Search Results (813)

To address the accumulation of construction and demolition waste (W&D), this study recycled it into regenerated fine aggregate and prepared 3D-printed mortars with replacement ratios ranging from 0% to 100%. The mechanical properties of hardened specimens were tested, and the degradation mechanisms of mechanical performance were investigated through SEM, MIP, and microhardness analysis. The carbon emissions of the materials were evaluated. The results indicated that while the 3D-printed mortar exhibited excellent buildability, its compressive strength, flexural strength, and interlayer bond strength gradually decreased with increasing replacement ratio. MIP results showed that as the replacement ratio of the W&D increased from 0% to 100%, the total porosity of the 3D-printed specimens significantly increased from 14.7433% to 27.5903%. SEM and microhardness images confirmed severe ITZ deterioration, and the average ITZ width increased from 31 to 79 μm. As the W&D replacement ratio increased from 0% to 100%, the total GWP decreased from 0.4043 to 0.3800 kg CO₂-eq/kg mortar. Maximizing the utilization of W&D is key to achieving efficient utilization of solid waste. Considering printability, mechanical performance, interlayer behavior, microstructural characteristics, and environmental impact in a comprehensive manner, the 80% W&D replacement ratio can be regarded as a relatively balanced and promising selection. This work not only suggests the technical feasibility of recycling W&D in 3D printing mortar, but also proposes a sustainable pathway to reduce carbon emissions in construction. Full article

To address the shortage of natural aggregates and freshwater, and promote the recycling of construction and demolition waste and localized construction materials for marine engineering, this study explores the electrochemical corrosion characteristics and deterioration mechanism of steel bars in recycled concrete aggregate (RCA)–seawater sea-sand concrete (SSC) concrete. Using RCA replacement rates (0%, 50%, 100%) as the core variable, specimens were prepared. Vacuum water saturation, open-circuit potential (OCP) monitoring, Tafel polarization scanning and electrochemical impedance spectroscopy (EIS) were adopted to study steel corrosion evolution within 180 days. The results show that RCA incorporation accelerates OCP negative drift and reduces passivation film stability, with more severe corrosion at higher replacement rates: the RCA100 group showed obvious corrosion after 60 days, while the RCA50 and RCA0 groups initiated corrosion at 90 days (RCA50 corroded faster). The surface mortar and internal microcracks of RCA enhance the water absorption and ion permeability of concrete, which, coupled with chloride ions, accelerates steel corrosion. This study clarifies the correlation between RCA replacement rate and corrosion parameters, providing data support for mix ratio optimization and marine engineering applications. Full article

The progression towards a circular economy in the construction sector has gained attention as a response to rising resource consumption and construction and demolition waste generation, with material reuse playing a central role. In this context, this study analyses the literature on reuse in the construction sector, examining its investigation over time and its relation to European regulatory frameworks and policy strategies. A systematic literature review was conducted using a structured search across the B-on, Scopus, and Web of Science databases. The search targeted peer-reviewed journal articles in English, published between 2008 and 2023, focusing on titles, abstracts, and keywords with predefined terms. A total of 78 articles met the inclusion criteria and were analysed. Research activity has increased in recent years, reflecting growing European policy attention, particularly the Waste Framework Directive, its 2018 amendment, and the Circular Economy Action Plan. Most studies address strategies to promote the circular economy, waste management practices, life cycle assessments, and the identification of barriers and opportunities to reuse. Despite the expanding literature, reuse remains insufficiently addressed. These findings underline the need for more targeted research and stronger integration between policy and practice to support effective reuse in the construction sector. Full article

The study focuses on the attempt to produce structural concrete, class C25/30 with exposure class XC3, using recycled aggregates derived from Excavation, Construction and Demolition Waste (ECDW) management. All the necessary properties of the recycled aggregates used were determined and four concrete mix compositions were made with recycled aggregate percentages ranging from 25% to 100%, while two more mix compositions were made with natural aggregates (NAs) to compare the results. A total of 78 cubic specimens, 13 from each mix, were obtained and their compressive strength, dynamic modulus of elasticity, rebound number, maximum deformation and maximum mass loss due to evaporation were determined at ages of 3, 7, 14, 28 and 90 days. The results show that 25–50% replacement with mixed recycled aggregates can satisfy the C25/30 strength class, whereas 100% replacement leads to significant strength and stiffness reductions. Overall, the study demonstrates that structural-grade recycled aggregate concrete is feasible up to moderate replacement levels, provided that the high water absorption and increased deformability associated with recycled aggregates are explicitly accounted for in mix design, curing and serviceability checks. Full article

The construction industry is a significant source of waste generation in any economy. The advancement in construction technologies and methods has brought about the concept of modular construction. Modular construction is considered as a preferred construction method over conventional construction methods mainly due to improved environmental performance and less waste generation. Nonetheless, processes involved in the use of modular construction generate a significant amount of waste though minimal as compared to the traditional mode of construction. Therefore, it is imperative to perform a comprehensive assessment of the factors that lead to waste generation in modular construction. This study aims to identify these factors as outlined in the existing literature and highlight their implications on the benefits of modular construction with an interest in the context of developing countries. A quantitative study was conducted to assess the views of construction professionals on identified factors that lead to waste generation in modular construction. The study targeted construction professionals with major emphasis on professionals with direct roles in the modular construction process. Fifteen factors were identified from the previous literature which were tested to evaluate their significance using the one-sample t-test. All factors proved significant and as such a principal component analysis was carried out to group the factors, evaluate the factor loadings and correlation patterns among the factors. The results specified “Non-conformance to building codes leading to demolition or rework”, “Incorrect assembly leading to module rework or disposal” and “Breakage or deformation of modules in transit” as the top three factors that lead to waste generation in modular construction. The findings of the study are useful to construction stakeholders by developing strategies to mitigate waste generation in modular construction. This study adds to the body of knowledge on modular construction, particularly in a developing-country context where modular construction projects are fewer. Full article

The growing reliance on virgin resources in construction, alongside accelerated urban development and the significant volumes of waste generated at the end-of-life phase of buildings, has intensified environmental impacts across the built environment. These challenges highlight the urgent need to transition towards a circular economy (CE) in the construction sector. At the same time, the sector’s ongoing digital transformation presents opportunities to enhance stakeholder collaboration and improve construction and demolition waste management (CDWM) practices. This paper aims to develop a conceptual framework for a Digital Information Management System (DIMS) to support CE implementation in construction through improved CDWM. Following the Design Science Research methodology, this paper addresses the first two stages: problem identification and solution proposition. A questionnaire survey with industry experts was conducted to validate the problem areas identified in the literature and assess the applicability of the proposed conceptual framework. The findings confirm critical gaps in CDWM, including limited stakeholder collaboration, fragmented processes, and the absence of lifecycle-spanning information systems, and validate the proposed conceptual framework solution, particularly the integration of BIM and IoT to support material and product flow tracking throughout the project lifecycle, supported by clearly defined stakeholder roles and engagements. However, respondents expressed reservations regarding Blockchain due to concerns about energy consumption and long-term data storage. Overall, the validated conceptual framework for DIMS provides a robust foundation for future studies, to focus on co-creating and developing a detailed conceptual model for DIMS for future real-world implementation. Full article

The resource utilization of construction and demolition waste (CDW) is crucial for advancing the green transformation of the construction industry, but it faces challenges such as insufficient upstream R&D motivation and low downstream market acceptance. To investigate the impact of corporate social responsibility (CSR) and sales effort on the recycled cement supply chain, in this study, a Stackelberg game model of a two-tier supply chain comprising a single recycled cement manufacturer and retailers is constructed. Under government subsidy conditions, four CSR sharing modes are systematically compared: no CSR (NS), manufacturer-borne (MS), retailer-borne (RS), and shared by both (TS). The results indicate the following: (1) CSR implementation reduces wholesale and retail prices while increasing sales effort, the incorporation rate of recycled aggregates, and market demand, with retailers bearing CSR yielding the most significant pull effect; (2) heightened sensitivity to sales effort incentivizes retailers to increase sales investment and encourages manufacturers to increase the incorporation rate of recycled aggregates, thereby increasing overall supply chain profits and utility; and (3) when the CSR coefficient does not exceed the critical value of 0.97, both manufacturer profits and retailer profits increase as the CSR level increases under the TS model; under the RS model, total supply chain profits and total utility reach their maximum. Corporate social responsibility (CSR) undertaken or jointly undertaken by retailers can better align economic and social objectives. This study provides theoretical foundations and practical insights for policy formulation and corporate decision-making in construction waste resource management. Full article

Construction and demolition activities generate over one-third of all waste produced within the European Union, with the largest fraction being mineral materials, and concrete representing up to 90% of this volume. In this context, the recycling of this type of waste is an important research topic with growing scientific and industrial relevance. While numerous studies have examined the influence of recycled concrete and other industrial waste on the technical performance of Portland cement-based composites, the antimicrobial resistance of these composites remains largely unexplored. Therefore, in this study we evaluate the effects of three different waste materials on the key properties of Portland cement mortar, as well as on its antimicrobial resistance; the investigated waste materials were fly ash (produced in thermal power plants), recycled concrete fines resulted from the mechanical processing of concrete waste generated in construction and demolition activities, as well as dried concrete slurry (a byproduct of concrete batching plants). The partial replacement of Portland cement with these concrete wastes slightly increased the mortar’s workability (up to 4.6%). However, it also led to an 11–12% reduction in compressive strength after 28 days of hardening. After 60 days of curing, the antimicrobial properties of these mortars were evaluated by assessing their effect on planktonic microbial growth and their anti-adherent capacity against the most common pathogenic strains (S. aureus, E. coli, P. aeruginosa, C. albicans, and C. parapsilosis). Antimicrobial assays were performed at two different concentrations of microbial suspensions, and the mortars exhibited significant antibiofilm properties against all strains, especially against E. coli. The study identified mortar formulations in which partial replacement of cement with construction, demolition, and industrial waste materials resulted in compressive strength and antimicrobial resistance comparable to those of conventional reference mortars. These findings highlight the potential to integrate recycled waste into Portland cement-based materials, supporting both structural integrity and microbial resistance and advancing sustainable construction practices. Full article

Accelerated urbanization and continuous infrastructure renewal have led to a rapid increase in construction and demolition waste (CDW), which accounts for approximately 20–50% of municipal solid waste in many developed countries. Consequently, effective management and resource utilization of CDW have become critical challenges for sustainable urban development. To address these challenges, this study develops an integrated analytical framework for CDW recycling systems. Specifically, it constructs a “cloud-edge-terminal” collaborative recycling system and clarifies the interactions among material, information, and value flows. A three-dimensional coupling framework is further established to reconceptualize CDW management as a multivariate decision-making problem, alongside a multidimensional evaluation structure to support practical implementation and system optimization. Methodologically, the study adopts an integrative review approach supported by knowledge mapping analysis. A structured literature search and screening process was conducted using the Web of Science Core Collection (2015–2026) to ensure transparency and reproducibility in the literature identification and sample construction. The results propose a multidimensional coupling framework integrating resource coordination, information communication, and market trading into a unified decision system. The framework contributes an engineering-oriented analytical paradigm that promotes hierarchical decision coordination, dynamic multi-objective regulation, and integrated management of CDW recycling systems. Full article

The built environment continues to encounter significant challenges related to waste generation and resource depletion, driving increased interest in circular economy strategies that extend material lifecycles and mitigate environmental impacts. This systematic review synthesises findings from 60 studies on waste-to-resource innovations across construction and household contexts. Although the existing literature predominantly addresses construction and demolition waste, this review foregrounds household operational waste, an area that remains insufficiently explored despite its importance for everyday resource recovery. The analysis examines how materials generated through routine use, maintenance, and minor renovation activities can be captured and redirected into productive resource streams, with particular attention to governance mechanisms such as Extended Producer Responsibility (EPR). The findings indicate that effective waste-to-resource systems depend on coherent regulatory frameworks and enforcement, economic incentives, enabling technologies, community engagement, and product design that facilitates reuse and disassembly. Key barriers include low public awareness, fragmented supply chains, high recovery costs, weak compliance mechanisms, and materials that are difficult to separate. The review concludes that improving waste-to-resource outcomes in the built environment requires coordinated action among producers, households, local authorities, and technology providers, and it articulates policy-relevant and community-oriented pathways to support more effective resource recovery systems. Full article

The depletion of natural aggregates and the rapid increase in construction and demolition waste have intensified the need for sustainable structural materials. Recycled aggregates (RAs) represent a promising alternative; however, their performance under elevated temperatures remains insufficiently investigated. This study examines the combined influence of recycled coarse and fine aggregates (RCFA) replacement ratios and fire exposure on the shear behavior of RC beams. Five replacement levels (0%, 25%, 50%, 75%, and 100%) were considered. A total of forty-five beams (1500 × 150 × 200 mm) were tested at 23 °C, 400 °C, and 600 °C. In addition, a finite element model was developed to validate the experimental findings. The results showed at 23 °C, increasing the RA content led to a moderate reduction in the ultimate shear capacity of approximately 6–10%. Fire exposure significantly aggravated strength degradation, with additional reductions of up to 11% at 400 °C and total losses reaching about 22% at 600 °C compared to the control beam at room temperature. Stiffness deterioration and crack propagation became more pronounced with higher temperatures and replacement ratios due to thermal damage to the cement matrix and interfacial transition zones. Nevertheless, moderate replacement levels (25–50%) maintained acceptable residual shear capacity and improved ductility and energy absorption. Numerical predictions closely matched experimental results, with load differences within 1–5%, confirming the model’s reliability. Full article

This study provides new experimental evidence indicating that powdered mineral wool waste traditionally classified as a non-reactive, non-recyclable insulation residue can function as a genuinely pozzolanic supplementary cementitious material when incorporated into Portland cement systems. Unlike previous work that has treated mineral wool exclusively as an inert filler, this research demonstrates that its amorphous silicate–aluminate phase becomes chemically active under high-alkalinity conditions. A combined experimental programme, including mechanical testing, assessment and SEM/EDS microstructural analysis, was used to evaluate replacement levels of 20%, 25%, and 40% in CEM I mortars, with CSA cement employed as a contrasting binder system. The results indicate a potential contribution of powdered mineral wool to strength development; however, this effect cannot be unequivocally attributed to pozzolanic activity alone. It may also be partially related to physical effects such as filler action and particle packing. SEM/EDS observations confirm the formation of secondary C–S–H and C–A–S–H gels, can function as a genuinely pozzolanic supplementary cementitious material. Therefore, the applied assessment approach should be treated as indicative, and further verification using complementary methods is required. This study provides new experimental evidence indicating mineral wool can potentially contribute to cementitious performance as a Supplementary Cementitious Material (SCM). However, these observations should be treated as qualitative and indicative rather than definitive proof of pozzolanic reaction. The study provides an environmentally relevant valorisation pathway for a problematic waste stream, showing that mineral wool residues containing only trace levels of immobilizable formaldehyde can be safely and effectively integrated into low-carbon binder technologies. These findings position powdered mineral wool as a previously overlooked, yet technically viable SCM, offering new opportunities for clinker reduction, waste circularity and sustainable cementitious material design. Full article

Construction and demolition waste (CDW) represents a critical environmental challenge in the building sector, with global generation exceeding 3.57 billion tonnes annually. The circular economy (CE) framework offers a transformative pathway through selective deconstruction and material recovery, yet implementation faces significant barriers including information asymmetry, supply chain fragmentation, and regulatory uncertainty. This study conducts a systematic literature review using the Context–Mechanism–Outcome (CMO) framework to analyze how computational methods, specifically Digital Twins (DT), Building Information Modeling (BIM), Internet of Things (IoT), blockchain, artificial intelligence, and robotics, act as enablers for resilience in CDW management. Following PRISMA 2020 guidelines and realist synthesis principles, we analyzed 42 high-quality empirical studies from Web of Science and Scopus (2015–2025). Our analysis identifies seven primary mechanisms: traceability (M1), simulation (M2), classification (M3), tracking (M4), collaboration (M5), analytics (M6) and robotics (M7). These mechanisms interact with four critical contexts (information asymmetry, supply chain fragmentation, economic uncertainty, operational risks) to generate outcomes at two levels: resilience capabilities (visibility, monitoring, collaboration, flexibility, anticipation) and performance indicators (recovery rates, cost reduction, CO₂ emissions mitigation, occupational safety). Key findings from the CMO analysis reveal that blockchain-enabled traceability increases material recovery rates by 15–25%, DT simulation reduces deconstruction costs by 20–30%, and computer vision automation improves sorting accuracy to 85–95%. The study contributes middle-range theories explaining how digital technologies enable circular transitions under specific contextual conditions, offering actionable strategic implications for researchers, project managers, technology developers, and policymakers committed to advancing computational economics in sustainable construction. Full article

Human activities significantly influence the risk levels of natural disasters, with the construction industry contributing heavily to waste production and resource depletion as the global population grows and housing demand rises. This research seeks to mitigate some of these impacts. To reduce the demand for natural aggregates, compressed earth blocks (CEBs) were formulated using recycled waste materials—specifically crushed concrete and glass sand—stabilized with cement. The resulting blocks exhibited physical, mechanical, and thermal properties that position them as viable candidates for construction purposes. Investigating the microstructure of these masonry units and its correlation with their macroscopic properties provides the technical foundation necessary for the building industry to adopt them in sustainable architecture for hot and humid climates. Methodologies including thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and SEM image analysis (SEM-IA) demonstrated strong correlations across the 12 formulations (four matrices at three cement concentrations each). For instance, matrices with 15% cement by weight—which achieved compressive strengths between 6.2 and 7.3 MPa—showed greater mass loss associated with intralayer water and hydration products, a reduction in both porosity and the interfacial transition zone (ITZ), and higher concentrations of silica and calcium. Full article