting monthly construction and demolition waste (C&DW) generation in the case study of Tehran, Iran. We have trained different prediction models using various AI algorithms, including multilayer perceptron neural network, radial basis function neural network, support vector machines, and adaptive neuro-fuzzy inference system (ANFIS). According to the findings, all employed AI algorithms demonstrated high prediction performance for C&DW forecasting models. The ANFIS model, with R2 = 0.96 and RMSE = 0.04209, was identified as the model that better represented the observed values of C&DW generation. The better efficiency of the ANFIS model could be due to its effective enhancement of neural networks to model subjective variables based on fuzzy logic capabilities. The developed prediction model can be employed as an efficient tool for policy and decision-making for C&DW management by predicting waste quantities in the future.

The climate benefits from cement carbonation are being overestimated

Rapid decarbonization of the cement industry is critical to meeting climate goals. Oversimplification of direct air capture benefits from hydrated cement carbonation has skewed the ability to derive decarbonization solutions. Here, we present both global cement carbonation magnitude and its dynamic effect on cumulative radiative forcing. From 1930–2015, models suggest approximately 13.8 billion metric tons (Gt) of CO2 was re-absorbed globally. However, we show that the slow rate of carbonation leads to a climate effect that is approximately 60% smaller than these apparent benefits. Further, we show that on a per kilogram (kg) basis, demolition emissions from crushing concrete at end-of-life could roughly equal the magnitude of carbon-uptake during the demolition phase. We investigate the sensitivity of common decarbonization strategies, such as utilizing supplementary cementitious materials, on the carbonation process and highlight the importance of the timing of emissions release and uptake on influencing cumulative radiative forcing. Given the urgency of determining effective pathways for decarbonizing cement, this work provides a reference for overcoming some flawed interpretations of the benefits of carbonation.

Research on the development and application of digital twin for the full life cycle of bridge engineering

Bridges play an important role in modern society, whereas many bridges are in poor condition and are characterized by complexity, randomness, and risk no matter what phase the bridges are in. Meanwhile, with advanced technologies such as IoT and Big Data, Digital Twin has been developed in different industries, such as aerospace. With multiple superiorities of real-time data detection, big data processing, full life-cycle management, etc., it is appropriate for bridge engineering. The paper aims to present a state-of-the-art literature review on the full life cycle of the application of Digital Twin in Bridge Engineering. The article discusses the relationship between Digital Twin and Building Information Model (BIM) and constructs a comprehensive framework for Digital Twin in Bridge Engineering. The review is classified into three main parts design and construction phase, operation and maintenance phase, and demolition phase based on different stages of the full life cycle. The results show the applications high potential and feasibility, and show that most of the current research focuses on the operation and maintenance phases. However, intensive research is still necessary to improve the accuracy, quality, efficiency, timeliness, and versatility of the Digital Twin in Bridge Engineering.

Embedding reuse into infrastructure projects by carrying out ‘pre-redevelopment audits’

There is significant potential for large infrastructure projects with multiple demolition phases to kick start a second-hand materials market and unlock a truly circular economy. Civil engineers are well placed to lead this by carrying out reuse appraisals, commonly known in the buildings sector as ‘pre-redevelopment audits’. The paper sets out current practice and emerging policies regarding reuse in the construction sector, then describes the steps for undertaking an effective audit. The aim is to assess and maximise the reuse and recovery of materials from the start, thereby helping to reduce the industry’s overall greenhouse gas emissions.

Reducing energy consumption in operation and demolition phases by integrating multi-objective optimization with LCA and BIM

Reducing energy consumption in operation and demolition phases by integrating multi-objective optimization with LCA and BIM

GHG emissions and energy consumption of residential buildings-a systematic review and meta-analysis.

Residential buildings generate significant greenhouse gas (GHG) emissions and consume energy throughout their life cycle. In recent years, research on GHG emissions and energy consumption of buildings has developed rapidly in response to the growing climate change and energy crisis. Life cycle assessment (LCA) is an important method for evaluating the environmental impacts of the building sector. However, LCA studies of buildings show widely varying outcomes across the world. Besides, environmental impact assessment from a whole life cycle perspective has been undeveloped and slow. Our work presents a systematic review and meta-analysis of LCA studies on GHG emissions and energy consumption in the preuse, use, and demolition stages of residential buildings. We aim to examine the differences among the results of diverse case studies and demonstrate the spectrum of variations under contextual disparities. Results show that residential building emits about 2928kg GHG emission and consumes about 7430 kWh of energy per m2 of gross building area on average throughout the life cycle. Residential buildings have an average GHG emission of 84.81% in the use phase, followed by the preuse phase and demolition phase; the mean energy consumption in the use stage occupied the largest share of 84.52%, followed by preuse stage and demolition stage. GHG emissions and energy use vary significantly in different regions due to different building types, natural conditions, and lifestyles. Our study stresses the compelling requirement to slash GHG emissions and optimize energy consumption from residential buildings by use of low carbon building materials, energy structure adjustment, consumer behavior transformation, etc.

Ten questions concerning prospective LCA for decision support for the built environment

It is essential to provide quantitative decision support when pursuing environmental impact mitigation efforts, particularly when considering resource and energy-demanding sectors such as the built environment. Life cycle assessment (LCA) provides widely recognized quantitative decision support regarding environmental performance. However, for long-lived products such as buildings, the usefulness of conventional LCA is limited as it relies on databases that only give a current or past representation of industrial processes. The emerging field of prospective LCA (pLCA) allows us to evaluate the results at a future point in time based on technological and socio-economic projections. This article builds on a systematic literature screening, ongoing discussions in the pLCA academic community, and hands-on experimentation with available software. The goal of the study is to 1) understand implications of how pLCA is conducted, and how it relates to the built environment; 2) Improve the documentation and credibility of pLCA and applied scenarios; And 3) identify practical tools and workflows that can make pLCA more accessible to practitioners. The study raises ten relevant questions when considering how to use pLCA for decision support in the built environment. This list of questions is not exhaustive nor definite, and recommendations are possible answers suggested by the authors. Using scenario narratives from energy and Integrated Assessment Models allows for systematic and consistent transformation of LCA databases to represent possible futures. However, there is a need for pLCA practitioners to improve documentation to ensure that the goal and scope of the LCA are compatible with the chosen future scenario. In the case of built environment, it is relevant to consider different projection years when modeling construction, operation, renovation, and demolition phases, respectively, as they span several decades. Not doing so can misestimate the effects changing socio-economic and technological contexts have on the life-cycle impact of buildings.

Life cycle assessment of high concentration organic wastewater treatment by catalytic wet air oxidation

There have been many studies on life cycle assessment in sewage treatment, but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology, especially in catalytic wet air oxidation (CWAO). There are no cases of using actual industrialized data onto life cycle assessment. This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO, and comprehensively explains the impact on the environment from three aspects: the construction phase, the operation phase and the demolition phase. In addition, sensitivity analysis and uncertainty analysis were performed. The results showed that the key factors affecting the environment were marine ecotoxicity, mineral resource consumption and global warming, the operation stage had the greatest impact on the environment, which was related to high power consumption during operation and emissions from the treatment process. Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity, and it also proved that global warming is mainly caused by pollutant emissions during operation phase. Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.

Stakeholders’ impact on the reuse potential of structural elements at the end-of-life of a building: A machine learning approach

The construction industry, and at its core the building sector, is the largest consumer of non-renewable resources, which produces the highest amount of waste and greenhouse gas emissions worldwide. Since most of the embodied energy and CO2 emissions during the construction and demolition phases of a building are related to its structure, measures to extend the service life of these components should be prioritised. This study develops a set of easy-to-understand instructions to facilitate the practitioners in assessing the social sustainability and responsibility of reusing the load-bearing structural components within the building sector. The results derived by developing and then employing advanced machine learning techniques indicate that the most significant social factor is the perception of the regulatory authorities. The second and third ranks among the social reusability factors belong to risks. Since there is a strong correlation between perception and risk, the potential risks associated with reusing structural elements affect the stakeholders’ perception of reuse. The Bayesian network developed in this study unveil the complex and non-linear correlation between variables, which means none of the factors could alone determine the reusability of an element. This paper shows that by using the basics of probability theory and combining them with advanced supervised machine learning techniques, it is possible to develop tools that reliably estimate the social reusability of these elements based on influencing variables. Therefore, the authors propose using the developed approach in this study to promote materials' circularity in different construction industry sub-sectors.

Perceptions Governing Sustainability in the UAE Construction Sector

Sustainability has a solid understanding on a broad level; however, in construction, there is no consensus about what it encompasses. Different practitioners perceive sustainability in construction from different perspectives. There are existing debates concerning the definition and scope of sustainable construction. Therefore, the aim of this research is to set a benchmark for the perceptions governing the understanding of sustainability in construction amongst practitioners working in the UAE’s construction sector. To collect the perceptions, the reviewed literature was condensed to develop an online survey that was validated by an expert panel and collected data from 129 industry professionals in 2022. The reliability of the collected data was confirmed using Cronbach’s alpha. Upon confirming the validity and reliability of the collected data, the analysis of the perceptions was done using descriptive statistics and the relative importance index. The findings confirm that the economic and social pillars are not as recognized as the environmental pillar. Stakeholders are familiar with implementing sustainable practices in the design and construction phases whereas contract formation, procurement and demolition phases had the lowest RII ranking. Stakeholders are informed about the environmental benefits of sustainable construction, but efforts to familiarize them with the benefits of the economic and social pillars should be amplified. The main barriers were the necessity for additional research and the difficulty to implement sustainable construction due to the lack of understanding about what it is. Data collected aligns with the main problem statement which is the lack of understanding about what sustainable construction entails. The contribution that this research has added to the body of knowledge is that the exclusive collection and analysis of the perceptions governing sustainability in the UAE’s construction industry should draw the attention of policymakers that the true meaning of sustainability has not yet infiltrated the construction industry and immediate intervention is mandatory to increase the awareness levels of the stakeholders working in the UAE’s construction industry about what sustainable construction is.

Technology Innovation for Sustainability in the Building Construction Industry: An Analysis of Patents from the Yangtze River Delta, China

Advances in technology provides the potential to innovate sustainability in the building construction industry. Drawing on the literature and expert reviews, this research discloses the potential of 14 specific technologies in waste minimisation, energy saving, and efficiency improvement for sustainable building construction and develops a conceptual framework engaging the building life cycle (the planning, construction, use and operation, and demolition phases) and the actors for assessing technological innovation at a local level. This framework is used to identify how technologies were innovated for sustainable building construction through the selected 3017 patent invention applications from the Yangtze River Delta (YRD), one of the fastest urbanising areas and the largest market for the building industry in China. Findings unveiled that innovation is uneven amongst the 14 technologies and the degree of mixing was relatively low in the YRD. The contribution of the technological innovation to sustainability is mainly actualised through efficiency improvements in building construction (2265) and through directly reducing waste (1094) and energy consumption (642). Some general-purpose technologies (e.g., blockchain, cloud computing), which assume to fundamentally innovate the industry, are mostly absent with less than 10 records each, leaving the potential for future adaptive technological innovation. Furthermore, state-owned enterprises as the main sources of patent inventions amongst applicants in the YRD may suggest the dissimilar path of China towards technology innovation compared to its Anglo-American counterparts.

Analyzing Embodied Energy and Embodied Water of Construction Materials for an Environmentally Sustainable Built Environment

Buildings consume over 40% of global energy in their construction and operations contributing to over 39% of global carbon emission each year. This huge environmental footprint presents an excellent opportunity to reduce energy use and help deliver an environmentally sustainable built environment. Most of the energy is consumed by buildings as embodied energy (EE) and operational energy (OE). EE is used directly and indirectly during buildings’ initial construction, maintenance and replacement, and demolition phases through construction products and services. OE is used in the processes of heating, cooling, water heating, lighting, and operating building equipment. Most environmental optimization research has been centered on energy and carbon emission overlooking another critical sustainability aspect, water use. Each building also consumes a significant amount of freshwater as embodied water (EW) or virtual water in its initial construction, maintenance and replacement, and demolition phases. Since each primary and secondary energy source depletes water in its extraction, refinement or production, there is also a water expense associated with EE and OE use that must also be included in total EW use. The total EW, therefore, includes both non-energy and energy related water use. Research suggests that there are tradeoffs between EE and EW that may complicate design decisions such as material selection for environmental sustainability. In other words, a material selected for its lower EE may have higher EW and selecting such a material may not help reach environmental sustainability goals since water scarcity is becoming a grave problem. In this paper, we created an input-output-based hybrid (IOH) model for calculating and comparing EE and EW of building materials frequently used in building construction. The main goal is to examine and highlight any tradeoffs that may exist when selecting one material over another. The results reveal that there is a weak correlation between EE and total EW that is the sum of energy and non-energy water use, which means that a design decision made solely based on EE may conflict with EW. The share of energy related water use in total EW of construction materials also varies significantly (2.5%-31.2%), indicating that reducing energy use alone may not be sufficient to reduce freshwater use; additional efforts may be needed to decrease the use of materials and processes that are water intensive. The results of this study are significant to achieving the goal of creating a truly sustainable built environment.

The use of near-infrared autofluorescence during total laryngectomy with hemi- or total thyroidectomy.

The aim of this study is to describe the use of near-infrared autofluorescence (NIR-AF) to identify and preserve parathyroid glands (PGs) in a group of patients with advanced hypopharyngeal/laryngeal cancer undergone total (pharyngo)laryngectomy with hemi- or total thyroidectomy. At San Raffaele Hospital, Milan (Italy), from January 2021 to May 2021, 7 patients affected by cT4a laryngeal squamous cell carcinoma (SCC) underwent surgery using an autofluorescence detection system (Fluobeam-Fluoptics®). For proper surgical planning, the demolition phase envisaged extension of the intervention to 4 hemithyroidectomies and 3 total thyroidectomies associated, respectively, with homolateral or bilateral CCND. Serum calcium, ionized calcium, and parathyroid hormone (PTH) levels at post-operative day (POD) 1 and 2 and at 2weeks after surgery were monitored. Finally, we compared the data obtained with a cohort of patients who underwent surgery without the adoption of NIR-AF. With the use of NIR-AF, 18/20 PGs were identified, of which 7/18 were preserved exclusively thanks to the use of autoflorescence. The technique also made it possible to identify and isolate three PGs from the surgical specimen, which were subsequently transplanted only after intraoperative histological confirmation. On POD-1, 3/7 patients (42.8%) were hypocalcemic; on POD-2 and after 2weeks only 1/7 patient (14.2%) was hypocalcemic. Comparing the two groups, we highlighted that the utilization of NIR-AF was related to a significant decrease of median serum (p = 0.026) and ionized calcium levels (p = 0.017) 2weeks after surgery. Using this new technology, in no case did definitive histological examination reveal the presence of PGs in the surgical specimen, reaching an accuracy of 100%. In our cohort of patients who underwent total (pharyngo)laryngectomy with hemi- or total thyroidectomy, the use of near-infrared autofluorescence improved medium term postoperative hypocalcemia rates. This new technology helps to achieve a better calcemic outcome compared to the standard naked eye approach, since it helps the surgeon to identify and preserve parathyroid glandular tissue with a lower incidence of post-operative hypocalcemia.

A Systematic Literature Review (SLR) on The Strategies of Managing Waste in Relative to Green Building (GB) Practice

The construction industry is very important for a developing country, but the rapid development has caused an excessive generalization of solid construction and demolition (C&D) waste. Many solutions have been discovered to prevent C&D waste from destroying the environment—one of them being the implementation of ‘green building’ (GB) that focuses on construction activity that is best able to minimize pollution. Therefore, the strategies employed in waste management are becoming vital, especially in GB, as they must be able to cope with future sustainability developments. Hence, this paper attempts to review the strategies for waste management relative to green building practices. The systematic literature review (SLR) method was employed to achieve the aims and objectives of this research paper. Findings from the SLR indicate that construction waste can be minimized during the planning or design stage, the managing or construction period as well as demolition phase. C&D waste can be controlled by selecting the prefabricated materials, good site management skills that help with on-site coordination, communication, just-in-time (JIT) ordering and receiving of materials, training of workers that can be achieved by reducing C&D waste. Furthermore, the reusing and recycling of C&D waste during the construction period can be the strategies in managing waste. Besides that, in the aspect of GB practice, waste management can be controlled by applying sustainable operation, resources management, and environmental health in every decision-making throughout the development lifecycle.

Influence of underlying surface change caused by urban renewal on land surface temperatures in Central Guangzhou

Land use change during urban renewal can have important impacts on ecological and environment indices. Exploring the impact of different urban renewal modes on land surface temperature (LST) is significant to city planning and the realization of urban sustainability. In this study, we selected five urban renewal regions of Central Guangzhou that are undergoing comprehensive or micro transformation. Deeplab V3+ was used to extract land use data from high-resolution remote sensing images; combined with LST data retrieved from Landsat series images, Pearson correlation analysis and geographically and temporally weighted regression (GTWR) analysis were used to explore the spatiotemporal heterogeneity of LST affected by underlying surface changes that were caused by urban renewal. The results indicate that urban renewal in all regions generated positive effects on LST reduction. However, comprehensive transformations in the diversity of land use types and more landscape pattern changes had higher potential for LST cooling effect than micro transformations. Owing to the heating effect of concrete, the LST peak point usually occurred in the block demolition phase of urban renewal. The transformation from dense low-rise to scattered high-rise buildings achieved LST cooling effect through shadows and ventilation to heat dissipation. In addition, parks with large areas of trees had stronger cooling capacity than other vegetation or farmland patches, and scattered vegetation patches played the role of connecting the influence of vegetation. Overall, appropriate transformation of architecture and green space landscape patterns are crucial to achieve LST cooling effect during urban renewal.

(Computationally) designing out waste: Developing a computational design workflow for minimising construction and demolition waste in early-stage architectural design

In the architecture, engineering and construction (AEC) industry, waste is oft framed as an economic problem typically addressed in a building’s construction and demolition phase. Yet, architectural design decision-making can significantly determine construction waste outcomes. Following the logic of zero waste, this research addresses waste minimisation ‘at the source’. By resituating the problem of construction waste within the architectural design process, the research explores waste as a data and informational problem in a design system. Accordingly, this article outlines the creation of an integrated computational design decision support waste tool that employs a novel data structure combining HTML-scraped material data and historic building information modelling (BIM) data to generate waste evaluations in a browser-based 3D modelling platform. Designing an accessible construction waste tool for use by architects and designers aims to heighten awareness of the waste implications of design decisions towards challenging the systems of consumption and production that generate construction and demolition waste.

Hambatan Penerapan Konstruksi Berkelanjutan: Perspektif Pemerintah

Sustainable construction is a way for the construction industry to achieve sustainable development by considering social, economic, environmental, and cultural issues. Policies for implementing sustainable construction in infrastructure delivery are still not clearly understood, resulting in challenging implementation by planners and contractors. This research study identifies the barriers to implementing sustainable construction in developing infrastructure projects in Bina Marga, Cipta Karya, Sumber Daya Air, and Perumahan Permukiman sectors in North Sulawesi Province. Data collection using semi-structured interviews involved 23 informants from these four sectors. The results of the study found that the barriers evenly occur throughout the life cycle of an infrastructure project in four sectors, namely: (1) the programming phase related to strategic planning documents and identification of barriers, (2) the technical planning phase related to technical understanding and competence service providers, (3) construction implementation phase related to expert consultants, service provider competence, and green construction technology, (4) utilization phase related to socialization, promotion, and education, (5) demolition phase related to mechanisms and availability of resources. The study results provide academic-based information for the government to minimize barriers to implementing sustainable construction policies throughout Indonesia.

Optimization of Material Recovery Strategies in the Demolition Phase of Buildings – A Case Study

Globally, the construction industry is one of the most environmentally catastrophic industries, with a significant effect on the raw materials usage, their commitment of use throughout their whole life cycle, and the atmosphere in which they work. Between 1950 and 2010, global average material consumption rose from 5.0 t to 10.3 ton per capita per year, owing to population growth, industrialization, and increased socio-economic strength. Moreover, this industry uses 35% of produced energy and releases 40% of carbon dioxide into the Earth's atmosphere. One hundred fifty million tons of CDW is made in India according to the BMPTC, and less than 1% is reutilized properly added to that the 55% of total solid waste in India are from the construction industry. The waste produced during the demolition can be well utilized if managed and appropriately recovered, which directly reduces the virgin raw material usage in the new construction, decreasing the amount ending in the landfill. This study aims to understand the strategies and technology for material recovery after the building's life. The literature review will be taken up to list the different strategy in practice for material recovery. The techniques for material recovery are discussed to understand more in detail. This research helps find the other methods for material recovery and equipment and technology during the demolition and reconstruction of the RCC framed structure. The bottlenecks in the adoption of the various strategy are studied in this research.