Search Results (53)

The construction industry faces a growing challenge in managing waste materials, making the development of sustainable alternatives critical. This study investigates the preparation of geopolymers using construction and demolition waste materials, such as cement, brick, and glass waste. Specifically, crushed glass was used to produce sodium silicate, a key source of silicate ions and alkali necessary in geopolymerization processes. The performance of this in-house activator was compared to that of the commercial counterpart. Seven geopolymer formulations were prepared and characterized using SEM-EDX, ATR-FTIR, and XRD techniques. Chemical resistance against harsh environments was assessed through a 7-day immersion in water, hydrochloric acid (pH ~ 1), and sodium hydroxide (pH ~ 13) solutions. The samples were then dried and weighed to determine mass loss, revealing the promising resistance of specific formulations. Similarly, Portland cement specimens of the same dimensions as the geopolymer ones were prepared, tested, and compared to the geopolymers. Our study emphasizes the potential of transforming waste materials into high-performance, resistant geopolymers for construction materials. By optimizing waste-derived geopolymers, we may achieve significant environmental benefits through waste recycling and contribute to advancing sustainable construction technology. Full article

Sustainable construction and demolition waste (CDW) management have been widely discussed. For a city seeking urban renewal or transformation, aging houses are remodeled, which creates a large amount of CDW. Taiwan is located in an earthquake-prone area with many aging houses. Sustainable CDW management is extremely urgent for such cities or countries. This study presented the current CDW state in Taiwan and suggested possible management strategies. Material flow analysis was conducted to understand the use and distribution of the construction materials. This shows that 100% of the raw material of concrete is imported, whereas 100% of the raw material of brick is domestic. Half of recycled steel is used as a raw material in steel products. The predicted CDW from aging houses was calculated and could be a sustainable source for these materials. However, waste concrete and brick are currently mostly used as subgrade filling materials but are not recycled to produce new construction materials. There are three obvious challenges in CDW management: the lack of cost-effective recycling technology, the increasing quantity of CDW, and the limits of refilled land and landfill volume. However, three opportunities have also emerged: the high potential for reducing carbon emissions from CDW, improved recycling technology, and increasing awareness of the circular economy. This study concludes that reducing the amount of CDW, increasing the lifespan of buildings, increasing the use of reuse or recycled CDW, and proper management of final waste disposal help reduce waste and build a nearly zero-carbon-emission construction industry. Full article

Wood construction waste circularity presents enormous potential to significantly de-crease total greenhouse gas (GHG) emissions in the European Union (EU). Latvia could become a frontrunner due to its historic relationship with forestry, wood construction practises and unused potential of the innovative application of wood. This research examines what the potential of “circular wood” in Latvia is, how ready the Latvian wood house construction sector is to engage in a circular economy and wood waste circularity and whether the legal framework is ready to support wood waste management in the country. This study presents a combined approach for systematic wood construction product circularity assessment that includes a review of existing EU and Latvian frameworks for construction and demolition waste (CDW) management and wood construction, a general analysis of wood waste recycling systems and technologies, a quantitative data analysis of construction waste management in Latvia and qualitative data analysis of the Latvian wood house construction sector, and interviews with a focus group of Latvian wood industry representatives. The Latvian scope has allowed us to clarify the pattern methodology and impact points to be replicated, tested and measured further on a broader scale, in other countries, or throughout the whole EU. The main findings reveal a potential life cycle assessment (LCA) verifying the circularity of wood and limitations of wood construction waste circularity in Latvia in terms of wood house construction industry readiness and a legal framework as well as overall social prejudices for circular construction. Findings indicate an overall awareness and level of willingness to participate and engage in the circular construction models among Latvians; however, proactiveness and support (legal and financial) is expected from the government and municipalities. The recommendations point towards improvements in wood waste data management, the wood construction sector and the overall impact on sustainable development goals. Full article

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%. Full article

The aim of this article was to conduct a spatial and territorial analysis of the urban mining potential of the European Metropolis of Lille (MEL), which had 1,174,273 inhabitants in 2018. This involved quantifying construction and demolition waste (CDW) deposits and analyzing their spatial distribution. The chosen quantification approach utilized building and demolition permits as input data, along with waste diagnostics for Construction and Building Materials Products (CBMPs) obtained from stakeholders in the building sector. Waste quantities were estimated using the production rate calculation method (GRC). Specifically, the calculation based on surface area combined with GIS geographic information systems. CDW quantities were categorized by demolition rehabilitation and construction; by type (hazardous non-hazardous inert); and by urban fabric. For the MEL area, the findings revealed that building sites covered the largest surface area, with over 8 million m² being constructed between 2013 and 2022. The construction activity, including renovation, is expected to constitute approximately 20% of the MEL’s building stock from 2013 to 2022. During the same period, 5.51% of the MEL’s building stock was demolished. This corresponds to nearly 6 million tons of CDW being generated during this period, averaging 661318 tons per year. Demolition sites contributed 73% of the total CDW production, compared to 22% for new construction and 4% for renovation sites. Inert waste continued to dominate the composition of waste, accounting for 90% of the total with 9% for non-hazardous waste and 1% for hazardous waste. Semi-detached and grouped houses business fabrics and townhouses or collective fabrics were identified as the primary type of waste-producing urban fabrics. Furthermore, our GIS-based methodology enabled the analysis of CDW quantity distribution by municipality, providing essential data for understanding the urban mining potential and the disparity between construction material requirements for new buildings and resources derived from building demolition. This approach facilitates the assessment of (1) a geographical area’s reliance on construction materials, and (2) the significance of reusing and recycling products equipment materials and waste (PEMW) in new construction to achieve circular economy objectives and to comply with the Extended Producer Responsibility (EPR) channel initiated in France in 2023. Over the period from 2013 to 2022, annual construction material requirements remained significantly higher than resources from building demolition and rehabilitation, ranging between 29% and 35%. Additionally, the analysis indicated a potential 41% rate of substitution of new construction materials with secondary primary materials in the MEL, varying by municipality and typology, with higher rates in rural communities and lower rates in urban communities. Full article

The public housing stock, called social housing, in Italy was developed between the 1950s and the 1980s. As of today, the first residential developments are almost nearing their end-of-life age and are in need of urgent and intensive renovation. The European Commission, with the Renovation Wave, has set a goal of doubling the rate of building renovation over the next 10 years, reducing emissions, improving energy performance, and promoting decarburization. Renovation interventions, including structural, functional, energy, and plant upgrading interventions, etc., are to be preferred over integral demolition and reconstruction interventions, which have significant repercussions in terms of managerial and social discomfort. The case studies examined concern renovation interventions aimed at energy efficiency, functional adaptation of housing, as well as façade restyling. The design variants analyzed were evaluated in terms of CO_2e emissions, according to life cycle inventory (LCI) and Environmental Product Declaration (EPD) approaches. This approach has a twofold purpose: to propose design guidelines, with low CO_2e emissions, through hypotheses of variants in the case studies, and to propose, to the economic operators, economically advantageous bidding scenarios in the procurement process. Full article

The increasing rate of population growth and urban expansion has led to a higher demand for fossil fuels, which, in turn, directly generate greenhouse gas emissions into the atmosphere. These emissions contribute to environmental problems such as global warming and climate change. This study aims to present the total life-cycle energy analysis (LCEA) of a single-family detached house designed with an energy conservation approach. Using a cradle-to-grave scope, this study quantifies the embodied energy in six stages of the building’s life cycle, i.e., initial, transportation, construction, operational, recurrent, and demolition. An input–output (IO)-based method was employed to construct a Thailand-specific embodied energy coefficient for 36 key building materials. This coefficient was then used to quantify both the initial embodied energy and the recurrent embodied energy in this study. The case-study house was broken down into 13 building materials. Concrete was the most consumed material, followed by fiber–cement, steel, and timber, in that order. However, the results of the embodied energy distribution for these materials revealed that fiber–cement ranked first, accounting for 29%. Steel was next, at 21%, followed by concrete at 18%, and, finally, aluminum at 12%. The case-study house had an initial embodied energy of 7.99 GJ/m² and a total life-cycle energy consumption of 0.66 GJ/m²/year. This study provides valuable information on LCEA for residential buildings, fostering public understanding of energy conservation in the Thai context. Furthermore, this study’s results can be applied to establish energy conservation guidelines for residential buildings. These guidelines can help reduce energy resource depletion, carbon emissions, and environmental problems, ultimately contributing to Thailand’s goal of achieving carbon neutrality by 2050. Full article

The criteria on green public procurement of the European Union establish that the economic budgets of building projects must be complemented by their derived environmental and social costs. These criteria are currently being adapted to the requirements related to the circular economy, such as the use of methods to evaluate buildings environmentally. However, most methods available in the European and Spanish markets require prior training, which makes their use difficult. This paper presents an evaluation method, CEACE, for housing construction based on the determination of their footprints (ecological, carbon, and water footprints), also called the footprint family, to which the economic and social evaluation is added, as is the quantification of the construction and demolition waste generated. This method is validated with the assessment of fifteen residential buildings in Andalusia and creates an indicator that will allow technicians, companies, and administrations to evaluate projects in accordance with the criteria of green public procurement. The method is sensitive to changes in the type of building, foundation solution, and underground construction. Full article

Strategies for the adaptive reuse of vernacular architecture are of utmost importance in the current context of social, economic, and environmental vulnerability. This article examines the design strategies of adaptive reuse in three cases of renowned architects of the so-called School of Porto developed across the second half of the 20th century, specifically between 1956 and 1991. The paper aims to introduce a new and deeper knowledge of the selected practices by critically documenting the whole process of the intervention (before, during, after) and not only the final result, as is common practice in specialized publications. The research methodology combines the bibliographical and archival research and interpretation of diverse graphic, photographic, and textual documentation with the production of analytical drawings. The demolitions/additions color code (black/yellow/red) is applied to plans, sections, and elevations as an essential tool for understanding and communicating the transformations undertaken. The selected case studies are Além House (1956–1967) by Fernando Távora, Alcino Cardoso House (1971–1973; 1988–1991) by Álvaro Siza, and the House in Gerês (1980–1982) by Eduardo Souto de Moura. These projects show different strategies of intervention in built heritage, providing lessons on the reactivation of obsolete or abandoned rural constructions with new functions that are compatible with the preservation of their values (historical, landscape, constructive, social, and aesthetic) and guidelines for sustainable reuse. Full article

The building operation sector in China represents 22% of the national energy consumption and 22% of the carbon emission, of which urban residential buildings accounted for 24% in 2019. Such figures for the housing sector are projected to increase sharply in the near future, while China aims to peak CO₂ emissions by 2030 and reach neutrality before 2060. To reduce the impacts of the urban housing sector and address the energy use and waste generated by large-scale demolition and reconstruction, the central government started promoting the energy retrofit of urban residential buildings, raising such policies to the national strategic level. Jiangsu Province is one of the most urbanised, with a rapid growth in the energy consumption of residential buildings. The Multi-Danyuan and Single-Danyuan Apartment built in 1980–1999 are the most representative residential types in its urban areas. While still adequate functionally, they were designed and built to low energy standards and show significant potential for energy retrofit. Nonetheless, their current performance and energy-saving potential are under-researched, while more detailed and reliable data would be critical to support retrofit design and policy making. This study investigates and characterises the typical use and energy performance of the two building types. Additionally, seven measures and six retrofit scenarios were identified based on the optimal energy reductions and regulations from selected countries. The simulations indicate that, without intervention, the energy consumption of the typical urban residential buildings can reach 122 kWh/m² under the typical high-energy user scenario. By selecting a set of effective energy-saving measures, the operational energy use for heating and cooling can be reduced by up to 52.4%. Current local standards prove cost-efficient, although less effective in reducing energy use compared to international best practices, indicating potential improvements to the contribution of building retrofit towards achieving the national carbon reduction goals. Full article

Shantytowns still existed in many of Southern Europe’s major cities in the second half of the 20th century, although many have now been demolished. The purpose of this article is to highlight the history and evolution of some of the main shantytowns that remained in Barcelona in the mid-1970s, track their subsequent demolition, and reflect on the fate of the shanty dwellers. This form of self-build housing, usually lacking in basic services, played a vital role in providing shelter for immigrant families and the urban poor. A strong neighbourhood identity existed in many of these shantytowns, and national and local policies that aimed at their demolition and the re-housing of residents, often in low-quality housing blocks, proved problematic. The shantytowns studied here are La Perona, the Tres Turons, Campo de la Bota, and Ramon Casellas, which together comprised over 2000 shanty dwellings in the 1970s. Drawing on photographs taken at the time and existing literature, and using recent images from Google Earth, the demise of these shantytowns is examined, and the policies and plans that determined their fate are discussed. This article finds that the shanty dwellers experienced mixed fortunes, some being forcibly removed and re-housed in tower blocks with associated social-economic problems, whilst others played an active part in the design of replacement housing, implemented in situ where the shanty dwellings once existed. This article contributes to existing studies on shantytowns in Barcelona, which received scant attention from academics at the time, and which only now are being recognised as an important aspect of Barcelona’s urban history. Full article

The aim of this paper is to explore the rehabilitation strategies for multi-family dwellings on the level of function and techniques. The study employs its own methods of analysis using a sample of selected cases as a reference. Nearly 20% of EU buildings will have to be renovated by 2023, as almost 40% of the existing houses were built before 1980. The environmental impact of construction is among the highest among industrial activities due to the high consumption of resources and the generation of low-value waste at the construction and demolition stages. One way to reduce the environmental impact in this sector is to intervene in the building process, optimising the use of resources and waste generation. The principal objective of refurbishments is to reduce household energy consumption. However, the renovations in the housing sector should not be limited to energy considerations; the functional and technical aspects should also be considered. A new refurbishment model is necessary to focus on providing and improving the habitability of the housing stock and reducing the environmental impact by optimising the use of resources and waste generation. To achieve this, the renovations should be carefully monitored. Full article

The article deals with community resilience-oriented urban renewal in a geographical periphery, and the characteristic patterns of public housing built in the 1950s and 1960s. When the existing fabric is well-established and effectively serves the residents, demolition and redevelopment may not be the most strategic approach if they undermine the internal resilience of public housing based on functionality. The article addresses the question of how to add new construction and a new population to these patterns of public housing in the periphery without affecting the community resilience of longtime residents and the sense of urban vitality and innovation of the new population. In order to address this question, we examined the built environment’s qualities in relation to the population’s resilience. Specifically, we conducted a quality analysis of the built environment focusing primarily on walkability and connectivity, diversity and land uses, open public spaces, and visibility to internal and external views. The findings of the analysis recommend developing a multiple urban spatial network relying on the longtime community’s resilience and a new spatial network for the newcomers. This is a potentially win–win solution. The old neighborhoods remain, while at the same time an additional layer of housing and other land uses will be developed along the edges of existing neighborhoods. The proposed analysis will be demonstrated on the peripherical city of Kiryat Yam. Full article

The European Union (EU) is responsible for generating quantities ranging from 310 to almost 700 million tons of construction and demolition waste (CDW) per year. Consisting of over 70% inert material (concrete, ceramics, plaster, bricks, and rocks), CDW can be recycled for various uses, and studies on the concentration of the materials of interest are necessary to improve the management of this material and reduce waste. In CDW recycling plants in Spain, there is a significant presence of limestone from old houses (a common material used in civil construction before new construction materials and technologies emerged) that were demolished and mixed with CDW that can be recovered for use as aggregates in concretes with process density concentration processes such as water jigging. The jigging process is based on the difference in density between materials, allowing the concentration of the densest material at the bottom of the jig. Concrete, conventional construction bricks, and rocks from old houses were taken separately and then were crushed and mixed based on binary and ternary tests, and each test was performed in this study by applying the jigging separation method. The physical characterization tests of these materials was carried out to observe the jigging performance in the concentration of rocks as well as the aggregates present in concrete. Binary tests (with two different materials) and ternary tests (with three different materials) were carried out to analyze the concentration of particles with a density greater than 2.55 g/cm³. The efficiency of jigging in the concentration of these materials was proven, and products were generated with more than 70% recovery of this material, with a concentration comprised of more than 95% rocks and concrete. Full article

Against the backdrop of rapid urbanization, with the expansion of administrative boundaries, some former villages have been transformed from administrative to urban in the sense that they have become special “village-to-city areas”; in this context, the housing pattern, which was previously dominated by self-built houses, is facing many challenges. In particular, the frequent occurrence of safety accidents in self-built houses in the village conversion areas in recent years constitutes an important component of urban spatial vulnerability. However, the ensuing “one-size-fits-all” ban on self-built housing has also raised concerns among scholars. In order to better guide the planning and construction of self-built houses, official safety inspections, planning guidance, and institutional constraints are essential. However, the safety inspection of self-built houses across China is difficult. On the one hand, it is challenging to obtain data on individual buildings (e.g., age, use, building structure ratio, foundation, structural condition, illegal demolition and alteration, and illegal use), and the methods of obtaining such data rely mainly on the basic checking of the safety grids under the responsibility of grassroots safety officers. However, the current organizational system of safety officers is not perfect, and the relevant evaluation training also has limitations. On the other hand, due to the city’s finances, development stage, and other reasons, the agricultural-to-residential areas in the cities of poverty-stricken counties are not likely to be renewed as rapidly as the cities of developed regions but instead may face long-term renewal timelines. Therefore, for the agricultural resettlement areas in the cities of poverty-stricken counties, it is necessary to screen the current problems, systematically study the mechanism and strategy of their renewal based on the management framework of the whole process, and carry out the organic renewal of self-built houses, so as to gradually realize a safe and resilient development mode. This paper establishes a framework for the renewal of self-built houses oriented to security resilience based on the theory of fortress land under the urban form theory of Conzen. Taking Lianhua County as a case study, we analyze the problems and issues related to self-built housing areas through an investigation of the current situation. Then, in response to the existing problems, based on the comprehensive investigation of the safety of self-built houses, we clarify the planning objectives and value orientation and suggest (i) the adoption of hierarchical and classified planning and construction control for the self-built housing areas of villages converted to residences in accordance with the local conditions; (ii) the enhancement of government supervision in the use of self-built houses and the establishment of laws and regulations; and (iii) renewal planning in an orderly manner to enhance the safety resilience of the self-built housing areas. Based on the renewal study of self-built houses in Lianhua County, a systematic exploration of the planning, construction, and governance strategies of self-built houses in China is carried out, which can provide a reference for the decision making of relevant departments. Full article