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Buildings, Volume 15, Issue 20 (October-2 2025) – 39 articles

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31 pages, 7915 KB  
Article
Extreme Environment Habitable Space Design: A Case Study of Deep Underground Space
by Xiang Li and Rui Liu
Buildings 2025, 15(20), 3673; https://doi.org/10.3390/buildings15203673 (registering DOI) - 12 Oct 2025
Abstract
The deterioration of the global climate and accelerated urbanization have led to intense pressure on surface space resources. As a strategic development field, deep underground space has become a crucial direction for alleviating human habitation pressure. However, current research on deep underground space [...] Read more.
The deterioration of the global climate and accelerated urbanization have led to intense pressure on surface space resources. As a strategic development field, deep underground space has become a crucial direction for alleviating human habitation pressure. However, current research on deep underground space mostly focuses on fields such as geology and medicine, while the design of habitable environments lacks interdisciplinary integration and systematic approaches. Taking deep underground space as the research object, this study first clarifies the interdisciplinary research context through bibliometric analysis. Then, combined with geological data (ground temperature, groundwater, and ground stress, etc.) from major cities in China, it defines the characteristics of the in situ environment and the characteristics of the development and utilization of deep underground space. By comparing the habitable design experiences of extreme environments, such as space stations, Moon habitats, and desert survival modules, the study extracts five categories of design elements: natural conditions, construction status, social economy, users, and existing resources. Ultimately, it establishes a demand-oriented, five-dimensional habitable design methodology covering in situ environment adaptation, living support, medical and health services, resilience and flexibility, and existing space renovation. This research clarifies the differentiated design strategies for hundred-meter-level and kilometer-level deep underground spaces, providing theoretical support for the scientific development of deep underground space and serving as a reference for habitable design in other extreme environments. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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18 pages, 5224 KB  
Article
Study on the Negative Skin Friction on Bridge Pile Foundations Induced by Backfilling in Karst Areas
by Huiyun Chen, Zhongju Feng, Xiaodong Wei and Ya Li
Buildings 2025, 15(20), 3672; https://doi.org/10.3390/buildings15203672 (registering DOI) - 12 Oct 2025
Abstract
The load transfer mechanism of piles in karst cavity areas was investigated through field tests, and an orthogonal test was carried out to establish a calculation method for negative skin friction induced by backfilling. The results indicate that the negative skin friction of [...] Read more.
The load transfer mechanism of piles in karst cavity areas was investigated through field tests, and an orthogonal test was carried out to establish a calculation method for negative skin friction induced by backfilling. The results indicate that the negative skin friction of piles is strongly influenced by the type of cavity. When cavities were completely filled with limestone breccia mixed with silty clay and the applied load reached 3628 kN, the unit side friction ranged from 15 to 22 kPa. In contrast, when cavities remained unfilled, soil settlement occurred around the pile after backfilling, leading to the development of negative skin friction. For cavities with heights of 3–12 m, it is recommended that the bearing capacity of piles be calculated by considering negative skin friction at depths of 0H, 0.106H, 0.214H, and 0.271H (where H denotes the cavity height). Based on 21 orthogonal tests, the sensitivity ranking of factors affecting negative skin friction was determined as follows: cavity height > elastic modulus of backfill > pile diameter > cavity span > pile length > cavity position. The calculated values of negative skin friction were further validated against engineering data, showing a variation trend consistent with the test results, with a relative error of only 7.4%. Full article
(This article belongs to the Section Building Structures)
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27 pages, 13950 KB  
Article
Predicting Perceived Restorativeness of Urban Streetscapes Using Semantic Segmentation and Machine Learning: A Case Study of Liwan District, Guangzhou
by Wenjuan Kang, Ni Kang and Pohsun Wang
Buildings 2025, 15(20), 3671; https://doi.org/10.3390/buildings15203671 (registering DOI) - 12 Oct 2025
Abstract
Urban streetscapes are among the most frequently encountered spatial environments in daily life, and their restorative visual features have a significant impact on well-being. Although existing studies have revealed the relationship between streetscape environments and perceived restorativeness, there remains a lack of scalable, [...] Read more.
Urban streetscapes are among the most frequently encountered spatial environments in daily life, and their restorative visual features have a significant impact on well-being. Although existing studies have revealed the relationship between streetscape environments and perceived restorativeness, there remains a lack of scalable, data-driven methods for quantifying such perception at the street level. This study proposes an interpretable and replicable framework for predicting streetscape restorativeness by integrating semantic segmentation, perceptual evaluation, and machine learning techniques. Taking Liwan District of Guangzhou as a case study, street-view images (SVIs) were collected and processed using the Mask2Former model to extract the following five key visual metrics: greenness, openness, enclosure, walkability, and imageability. Based on the Perceived Restorativeness Scale (PRS), an online questionnaire was designed from four dimensions (fascination, being away, compatibility, and extent) to score a random sample of images. A random forest model was then trained to predict the perceptual levels of the full dataset, followed by K-means clustering to identify spatial distribution patterns. The results revealed that there were significant differences in visual characteristics among high, medium, and low restorativeness street types. The proposed framework enables scalable, data-driven evaluation of perceived restorativeness across diverse urban streetscapes. By embedding perceptual metrics into large-scale urban analysis, the framework offers a replicable and efficient approach for identifying streets with low restorative potential—thus providing urban planners and policymakers with a novel tool for prioritizing street-level renewal, improving public well-being, and supporting perception-oriented urban design without the need for labor-intensive fieldwork. Full article
21 pages, 6587 KB  
Article
Mechanical Performance and Shrinkage Behavior of Ultrahigh-Performance Concrete with Ferronickel Slag Under Various Curing Conditions
by Yong-Sik Yoon, Gi-Hong An, Kyung-Taek Koh and Gum-Sung Ryu
Buildings 2025, 15(20), 3670; https://doi.org/10.3390/buildings15203670 (registering DOI) - 12 Oct 2025
Abstract
The main objective of this study was to evaluate the long-term mechanical performance and shrinkage behavior of ultrahigh-performance concrete (UHPC) in which the granulated ground blast-furnace slag (GGBFS), used as part of the binder, is replaced partially or fully with ferronickel slag (FNS). [...] Read more.
The main objective of this study was to evaluate the long-term mechanical performance and shrinkage behavior of ultrahigh-performance concrete (UHPC) in which the granulated ground blast-furnace slag (GGBFS), used as part of the binder, is replaced partially or fully with ferronickel slag (FNS). The aim was to identify potential strength reduction and expansion problems associated with the use of FNS powder. For steam-cured UHPC, the compressive strength of the FNS100 (124.8 MPa) was comparable to that of the control case (FNS0, 125.1 MPa), and the tensile strength showed only a 0.3 MPa difference. Under constant-temperature and constant-humidity conditions, all mixtures satisfied the design strength standard of 120 MPa by the end of the curing period. Considering constant-temperature and constant-humidity conditions, shrinkage evaluation revealed that the FNS100_NON_AD (no shrinkage-reducing and expansive agents) exhibited 3.8 times greater shrinkage compared to FNS0, while other mixtures remained within a narrow range. These results indicate that shrinkage was governed more by the presence and type of admixtures than by the FNS replacement rate itself. This study demonstrated that FNS has sufficient potential for use as a binder in UHPC and encourages further research to optimize admixture use for long-term durability and shrinkage control. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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17 pages, 492 KB  
Article
From Building Emissions to Resident Well-Being: The Role of Environmental Pollution Perception
by Yuanping Wang, Yu He, Caigui Zheng and Payam Rahnamayiezekavat
Buildings 2025, 15(20), 3669; https://doi.org/10.3390/buildings15203669 (registering DOI) - 12 Oct 2025
Abstract
In recent years, there has been growing recognition that reducing environmental pollution, particularly from building emissions, is essential for improving residents’ well-being. Buildings contribute substantially to worldwide greenhouse gas and pollutant emissions, making effective mitigation strategies a priority in achieving Sustainable Development Goals [...] Read more.
In recent years, there has been growing recognition that reducing environmental pollution, particularly from building emissions, is essential for improving residents’ well-being. Buildings contribute substantially to worldwide greenhouse gas and pollutant emissions, making effective mitigation strategies a priority in achieving Sustainable Development Goals (SDGs). Using data from the 2021 China General Social Survey (CGSS), this study examines the relationship between perceived building environmental pollution and residents’ well-being, as well as the mechanism underlying this relationship, through an ordered probit model. The results indicate that higher levels of building environmental pollution significantly reduce residents’ well-being. To explore heterogeneity, the sample was further divided by urban–rural differences, local environmental protection expenditure level, and geographic region. The research found that residents with lower environmental protection expenditures, residents in rural areas and those in the central region are more likely to be negatively affected by building environmental pollution, with the correlation coefficients being −0.111, −0.104 and −0.101 respectively. Furthermore, the analysis indicates that annual income, the number of children, and type of work have moderating effects on this relationship, with correlation coefficients of 0.047, −0.054, and −0.095 respectively. Overall, this study provides empirical evidence for perceiving the social impact of building pollution in the context of building-related emissions and offers policy-related insights for strengthening environmental protection measures in the construction industry to enhance residents’ well-being. Full article
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20 pages, 2608 KB  
Article
Analysis of Multi-Stage Slope Displacement and Internal Force of Supporting Structure of Frame Prestressed Anchor Cable Support
by Jingbang Li, Yanpeng Zhu, Shuaihua Ye, Nianxiang Li and Bo Liu
Buildings 2025, 15(20), 3668; https://doi.org/10.3390/buildings15203668 (registering DOI) - 11 Oct 2025
Abstract
Relying on an engineering case, this study establishes an analysis model using PLAXIS 3D and GeoStudio, and compares and analyzes the slope deformation and internal force of the supporting structure with different slope grades and different platform widths at the same height. The [...] Read more.
Relying on an engineering case, this study establishes an analysis model using PLAXIS 3D and GeoStudio, and compares and analyzes the slope deformation and internal force of the supporting structure with different slope grades and different platform widths at the same height. The results show that the greatest displacement manifests in the lower segments of the slope, which is 12.99 mm, and the maximum anchoring force manifests in the mid-level and lower segments of the slope, which is 288.1 kN. A close correlation is observed between the simulated horizontal displacement of the slope, the maximum axial force of the anchor cable, and the corresponding field measurement results, indicating that the model parameters are satisfactory and that the resulting calculations are reliable. In consideration of the comprehensive stability of the slope, the stability coefficient increased by approximately 1.42% with two-stage slope support and by about 3.48% with four-stage slope support. The axial force of anchor cables was reduced by around 9.5% under two-stage grading, while four-stage grading decreased the maximum axial force of the middle–lower anchors by nearly 27%. The distance between the entrance and exit of the overall sliding surface and the slope surface also decreases with the increase in slope grading and platform width. This study systematically evaluates the combined effects of slope grading, platform width, and frame prestressed anchors. When site conditions permit, slope grading should be prioritized over simply widening the platform, as grading more effectively enhances slope stability and reduces anchor cable loads. Full article
(This article belongs to the Section Building Structures)
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25 pages, 1422 KB  
Article
Bayesian-Optimized Ensemble Models for Geopolymer Concrete Compressive Strength Prediction with Interpretability Analysis
by Mehmet Timur Cihan and Pınar Cihan
Buildings 2025, 15(20), 3667; https://doi.org/10.3390/buildings15203667 (registering DOI) - 11 Oct 2025
Abstract
Accurate prediction of geopolymer concrete compressive strength is vital for sustainable construction. Traditional experiments are time-consuming and costly; therefore, computer-aided systems enable rapid and accurate estimation. This study evaluates three ensemble learning algorithms (Extreme Gradient Boosting (XGB), Random Forest (RF), and Light Gradient [...] Read more.
Accurate prediction of geopolymer concrete compressive strength is vital for sustainable construction. Traditional experiments are time-consuming and costly; therefore, computer-aided systems enable rapid and accurate estimation. This study evaluates three ensemble learning algorithms (Extreme Gradient Boosting (XGB), Random Forest (RF), and Light Gradient Boosting Machine (LightGBM)), as well as two baseline models (Support Vector Regression (SVR) and Artificial Neural Network (ANN)), for this task. To improve performance, hyperparameter tuning was conducted using Bayesian Optimization (BO). Model accuracy was measured using R2, RMSE, MAE, and MAPE. The results demonstrate that the XGB model outperforms others under both default and optimized settings. In particular, the XGB-BO model achieved high accuracy, with RMSE of 0.3100 ± 0.0616 and R2 of 0.9997 ± 0.0001. Furthermore, Shapley Additive Explanations (SHAP) analysis was used to interpret the decision-making of the XGB model. SHAP results revealed the most influential features for compressive strength of geopolymer concrete were, in order, coarse aggregate, curing time, and NaOH molar concentration. The graphical user interface (GUI) developed for compressive strength prediction demonstrates the practical potential of this research. It contributes to integrating the approach into construction practices. This study highlights the effectiveness of explainable machine learning in understanding complex material behaviors and emphasizes the importance of model optimization for making sustainable and accurate engineering predictions. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
27 pages, 19519 KB  
Article
Low-Carbon Climate-Resilient Retrofit Pilot: Construction Report
by Hamish Pope, Mark Carver and Jeff Armstrong
Buildings 2025, 15(20), 3666; https://doi.org/10.3390/buildings15203666 (registering DOI) - 11 Oct 2025
Abstract
Deep retrofits are one of the few pathways to decarbonize the existing building stock while simultaneously improving climate resilience. These retrofits improve insulation, airtightness, and mechanical equipment efficiency. NRCan’s Prefabricated Exterior Energy Retrofit (PEER) project developed prefabricated building envelope retrofit solutions to enable [...] Read more.
Deep retrofits are one of the few pathways to decarbonize the existing building stock while simultaneously improving climate resilience. These retrofits improve insulation, airtightness, and mechanical equipment efficiency. NRCan’s Prefabricated Exterior Energy Retrofit (PEER) project developed prefabricated building envelope retrofit solutions to enable net-zero performance. The PEER process was demonstrated on two different pilot projects completed between 2017 and 2023. In 2024, in partnership with industry partners, NRCan developed new low-carbon retrofit panel designs and completed a pilot project to evaluate their performance and better understand resiliency and occupant comfort post-retrofit. The Low-Carbon Climate-Resilient (LCCR) Living Lab pilot retrofit was completed in 2024 in Ottawa, Canada, using low-carbon PEER panels. This paper outlines the design and construction for the pilot, including panel designs, the retrofitting process, and post-retrofit building and envelope commissioning. The retrofitting process included the design and installation of new prefabricated exterior retrofitted panels for the walls and the roof. These panels were insulated with cellulose, wood fibre, hemp, and chopped straw. During construction, blower door testing and infrared imaging were conducted to identify air leakage paths and thermal bridges in the enclosure. The retrofit envelope thermal resistance is RSI 7.0 walls, RSI 10.5 roof, and an RSI 3.5 floor with 0.80 W/m2·K U-factor high-gain windows. The measured normalized leakage area @10Pa was 0.074 cm2/m2. The net carbon stored during retrofitting was over 1480 kg CO2. Monitoring equipment was placed within the LCCR to enable the validation of hygrothermal models for heat, air, and moisture transport, and energy, comfort, and climate resilience models. Full article
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29 pages, 4806 KB  
Article
Analytical Investigation of CFRP- and Steel Plate-Strengthened RC Beams with Partially Unbonded Reinforcement
by Riliang Li and Riyad S. Aboutaha
Buildings 2025, 15(20), 3665; https://doi.org/10.3390/buildings15203665 (registering DOI) - 11 Oct 2025
Abstract
This study investigates the flexural behavior of reinforced concrete (RC) beams strengthened with externally bonded Carbon Fiber Reinforced Polymer (CFRP) or steel plate (SP), with partial debonding between internal steel reinforcement and surrounding concrete. A finite element model was developed using ABAQUS (v2021) [...] Read more.
This study investigates the flexural behavior of reinforced concrete (RC) beams strengthened with externally bonded Carbon Fiber Reinforced Polymer (CFRP) or steel plate (SP), with partial debonding between internal steel reinforcement and surrounding concrete. A finite element model was developed using ABAQUS (v2021) and validated against existing experimental data by others. A total of 296 beam models were analyzed to assess the effects of shear span-to-depth ratio (av/d), reinforcement ratio (ρ), debonding degree (λ), strengthening material type (CFRP/SP), and material thickness (t) on residual flexural strength. Based on the finite element analysis (FEA) results, analytical models were proposed using a dimensionless parameter Ψ, defined as the ratio of equivalent plastic region length to neutral axis depth. Analytical models were developed in IBM SPSS Statistics (Version 30) and showed strong agreement with FEA results. The findings provide insight into the influence of reinforcement debonding on structural behavior and support improved prediction of residual flexural capacity in strengthened RC beams with partially unbonded reinforcement. Full article
(This article belongs to the Special Issue Assessment and Retrofit of Reinforced Concrete Structures)
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29 pages, 11785 KB  
Article
Mechanical Response of Composite Wood–Concrete Bonded Facade Under Thermal Loading
by Roufaida Assal, Laurent Michel and Emmanuel Ferrier
Buildings 2025, 15(20), 3664; https://doi.org/10.3390/buildings15203664 (registering DOI) - 11 Oct 2025
Abstract
The integration of wood and concrete in building structures is a well-established practice typically realized through mechanical connectors. However, the thermomechanical behavior of wood–concrete composite façades assembled via adhesive bonding remains underexplored. This study introduces a novel concept—the adhesive-bonded wood–concrete façade, termed “Hybrimur”—and [...] Read more.
The integration of wood and concrete in building structures is a well-established practice typically realized through mechanical connectors. However, the thermomechanical behavior of wood–concrete composite façades assembled via adhesive bonding remains underexplored. This study introduces a novel concept—the adhesive-bonded wood–concrete façade, termed “Hybrimur”—and evaluates the response of these façade panels under thermal gradients, with a focus on thermal bowing phenomena. Four full-scale façade prototypes (3 m high × 6 m wide), consisting of 7 cm thick concrete and 16 cm thick laminated timber (GL24h), were fabricated and tested both with and without insulation. Two reinforcement types were considered: fiberglass-reinforced concrete and welded mesh reinforcement. The study combines thermal analysis of temperature gradients at the adhesive interface with analytical and numerical methods to investigate thermal expansion effects. The experimental and numerical results revealed thermal strains concentrated at the wood–concrete interface without inducing panel failure. Thermal bowing (out-of-plane deflection) exhibited a nonlinear behavior influenced by the adhesive bond and the anisotropic nature of the wood. These findings highlight the importance of accounting for both interface behavior and wood anisotropy in the design of hybrid façades subjected to thermal loading. A tentative finite element model is proposed that utilizes isotropic wood with properties that limit the accuracy of the results obtained by the model. Full article
(This article belongs to the Special Issue The Latest Research on Building Materials and Structures)
21 pages, 859 KB  
Article
The Moderating Role of Organizational Culture on Barriers and Drivers of Sustainable Construction Practices in Saudi Arabia’s Construction Industry: A Circular Economy Perspective
by Muhammad Abdul Rehman and Dhafer Ali Alqahtani
Buildings 2025, 15(20), 3663; https://doi.org/10.3390/buildings15203663 (registering DOI) - 11 Oct 2025
Abstract
The linear construction model is characterized by resource-intensive processes that generate significant waste, whereas adopting circular economy principles facilitates sustainable, adaptable, and recyclable building practices to mitigate waste and conserve resources. The primary objective of this study is to empirically analyze the impact [...] Read more.
The linear construction model is characterized by resource-intensive processes that generate significant waste, whereas adopting circular economy principles facilitates sustainable, adaptable, and recyclable building practices to mitigate waste and conserve resources. The primary objective of this study is to empirically analyze the impact of barriers and drivers on sustainable construction practices and to evaluate the role of organizational culture in moderating this relationship. This study, grounded in Circular Economy theory, distributed 210 questionnaires using simple random sampling to large contractors (501–3000 employees) in Saudi Arabia’s Eastern Region, yielding 154 acceptable responses and a 73% completion rate. Data analysis was conducted using SmartPLS software, revealing that barriers, drivers and organizational culture positively impact sustainable construction practices, with organizational culture also positively moderating the connection among drivers and sustainable construction practices. However, organizational culture was not observed to substantially influence the connection between barriers and sustainable practices. The results highlight the main contribution of organizational culture in supporting sustainable development, offering significant theoretical contributions and practical implications for industry leaders and policymakers to develop regulatory framework and implement strategies that support sustainability. Full article
(This article belongs to the Special Issue A Circular Economy Paradigm for Construction Waste Management)
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29 pages, 6094 KB  
Review
Blockchain Oracles for Digital Transformation in the AECO Industry: Securing Off-Chain Data Flows for a Trusted On-Chain Environment
by Liupengfei Wu, Frank Ghansah, Yuanben Zou and Benjamin Ababio
Buildings 2025, 15(20), 3662; https://doi.org/10.3390/buildings15203662 (registering DOI) - 11 Oct 2025
Abstract
As noted in recent blockchain review articles, several blockchain studies have attracted attention to the architecture, engineering, construction, and operation (AECO) industry. The reason is that blockchain offers opportunities to revolutionize the AECO industry owing to its transparency, traceability, and immutability. However, these [...] Read more.
As noted in recent blockchain review articles, several blockchain studies have attracted attention to the architecture, engineering, construction, and operation (AECO) industry. The reason is that blockchain offers opportunities to revolutionize the AECO industry owing to its transparency, traceability, and immutability. However, these benefits cannot be realized without blockchain “oracles”. Oracles are intermediary agents that connect blockchain systems to real-world applications. They function by collecting and verifying off-chain data, which is then fed into the blockchain for use by smart contracts. To investigate this uncharted territory, this paper adopts a hybrid research method of descriptive, bibliometric and content analysis; cross-mapping; and gap analysis to identify the trend; key topics; current status; future directions; and governance, ethical, legal, and social implications (GELSI) framework of blockchain oracles. This paper contributes to the body of knowledge by synthesizing trends, current status, key topics, and GELSI of blockchain oracles, promoting areas of improvement, and bridging knowledge gaps on blockchain oracles in the AECO industry. Full article
23 pages, 16680 KB  
Article
Interpretation of Dominant Features Governing Compressive Strength in One-Part Geopolymer
by Yiren Wang, Yihai Jia, Chuanxing Wang, Weifa He, Qile Ding, Fengyang Wang, Mingyu Wang and Kuizhen Fang
Buildings 2025, 15(20), 3661; https://doi.org/10.3390/buildings15203661 (registering DOI) - 11 Oct 2025
Abstract
One-part geopolymers (OPG) offer a low-carbon alternative to Portland cement, yet mix design remains largely empirical. This study couples machine learning with SHAP (Shapley Additive Explanations) to quantify how mix and curing factors govern performance in Ca-containing OPG. We trained six regressors—Random Forest, [...] Read more.
One-part geopolymers (OPG) offer a low-carbon alternative to Portland cement, yet mix design remains largely empirical. This study couples machine learning with SHAP (Shapley Additive Explanations) to quantify how mix and curing factors govern performance in Ca-containing OPG. We trained six regressors—Random Forest, ExtraTrees, SVR, Ridge, KNN, and XGBoost—on a compiled dataset and selected XGBoost as the primary model based on prediction accuracy. Models were built separately for four targets: compressive strength at 3, 7, 14, and 28 days. SHAP analysis reveals four dominant variables across targets—Slag, Na2O, Ms, and the water-to-binder ratio (w/b)—while the sand-to-binder ratio (s/b), temperature, and humidity are secondary within the tested ranges. Strength evolution follows a reaction–densification logic: at 3 days, Slag dominates as Ca accelerates C–(N)–A–S–H formation; at 7–14 days, Na2O leads as alkalinity/soluble silicate controls dissolution–gelation; by 28 days, Slag and Na2O jointly set the strength ceiling, with w/b continuously regulating porosity. Interactions are strongest for Slag × Na2O (Ca–alkalinity synergy). These results provide actionable guidance: prioritize Slag and Na2O while controlling w/b for strength. The XGBoost+SHAP workflow offers transparent, data-driven decision support for OPG mix optimization and can be extended with broader datasets and formal validation to enhance generalization. Full article
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31 pages, 16725 KB  
Article
Climatic Adaptation-Based Evaluation of Vernacular Anatolian Houses: A Comparative Analysis of Stone and Adobe Materials in Terms of Energy, Environment, and Thermal Comfort
by Elif Gizem Yetkin and Gonca Özer Yaman
Buildings 2025, 15(20), 3660; https://doi.org/10.3390/buildings15203660 (registering DOI) - 11 Oct 2025
Abstract
In terms of ensuring the sustainability of vernacular building culture, the evaluation of buildings should consider not only visual and cultural values but also energy efficiency, environmental impact, and indoor thermal comfort. This study comparatively examines the performance of stone and adobe wall [...] Read more.
In terms of ensuring the sustainability of vernacular building culture, the evaluation of buildings should consider not only visual and cultural values but also energy efficiency, environmental impact, and indoor thermal comfort. This study comparatively examines the performance of stone and adobe wall materials, widely used in Anatolia, under different climatic conditions. In the simulations conducted using DesignBuilder software, building geometry and indoor use scenarios were kept constant, while only exterior wall material and climate data were treated as variables. Annual data for the year 2023 were analyzed. The findings indicate that adobe-walled structures stand out in hot and transitional climates with lower heating and cooling energy demands, reduced electricity consumption, lower carbon emissions, and better thermal comfort conditions. In Kars, representing a cold continental climate, both materials remained outside comfort thresholds; however, adobe structures performed better in terms of energy use, environmental impact, and thermal comfort. This comprehensive evaluation highlights the potential of climate-responsive use of local materials and offers valuable contributions to design strategies focused on sustainability and cultural heritage. The results present not only context-specific insights for Anatolia but also universally applicable, generalizable recommendations for other regions with similar climatic conditions and vernacular building cultures. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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26 pages, 3185 KB  
Article
Preparation and Performance Research of Ultra-High-Performance Concrete Incorporating Municipal Solid Waste Incineration Bottom Ash
by Fengli Liu, Yize He, Junhua Liu, Wu Li, Xiaofei Hao and Chang Liu
Buildings 2025, 15(20), 3659; https://doi.org/10.3390/buildings15203659 (registering DOI) - 11 Oct 2025
Abstract
Low carbon, low cost and sustainability are important development trends of ultra-high-performance concrete (UHPC). In this study, municipal solid waste incineration bottom ash (MSWIBA) was used to replace 5%, 10%, 20% and 30% of quartz sand (QS), respectively, and the effect of the [...] Read more.
Low carbon, low cost and sustainability are important development trends of ultra-high-performance concrete (UHPC). In this study, municipal solid waste incineration bottom ash (MSWIBA) was used to replace 5%, 10%, 20% and 30% of quartz sand (QS), respectively, and the effect of the MSWIBA substitution rate on the workability, wet packing density, mechanical properties, shrinkage, resistance to chloride ion corrosion, and resistance to sulfate corrosion of UHPC was studied. The mechanism analysis was carried out by combining X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) tests, and UHPC heavy metal leaching tests, environmental impact assessment, and economic analysis were conducted. Results show that the active silicon and aluminum components in MSWIBA reacted with cement hydration products to optimize the matrix density. MSWIBA has an internal curing effect, which is beneficial for reducing the shrinkage of UHPC. When the MSWIBA replacement rate is 10%, the 28-day compressive strength of MSWIBA-UHPC is 128.7 MPa, which is equivalent to the benchmark group. The fluidity, corrosion resistance and heavy metal leaching all meet the requirements. The energy consumption, carbon emissions and costs are reduced by 0.22%, 2.30% and 6.67%, respectively. The research results can provide a reference for the development of ecological UHPC with economic, low-carbon and environmental benefits, as well as the harmless disposal and resource utilization of hazardous wastes such as MSWIBA. Full article
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25 pages, 22602 KB  
Article
Model Tests and Interpretation of Earth Pressure Behind Existing and Newly Added Double-Row Piles Retaining Underground Supplementary Excavation
by Yiming Jin, Feng Yu, Jiahui Ye and Zijun Wang
Buildings 2025, 15(20), 3658; https://doi.org/10.3390/buildings15203658 (registering DOI) - 11 Oct 2025
Abstract
In urban redevelopment, adding basements beneath existing buildings often requires specialized retaining structures, such as existing and newly added double-row piles, yet their complex load-sharing mechanism is not yet fully understood. This study addresses this gap through a series of physical model tests, [...] Read more.
In urban redevelopment, adding basements beneath existing buildings often requires specialized retaining structures, such as existing and newly added double-row piles, yet their complex load-sharing mechanism is not yet fully understood. This study addresses this gap through a series of physical model tests, systematically investigating the influence of two key variables: the row spacing and the newly added/existing pile length ratio. The results reveal that row spacing is a critical factor governing the system’s stability and cooperative behavior. The newly added piles bear the majority of the earth pressure, effectively shielding the existing piles. A distinct, layered pressure distribution was observed in the inter-row soil, a phenomenon that classical earth pressure theories cannot adequately predict. Based on a comprehensive evaluation of structural performance, deformation control, and stability, this study proposes an optimized configuration with a row spacing of 4D and a newly added/existing pile length ratio of 9/6. This configuration achieves an effective balance between structural performance and economic efficiency, offering valuable practical guidance for the design of supplementary retaining systems in basement addition projects. Full article
(This article belongs to the Section Building Structures)
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16 pages, 4097 KB  
Article
Experimental Study on the Rotary Adhesion of Shield Cutterhead Tunneling in Clay Strata at Different Temperatures
by Tao Zhang, Zhe Yuan, Jingchun Pang, Wenqiu Li and Zeen Wan
Buildings 2025, 15(20), 3657; https://doi.org/10.3390/buildings15203657 (registering DOI) - 11 Oct 2025
Abstract
In the process of shield tunneling in clayey strata, the fine-grained clay mineral components in the soil easily adhere to the cutter plate. The clay adhering to the cutterhead and the soil compartment then solidifies and hardens, which results in the production of [...] Read more.
In the process of shield tunneling in clayey strata, the fine-grained clay mineral components in the soil easily adhere to the cutter plate. The clay adhering to the cutterhead and the soil compartment then solidifies and hardens, which results in the production of mud cake and clogging. At present, research on cutter plates in clayey ground is limited and has focused mostly on static tests or simplified models. There is a lack of in-depth studies on the effect of temperature on clay adhesion, which is crucial for understanding the clogging risks. In this study, we independently researched and developed a rotary adhesion tester to investigate the adhesion effect and adhesion force change in a shield cutter plate under the influence of different temperatures, water contents (ω), and clay types, revealing the change rule of the adhesion effect under the joint influence of the temperature and the consistency index (Ic). This study provides experimental evidence and an empirical model for assessing the clogging risk in shield tunneling through clay strata, offering valuable insights that support the efficient operation of earth pressure balance (EPB) shields. Full article
(This article belongs to the Section Building Structures)
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42 pages, 3394 KB  
Article
Synergistic Air Quality and Cooling Efficiency in Office Space with Indoor Green Walls
by Ibtihaj Saad Rashed Alsadun, Faizah Mohammed Bashir, Zahra Andleeb, Zeineb Ben Houria, Mohamed Ahmed Said Mohamed and Oluranti Agboola
Buildings 2025, 15(20), 3656; https://doi.org/10.3390/buildings15203656 (registering DOI) - 11 Oct 2025
Abstract
Enhancing indoor environmental quality while reducing building energy consumption represents a critical challenge for sustainable building design, particularly in hot arid climates where cooling loads dominate energy use. Despite extensive research on green wall systems (GWSs), robust quantitative data on their combined impact [...] Read more.
Enhancing indoor environmental quality while reducing building energy consumption represents a critical challenge for sustainable building design, particularly in hot arid climates where cooling loads dominate energy use. Despite extensive research on green wall systems (GWSs), robust quantitative data on their combined impact on air quality and thermal performance in real-world office environments remains limited. This research quantified the synergistic effects of an active indoor green wall system on key indoor air quality indicators and cooling energy consumption in a contemporary office environment. A comparative field study was conducted over 12 months in two identical office rooms in Dhahran, Saudi Arabia, with one room serving as a control while the other was retrofitted with a modular hydroponic green wall system. High-resolution sensors continuously monitored indoor CO2, volatile organic compounds via photoionization detection (VOC_PID; isobutylene-equivalent), and PM2.5 concentrations, alongside dedicated sub-metering of cooling energy consumption. The green wall system achieved statistically significant improvements across all parameters: 14.1% reduction in CO2 concentrations during occupied hours, 28.1% reduction in volatile organic compounds, 20.9% reduction in PM2.5, and 13.5% reduction in cooling energy consumption (574.5 kWh annually). Economic analysis indicated financial viability (2.0-year payback; benefit–cost ratio 3.0; 15-year net present value SAR 31,865). Productivity-related benefits were valued from published relationships rather than measured in this study; base-case viability remained strictly positive in energy-only and conservative sensitivity scenarios. Strong correlations were established between evapotranspiration rates and cooling benefits (r = 0.734), with peak performance during summer months reaching 17.1% energy savings. Active indoor GWSs effectively function as multifunctional strategies, delivering simultaneous air quality improvements and measurable cooling energy reductions through evapotranspiration-mediated mechanisms, supporting their integration into sustainable building design practices. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
31 pages, 2935 KB  
Article
A Novel Earth-to-Air Heat Exchanger-Assisted Ventilated Double-Skin Facade for Low-Grade Renewable Energy Utilization in Transparent Building Envelopes
by Zhanzhi Yu, Fei Liu, Wenke Sui, Rui Wang, Chong Zhang, Xiaoxiao Dong and Xinhua Xu
Buildings 2025, 15(20), 3655; https://doi.org/10.3390/buildings15203655 (registering DOI) - 11 Oct 2025
Abstract
Transparent building envelopes significantly increase energy demands due to low thermal resistance and solar heat gain, while conventional double-skin facades may lead to overheating and high cooling loads in the summer. This study proposes a novel earth-to-air heat exchanger (EAHE)-assisted ventilated double-skin facade [...] Read more.
Transparent building envelopes significantly increase energy demands due to low thermal resistance and solar heat gain, while conventional double-skin facades may lead to overheating and high cooling loads in the summer. This study proposes a novel earth-to-air heat exchanger (EAHE)-assisted ventilated double-skin facade (VDSF) system utilizing low-grade shallow geothermal energy for year-round thermal regulation of transparent building envelopes. A numerical model of this coupled system was developed and validated to estimate the thermal performance of the EAHE-assisted VDSF system in a hot-summer-and-cold-winter climate. Parametric study was conducted to investigate the impact of some key design parameters on thermal performance of the EAHE-assisted VDSF system and further reveal recommended design parameters of this coupled system. The results indicate that the EAHE-VDSF system reduces annual accumulated cooling loads by 20.3% to 76.5% and heating loads by 19.6% to 47.1% in comparison to a conventional triple-glazed, non-ventilated facade. The cavity temperature of the VDSF decreases by 15 °C on average in the summer, effectively addressing the overheating issue in DSFs. The proposed coupled EAHE-VDSF system shows promising energy-saving potential and ensures stability and consistency in the thermal regulation of transparent building envelopes. Full article
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19 pages, 3824 KB  
Article
Effects of Incorporating Iron-Rich Slag on the Performance of Calcium Sulfoaluminate Cement: Strength Development, Hydration Mechanisms and Microstructure
by Rong Wang, Haixing Liu, Xiaohua Yang, Chao Peng, Taibing Wei and Huawei Li
Buildings 2025, 15(20), 3654; https://doi.org/10.3390/buildings15203654 (registering DOI) - 11 Oct 2025
Abstract
Using solid waste from the non-ferrous metal industry as non-traditional supplementary cementitious material has attracted increasing attention. In this study, iron-rich slag (IRS) was incorporated into calcium sulfoaluminate cement (CSC) to improve its properties, and its strength development and hydration mechanism were systematically [...] Read more.
Using solid waste from the non-ferrous metal industry as non-traditional supplementary cementitious material has attracted increasing attention. In this study, iron-rich slag (IRS) was incorporated into calcium sulfoaluminate cement (CSC) to improve its properties, and its strength development and hydration mechanism were systematically evaluated. Three types of IRS with distinct particle size characteristics were fabricated through mechanical grinding, and their effects on the strength development and hydration heat evolution of CSC-based materials were investigated. Furthermore, several solid-phase analysis methods were employed to characterize the hydration mechanisms and microstructural characteristics of IRS-containing CSC-based materials. The results show that mechanical grinding enhances the reactivity of IRS in CSC-based systems, which in turn facilitates the generation of hydrates like ettringite (AFt), AH3, and C–S–H gel, thereby improving their strength. The incorporation of IRS effectively decreases the total hydration heat released by CSC-based materials within 24 h. Furthermore, evidence from EDS analysis suggests the possible isomorphic substitution of Al3+ by Fe3+ in AFt, which, along with the slower reaction kinetics of Fe-AFt, may contribute to the improved late-age strength development of CSC-based materials. This study proposes a sustainable strategy for producing high-performance CSC-based materials and offers a potential approach for the high-value use of non-ferrous metal industry solid waste in construction materials, thereby demonstrating both scientific value and practical engineering significance. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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18 pages, 3193 KB  
Article
Developing a National Climate Adaptation Framework for the Design of Moisture-Resilient Buildings
by Tore Kvande and Berit Time
Buildings 2025, 15(20), 3653; https://doi.org/10.3390/buildings15203653 (registering DOI) - 11 Oct 2025
Abstract
Risk assessment for moisture safety—particularly in the context of future climate scenarios—is not yet a routine component of building design practices. Key challenges include: (1) uncertainty over who is responsible for conducting assessments, (2) ambiguity regarding the appropriate timing, and (3) a lack [...] Read more.
Risk assessment for moisture safety—particularly in the context of future climate scenarios—is not yet a routine component of building design practices. Key challenges include: (1) uncertainty over who is responsible for conducting assessments, (2) ambiguity regarding the appropriate timing, and (3) a lack of clear guidance on integrating climate data into the process. To meet the challenges, this article explores and evaluates the development of a national climate adaptation framework for designing moisture-resilient buildings in alignment with projected future climate conditions and the requirements of the Norwegian Planning and Building Act. In noteworthy detail the article presents the general approach/steps followed in the research and the qualitative climate risk assessment elements to be considered in the design process of buildings. The framework has been co-produced with the Norwegian construction industry and public sector and introduces structured checklists and division of responsibilities (architects, engineers, etc.) to clarify and operationalize this. The mainstreaming of climate adaptation requires further refinement and broader integration of climate indices into building guidelines. These indices enable more accurate moisture performance predictions and help eliminate unsuitable solutions for specific zones. The framework—reinforced by tools such as the SINTEF Building Research Design Guides (Byggforskserien)—offers a comprehensive, evolving approach to moisture resilience, dependent on ongoing tool development, clarified roles, and wider uptake of climate-sensitive risk assessments. Full article
(This article belongs to the Special Issue Climate Resilient Buildings: 2nd Edition)
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21 pages, 3823 KB  
Article
Bridging World Heritage and Local Heritage: Incorporating the Buffer Zone Concept into Chinese Architectural Heritage Protection
by Ye Cao, Ruobing Han and Zhejun Luo
Buildings 2025, 15(20), 3652; https://doi.org/10.3390/buildings15203652 - 10 Oct 2025
Abstract
Buffer zones are essential for the protection of the Outstanding Universal Value (OUV) of World Heritage properties. In China, to address the limitations of the prevailing “two-line” delineation system for architectural heritage protection, this study introduces the concept of buffer zone as a [...] Read more.
Buffer zones are essential for the protection of the Outstanding Universal Value (OUV) of World Heritage properties. In China, to address the limitations of the prevailing “two-line” delineation system for architectural heritage protection, this study introduces the concept of buffer zone as a new perspective on heritage management. Focusing on the Cao Family Compound—a representative residence of Shanxi Merchants—this research situates the site within a broader cultural network to fully articulate its historical and social values. The methodology unfolds in three phases: (1) comprehensive identification of 47 spatial elements contributing to the compound’s significance, through field investigation, literature review, analysis of historical imagery and architectural drawing, and oral history interview; (2) systematic evaluation of each element’s value contribution to the compound based on six criteria across two dimensions, employing the Analytic Hierarchy Process (AHP) and Weighted Sum Method (WSM); (3) spatial visualization and hierarchical buffer zone delineation conducted via ArcGIS-based data modeling and the Natural Breaks classification method. This integrated approach establishes a holistic and structured framework that bridges architectural heritage with its setting, providing practical guidance for policymakers and conservation practitioners. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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27 pages, 8648 KB  
Article
Sustainability Assessment of Demountable and Reconfigurable Steel Structures
by Adrián Ouro Miguélez, Félix Fernández Abalde, Manuel Cabaleiro Núñez and Fernando Nunes Cavalheiro
Buildings 2025, 15(20), 3651; https://doi.org/10.3390/buildings15203651 (registering DOI) - 10 Oct 2025
Abstract
Steel structures that support machines and industrial process installations should ideally be flexible, adaptable, and easily reconfigurable. However, in current practice, new profiles are frequently used and discarded whenever layout modifications are required, leading to considerable material waste, increased costs, and environmental burdens. [...] Read more.
Steel structures that support machines and industrial process installations should ideally be flexible, adaptable, and easily reconfigurable. However, in current practice, new profiles are frequently used and discarded whenever layout modifications are required, leading to considerable material waste, increased costs, and environmental burdens. Such practices conflict with the principles of the circular economy, in which reusability is preferable to recycling. This paper presents a life cycle sustainability assessment (life cycle cost, LCC, and life cycle assessment, LCA) applied to six structural typologies: (a) welded IPE profiles, (b) bolted IPE profiles, (c) welded tubular profiles, (d) bolted tubular profiles, (e) clamped IPE profiles with demountable joints, and (f) flanged tubular profiles with demountable joints. The assessment integrates structural calculations with an updatable database of costs, operation times, and service lives, providing a systematic framework for evaluating both economic and environmental performance in medium-load industrial structures (0.5–9.8 kN/m2). Application to nine representative case studies demonstrated that demountable clamped and flanged joints become economically competitive after three life cycles, and after only two life cycles under high-load conditions (9.8 kN/m2). The findings indicate relative cost savings of up to 75% in optimized configurations and carbon-footprint reductions of approximately 50% after three cycles. These results provide quantitative evidence of the long-term advantages of demountable and reconfigurable steel structures. Their capacity for repeated reuse without loss of performance supports sustainable design strategies, reduces environmental impacts, and advances circular economy principles, making them an attractive option for modern industrial facilities subject to frequent modifications. Full article
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21 pages, 3473 KB  
Article
Vertical Bearing Behavior of Reinforced Composite Piles in Dense Sandy Soils
by Rui Zhang, Jinsong Tu, Donghua Wang, Lintao Fang and Mingxing Xie
Buildings 2025, 15(20), 3650; https://doi.org/10.3390/buildings15203650 - 10 Oct 2025
Abstract
Reinforced composite prestressed concrete hollow square (RCPHS) piles, installed through pre-drilling, grouting, and static jacking, integrate the large lateral contact area of cement–soil casings with the high strength and stiffness of prestressed concrete cores. This study combines full-scale vertical static load tests and [...] Read more.
Reinforced composite prestressed concrete hollow square (RCPHS) piles, installed through pre-drilling, grouting, and static jacking, integrate the large lateral contact area of cement–soil casings with the high strength and stiffness of prestressed concrete cores. This study combines full-scale vertical static load tests and finite-element (FE) simulations to explore the interaction among the core pile, plain-concrete casing, and surrounding soil. Results show that, at 3600 kN, RCPHS piles exhibit 76% less pile-head settlement compared to PHS piles, and a 36.5% reduction in pile-material expenditure is achieved using the RCPHS scheme. At the same settlement of 23 mm, RCPHS piles carry 87% more load than PHS piles. A 3D FE model developed in ABAQUS reveals that the core pile carries approximately 94% of the applied load. When the load exceeds 4180 kN, the axial force in the casing sharply increases at depths of 7–10 m. The simulated P–s curves align well with field measurements, confirming model accuracy. The superior performance of RCPHS piles is attributed to the graded elastic modulus and coordinated stress distribution of the core–casing–soil system, which enhances interface friction and overall load capacity. These findings provide a foundation for the design optimization of RCPHS piles in dense sandy foundations. Full article
(This article belongs to the Section Building Structures)
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21 pages, 5540 KB  
Article
Migration Architecture and Its Impact on the Rural Territory in Saraguro: Consequences of New Construction in the Quisquinchir Community
by Karina Monteros Cueva and Jéssica Andrea Ordoñez Cuenca
Buildings 2025, 15(20), 3649; https://doi.org/10.3390/buildings15203649 - 10 Oct 2025
Abstract
The indigenous community of Quisquinchir, in Saraguro (Loja, Ecuador), is facing a process of transformation of the rural Andean landscape associated with internal and external migration, as well as the influence of foreign architectural models. The new buildings symbolize, in the collective imagination, [...] Read more.
The indigenous community of Quisquinchir, in Saraguro (Loja, Ecuador), is facing a process of transformation of the rural Andean landscape associated with internal and external migration, as well as the influence of foreign architectural models. The new buildings symbolize, in the collective imagination, modernity and progress; however, they are alien to the natural environment characterized by the practice of agricultural and livestock activities. Although previous studies have described the loss of Andean vernacular architecture, its recent evolution in clear typologies has not been systematized. The objective of this study is to assess the current state of traditional dwellings and understand how migration reconfigures the landscape, collective memory, building traditions, and cultural identity of their inhabitants. Based on direct observation, photographic and stratigraphic analysis, and secondary sources, five typologies were identified: traditional one-story, traditional two-story, hybrid one-story, hybrid two-story, and eclectic. This classification indicates the replacement of earthen walls with cement blocks in 37% of the dwellings and of tile roofs with zinc roofs in 29%. However, 35% of the houses retain their traditional morphology and materials. These results and their classification are fundamental contributions to the design of local public policies that generate adequate interventions respectful of the environment. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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19 pages, 1002 KB  
Article
How Should Property Investors Make Decisions Amid Heightened Uncertainty: Developing an Adaptive Behavioural Model Based on Expert Perspectives
by Albert Agbeko Ahiadu, Rotimi Boluwatife Abidoye and Tak Wing Yiu
Buildings 2025, 15(20), 3648; https://doi.org/10.3390/buildings15203648 - 10 Oct 2025
Abstract
In a significant transition from classical theories of efficient markets and perfectly rational investors, the recent literature has increasingly acknowledged the importance of the human element and external market conditions in decision-making. However, the application of adaptive market frameworks in the property sector [...] Read more.
In a significant transition from classical theories of efficient markets and perfectly rational investors, the recent literature has increasingly acknowledged the importance of the human element and external market conditions in decision-making. However, the application of adaptive market frameworks in the property sector remains underexplored. This gap is particularly pronounced in the commercial property market, where structural inefficiencies, such as information asymmetry and illiquidity, amplify decision-making complexity. Given that investor rationality tends to diminish as uncertainty and complexity increase, this study explored how private commercial property investors adapt their strategies amid heightened uncertainty. The perspectives of seven experienced property experts were thematically analysed to highlight recurring patterns, which were then integrated into a conceptual mind map. The findings reveal that while economic fundamentals are the constant drivers of capital allocation decisions, investors process these signals through the lens of adaptive behaviour based on intuition, experience, risk perceptions, and herding. This relationship becomes more pronounced under conditions of heightened uncertainty, where investors seek to supplement available information with sentiment due to weaker signals and declining confidence in fundamentals. Sustainable investing and technology integration also emerged as core considerations, but interest among private investors is subdued due to ambiguous value propositions regarding the long-term economic benefits of a green premium. These findings offer practical insights into how external market conditions influence property investment decisions and provide a platform for operational models of investment decision-making that integrate adaptive behaviour. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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18 pages, 4082 KB  
Article
Electrochemical and Gravimetric Assessment of Steel Rebar Corrosion in Chloride- and Carbonation-Induced Environments
by Sejong Kim and Jong Kwon Choi
Buildings 2025, 15(20), 3647; https://doi.org/10.3390/buildings15203647 - 10 Oct 2025
Abstract
This study investigates the corrosion performance of reinforced steel in concrete subjected to carbonation and chloride ingress. Four systems were examined: normal concrete (NC15), chloride-exposed (ClC15), carbonated (COC15), and chloride-exposed carbonated concrete (COClC15). A comprehensive assessment was carried out using electrochemical testing, gravimetric [...] Read more.
This study investigates the corrosion performance of reinforced steel in concrete subjected to carbonation and chloride ingress. Four systems were examined: normal concrete (NC15), chloride-exposed (ClC15), carbonated (COC15), and chloride-exposed carbonated concrete (COClC15). A comprehensive assessment was carried out using electrochemical testing, gravimetric weight loss, chloride profiling, Temkin adsorption isotherm modeling, and SEM analysis. Electrochemical results showed a marked increase in corrosion activity under combined chloride–carbonation exposure. The highest corrosion current density (icorr) was obtained in COClC15 (0.4779 µA/cm2), compared with only 0.0106 µA/cm2 for NC15. Gravimetric analysis confirmed these findings, with COClC15 exhibiting a corrosion rate nearly 1.5 times greater than ClC15 and 52 times higher than NC15 after 120 days. Chloride profiling revealed reduced binding efficiency in carbonated concrete; at 5 mm depth, COClC15 bound only 0.06% chloride, while ClC15 retained 0.43%. The Temkin adsorption isotherm further quantified the weakened binding capacity. The binding coefficient (β) of COClC15 was considerably lower than ClC15 and NC15, reflecting the impact of C–S–H decalcification and aluminate phase transformation into carboaluminates, which restrict Friedel’s salt formation. SEM micrographs corroborated these observations, showing extensive microstructural degradation in COClC15. This study revealed that the synergy of carbonation and chloride ingress reduces chloride-binding capacity, accelerates depassivation, and severely compromises the durability of reinforced concrete in aggressive environments. Full article
(This article belongs to the Special Issue Research on Corrosion Resistance of Reinforced Concrete)
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25 pages, 6872 KB  
Review
Biophilic Façades: The Potentiality of Bioreceptive Concrete
by Ronaldas Jakubovskis
Buildings 2025, 15(20), 3646; https://doi.org/10.3390/buildings15203646 - 10 Oct 2025
Abstract
The growth of microorganisms and lower plants on building walls may respond the central principle of the biophilic design: sustained engagement with nature. As such, bioreceptive concrete has great potential to increase the biodiversity in our cities. In addition, by actively participating in [...] Read more.
The growth of microorganisms and lower plants on building walls may respond the central principle of the biophilic design: sustained engagement with nature. As such, bioreceptive concrete has great potential to increase the biodiversity in our cities. In addition, by actively participating in the carbon and nitrogen cycles, biologically active, bioreceptive concrete has the potential to reduce the building’s environmental impact considerably. In the present study, we analyze the biological growth on concrete and critically review the current research approaches in the bioreceptivity evaluation. The uncontrolled and unaesthetic growth of fungal colonies, poor long-term survivability of the laboratory-developed biofilms, and a lack of field applications were identified among the major factors that hinder the practical application of bioreceptive concrete in the building envelope. Our ongoing field tests have shown that concrete’s controlled and aesthetically pleasant greening may be achieved in several years. We argue that such nature-integrated solutions would emphasize the beauty of the aging buildings while offering clear, practical benefits. Full article
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33 pages, 15695 KB  
Article
Seismic Performance of Existing Reinforced Concrete L-Shaped Columns Strengthened with Wing Walls
by Weilun Wang, Jiaqi Liao, Zixuan Li, Mingyuan Xie, Changle Fang, Muhammad Abdullah and Mingyang Zhang
Buildings 2025, 15(20), 3645; https://doi.org/10.3390/buildings15203645 - 10 Oct 2025
Abstract
In this study, the seismic performance of reinforced concrete (RC) L-shaped columns, strengthened with 100 mm and 150 mm wing walls, was determined using quasi-static tests. A total of nine L-shaped column specimens were designed and tested under cyclic loading. This study found [...] Read more.
In this study, the seismic performance of reinforced concrete (RC) L-shaped columns, strengthened with 100 mm and 150 mm wing walls, was determined using quasi-static tests. A total of nine L-shaped column specimens were designed and tested under cyclic loading. This study found that strengthening with wing walls increased the lateral stiffness and horizontal load bearing capacity of L-shaped columns. Notably, such improvement was found to be more significant under higher axial compression ratios, exhibiting maximum increases of 254% and 194% in load bearing capacity, in the positive and negative loading directions, respectively. Additionally, ductility was influenced by the wing wall length and axial compression ratios. Under a low axial compression ratio, the ductility coefficient first increased and then decreased with an increase in the wall length. Conversely, under a high axial compression ratio, ductility was consistently improved with increasing wall length. Furthermore, finite element (FE) models were established, and they successfully validated the experimental results, such as load–displacement responses, hysteresis behavior, skeleton curves and ultimate bearing capacity. The numerical results further strengthened the significant effect of the wing wall addition on the seismic performance of the L-shaped columns. Based on the results, a lateral capacity calculation formula is developed, providing a reliable method for assessing the seismic performance of the strengthened L-shaped columns. Therefore, the findings of this study present theoretical insights and practical guidance for the seismic retrofitting of existing RC structures with special-shaped columns. Full article
(This article belongs to the Special Issue Strengthening and Rehabilitation of Structures or Buildings)
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18 pages, 2058 KB  
Article
Assessing the Role of Sunlight Exposure in Lighting Performance and Lighting Energy Performance in Learning Environments: A Case Study in South Korea
by Hong Soo Lim and Gon Kim
Buildings 2025, 15(20), 3644; https://doi.org/10.3390/buildings15203644 - 10 Oct 2025
Abstract
In South Korea, sunlight rights and daylight rights are legally distinguished, yet no standardized methodology exists for their quantitative assessment. Current evaluations of sunlight rights are narrowly defined, relying on the duration of direct solar penetration at the window center during the winter [...] Read more.
In South Korea, sunlight rights and daylight rights are legally distinguished, yet no standardized methodology exists for their quantitative assessment. Current evaluations of sunlight rights are narrowly defined, relying on the duration of direct solar penetration at the window center during the winter solstice, while excluding reflected and diffuse light. This restrictive approach has led to confusion among both researchers and legal practitioners, as it diverges from daylighting evaluations that account for indoor brightness and energy performance. The recent enactment of regulations to secure solar access in schools has further intensified disputes between educational institutions striving to protect students’ visual comfort and developers seeking to maximize building potential. To address this gap, this study proposes an evaluation framework tailored to the Korean context. A reference classroom model representative of standard Korean schools was developed, and simulations were conducted by introducing obstructing building masses to block direct sunlight. The methodology evaluated key variables, including time of day and solar altitude, and analyzed daylighting performance and lighting-related energy consumption under obstructed conditions. The results show that blocking sunlight through south-facing windows reduces daylighting performance by 89% to 98%, leading to additional reliance on artificial lighting, with energy use increasing between 128 Wh and 768 Wh. These findings underscore the limitations of current legal interpretations based solely on sunlight duration and highlight the necessity of adopting performance-based evaluation methods. Protecting school sunlight rights through such approaches is essential to enhancing classroom visual environments and reducing energy demand. Full article
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