Search Results (1,813)

This study investigates seismic loads in single-story masonry buildings with walls of varying heights and thicknesses, and determines optimum wall dimensions for seismic resistance using the Taguchi method. For this purpose, 25 (5 × 5 = 25) different masonry building models were created with thicknesses of 16, 20, 24, 28, and 32 cm and heights of 260, 280, 300, 320, and 340 cm. The building models were analysed using a software package in accordance with the 2018 Turkish Building Earthquake Code (2018 TBEC). C-30 concrete and S-420 steel were used in the designed building models. A 12 cm thick reinforced concrete slab was placed on top of the masonry walls. A live load of 0.2 t/m² was designed on the slab, and the mortar strength of the brick wall was taken as 30 MPa. When a building model with a height of 260 cm and a thickness of 16 cm was used as a reference, it was observed that the seismic resistance of other building models increased by approximately 72%, while shear forces increased by approximately 89% in the “x” direction and approximately 95% in the “y” direction. Furthermore, it was observed that as the ratio of wall height to wall thickness increased, the seismic resistance of the building models decreased. The seismic resistance of 25 different building models was analysed using the Taguchi method, depending on wall thickness and wall height. The analysis revealed that the building model with walls 24 cm thick and 340 cm high was the most resistant to shear forces, while the building model with walls 32 cm thick and 340 cm high provided the best resistance to seismic loads. Full article

In China, a significant portion of construction and demolition waste (CDW) consists of clay bricks and concrete, which can be processed into recycled brick–concrete aggregate (RBCA). This study explores the utilization of compositely modified RBCA as a substitute for natural coarse aggregate in concrete. Two distinct composite modification methods were applied to pretreat RBCA, and then the resistance of the resulting recycled brick–concrete aggregate concrete (RBCAC) to sulfate attack and freeze–thaw cycles was systematically examined and elucidated the underlying enhancement mechanisms. The experimental data revealed a clear trend: increasing the proportion of RBCA in the concrete mix correlates with a marked decline in its durability performance. In contrast, the application of composite modification techniques yielded a significant enhancement in durability. This improvement is primarily attributed to the mitigation of weak interfacial zones and the promotion of a more compact microstructure within the interfacial transition zone (ITZ). Consequently, the observed enhancement in durability metrics can be principally ascribed to this microstructural optimization. This research offers substantive theoretical insights that can facilitate the broader adoption of compositely modified RBCA in the production of sustainable concrete, contributing to waste valorization and resource conservation. Full article

Embodied-carbon accounting is increasingly required at the early design stage to guide material and construction choices during design iterations. However, many life-cycle assessment (LCA) workflows and centralized building information modeling (BIM)–LCA plugins still rely on fragmented data, non-transparent mapping rules, and limited cross-project reuse, which slows rapid iteration. This study develops an open and traceable embodied-carbon assessment workflow driven by BIM object geometry and semantic attributes and demonstrates it through a single case study, enabling automated accounting for the A1–A3 stages from model input to result reporting. The framework is implemented as a Revit add-in prototype connected to an open-data platform. It uses assemblies as standardized assessment units, applies configurable rule-based mapping, and performs unit normalization to link model quantities with carbon factors. A single three-story brick–concrete residential building in Wuhan with an LoD 300 model is used as the sole validation case to demonstrate workflow feasibility, report coverage, and time metrics. The case yields an A1–A3 embodied-carbon intensity of approximately 333 kgCO₂ e/m², dominated by the structural system. Rule mapping achieves 82% coverage within the defined accounting scope. Compared with manual workflows (290–380 min), first-time accounting is reduced to 83–98 min and further to within 30 min when assemblies and rules are reused. Contribution decomposition shows a concentrated pattern and supports traceability from assemblies to material types. Overall, within the tested scope, the Revit-based prototype provides efficient and verifiable embodied-carbon feedback for early-stage design. Full article

Valorizing construction and demolition waste (CDW) via alkaline activation enables low-carbon binders. This study assesses binary geopolymers formulated with recycled brick powder (PLR) and recycled concrete powder (PCR) in seven precursor ratios (0–100% PCR), activated with a ternary NaOH/Na₂SiO₃/KOH solution (silicate modulus M_s ≈ 3.2) at L/B = 0.15, and cured for 7, 14, and 28 days. Compressive strength (fc), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) were used to link microstructure–phases–properties. A local maximum in fc at ~30% PCR (16.2 MPa at 28 d) was observed versus 0% PCR (14.2 MPa) and ≥50% PCR (13.8 → 10.1 MPa at 28 d). XRD indicated a reduction in inherited crystalline phases and an increased amorphous fraction at ~30% PCR; FTIR (normalized peak position and FWHM of the T–O–Si band, not absolute intensity) suggested higher network extension; SEM-EDS (local/semiquantitative) showed a moderate rise in Ca that supports C-A-S-H domains bridging the N-A-S-H network. At a high PCR, excess Ca simplified mineralogy (quartz/portlandite dominance), promoted competitive routes (C-S-H/carbonation), reintroduced microdefects, and reduced fc. A theoretical oxide balance per mix identified a compositional window where Ca/(Si + Al) ≈ 0.35–0.45 coincides with the mechanical optimum and with XRD/FTIR tracers. Overall, a ~30% PCR window maximizes co-reticulation of N-A-S-H/C-A-S-H and densification without compromising aluminosilicate continuity, providing transferrable design and process-control criteria for CDW-based geopolymer binders. Full article

Recycled powder (RP), a by-product with a particle size smaller than 150 μm, is generated during the processing of construction and demolition waste (CDW) for recycled aggregate production. RP mainly consists of recycled concrete powder and recycled brick powder. Previous studies have demonstrated that RP can serve as a supplementary cementitious material (SCM) in concrete production. Due to the heterogeneity of parent materials with different ages, service environments, and compositions, the physicochemical properties and reactivity of RP vary significantly, which largely accounts for the inconsistent results reported in the literature. This paper presents a critical review of the application of RP as an SCM in construction. The preparation technologies, chemical and physical properties, microstructural characteristics, and activation methods of RP are systematically examined. Owing to its irregular and rough surface morphology, RP tends to reduce workability and increase water demand when incorporated as an SCM. Nevertheless, when the replacement level and median particle size are limited (typically below 30% and 20 μm, respectively), RP can contribute through micro-filling, nucleation, and limited pozzolanic effects, thereby mitigating adverse impacts on mechanical and durability properties. The mechanisms and effectiveness of mechanical grinding, thermal activation, chemical activation, and CO₂ treatment are comparatively evaluated. Moreover, the incorporation of RP in cement-based materials offers significant economic and environmental benefits. Full article

The residential building sector is a significant source of global energy consumption and carbon emissions, especially in rapidly changing rural areas. In China, the shift from vernacular courtyard dwellings to modern rural housing has altered the relationship among architectural form, thermal comfort (TC), and energy use. Vernacular dwellings in northern China employ passive strategies, such as courtyard-centred layouts, high thermal-mass envelopes, and natural ventilation, to achieve summer comfort with minimal energy input. In contrast, modern dwellings (brick–concrete) depend more on mechanical cooling and consume more electricity. This study investigates how dwelling type, spatial configuration, building materials, courtyard configuration, thermal comfort, and housing satisfaction interact to shape residential environmental adaptability in rural Handan, Hebei Province. A questionnaire survey of 383 households was analysed using Partial Least Squares Structural Equation Modelling (PLS-SEM). To supplement perceptual data, summer electricity consumption was monitored in 20 typical dwellings from June to August 2025, and on-site measurements of air temperature, relative humidity, and courtyard air velocity were conducted in six representative cases. The results indicate that dwelling type significantly affects spatial configuration and courtyard form, while spatial configuration and courtyard characteristics together influence material performance. Thermal comfort is identified as a key mediating variable with a strong direct impact on housing satisfaction. Field measurements confirm that vernacular dwellings have lower summer electricity consumption, more stable thermal conditions, improved humidity regulation, and higher courtyard air velocity, indicating superior passive cooling potential. These findings provide empirical evidence that incorporating vernacular passive design principles into contemporary rural housing can improve thermal comfort and reduce energy dependence, thereby supporting climate-responsive, low-carbon rural revitalization strategies. Full article

In the context of minimally invasive spine surgery, accurately estimating the 3D coordinates of the vertebrae from intraoperative 2D X-ray images is crucial for aligning preoperative data with the patient’s real-time posture. However, existing methods are hindered by the ill-posed nature of 2D-to-3D localization and the distinctive anatomical features of the spinal column, leading to ambiguities and reduced accuracy. In this paper, we introduce X2P-net, a novel prompt-guided and semantic context-enhanced 2D/3D vertebra detection framework. To achieve this, we design a novel Transformer architecture, referred to as BrickFormer, which can automatically extract the refined vertebral foreground context at low computational cost using a dual-attention mechanism. Comprehensive experiments were conducted to validate the proposed approach on two datasets: a large-scale synthetic dataset (BiSpineX) and a sheep spine dataset (SheepSpineX). Results obtained from these experiments demonstrate superior landmark localization performance of the proposed method compared to other state-of-the-art methods. Specifically, on the BiSpineX dataset, X2P-Net achieves percentages of 96.9% and 98.8% at 10 mm and 20 mm thresholds, respectively, a mean position error of 2.99 mm, and an $AUC$ of 0.9923. Similar superior performance was also observed when the proposed method was applied to the SheepSpineX dataset, with percentages of 98.4% and 100.0% at 10 mm and 20 mm thresholds, respectively, a mean position error of 1.08 mm, and an $AUC$ of 0.9972. Full article

This article shows the possibilities of using passive air conditioning methods in real conditions during the fattening of chickens in the summer with high outdoor temperatures. On a farm in three halls with the same interior equipment, the effect of different constructions of walls and roofs of buildings on the internal thermal and humidity microclimate was investigated. Microclimatic conditions and chickens’ performance were compared in two identical lightweight panel halls (49,000 chickens each) with light aluminum roof sheets (L* = 81.4 ± 0.4), and against conditions and results in a massive brick house (31,200 chickens) with a dark eternit roof (L* = 35.7 ± 3.5). The dark color of the roof surfaces and parts of the walls of the brick house accelerated the increase in air temperature in the house. The air temperature was 0.7 to 2 K higher in the house with darker surfaces, which was also reflected in a higher THI. The duration of chickens’ stay in conditions of higher heat stress (THI above 28.3) was 1.84 times longer in this house than in houses with light surfaces, which had the effect of increasing water consumption by 30%. The effect of heat accumulation of the brick structure on the attenuation of high temperature was not significant. Full article

As a natural building material, rammed earth has gained significant attention due to its environmental friendliness, low cost, and sustainability. This study conducted a dynamic simulation of heat and moisture transfer in rammed earth and brick buildings to compare their energy performance under identical conditions. The results indicated that the annual minimum indoor temperature in rammed earth buildings was 0.7 °C higher, while the maximum was 0.4 °C lower than that in brick buildings. The minimum and maximum indoor relative humidities were 11.4% higher and 9.6% lower, respectively, in rammed earth buildings, with an annual average of 69.2%, which is slightly lower than that of brick buildings. The annual heating and cooling energy consumption in brick buildings was 1.37 and 1.2 times greater, respectively, than in rammed earth buildings, and their monthly dehumidification demands were consistently higher. The effect of wall thickness on energy consumption revealed that increasing the thickness from 200 to 250 mm reduced energy use by 9.3%, whereas an increase from 450 to 500 mm yielded a 4.2% reduction. When the wall thickness exceeded 400 mm, the energy savings were marginal (<5%), whereas the construction costs and space occupancy increased. Therefore, a wall thickness of 350–400 mm is recommended to optimize the trade-off between energy efficiency, thermal-moisture performance, and cost-effectiveness. Full article

It is a common phenomenon that the stairs of modern historical brick–timber buildings cannot meet existing fire protection specifications, something which has become a difficulty in their renovation. In response, this study proposes two different renovation strategies for the Hui-shaped Chinese Baroque brick–timber building in Harbin and constructs multiple fire scenarios. Using a coupled PyroSim–Pathfinder (version 2023.2.0816) simulation approach, a finite element model of the building under fire and a corresponding evacuation model are established. The aim is to investigate how variations in stair width, number, position, and overall building scale under the two renovation strategies influence evacuation movement time and the number of evacuation failures, and to compare the effectiveness of common fire protection measures. The results show that, for the same stair configuration and building mass, the fire development patterns of the two renovation strategies are similar. Increasing the stair width from the original 0.9 m to 1.1 m produces no significant improvement in evacuation performance. When the number of indoor existing stairways increases from one to two, the proportion of occupants evacuated safely rises from 68% to 91%. External corridor staircases provide the best evacuation performance, and a single such stair can satisfy the safe evacuation of all occupants. When the same additional floor area is provided, increasing the number of storeys extends the evacuation movement time by approximately twice that caused by increasing the building footprint. Automatic sprinkler systems and mechanical smoke exhaust systems exhibit more pronounced fire protection effects. Full article

The Church of San Juan del Hospital in Valencia (Spain) is a Gothic church whose main architectural feature—the western façade—remained unresolved, posing structural and compositional challenges. The intervention addressed this issue while preserving the historical integrity of the building and its heritage context. A systematic methodology was applied, following principles of reversibility, sustainability, and compatibility with medieval ribbed-vault construction. The project resolved five key aspects: completion of the nave’s façade, coverage of the former atrium remains, access from the north courtyard, compositional coherence of the west courtyard front, and integration of the church and museum entrances. Contemporary materials and techniques, including aluminum, recycled wood, and handmade ceramic brick, were selected to harmonize with historic stonework, ensure durability, and minimize environmental impact. Design strategies guided visual perception, emphasizing the lower façade and resolving dispersive compositional elements, while creating functional spaces for ventilation, climate control, and circulation. This intervention demonstrates how a methodical, heritage-sensitive approach can solve complex architectural problems, combining innovation with historical authenticity, and enhancing both the functionality and aesthetic experience of the Church of San Juan del Hospital. Full article

The construction industry is a major consumer of natural resources and a significant source of CO₂ emissions. Although numerous studies have addressed cement reduction through supplementary materials, the replacement of natural aggregates has received less attention despite its high environmental relevance. Practical application of recycled aggregate concrete remains limited due to complex classification and testing requirements. This study investigates the use of locally crushed construction and demolition waste as aggregate for new structural concrete with minimal on-site preparation. The goal was to maximize recycled material utilization while ensuring adequate performance. Demolition materials from normal- and high-strength concrete, 3D-printed concrete, and fired clay bricks were crushed using jaw and impact crushers, and the entire particle size curve was incorporated into new mixtures. Two compositions were tested: 50% and 75% recycled aggregate combined with natural quartz sand, without increasing cement content. Compressive strength and density were evaluated at 28 and 90 days. High-strength concrete waste provided strengths close to the reference mixture, while normal concrete and brick aggregates resulted in lower but still structural-grade concretes. The strengths achieved ranged between 35 MPa and 73 MPa, which is between 48% and 98% of the reference value, respectively. A linear relationship was found between density and compressive strength, enabling estimation from simple measurements. The results confirm that uncontaminated demolition waste can be efficiently reused on site with limited testing, supporting circular construction and reduced environmental impact. Full article

Groundwater, a critical resource for regional water security and public health, faces escalating threats from heavy metal contamination—a pressing environmental challenge worldwide. This study focuses on the central-south Hunan region of China, a mineral-rich, densely populated area characterized predominantly by non-point-source pollution, aiming to systematically unravel the spatial patterns, source contributions, and associated health risks of heavy metals in local groundwater. Based on 717 spring and well water samples collected in 2024, we determined pH and seven heavy metals (As, Cd, Pb, Zn, Fe, Mn, and Tl). By integrating hydrogeological zoning, lithology, topography, and river networks, the study area was divided into 11 assessment units, clearly revealing the spatial heterogeneity of heavy metals. The results demonstrate that exceedances of Cd, Pb, and Zn were sporadic and point-source-influenced, whereas As, Fe, Mn, and Tl showed regional exceedance patterns (e.g., Mn exceeded the standard in 9.76% of samples), identifying them as priority control elements. The spatial distribution of heavy metals was governed the synergistic effects of lithology, water–rock interactions, and hydrological structure, showing a distinct “acidic in the northeast, alkaline in the southwest” pH gradient. Combined application of the APCS-MLR and PMF models resolved five principal pollution sources: an acid-reducing-environment-driven release source (contributing 76.1% of Fe and 58.3% of Pb); a geogenic–anthropogenic composite source (contributing 81.0% of Tl and 62.4% of Cd); a human-perturbation-triggered natural Mn release source (contributing 94.8% of Mn); an agricultural-activity-related input source (contributing 60.1% of Zn); and a primary geological source (contributing 89.9% of As). Monte Carlo simulation-based health risk assessment indicated that the average hazard index (HI) and total carcinogenic risk (TCR) for all heavy metals were below acceptable thresholds, suggesting generally manageable risk. However, As was the dominant contributor to both non-carcinogenic and carcinogenic risks, with its carcinogenic risk exceeding the threshold in up to 3.84% of the simulated adult exposures under extreme scenarios. Sensitivity analysis identified exposure duration (ED) as the most influential parameter governing risk outcomes. In conclusion, we recommend implementing spatially differentiated management strategies: prioritizing As control in red-bed and granite–metamorphic zones; enhancing Tl monitoring in the northern and northeastern granite-rich areas, particularly downstream of the Mishui River; and regulating land use in brick-factory-dense riparian zones to mitigate disturbance-induced Mn release—for instance, through the enforcement of setback requirements and targeted groundwater monitoring programs. This study provides a scientific foundation for the sustainable management and safety assurance of groundwater resources in regions with similar geological and anthropogenic settings. Full article

Geopolymer mortars were produced from construction and demolition waste using a binary binder of recycled brick powder/recycled concrete powder (RBP/RCP = 70/30 wt%), activated with a hybrid alkaline solution (NaOH/Na₂SiO₃/KOH) and reinforced with sisal fibres at 0–2 wt%. Mechanical performance (compression and three-point bending) and microstructure–phase evolution (XRD, FTIR, SEM-EDS) were assessed after low-temperature curing. Sisal addition delivered a strength–toughness trade-off with a reproducible optimum at ~1.0–1.5 wt%; at 2.0 wt%, fibre clustering and connected porosity reduced the effective load-bearing section, penalising flexure more than compression. Microstructural evidence indicates coexistence and co-crosslinking of N-A-S-H and C-(A)-S-H gels—enabled by Ca from RCP—leading to matrix densification and improved fibre–matrix anchorage. Fractographic features (tortuous crack paths, bridging, and extensive pull-out at ~1.5 wt%) are consistent with an extended post-peak response and higher fracture work without compromising early-age strength. This study achieves the following: (i) it identifies a practical reinforcement window for sisal in RBP/RCP geopolymers, (ii) it links gel chemistry and interfacial phenomena to macroscopic behaviour, and (iii) it distils processing guidelines (gradual addition, workability control, gentle deaeration, and constant A/S) that support reproducibility. These outcomes provide a replicable, low-embodied-CO₂ route to fibre-reinforced geopolymer mortars derived from CDW for non-structural and semi-structural applications where flexural performance and post-peak behaviour are critical. Full article

Artificial reefs are an important tool for marine ecological restoration and fishery resource proliferation, and are widely used around the world. Among them, Japan, the United States, China, South Korea, Australia, and the Mediterranean coastal countries have particularly invested in scientific research and practice in this field, and the reefs’ material selection, structural performance, and ecological benefits have attracted much attention. The purpose of this paper is to summarize the preparation methods, characterization methods (such as microstructure analysis and mechanical tests) and mechanical properties (such as compressive strength and durability) of new concrete materials (steel slag-blast furnace slag concrete, oyster shell concrete, sulfoaluminate cement concrete, recycled brick concrete, silica fume concrete, and banana peel filler concrete) that artificial reefs and ceramic artificial reefs developed in recent years, and to explore the resource utilization potential of different waste materials. At the same time, the biostatistical methods (such as species abundance and community diversity) of wood, shipwreck, steel, rock, waste tire, and ordinary concrete artificial reefs and their effects on the marine environment were compared and analyzed. In addition, the potential impact of artificial reef deployment on local fishermen’s income was also assessed. It is found that the use of steel slag, blast furnace slag, sulfoaluminate cement, and silica fume instead of traditional Portland cement can better improve the mechanical properties of concrete artificial reefs (compressive strength can be increased by up to 20%) and reduce the surface pH to neutral, which is more conducive to the adhesion and growth of marine organisms. The compressive strength of oyster shell concrete and banana peel filler concrete artificial reef is not as good as that of traditional Portland cement concrete artificial reef, but it still avoids the waste of a large amount of solid waste resources, provides necessary nutritional support for aquatic organisms, and also improves its chemical erosion resistance. The deployment of artificial reefs of timber, wrecks, steel, rock, waste tires, and ordinary concrete has significantly increased the species richness and biomass in the adjacent waters and effectively promoted the development of fisheries. Cases show that artificial reefs can significantly increase fishermen’s income (such as an increase of about EUR 13 in the value of a unit effort in a certain area), but the long-term benefits depend on effective supervision and community co-management mechanisms. This paper provides a scientific basis for the research and development of artificial reef materials and the optimization of ecological benefits, and promotes the sustainable development of marine ecological restoration technology and fishery economy. Full article