Buildings

23 pages, 4969 KB

Open AccessArticle

Experimental Study on Mechanical Properties of Hybrid Fiber Desert Sand Recycled Aggregate Concrete

by Yanlin Guan, Yaqiang Yang, Jianzhe Shi, Daochuan Zhou, Bitao Wu, Wenping Du, Shanshan Yu and Jing Cui

Buildings 2025, 15(21), 3857; https://doi.org/10.3390/buildings15213857 (registering DOI) - 24 Oct 2025

Abstract

In response to the issues of microcrack susceptibility, high brittleness, and unstable mechanical properties of desert sand recycled aggregate concrete (DSRAC), this study experimentally investigated the mechanical performance of DSRAC reinforced with hybrid steel–FERRO fibers. By testing macroscopic properties (compressive, splitting tensile, and [...] Read more.

In response to the issues of microcrack susceptibility, high brittleness, and unstable mechanical properties of desert sand recycled aggregate concrete (DSRAC), this study experimentally investigated the mechanical performance of DSRAC reinforced with hybrid steel–FERRO fibers. By testing macroscopic properties (compressive, splitting tensile, and flexural strengths) under different desert sand replacement ratios and fiber dosages, combined with microscopic analysis, the fiber-matrix interfacial behavior and toughening mechanism were clarified. The results showed that (1) DSRAC achieved optimal compressive strength when desert sand replaced 30% natural sand, with an obvious early strength enhancement; (2) both steel fibers and FERRO fibers independently improved DSRAC’s mechanical properties, while their hybrid combination (especially F0.15-S0.5 group) exhibited a superior synergistic strengthening effect, significantly outperforming single-fiber groups; (3) the established constitutive model accurately described the stress–strain response of hybrid fiber-reinforced DSRAC; (4) microscopic observations confirmed fibers inhibited crack propagation via bridging and stress dispersion, with hybrid fibers exerting multi-scale synergistic effects. This study provided theoretical–technical support for resource utilization of desert sand and recycled aggregates, and offered practical references for localized infrastructure materials (e.g., rural road subgrades and small-span culverts) in desert-rich regions and high-value reuse of construction waste in prefabricated components, advancing eco-friendly concrete in sustainable construction. Full article

(This article belongs to the Special Issue Fiber-Reinforced Polymers and Fiber-Reinforced Concrete in Civil Engineering—2nd Edition)

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19 pages, 2115 KB

Open AccessArticle

Application of Digital Twin Platform for Prefabricated Assembled Superimposed Stations Based on SERIC and IoT Integration

by Linhai Lu, Jiahai Liu, Bingbing Hu, Yingqi Gao, Qianwei Xu, Yanyun Lu and Guanlin Huang

Buildings 2025, 15(21), 3856; https://doi.org/10.3390/buildings15213856 (registering DOI) - 24 Oct 2025

Abstract

Prefabricated stations utilizing digital modeling techniques demonstrate significant advantages over traditional cast-in-place methods, including improved dimensional accuracy, reduced environmental impact, and minimized material waste. To maximize these benefits, this study develops a digital twin platform for prefabricated assembled superimposed stations through the integration [...] Read more.

Prefabricated stations utilizing digital modeling techniques demonstrate significant advantages over traditional cast-in-place methods, including improved dimensional accuracy, reduced environmental impact, and minimized material waste. To maximize these benefits, this study develops a digital twin platform for prefabricated assembled superimposed stations through the integration of Digital Twin Scene–Entity–Relationship–Incident–Control (SERIC) modeling with IoT technology. The platform adopts a “1+5+N” architecture that implements model-data separation, lightweight processing, and model-data association for SERIC model management, while IoT-enabled data acquisition facilitates lifecycle data sharing. By integrating BIM models, engineering data, and IoT sensor inputs, the platform employs multi-source analytics to monitor construction progress, enhance safety surveillance, ensure quality control, and optimize designs. Implementation at Jinan Metro Line 8’s prefabricated underground station confirms the SERIC-IoT digital twin’s efficacy in advancing sustainable, high-quality rail transit development. Results demonstrate the platform’s capacity to improve construction efficiency and operational management, aligning with urban rail objectives prioritizing sustainability and technological innovation. This study establishes that integrating SERIC modeling with IoT in digital twin frameworks offers a robust approach to modernizing prefabricated station construction, with scalable applications for future smart transit infrastructure. Full article

(This article belongs to the Section Building Structures)

20 pages, 3591 KB

Open AccessArticle

Numerical Simulation and Model Validation of Multispiral-Reinforced Concrete Columns’ Response to Cyclic Loading

by Luboš Řehounek and Michal Ženíšek

Buildings 2025, 15(21), 3855; https://doi.org/10.3390/buildings15213855 (registering DOI) - 24 Oct 2025

Abstract

In regions where seismic loads pose a significant danger to the structural stability of buildings, developing sustainable solutions for increasing the ductility of structural members is of great importance. One of the contemporary, emerging approaches is to use the greater confinement of concrete [...] Read more.

In regions where seismic loads pose a significant danger to the structural stability of buildings, developing sustainable solutions for increasing the ductility of structural members is of great importance. One of the contemporary, emerging approaches is to use the greater confinement of concrete using multispiral reinforcement. A numerical model of two variants of Multispiral-Reinforced Concrete Columns (MRCCs) that differ in their axial loads using FEA was developed and validated. A non-linear combined fracture-plasticity concrete model with the crack band approach and an embedded reinforced model with bond slip were used. The main finding is that higher axial loads do not significantly increase the stiffness response, but reduce ductility (achieved drift). The achieved force agreement between the simulation and the experiment is within

2 %

at the peak and within

24 %

at the largest column drift in the post-peak region. For the purpose of rapid prototyping, a plugin that enables the user to quickly change various properties of MRCC geometry using an automated approach instead of modeling individual variants from zero is proposed. This overall approach was developed to both save on user time spent modeling and on the great costs that involve manufacturing and testing of real-scale specimens. Full article

(This article belongs to the Special Issue Concrete in the Digital Age: Advanced Simulations for Structural Innovation)

31 pages, 1915 KB

Open AccessArticle

Framework for the Verification of Geometric Digital Twins: Application in a University Environment

by Iryna Osadcha, Jaime B. Fernandez, Darius Pupeikis, Vytautas Bocullo, Muhammad Intizar Ali and Andrius Jurelionis

Buildings 2025, 15(21), 3854; https://doi.org/10.3390/buildings15213854 (registering DOI) - 24 Oct 2025

Abstract

Digital Twins rely on accurate geometric models to ensure reliable representation, yet maintaining and updating these models remains a persistent challenge. This paper addresses one aspect of this challenge by focusing on the verification of photogrammetry-based models. It introduces a verification framework that [...] Read more.

Digital Twins rely on accurate geometric models to ensure reliable representation, yet maintaining and updating these models remains a persistent challenge. This paper addresses one aspect of this challenge by focusing on the verification of photogrammetry-based models. It introduces a verification framework that defines measurable data quality elements and establishes conditions to assess whether model quality is maintained, improved, or degraded. Validation through a university building case study demonstrates the framework’s ability to detect quality differences between visually similar models. Meeting only one of the three verification conditions, the new model shows quality degradation, primarily due to reduced positional accuracy and resolution, making it unsuitable to replace the previous version used in the Digital Twin. Additionally, the developed web tool prototype enables the automated calculation of the framework’s verification scores. This study contributes to the growing discussion on Digital Twin maintenance by providing practical insights for improving the reliability of geometric models. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

25 pages, 1615 KB

Open AccessArticle

Performance Assessment of a Landfill Expansion Stabilized with Reinforced Fill Structure Using Numerical Analysis

by Ahsan Rehman Khan and Gemmina Di Emidio

Buildings 2025, 15(21), 3853; https://doi.org/10.3390/buildings15213853 (registering DOI) - 24 Oct 2025

Abstract

This study investigates the feasibility of landfill expansion using the limit equilibrium and finite element methods. A 15.5 m high reinforced fill structure (RFS) was analyzed to assess how fill type, consolidation rate, geometric configuration, waste strength, compaction and the inclusion of banquettes [...] Read more.

This study investigates the feasibility of landfill expansion using the limit equilibrium and finite element methods. A 15.5 m high reinforced fill structure (RFS) was analyzed to assess how fill type, consolidation rate, geometric configuration, waste strength, compaction and the inclusion of banquettes affect horizontal displacement, differential settlement, reinforcement strain and facing behavior. The baseline configuration demonstrated acceptable settlement, reinforcement strain, and gabion performance but exceeded allowable horizontal displacement limits. The scenarios including increasing consolidation rate and substitution with sand backfill further aggravated displacements, whereas banquettes significantly reduced lateral movement and settlement, demonstrating their effectiveness in stabilizing slopes. Enhancing the industrial waste properties decreased displacements substantially improving overall stability. Geometric modifications, such as widening the reinforced zone, enhanced displacement control, while higher compaction achieved the best global performance, albeit with increased gabion compressibility. Extending geogrid length provided only marginal improvements beyond a certain threshold. Overall, banquettes, enhanced waste properties, and improved compaction were identified as the most effective strategies for stable efficient landfill expansion, emphasizing the importance of displacement control and reinforcement–facing interaction. Full article

24 pages, 3475 KB

Open AccessArticle

Mechanical and Fatigue Performance of Recycled Concrete Aggregate Blended with Waste Tyre Rubber Stabilised with Slag for Pavement Application

by Fatima Juveria, Janitha Migunthanna, Pathmanathan Rajeev and Jay Sanjayan

Buildings 2025, 15(21), 3852; https://doi.org/10.3390/buildings15213852 (registering DOI) - 24 Oct 2025

Abstract

Waste tyre rubber (TR) from end-of-life tyres poses a major environmental challenge. Therefore, recycling this waste into useful applications contributes to sustainable waste management strategies and supports a circular economy. Rubber possesses properties that can enhance the flexibility and ductility of pavements, making [...] Read more.

Waste tyre rubber (TR) from end-of-life tyres poses a major environmental challenge. Therefore, recycling this waste into useful applications contributes to sustainable waste management strategies and supports a circular economy. Rubber possesses properties that can enhance the flexibility and ductility of pavements, making it a feasible material for use in road infrastructure. This study investigates the mechanical and fatigue performance of recycled concrete aggregates (RCA) mixed with waste TR. RCA was partially replaced at three different levels: 5%, 10% and 15% by weight. To mitigate the loss in mechanical strength associated with rubber inclusion, the TR + RCA mixes were stabilised through geopolymerisation using slag as a precursor. The unconfined compressive strength (UCS) increased with higher binder content. For instance, the mix containing 15% TR and stabilised with 5% slag geopolymer achieved a UCS of only 0.7 MPa, whereas increasing the binder content to 15% raised the UCS to 2.2 MPa. Similarly, resilient modulus improved with increasing slag content. Results from the four-point bending fatigue test showed that replacing RCA with rubber particles enhanced the fatigue performance of the mixes. The initial fatigue modulus of 100% RCA mix stabilised with 15% binder was 13,690 MPa, which reduced to 9740 MPa when 10% TR was introduced. In contrast, the number of cycles to reach half the initial modulus increased by four times when the TR content was raised from 0% to 15%. Microstructural observations of the slag-stabilised TR + RCA mixes showed improved microstructure due to geopolymerisation. Only insignificant traces of arsenic (<0.0008 mg/L) and barium (<0.000208 mg/L) were present in the TR + RCA mixes, while all other concerning heavy metals, including mercury and lead, were not detected in the leaching test. This indicates that there is no potential risk of soil or groundwater contamination, confirming the environmental safety of using slag geopolymer-stabilised TR + RCA mixes in subbase applications. Full article

(This article belongs to the Special Issue Analysis of Performance in Green Concrete Structures)

18 pages, 885 KB

Open AccessArticle

Construction and Application of a Multi-Dimensional Quality Gain–Loss Function for Dam Concrete Based on Gaussian Process

by Bo Wang, Qikai Li, Liang Pei, Pengyuan Li, Hongxiang Li, Xiangtian Nie and Tianyu Fan

Buildings 2025, 15(21), 3851; https://doi.org/10.3390/buildings15213851 (registering DOI) - 24 Oct 2025

Abstract

As a critical component of China’s major infrastructure, the quality and safety of hydraulic engineering projects are directly linked to national economic security. Therefore, research on construction quality management of hydraulic concrete is of great importance. Traditional quality gain–loss functions often fail to [...] Read more.

As a critical component of China’s major infrastructure, the quality and safety of hydraulic engineering projects are directly linked to national economic security. Therefore, research on construction quality management of hydraulic concrete is of great importance. Traditional quality gain–loss functions often fail to fully capture the correlations among multiple quality characteristics, the varying weights of these characteristics in overall quality performance, and the presence of multiple influencing factors. To address these limitations, this study employs Gaussian process regression to construct a multivariate and multidimensional quality gain–loss function model. The signal-to-noise ratio is used to represent the interactions among different quality characteristics, while a gain–loss cost matrix is introduced to account for the contribution of each characteristic to the overall function. A case study on summer dam concrete construction is presented to demonstrate the applicability of the proposed model. The results show that the gain–loss values range from a minimum of 1.09 to a maximum of 11.7, which are significantly lower than those obtained using the dimensionless standardized multivariate quality gain–loss function developed by Artiles-León, thereby validating the effectiveness and rationality of the proposed approach. Full article

(This article belongs to the Section Building Structures)

29 pages, 1895 KB

Open AccessArticle

Case Study on Ultra-High-Performance-Concrete-Reinforced Autoclaved Lightweight Concrete: Multi-Scale Optimization of Autogenous Shrinkage, Interface, and Structure

by Jianxin Li, Duochao Xie, Yilin Su, Tiezhi Zhang and Yan Guan

Buildings 2025, 15(21), 3850; https://doi.org/10.3390/buildings15213850 (registering DOI) - 24 Oct 2025

Abstract

Autoclaved lightweight concrete (ALC) exhibits considerable potential as a wall material in prefabricated structures, but its high water absorption and limited mechanical properties limit its widespread application. Ultra-high-performance concrete (UHPC), which possesses superior mechanical strength and durability, presents a promising reinforcement strategy. This [...] Read more.

Autoclaved lightweight concrete (ALC) exhibits considerable potential as a wall material in prefabricated structures, but its high water absorption and limited mechanical properties limit its widespread application. Ultra-high-performance concrete (UHPC), which possesses superior mechanical strength and durability, presents a promising reinforcement strategy. This study proposes the development of a UHPC-ALC composite wall material to enhance structural performance. The effects of shrinkage-reducing agent (SRA) content and expansive agent (EA) dosage on UHPC properties were systematically investigated. Results indicate that increasing SRA content improves the fluidity of UHPC and significantly reduces early autogenous shrinkage while the optimal EA dosage enhances both its mechanical properties and volume stability. Furthermore, an interfacial agent was employed to enhance the bonding performance between UHPC and ALC resulting in an average bonding strength of 0.93 MPa which represents a 675% increase compared with the untreated group. Finite element simulations and mechanical tests revealed that the composite material demonstrates a compressive strength of 11.2 MPa and a flexural strength of 6.8 MPa which corresponds to increases of 111.3% and 325%, respectively, relative to monolithic ALC. The composite demonstrated ductile failure and the experimental damage modes were consistent with those of the simulation results. This study offers guidance for optimizing UHPC-based composite wall materials via the multi-scale regulation of shrinkage behavior, interfacial properties, and structural design. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

18 pages, 5577 KB

Open AccessArticle

Research on Intelligent Identification Model of Cable Damage of Sea Crossing Cable-Stayed Bridge Based on Deep Learning

by Jin Yan, Yunkai Zhao, Changqing Li and Jiancheng Lu

Buildings 2025, 15(21), 3849; https://doi.org/10.3390/buildings15213849 (registering DOI) - 24 Oct 2025

Abstract

To accurately evaluate the health condition of the cables of a cross-sea cable-stayed bridge under typhoon effects and to improve the efficiency of damage identification, an accurate bridge damage identification method combining convolutional neural network (CNN) and Bidirectional Long Short-Term Memory (BiLSTM) is [...] Read more.

To accurately evaluate the health condition of the cables of a cross-sea cable-stayed bridge under typhoon effects and to improve the efficiency of damage identification, an accurate bridge damage identification method combining convolutional neural network (CNN) and Bidirectional Long Short-Term Memory (BiLSTM) is proposed. A numerical model of the cable-stayed bridge was first established in ANSYS. Based on the monitoring data of Super Typhoon Mujigae, a three-dimensional fluctuating wind field was generated by harmonic synthesis. Through transient analysis, the static and dynamic responses of the cable-stayed bridge under typhoon loads were analyzed, and the critical cable locations most susceptible to damage were identified. Subsequently, the acceleration signals of the structural damage states under typhoon were extracted, and the damage-sensitive features were obtained through the Hilbert transform. Finally, an intelligent damage identification model for cable-stayed bridges was established by combining CNN and BiLSTM, and the identification results were compared with those obtained using CNN and BiLSTM individually. The results indicate that the neural network model combining CNN and BiLSTM performs significantly better than either CNN or BiLSTM alone in predicting both the location and degree of damage. Compared with the standalone CNN and BiLSTM models, the proposed hybrid CNN–BiLSTM network improves the accuracy of damage-location identification by 1.6% and 2.42%, respectively, and achieves an overall damage-degree identification accuracy exceeding 98%. The findings of this study provide theoretical and practical support for the intelligent operation and maintenance of cable-stayed bridges in coastal regions. The proposed approach is expected to serve as a valuable reference for evaluating large-span bridge structures under extreme wind conditions. Full article

(This article belongs to the Section Building Structures)

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24 pages, 987 KB

Open AccessArticle

Meta-Learning Enhanced 3D CNN-LSTM Framework for Predicting Durability of Mechanical Metal–Concrete Interfaces in Building Composite Materials with Limited Historical Data

by Fangyuan Cui, Lie Liang and Xiaolong Chen

Buildings 2025, 15(21), 3848; https://doi.org/10.3390/buildings15213848 (registering DOI) - 24 Oct 2025

Abstract

We propose a novel meta-learning enhanced 3D CNN-LSTM framework for durability prediction. The framework integrates 3D microstructural data from micro-CT scanning with environmental time-series data through a dual-branch architecture: a 3D CNN branch extracts spatial degradation patterns from volumetric data, while an LSTM [...] Read more.

We propose a novel meta-learning enhanced 3D CNN-LSTM framework for durability prediction. The framework integrates 3D microstructural data from micro-CT scanning with environmental time-series data through a dual-branch architecture: a 3D CNN branch extracts spatial degradation patterns from volumetric data, while an LSTM network processes temporal environmental factors. To address data scarcity, we incorporate a prototypical network-based meta-learning module that learns class prototypes from limited support samples and generalizes predictions to new corrosion scenarios through distance-based probability estimation. Additionally, we develop a dynamic feature fusion mechanism that adaptively combines spatial, environmental, and mechanical features using trainable attention coefficients, enabling context-aware representation learning. Finally, an interface damage visualization component identifies critical degradation zones and propagation trajectories, providing interpretable engineering insights. Experimental validation on laboratory specimens demonstrates superior accuracy (74.6% in 1-shot scenarios) compared to conventional methods, particularly in aggressive corrosion environments where data scarcity typically hinders reliable prediction. The visualization system generates interpretable 3D damage maps with an average Intersection-over-Union of 0.78 compared to ground truth segmentations. This work establishes a unified computational framework bridging microstructure analysis with macroscopic durability assessment, offering practical value for infrastructure maintenance decision-making under uncertainty. The modular design facilitates extension to diverse interface types and environmental conditions. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

23 pages, 714 KB

Open AccessArticle

Strategies for Implementing the Circular Economy in the Built Environment

by Sandra Przepiórkowska, Dagmara Kociuba and Waldemar Kociuba

Buildings 2025, 15(21), 3847; https://doi.org/10.3390/buildings15213847 (registering DOI) - 24 Oct 2025

Abstract

In recent years, European cities have implemented numerous initiatives to reduce the use of resources and improve the resilience of climate change by promoting shifts toward the circular economy (CE). This comparative case study investigated the results of the applications of the CE [...] Read more.

In recent years, European cities have implemented numerous initiatives to reduce the use of resources and improve the resilience of climate change by promoting shifts toward the circular economy (CE). This comparative case study investigated the results of the applications of the CE model in the built environment from two different national approaches and perspectives of strategic planning in capitals that represent the “old” (Copenhagen) and “new” (Ljubljana) European Union (EU) member states. This paper introduces the original methodology to assess the implementation of the strategic approaches in the adaptation of the CE in architecture and urban design using a set of 10 selecting indicators. Although both cities have ambitious strategic goals and are undertaking actions aimed at shifting to the CE, they are driven by different motivations (climate crisis vs. urban revitalization and zero waste policy) and exhibit different implementation patterns (top-down systemic/institutional vs. gradual/sectoral). The results highlight the key role of a comprehensive approach to CE implementation, particularly the development of institutional frameworks and dedicated infrastructure and digital tools for transition management, the involvement of external stakeholders in the circular vision, wide-range educational activities, and the promotion of CE initiatives. However, limitations resulting from the lack of a comprehensive and standardized measurement framework pose a challenge to effectively accelerate progress in the shift toward a CE in the built environment. The main contributions of this study are: (1) to identify and verify the methods and strategies undertaken by European cities for the adaptation of a CE in the built environment and (2) demonstrate the different dimensions, levels, and the most relevant factors in the strategic management of the processes of transformation toward the CE. In addition, recommendations for future implementations based on CE systems are indicated. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

31 pages, 10272 KB

Open AccessArticle

Climate-Responsive Design for Sustainable Housing: Thermal Comfort, Spatial Configuration, and Environmental Satisfaction in Subtropical Void Decks

by Shan Chen, Jinbo Feng, Fei Xue and Qiong Hu

Buildings 2025, 15(21), 3846; https://doi.org/10.3390/buildings15213846 (registering DOI) - 24 Oct 2025

Abstract

With rapid urbanization and intensifying climate change impacts, the thermal comfort performance of semi-outdoor spaces has emerged as a critical issue in sustainable urban design and housing development. However, the unique void decks of residential environments remain underexplored in the existing literature. This [...] Read more.

With rapid urbanization and intensifying climate change impacts, the thermal comfort performance of semi-outdoor spaces has emerged as a critical issue in sustainable urban design and housing development. However, the unique void decks of residential environments remain underexplored in the existing literature. This study addresses the knowledge gap by investigating how morphological characteristics influence microclimatic conditions and user satisfaction in high-density subtropical residential environments. Field measurements and questionnaire surveys were conducted across 18 void decks in four representative Shenzhen communities during summer 2024, examining air temperature, relative humidity, wind velocity, mean radiant temperature, and UTCI alongside users’ thermal perceptions. Hierarchical cluster analysis identified three distinct typologies based on spatial attributes: North–South-Ventilated (NS-VD), Single-Directional (SD-VD), and Oblique-Oriented (OO-VD). Ridge regression analysis revealed seven critical configuration variables—height-to-depth ratio, orientation, angle with wind, number of open sides, sky view factor, green view factor, and height from ground—collectively explaining 51.2% of UTCI variation. The results were as follows: (1) we identified morphological typologies and quantify microclimate variations across spatial configurations; (2) established quantitative relationships between objective thermal metrics and subjective thermal perceptions; and (3) developed evidence-based design recommendations for enhancing thermal environments in subtropical residential contexts. The findings support climate-responsive design for high-density residential environments by providing a scientific basis for optimizing microclimates and enhancing community vitality. Full article

(This article belongs to the Special Issue Sustainable Housing and Urban Planning: Enhancing Well-Being Through Environmental Design)

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35 pages, 2579 KB

Open AccessSystematic Review

Semantic Web Technologies in Construction Facility Management: A Bibliometric Analysis and Future Directions

by Rafay Ali Bukhari Syed, Rosa Agliata, Ippolita Mecca and Luigi Mollo

Buildings 2025, 15(21), 3845; https://doi.org/10.3390/buildings15213845 (registering DOI) - 24 Oct 2025

Abstract

The Facility Management (FM) sector is often hampered by data fragmentation and poor interoperability, hindering operational efficiency. To overcome these challenges, Semantic Web Technologies (SWTs) offer a robust framework by enabling machine-readable data integration. However, the application of SWTs in FM is underexplored. [...] Read more.

The Facility Management (FM) sector is often hampered by data fragmentation and poor interoperability, hindering operational efficiency. To overcome these challenges, Semantic Web Technologies (SWTs) offer a robust framework by enabling machine-readable data integration. However, the application of SWTs in FM is underexplored. Therefore, this study systematically analyzes the structure, evolution, and emerging trends of SWT applications in FM to provide a clear research roadmap. A systematic literature review and bibliometric analysis were conducted on a final dataset of 107 academic articles using co-citation and keyword co-occurrence analysis. The results reveal that research in this domain has experienced exponential growth since 2021, with publications concentrated in high-impact journals. While a core group of influential authors has emerged, international collaboration remains fragmented. Thematic analysis identified a clear evolutionary trajectory from foundational concepts like BIM and ontologies toward applied Digital Twins and, most recently, advanced automation using Knowledge Graphs. This study provides a comprehensive roadmap for future inquiry, highlighting the need to mature technology integration, advance applied digital twins, and develop domain-specific ontologies to create more intelligent facilities. Ultimately, this study provides managers and policy-makers with a data-driven reference for strategically prioritizing investments in digitalization to achieve sustainable facility operation. Full article

(This article belongs to the Special Issue Innovative Approaches to Sustainability Management and Digital Integration in the Built Environment)

22 pages, 7355 KB

Open AccessArticle

Monitoring Progress and Standardization of Work Using Artificial Intelligence—Evolution of NORMENG Project

by Zvonko Sigmund, Kristijan Vilibić, Ivica Završki and Matej Mihić

Buildings 2025, 15(21), 3844; https://doi.org/10.3390/buildings15213844 (registering DOI) - 24 Oct 2025

Abstract

This paper represents initial research with the aim to establishes a baseline for subsequent research into AI-based construction monitoring, building upon the NORMENG project in Croatia, which previously integrated photogrammetry, laser scanning, and BIM-based methods. The study tests general purpose AI’s ability to [...] Read more.

This paper represents initial research with the aim to establishes a baseline for subsequent research into AI-based construction monitoring, building upon the NORMENG project in Croatia, which previously integrated photogrammetry, laser scanning, and BIM-based methods. The study tests general purpose AI’s ability to detect materials and estimate quantities, aiming to assess whether a broad, context-aware AI system can match the precision of specialized, domain-specific tools or even human work needed for productivity estimations. While the AI demonstrated potential for basic entity detection and preliminary quantity estimations, it showed significant limitations in delivering fine-grained, temporally accurate breakdowns without targeted adaptation. The findings underscore the need for domain-specific fine-tuning and human-in-the-loop validation to transform AI into a reliable tool for construction management. This initial contribution provides empirical insights and actionable recommendations for advancing automated progress monitoring in the construction sector. Full article

(This article belongs to the Special Issue Applying Artificial Intelligence in Construction Management)

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36 pages, 14983 KB

Open AccessArticle

Seismic Performance of a Brazilian RC Frame Structure Designed Considering Different Scenarios Based on Eurocodes 2 and 8

by Camila Carobeno, Gustavo Siqueira, José Melo and Humberto Varum

Buildings 2025, 15(21), 3843; https://doi.org/10.3390/buildings15213843 (registering DOI) - 24 Oct 2025

Abstract

In low to medium-seismicity countries, seismic design is often not mandatory. Furthermore, zoning is frequently adopted to justify simplified calculations based on force methods without capacity criteria. However, risk analysis should merge vulnerability, threat, and exposure. So even regions with low seismicity can [...] Read more.

In low to medium-seismicity countries, seismic design is often not mandatory. Furthermore, zoning is frequently adopted to justify simplified calculations based on force methods without capacity criteria. However, risk analysis should merge vulnerability, threat, and exposure. So even regions with low seismicity can face potentially high consequences due to earthquakes. This is the case of Brazil, where seismic provisions were lacking until 2006 when the first standard was approved, being updated in 2023. Therefore, this study selected a typical RC frame configuration and focuses on assessing the differences in seismic performance between the provisions outlined in EN1992-1-1/EN1998-1 and ABNT NBR15421. The research highlights how different requirements affect low and medium-seismicity regions. Hence, the methodology and conclusions can serve as a guide for decision-making in other countries regarding impact and effectiveness. There are considered different scenarios of design, seismicity, and ductility class. The nonlinear static Pushover analysis was conducted and also validated with nonlinear dynamic Time-history analysis. The assessment of the results is based on the design assumptions, capacity curves, collapse mechanism, IDA curves, PSDM, damage limit states and cost-benefits. Non-seismic design structures had a premature brittle collapse. The global ductility condition was the main key to changing into a ductile mechanism, and seismic detailing was the variable that addresses the ductility level. Full article

(This article belongs to the Special Issue Research on the Seismic Performance of Reinforced Concrete Structures)

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18 pages, 4954 KB

Open AccessArticle

Finite Element Analysis of Shaft Excavation Stability Using Raise Boring Machine (RBM) Method in Karst Strata with Multiple Cavities

by Yongqiao Fang, Guofeng Wang, Kaifu Ren, Fayi Deng and Haiyan Xu

Buildings 2025, 15(21), 3842; https://doi.org/10.3390/buildings15213842 (registering DOI) - 24 Oct 2025

Abstract

This study investigates the excavation stability of vertical shafts using the Raise Boring Machine (RBM) method in karst strata with multiple cavities, based on the ventilation shaft project of the Zimuyan Tunnel along the Wudao Expressway. A three-dimensional numerical model was established using [...] Read more.

This study investigates the excavation stability of vertical shafts using the Raise Boring Machine (RBM) method in karst strata with multiple cavities, based on the ventilation shaft project of the Zimuyan Tunnel along the Wudao Expressway. A three-dimensional numerical model was established using ABAQUS (version 6.14) to simulate the RBM excavation process and to analyze the effects of cavity positions and depths on the stability of the surrounding rock during excavation. The results show that (1) when the cavities are located at the same position and depth, the radial displacement of the surrounding rock during the reverse reaming stage is reduced by approximately 60% on average compared to that during the forward reaming stage, and the radial stress is also significantly lower during the reverse reaming process; (2) when the cavities are at the same depth, symmetrically distributed cavities cause the surrounding rock displacement to increase by 15–20% compared to vertically aligned cavities, and the stress distribution becomes more complex; and (3) when the cavities are at the same horizontal position but located on different planes, the stability of the surrounding rock improves as the distance between the two cavities increases. Full article

(This article belongs to the Special Issue Research on the Construction Mechanical Behavior and Deformation Characteristics of Lining Structure—2nd Edition)

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29 pages, 2291 KB

Open AccessSystematic Review

Emerging Trends in the Use of Recycled Sand in Mortar: A Systematic Review

by Thaís Renata de S. Sampaio, Rodrigo Pierott, Carina Mariane Stolz, Mayara Amario and Assed N. Haddad

Buildings 2025, 15(21), 3841; https://doi.org/10.3390/buildings15213841 (registering DOI) - 24 Oct 2025

Abstract

This systematic review applies the PRISMA methodology (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) to evaluate the use of recycled sand, obtained from construction and demolition waste (CDW), in mortars for civil construction. A total of 24 studies published between 2020 and [...] Read more.

This systematic review applies the PRISMA methodology (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) to evaluate the use of recycled sand, obtained from construction and demolition waste (CDW), in mortars for civil construction. A total of 24 studies published between 2020 and 2025 were analyzed, retrieved from the Scopus and Web of Science databases. The main objective is to assess the technical feasibility and environmental benefits of recycled sand in mortars, while addressing research gaps such as the lack of standardized methodologies and the limited understanding of durability at higher replacement levels. Given the significant resource consumption and waste generation in the construction sector, the study highlights emerging trends in adopting recycled sand as a sustainable alternative to natural aggregates. Findings indicate that optimal replacement levels range between 30 and 50% in ordinary Portland cement (OPC) mortars, and up to 100% in geopolymer mixtures when appropriate processing and activation methods are applied, without compromising mechanical performance. Reported benefits include cost reduction, lower carbon footprint, and enhanced compactness. However, challenges such as higher porosity and the need for optimized mix designs, and high heterogeneity of CDW sources and processing methods remain. Overall, the review confirms that recycled sand is a technically viable and environmentally beneficial material for mortar production, though future research must focus on harmonizing test protocols and long-term performance evaluation. In addition, a bibliometric analysis was conducted to map scientific output on this topic, identifying key countries, journals, and publication trends. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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16 pages, 4882 KB

Open AccessArticle

Dynamic Response and Damage Analysis of Variable Section Pile Group Foundation at Liquefaction Site Under Different Seismic Intensities

by Shi-Hao Zhou, Zhong-Ju Feng, Cong Zhang, Cheng-Cheng Zhang, Ji-Kun Wang and Si-Qi Wang

Buildings 2025, 15(21), 3840; https://doi.org/10.3390/buildings15213840 - 24 Oct 2025

Abstract

Liquefaction-induced failure of pile foundations remains a critical challenge in seismic bridge engineering, particularly for large-diameter variable-section piles widely used in deep foundations. To address the limited understanding of their dynamic behavior in liquefiable soils, this study conducted large-scale shaking table tests on [...] Read more.

Liquefaction-induced failure of pile foundations remains a critical challenge in seismic bridge engineering, particularly for large-diameter variable-section piles widely used in deep foundations. To address the limited understanding of their dynamic behavior in liquefiable soils, this study conducted large-scale shaking table tests on single and group pile foundations at the Xiang’an Bridge site in Xiamen. The model reproduced a stratified saturated sandy soil profile to examine pore pressure evolution, acceleration response, horizontal displacement, and bending moment under seismic intensities of 0.15 g, 0.25 g, 0.35 g, and 0.45 g. The experimental results validated the model’s reliability and revealed clear performance distinctions between the two pile types. As seismic intensity increased, the stable pore pressure ratio rose from 0.72 to 0.86, indicating progressive liquefaction. Compared with the single pile, the pile group exhibited 15–25% lower peak acceleration and displacement, and a delayed occurrence of maximum response by about 1.3 s. Damage occurred at 0.35 g for the single pile but only at 0.45 g for the pile group, accompanied by a more minor reduction in fundamental frequency (32.44% vs. 52.90%). These results demonstrate that the pile group effect mitigates the impact of liquefaction and enhances seismic resistance. The study provides experimental validation and quantitative insight into the dynamic response mechanisms of variable-section pile group foundations, contributing novel guidance for the seismic design of bridge foundations in liquefaction-prone regions. Full article

(This article belongs to the Section Building Structures)

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21 pages, 4809 KB

Open AccessArticle

Model with GA and PSO: Pile Bearing Capacity Prediction and Geotechnical Validation

by Haobo Jin, Zhiqiang Li, Qiqi Xu, Qinyang Sang and Rongyue Zheng

Buildings 2025, 15(21), 3839; https://doi.org/10.3390/buildings15213839 - 23 Oct 2025

Abstract

Accurate prediction of the ultimate bearing capacity (UBC) of single piles is essential for safe and economical foundation design, as it directly impacts construction safety and resource efficiency. This study aims to develop a hybrid prediction framework integrating Genetic Algorithm (GA) and Particle [...] Read more.

Accurate prediction of the ultimate bearing capacity (UBC) of single piles is essential for safe and economical foundation design, as it directly impacts construction safety and resource efficiency. This study aims to develop a hybrid prediction framework integrating Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) to optimize a Backpropagation Neural Network (BPNN). GA performs global exploration to generate diverse initial solutions, while PSO accelerates convergence through adaptive parameter updates, balancing exploration and exploitation. The primary objective of this study is to enhance the accuracy and reliability of UBC prediction, which is crucial for informed decision-making in geotechnical engineering. A dataset consisting of 282 high-strain dynamic load tests was employed to assess the performance of the proposed GA-PSO-BPNN model in comparison with CNN, XGBoost, and traditional dynamic formulas (Hiley, Danish, and Winkler). The GA-PSO-BPNN achieved an R² of 0.951 and an RMSE of 660.13, outperforming other AI models and traditional approaches. Furthermore, SHAP (SHapley Additive exPlanations) analysis was conducted to evaluate the relative importance of input variables, where SHAP values were used to explain the contribution of each feature to the model’s predictions. The findings indicate that the GA-PSO-BPNN model provides a robust, cost-efficient, and interpretable approach for UBC prediction, which aligns with current sustainability goals by optimizing resource usage in foundation design. This model shows significant potential for practical use across various geotechnical settings, contributing to safer, more sustainable infrastructure projects. Full article

(This article belongs to the Section Building Structures)

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23 pages, 8650 KB

Open AccessArticle

Feasibility Study on the “New Traditional” Model and Energy-Saving Strategy for Chinese–Korean Vernacular Living Under the Construction of Border Villages

by Weiming Chu, Junjie Xiang and Changjie Jin

Buildings 2025, 15(21), 3838; https://doi.org/10.3390/buildings15213838 - 23 Oct 2025

Abstract

In the context of China’s rural revitalization strategy, improving the livability and sustainability of traditional dwellings in border regions has become a critical priority. This study examines Chinese–Korean houses in border villages, where field investigations and quantitative analysis reveal persistent challenges: poor indoor [...] Read more.

In the context of China’s rural revitalization strategy, improving the livability and sustainability of traditional dwellings in border regions has become a critical priority. This study examines Chinese–Korean houses in border villages, where field investigations and quantitative analysis reveal persistent challenges: poor indoor thermal comfort and high energy consumption due to outdated building envelopes and inefficient heating systems. To address these issues, we propose an integrated retrofitting solution that combines building-integrated photovoltaics (BIPV) and ground-source heat pump (GSHP) technologies. Unlike previous studies focusing on isolated applications, our approach emphasizes the synergistic integration of active energy generation and high-efficiency thermal regulation, while preserving the architectural and cultural identity of traditional dwellings. Pilot results demonstrate significant improvements in PMV (Predicted Mean Vote) and economic viability, and achieve a high level of esthetic and cultural compatibility. Modular BIPV integration provides on-site renewable electricity without altering roof forms, while GSHP ensures stable, efficient heating and cooling year-round. This solution offers a replicable, regionally adaptive model for low-carbon rural housing transformation. By aligning technological innovation with cultural preservation and socioeconomic feasibility, the study contributes to a new paradigm of rural development, supporting ecological sustainability, ethnic unity, and border stability. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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12 pages, 242 KB

Open AccessArticle

A Cost–Benefit Analysis of BIM Methodology Implementation in the Preparation and Construction Phase of Public Sector Projects

by Luboš Věrný and Josef Žák

Buildings 2025, 15(21), 3837; https://doi.org/10.3390/buildings15213837 - 23 Oct 2025

Abstract

This article evaluates both economic and non-economic benefits associated with the implementation of Building Information Modeling (BIM) and the digitization of processes within public sector construction projects of the Czech public sector organization (PSO). The study is based on empirical data from three [...] Read more.

This article evaluates both economic and non-economic benefits associated with the implementation of Building Information Modeling (BIM) and the digitization of processes within public sector construction projects of the Czech public sector organization (PSO). The study is based on empirical data from three real projects: the Children’s Sanatorium with Speleotherapy, the Air Rescue Services Base, and the Neurorehabilitation Center. For one of those projects, cost–benefit analysis (CBA) was applied to quantify direct financial savings and indirect operational improvements; however, other projects supported the investigation. Data sources include real project data such as BIM documentation and project budgets. The analysis reveals that BIM adoption led to measurable reductions in rework, improved coordination among stakeholders, and enhanced facility management efficiency, resulting in a cost–benefit ratio of more than 4.5. Results from this article support the results of other already made research and prove the consistency of those results. These findings demonstrate the practical value of BIM in public infrastructure delivery and provide actionable insights for decision-makers seeking to improve project outcomes through digital transformation. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

14 pages, 876 KB

Open AccessArticle

Housing Price Bubble: The Case of Beijing

by Yongzhou Hou, Jiali Yuan, Xiaoqi Liu and Chengdong Yi

Buildings 2025, 15(21), 3836; https://doi.org/10.3390/buildings15213836 - 23 Oct 2025

Abstract

Beijing’s real estate market, a key part of China’s economy, plays a crucial role in the nation’s development. Any downturn or collapse in housing prices in the city would have severe consequences for both the real estate sector and the broader economy. This [...] Read more.

Beijing’s real estate market, a key part of China’s economy, plays a crucial role in the nation’s development. Any downturn or collapse in housing prices in the city would have severe consequences for both the real estate sector and the broader economy. This paper aims to explore whether a housing price bubble existed in Beijing from 2014 to 2024. This study investigates the areas where these price bubbles are mainly concentrated, analyzing various indicators, such as the house price-to-income ratio, house price-to-rent ratio, and control charts. This study employs the rational expectations model to measure potential price bubbles, integrating these indicators to assess housing price volatility. The findings indicate clear signs of a housing price bubble in 2016 and 2017. From the perspective of Beijing’s districts, Huairou, Pinggu, and Miyun exhibited clear signs of housing price bubbles, while Changping, Shunyi, and Chaoyang displayed comparatively minimal housing price bubbles. This study utilizes nearly a decade of fresh district-level data to study housing price bubbles in Beijing, which contributes to the exploration of the risks associated with Beijing’s real estate market. Full article

(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)

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25 pages, 1531 KB

Open AccessReview

Review of Cooling Effects from Roof Mitigation Strategies Against Urban Heat Island Effects

by Yuanchuan Yang, Zihao Pan, Binhua Zhang, Si Huang, Xiaoying Chen and Tingting Hong

Buildings 2025, 15(21), 3835; https://doi.org/10.3390/buildings15213835 - 23 Oct 2025

Abstract

The rapid increase in global human activities and urban surface modifications has exacerbated the urban heat island effect, prompting growing scholarly efforts to adopt various measures for mitigating heat islands worldwide. This paper reviews existing literature on rooftop mitigation of UHI, summarizes specific [...] Read more.

The rapid increase in global human activities and urban surface modifications has exacerbated the urban heat island effect, prompting growing scholarly efforts to adopt various measures for mitigating heat islands worldwide. This paper reviews existing literature on rooftop mitigation of UHI, summarizes specific existing rooftop mitigation measures, and examines the comparative effectiveness of various rooftop mitigation strategies in reducing urban heat islands. Findings indicate that cool roofs are the most effective rooftop measure for mitigating UHI, followed by green roofs and photovoltaic roofs. Simultaneously, the cooling effectiveness of rooftop mitigation strategies is influenced by their inherent characteristics (reflectivity, coverage, orientation, etc.), geographical and climatic features (latitude, humidity levels, temperature extremes, diurnal temperature variation, etc.), and urban morphology (building density, height, shape index, etc.). The research status summarized herein provides valuable insights for policy formulation and guides future studies, thereby promoting more innovative designs for sustainable urban roofs to mitigate UHI. Full article

(This article belongs to the Topic Climate, Health and Cities: Building Aspects for a Resilient Future)

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20 pages, 1574 KB

Open AccessArticle

Analysis of Torsional Vibration of Single Pile in Orthotropic Layered Soil

by Zixin Lian, Yanzhi Zhu and Yongzhi Jiu

Buildings 2025, 15(21), 3834; https://doi.org/10.3390/buildings15213834 - 23 Oct 2025

Abstract

To address the difficulty in obtaining analytical solutions for the torsional vibration response of pile foundations in orthotropic layered soil foundations subjected to torsional excitation at the pile top, this study investigates a layered recursive algorithm based on the Hankel transform. An integral [...] Read more.

To address the difficulty in obtaining analytical solutions for the torsional vibration response of pile foundations in orthotropic layered soil foundations subjected to torsional excitation at the pile top, this study investigates a layered recursive algorithm based on the Hankel transform. An integral transformation method is employed to reduce the dimensionality of the coupled pile–soil torsional vibration equations, converting the three-dimensional system of partial differential equations into a set of ordinary differential equations. Combining the constitutive properties of transversely anisotropic strata with interlayer contact conditions, a transfer matrix model is established. Employing inverse transformation coupled with the Gauss–Kronrod integration method, an explicit frequency-domain solution for the torsional dynamic impedance at the pile top is derived. The research findings indicate that the anisotropy coefficient of the foundation significantly influences both the real and imaginary parts of the impedance magnitude. The sequence of soil layer distribution and the bonding state at interfaces jointly affect the nonlinear transmission characteristics of torque along the pile shaft. Full article

(This article belongs to the Section Building Structures)

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20 pages, 8341 KB

Open AccessArticle

Numerical Investigation on the Diffusion and Ventilation Characteristics of Hydrogen-Blended Natural Gas Leakage in Indoor Spaces

by Bofan Deng, Xiaomei Huang, Shan Lyu and Dulikunjiang Aimaieraili

Buildings 2025, 15(21), 3833; https://doi.org/10.3390/buildings15213833 - 23 Oct 2025

Abstract

The blending of hydrogen significantly impacts the diffusion and safety characteristics of natural gas within indoor environments. This study employs ANSYS Fluent 2021 R1 to numerically investigate the diffusion and ventilation characteristics of hydrogen-blended natural gas (HBNG) leakage in indoor spaces. A physical [...] Read more.

The blending of hydrogen significantly impacts the diffusion and safety characteristics of natural gas within indoor environments. This study employs ANSYS Fluent 2021 R1 to numerically investigate the diffusion and ventilation characteristics of hydrogen-blended natural gas (HBNG) leakage in indoor spaces. A physical and mathematical model of gas leakage from pipelines is established to study hazardous areas, flammable regions, ventilation characteristics, alarm response times, safe ventilation rates, and the concentration distribution of leaked gas. The effects of hydrogen blending ratio (HBR), ventilation conditions, and space dimensions on leakage diffusion and safety are analyzed. Results indicate that HBNG leakage forms vertical concentration stratification in indoor spaces, with ventilation height being negatively correlated with gas concentration and flammable regions. In the indoor space conditions of this study, by improving ventilation conditions, the hazardous area can be reduced by up to 92.67%. Increasing HBR substantially expands risk zones—with pure hydrogen producing risk volumes over five times greater than natural gas. Mechanical ventilation significantly enhances indoor safety. Safe ventilation rates escalate with hydrogen content, providing quantitative safety criteria for HBNG implementation. The results underscore the critical influence of HBR and ventilation strategy on risk assessment, providing essential insights for the safe indoor deployment of HBNG. Full article

(This article belongs to the Special Issue Recent Developments and Future Perspectives in Heating, Ventilation and Air-Conditioning Systems of Buildings)

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21 pages, 4597 KB

Open AccessArticle

Early-Age Hydration Heat in Railway 60-Meter Precast Box Girders: Experimental Study and Experimental Simulation

by Xu Feng, Yuliang Cai, Fei Wang, Zhongda Lv, Wei Yang and Lei Wang

Buildings 2025, 15(21), 3832; https://doi.org/10.3390/buildings15213832 - 23 Oct 2025

Abstract

Large precast concrete box girders are susceptible to cracking due to excessive temperature differentials induced by early-age hydration heat, compromising structural reliability and durability. Investigating the early-age hydration heat in large precast box girders and proposing corresponding temperature control measures based on influencing [...] Read more.

Large precast concrete box girders are susceptible to cracking due to excessive temperature differentials induced by early-age hydration heat, compromising structural reliability and durability. Investigating the early-age hydration heat in large precast box girders and proposing corresponding temperature control measures based on influencing factor analysis is therefore essential. The present research employs field testing and numerical simulation of a 60 m precast railway box girder to develop a UMATHT subroutine and establish a refined finite element model incorporating temperature-dependent material properties and hydration degree. Results demonstrate that the early-age temperature field exhibits an initial rise followed by a decline. Pouring temperature exhibits a positive correlation with both peak temperature and maximum temperature differential; a 5 °C increase in pouring temperature elevates the temperature differential by nearly 1.8 °C. Cement content significantly affects peak temperature, with an average increase of approximately 5.4 °C per additional 50 kg/m³ of cement. Ambient wind speed exerts a greater influence on temperature evolution during the cooling phase than the heating phase. Increased ambient wind speed reduces the peak sectional temperature while concurrently increasing the surface temperature gradient on the windward side of the girder. Full article

(This article belongs to the Section Building Structures)

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26 pages, 6220 KB

Open AccessArticle

Research on Strategies for Creating an Age-Friendly Community Commercial Complex Environment in Shanghai

by Junyu Pan, Xinyao Lu and Yanzhe Hu

Buildings 2025, 15(21), 3831; https://doi.org/10.3390/buildings15213831 - 23 Oct 2025

Abstract

This study investigates the relationship between community commercial center spaces and elderly behavior, focusing on governance mechanisms that shape these spaces and their impact on enhancing elderly life and the community environment. Field research was conducted in the ‘Guohe 1000’ community commercial project [...] Read more.

This study investigates the relationship between community commercial center spaces and elderly behavior, focusing on governance mechanisms that shape these spaces and their impact on enhancing elderly life and the community environment. Field research was conducted in the ‘Guohe 1000’ community commercial project in Shanghai, targeting individuals aged 60 and above with independent mobility, including wheelchair users. Through behavioral observation and interviews, both individual and group activities were examined, emphasizing behavioral patterns, spatial domains, and social interactions. Findings reveal that factors such as gender, age, and social networks are positively correlated with the spatial development of community commercial centers. To foster elderly-friendly environments, improvements are needed in utilization balance, secondary activity spaces, age-sensitive design, and operational management. The paper’s novelty lies in two aspects: first, it broadens research into community commercial centers by tracing the construction process of spatial forms; second, it applies environmental behaviorism and environmental gerontology frameworks to integrate individual and collective elderly behaviors into systematic data collection and quantitative analysis. Together, these insights contribute to more inclusive strategies for designing and managing community commercial complexes that support active aging and enhance urban social sustainability. Full article

(This article belongs to the Special Issue Healthy Aging and Built Environment)

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48 pages, 37698 KB

Open AccessArticle

Transforming Construction Waste into High-Performance Alkali-Activated Paste with Microstructural and Predictive π Modelling Insights

by Israf Javed, Hamza Saeed and Abdullah Ekinci

Buildings 2025, 15(21), 3830; https://doi.org/10.3390/buildings15213830 - 23 Oct 2025

Abstract

The construction industry is among the most resource-intensive sectors, generating nearly 40% of global CO₂ emissions and over two billion tonnes of construction and demolition waste (CDW) annually. This study investigates the sustainable reuse of CDW in developing binder-free alkali-activated paste (AAP) [...] Read more.

The construction industry is among the most resource-intensive sectors, generating nearly 40% of global CO₂ emissions and over two billion tonnes of construction and demolition waste (CDW) annually. This study investigates the sustainable reuse of CDW in developing binder-free alkali-activated paste (AAP) using sodium hydroxide (NaOH) as an activator. Eleven formulations were prepared by varying the brick-to-total waste ratio (BW/TW: 0–1), NaOH concentrations (0–10%), and curing durations (7, 28, and 60 days). The mixes were evaluated for unconfined compressive strength (UCS), shear modulus (G_o), durability (wet–dry and freeze–thaw cycles), and microstructural evolution. Results showed significant improvements in mechanical and durability properties with increased NaOH content, BW/TW ratios up to 0.9, and longer curing times. The optimal mix (10% NaOH, BW/TW = 0.9, 60 days of curing) achieved a UCS of 28.7 MPa and a G_o of 30 GPa, while exhibiting minimal mass loss (<2% freeze–thaw; <3% wet–dry). Microstructural analyses revealed densified matrices and enhanced gel formation. A dimensional analysis using the Buckingham π theorem yielded a scalable predictive model that correlates material composition, alkaline activation, and curing with mechanical performance. The study underscores the feasibility of transforming CDW into durable, high-performance AAPs for sustainable infrastructure development. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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19 pages, 3569 KB

Open AccessArticle

Optimizing Built-in Refrigerator Integration: BEHAVIOR Model for Evaluating Kitchen Workflow and Spatial Adaptability

by Ying Gao, Yushu Chen, Alin Olarescu and Xinyou Liu

Buildings 2025, 15(21), 3829; https://doi.org/10.3390/buildings15213829 - 23 Oct 2025

Abstract

As ergonomic and user-centered kitchen design gains importance, integrating built-in appliances such as refrigerators has become common in modern households. However, spatial misalignment and circulation conflicts often disrupt kitchen routines. This study introduces the BEHAVIOR model (Behavioral Embeddedness Evaluation for Appliance-Versatile Integrated Operation [...] Read more.

As ergonomic and user-centered kitchen design gains importance, integrating built-in appliances such as refrigerators has become common in modern households. However, spatial misalignment and circulation conflicts often disrupt kitchen routines. This study introduces the BEHAVIOR model (Behavioral Embeddedness Evaluation for Appliance-Versatile Integrated Operation Routing), a multidimensional framework for evaluating the movement path adaptability of embedded refrigerators in integrated kitchen–dining environments. The model identifies eight behavioral dimensions: Body Clearance, Embedded Compatibility, Handling Logic, Accessibility, Visual Feedback, Interaction Conflict, Operating Time, and Routing Simplicity, from a user–space–product coordination perspective. Expert-based AHP weighting and user entropy methods were combined to construct adaptability scores across five kitchen layouts (L-shaped, U-shaped, single-line, G-shaped, and island). The findings indicate that Routing Simplicity and Accessibility are the core determinants of layout adaptability, while Operating Time and Body Space show layout-dependent variations. Interaction Conflict and Embedded Compatibility are significantly influenced by spatial compactness. This research identifies key behavioral bottlenecks in kitchen workflows and presents a scalable model for appliance–space compatibility analysis, contributing to behavioral product evaluation and highlighting the role of user dynamics in design decisions. Full article

(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)

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34 pages, 3289 KB

Open AccessArticle

Maximize Energy Efficiency in Homes: A Parametric Simulation Study Across Chile

by Aner Martinez-Soto, Gabriel Arias-Guerra, Alejandro Reyes-Riveros, Carlos Rojas-Herrera and Daniel Sanhueza-Catalán

Buildings 2025, 15(21), 3828; https://doi.org/10.3390/buildings15213828 - 23 Oct 2025

Abstract

This study assessed the impact of 39 active and passive energy efficiency measures on the energy demand of a prototype dwelling, modeled through parametric simulations in DesignBuilder across nine climatic zones in Chile, classified according to the Köppen system. Each measure was evaluated [...] Read more.

This study assessed the impact of 39 active and passive energy efficiency measures on the energy demand of a prototype dwelling, modeled through parametric simulations in DesignBuilder across nine climatic zones in Chile, classified according to the Köppen system. Each measure was evaluated individually (single-measure scenarios); three variation levels were evaluated to quantify their relative influence on energy demand. Results indicate that passive strategies are more effective in cold and humid climates, where increasing wall insulation thickness reduced energy demand by up to 45%, and improving airtightness achieved a 43% reduction. In contrast, in tundra climates or areas with high thermal variability, some measures, such as green façades or overhangs, increased energy demand by up to 49% due to the loss of useful solar gains. In desert climates, characterized by high diurnal temperature variation, thermal mass played a more significant role: high-inertia walls without additional insulation outperformed lightweight EPS-based solutions. The findings suggest that measure selection must be climate-adapted, prioritizing high-impact passive strategies and avoiding one-size-fits-all solutions. This work provides quantitative evidence to inform residential thermal design and support climate-sensitive energy efficiency policies. This study delivers a single-measure comparative atlas; future research should integrate multi-measure optimization together with comfort/cost metrics. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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