Search Results (480)

Background: During the firing stage of artisanal brick production, particulate matter and other pollutants are released into the air, to which children are particularly vulnerable. Objective: To compare the frequency of allergic diseases and impaired lung function among children exposed and unexposed to artisanal brick production. Methods: A cross-sectional comparative study was conducted among 386 children aged 6 to 14 years, recruited from a primary and a secondary school in Guanajuato, Mexico. Participants were classified as exposed (n = 193) or unexposed (n = 193) to artisanal brick production. Once parents and children voluntarily consented to participate, study procedures were initiated. Forced spirometry and anthropometric measurements were performed, and the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was administered. We assessed the frequency of respiratory symptoms, allergic diseases, and lung function abnormalities. We measured the frequency of respiratory symptoms, allergic diseases, and lung function abnormalities. Results: The mean age of the 386 children was 9.7 ± 1.7 years. Each group consisted of 103 girls and 90 boys. The most important risk factors for impaired lung function were living in the brickyard (OR = 6.9, 95% CI: 4.3–11.1; p = 0.001) and being male (OR = 3.6, 95% CI: 2.3–5.7; p = 0.001). The prevalence of impaired lung function was 13.5% in exposed and 4.1% in unexposed children (OR = 3.6, 95% CI: 1.5–8.1; p = 0.001). Most of the respiratory symptoms observed were obstructive and we found no difference in the frequency of allergic diseases, but respiratory symptoms were more frequent in exposed children. Conclusions: Respiratory symptoms and obstructive abnormalities in pulmonary function are more prevalent among children living in brickyards. Male sex and residence in the brickyard were the principal risk factors for impaired lung function. Full article

Conventional fired clay brick production is energy-intensive and associated with significant carbon emissions due to kiln firing and mass molding processes. In this context, extrusion-based additive manufacturing (AM), particularly Direct Ink Writing (DIW), has emerged as a potential alternative for shaping clay-based building units, enabling reduced material waste, the use of locally sourced clays and recycled additives, and the fabrication of complex geometries with enhanced thermal and structural performance. However, despite these advantages, the application of AM to clay bricks remains limited, as key challenges persist in terms of material rheology, interlayer bonding, production scalability, and the continued need for high-temperature firing, which constrains its environmental benefits. This study presents a scoping review of AM technologies applied to clay brick manufacturing, focusing on their technical feasibility, material requirements, and sustainability implications in comparison with conventional processes. Furthermore, current research trends are analyzed to identify existing gaps, particularly regarding industrial scalability and life cycle assessment (LCA), and to outline future research directions required for the development of a new generation of sustainable clay bricks. Full article

Traditional Chinese brick-and-stone archways are not merely architectural products shaped by geographical constraints; they also embody a highly rational structural logic. Drawing on the unique earthen environment of the Loess Plateau and the region’s traditions of brick-and-stone construction, the Jinzhong region of China has developed a distinct system of archways. Consequently, to deconstruct the mechanical wisdom inherent in the traditional building techniques of the Jinzhong region, this study selected residential buildings in Qi County and Pingyao, as well as Qing Dynasty (1636–1912 AD) official architecture, as case studies. Through field investigations into the masonry techniques of three typical vault forms—the single-centre arch, the double-centre arch, and the four-centre arch—the study revealed their evolutionary characteristics in terms of geometric form. Static numerical simulation analysis was conducted using the Abaqus CAE 2025 (Dassault Systèmes, Vélizy-Villacoublay, France) platform. The study found that, under a simulated surface load of 0.027 N/mm², different arch profiles exhibited significant quantitative mechanical differences, and their stress distributions and deformation thresholds showed distinct scenario-specific tendencies. The results show that, compared to a semicircular arch, the official double-centred arch reduces maximum displacement by approximately 20%, and the maximum principal stress decreased from 1.35 MPa to 1.215 MPa, effectively mitigating the risk of cracking at the arch crown. With this high sectional stiffness and displacement-constraining capability, it supports the high load requirements of defensive city fortifications. Compared to the Pingyao gentle-type four-centre arch, its maximum displacement increased by only about 10%, and the maximum principal stress rose by only about 8%. Therefore, given similar mechanical performance but considering construction feasibility, the official double-centred arch was selected for the construction of defensive city fortifications. Furthermore, although the stress concentration at the corners (arch feet) of the Pingyao gentle-curved four-centred arch is approximately 4.8% higher than that of the pointed four-centred arch, its spatial utilization is improved by 15–20%; This geometric trade-off achieved through composite curvature maximizes interior clear space while maintaining structural stability, aligning with the functional requirements of guyao architecture for large-span living spaces. Meanwhile, the semicircular vaults of Qi County demonstrate universal value in low-load residential door and window components due to their low construction threshold. These quantitative data and qualitative observations indicate that the evolution of traditional forms is not merely an esthetic pursuit, but rather a precise optimization of structural performance within the constraints of material strength. This coupled relationship between “geometric form, load-bearing mechanism and usage context” confirms the inherent principles of resource efficiency and performance balance within traditional building systems. The quantitative assessment framework established in this study provides scientific guidance, grounded in construction logic, for the preventive conservation and precise reinforcement strategies of historic masonry structures. Full article

Sea buckthorn (Hippophae rhamnoides L.) leaves are rich in nutrients and bioactive constituents, with great potential for fermented tea development. It has been demonstrated that Fuzhuan brick tea processing can improve sea buckthorn leaf tea flavor, but the underlying microbial succession remains unexplored. Therefore, we characterized the dynamic succession and interrelationships of bacterial and fungal communities via Illumina NovaSeq 6000 sequencing. β-diversity analysis revealed successive shifts in microbial community structure, with fungal communities changing mainly in the early stage and bacterial communities varying more in the late stage of fermentation. The relative abundance of Pseudomonas, a genus frequently associated with flavor formation and tea quality, increased steadily. Fungal taxonomic analysis revealed that the genus Aspergillus, particularly the species Aspergillus chevalieri, remained dominant throughout the fermentation process. Linear discriminant analysis effect size indicated an enrichment of microbial taxa typical of fermentation, accompanied by a relative reduction in putative opportunistic microbes. Additionally, Aspergillus exhibited significant negative correlations with five key differentially abundant bacterial genera. Interestingly, microbial co-occurrence networks suggested an overall tendency toward coexistence rather than mutual exclusion between the bacterial and fungal communities. This work provides a theoretical foundation for the development of novel fermented sea buckthorn leaf tea products. Full article

The construction sector is a major consumer of raw materials and a significant source of greenhouse gas emissions, necessitating data-driven approaches to support circular economy implementation and sustainable project management. This study develops an integrated framework combining machine learning-based material stock prediction, carbon footprint assessment, and Environmental, Social, and Governance (ESG) performance evaluation for construction projects. A dataset of 128 residential buildings was compiled from official use-permit documentation. After dimensionality reduction using variance filtering and Spearman correlation analysis, 25 regression algorithms were evaluated to estimate quantities of concrete, reinforcement, and brick products. The K-Nearest Neighbor (KNN) Regressor achieved the best predictive performance, with mean absolute percentage errors of 10.64% for concrete, 10.23% for reinforcement, and 16.05% for brick products. Predicted material quantities were used to calculate CO₂ emissions across materialization, demolition, and disposal phases under linear and circular scenarios. The results indicate that circular economy implementation significantly reduces total emissions, particularly for concrete, with reductions of up to 97% under idealized full-substitution conditions, representing an upper-bound estimate. ESG assessment using the Delphi method identified environmental indicators as the most significant sustainability dimension. The proposed framework enables early-stage emission estimation and supports informed decision-making toward low-carbon and resource-efficient construction practices. Full article

With a modest estimate of 11 million workers and high greenhouse gas emissions, the Indian brick sector is a relevant study for understanding how low-carbon energy transition impacts justice for the society, environment, and livelihoods. This empirical article provides an analysis of the ongoing policy-driven energy efficiency transition and justice trade-offs and benefits in the brick production sector in the state of Bihar. The transition is explored in a larger framework of power relations and vulnerability to determine whether the policies enable or challenge transformative justice for the labour force, nature and future generations. Present policies focus on regulations and financial incentives relevant for entrepreneurs with pre-existing skills, network and financial resources. Further, present policy narratives lack attention to mechanisms that reproduce the socio-economic inequality of the brick labour force, and implications for balancing different livelihood and environmental objectives. We conclude that the findings emphasise the need for integrating a wider variety of social dimensions and relevant support schemes to overcome inequality barriers and safeguard the environment for future generations. Full article

Although prior research focused on Baghdad has identified variability in fine particulate matter concentrations (PM_2.5) and their origins, there remains uncertainty in the identification of the relative importance of local and long-range PM_2.5 sources. This study analysed hourly air pollutant concentrations and meteorological data from three monitoring sites over the year 2019 in Baghdad, namely Al-Wazeriya (WZ), Al-Andalus Square (AS), and Al-Saiydiya (SA) sites, to determine the nature of PM_2.5 sources. Multi-stage statistical models were utilised to address inherent data limitations and varying sampling dates caused by limitations on power supplies to monitoring equipment, thus improving the identification of urban particulate sources. Bivariate polar plots, concentration ratios, and conditional bivariate probability function (CBPF) plots were used to identify local sources of PM_2.5. Potential Source Contribution Function (PSCF) and concentration weighted trajectory (CWT) methods were employed for distant and regional source apportionment. Domestic diesel generators are suggested to be the primary local source of PM_2.5 pollutants in Baghdad’s WZ area (categorised as residential with significant traffic volumes). Gasoline- and diesel-fueled motor vehicles significantly contribute to PM_2.5 concentrations in the AS and SA areas, which are commercial areas with the latter having close proximity to motorway sources. Additional impacts result from gas flaring and thermal power plants in these regions. Long-range PM_2.5 transport may be attributed to the combustion of low-quality heavy fuel oils from several potential sources, including Nahrawan brick factories, oil fields, and Al-Musayyab thermal power plants, primarily towards the northeast, east, and southeast of Baghdad. Transboundary contributions to PM_2.5 concentrations in Baghdad were also identified, from industrial sources in western Iran and eastern Syria, as well as dust particulates, and oil and gas production from southwestern Iran’s Khuzestan Province, Kuwait, and the Arabian Gulf. Low to medium wind speeds (1–4 ms⁻¹) were linked with the highest source contributions, suggesting local emission sources to be the most significant contributors to high PM_2.5 at the studied sample locations. Full article

Certain clayey soils are susceptible to swelling and shrinkage due to moisture variations, which can lead to ground deformation and structural damage. Although traditional stabilization methods using lime and cement are effective, they involve high energy consumption and significant CO₂ emissions. In response to sustainability concerns, this study investigates the potential of in situ geopolymer stabilization of clay soils using industrial by-products as eco-friendly binders. Experimental studies were conducted on clay specimens stabilized with geopolymer binders produced from fly ash and waste brick powder activated by alkaline solutions. The selected clay exhibited stiff to very stiff behavior and was used as a reference material to ensure reliable evaluation without the influence of severe initial degradation. Reference samples with identical water content but without alkaline activation were also prepared. The primary objective was to assess geopolymers as a sustainable alternative to conventional binders, focusing on moisture sensitivity and long-term mechanical performance. Laboratory strength tests demonstrated that geopolymer-treated specimens exhibited significantly higher strength compared to untreated samples, indicating substantial improvement in engineering properties. Furthermore, Scanning Electron Microscopy (SEM) analyses revealed that the combination of dual activators (NS+NH) and thermal curing at 85 °C transformed the weak clay matrix into a dense, fibrous geopolymer network. However, the high curing temperature was primarily used to study the reaction mechanisms; the practical applicability of the method should be evaluated based on results obtained at ambient temperature. This structure enhanced particle bonding and mechanical interlocking by filling voids within the matrix. Overall, the findings confirm that geopolymer stabilization using industrial waste materials is an effective and environmentally sustainable alternative to conventional soil stabilization techniques, contributing to reduced carbon emissions in geotechnical engineering. Full article

Using solid waste as supplementary cementitious materials (SCMs) is an effective strategy for promoting low-carbon construction development. However, single or binary systems often exhibit mismatched reaction kinetics, thereby limiting their performance at high cement replacement rates. This study focuses on a novel low-carbon concrete designed based on reaction sequence coordination, containing recycled brick powder (RBP), ground granulated blast-furnace slag (GGBS), and self-combusting coal gangue (SCCG). The effects of RBP, GGBS, and SCCG on the hydration process and microstructure of the novel low-carbon concrete with different replacement levels have been studied by testing compressive strength, workability, and durability and observing microstructural changes. The results showed that an optimized ternary composition with an RBP:GGBS:SCCG ratio of 4:3:1 achieves a cement replacement level of 30% while exhibiting a 28-day compressive strength of 38.26 MPa, representing a 14.2% increase compared with plain cement mortar. Microstructural analyses indicate that this enhanced performance results from a time-dependent reaction sequence, in which GGBS contributes predominantly at early ages by supplying calcium, whereas RBP and SCCG mainly participate through delayed pozzolanic reactions and pore refinement at later ages. Consequently, the optimized ternary mortar exhibits a water absorption of 11.12% and a 27.2% reduction in electrical flux. This study aims to provide practical strategies for enhancing the performance of low-carbon cementitious materials through a reaction sequence coordination design approach, thereby improving the utilization efficiency of solid waste in the production of low-carbon building materials. Full article

The recycling of waste clay bricks as raw materials for cement-based materials presents an effective solution to ecological pollution and resource shortages. Previous research has separately examined the effects of recycled brick fine aggregate and recycled brick powder on mortar or concrete, but few studies have investigated their combined use. This study aims to clarify the synergistic effect of recycled brick fine aggregate (RBA) and recycled brick powder (RBP) on mortar performance, quantify the influence of the RBP substitution rate on hydration characteristics and microstructural evolution, and determine the optimal mix proportion and curing system for fully recycled brick mortar. Mortar was prepared using 100% RBA and RBP at substitution rates of 0%, 10%, 20%, and 30%. The physical properties, mechanical performance, and durability of the mortar were evaluated, alongside an analysis of its microstructural morphology, mineral composition, and pore structure. The results indicate that adding an appropriate amount of RBP helped maintain the flowability of the mortar. As the RBP substitution rate increased, the mortar strength generally decreased in the early stages, but long-term curing (≥90 days) effectively mitigated this decline. The inclusion of RBP improved chloride ion permeability, with the 20% substitution rate achieving a favorable balance between compressive strength, fluidity, and durability without significantly affecting carbonation resistance. Microstructural analysis revealed that RBP regulated the morphology of hydration products and optimized the pore structure of the mortar, while the mineral composition of hydration products was similar to that of natural mortar. These findings provide a theoretical basis and technical support for the high-value utilization of construction and demolition waste in cement-based materials. Full article

This study investigates the feasibility of utilising alkali-activated slag (AAS) and construction demolition waste (CDW) as cemented paste backfill materials. The fluidity, unconfined compressive strength, bleeding rate, and sulfate resistance of AAS-CDW backfill systems were systematically analysed. Hydration mechanisms were characterised using SEM-EDS and XRD. A novel backfill system and application process were developed and implemented in Jining Coal Mine, Shandong Province. Results indicate that a 30% waste red brick addition enhances 28-day compressive strength by 9.3% and reduces the bleeding rate by 32%, while a 10% fly ash addition optimises slurry fluidity. Notably, the AAS-based backfill exhibits superior mechanical properties and sulfate resistance compared to ordinary Portland cement (OPC)-based systems. The 28-day compressive strength of the AAS backfill reached 5.31 MPa, which is 53.4% higher than that of the OPC backfill, and its strength loss rate after sulfate attack was reduced by 13%. The solid waste utilisation rate of the AAS backfill approaches 100%. Hydration products primarily comprise ettringite (Aft), C-A-S-H gel, and hydrotalcite (HT), resulting in higher compactness than OPC-RA mixtures. Full article

Global interest in sustainable building materials is increasing due to growing concerns regarding the environmental impacts of conventional construction materials, particularly fired clay bricks. Compressed Stabilized Earth Blocks (CSEBs) have emerged as a viable, cost-effective, and environmentally sustainable alternative for building construction. The incorporation of waste-derived additives in CSEBs not only addresses waste management challenges but also enhances the functional performance of earthen materials. This study presents a comprehensive synthesis of existing research on the influence of fibers, binders, stabilizers, and production processes on the performance characteristics of CSEBs. A systematic literature review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines, resulting in the identification and analysis of 256 relevant studies. The selected literature was synthesized using the Theories, Contexts, Characteristics, and Methodologies (TCCM) framework to map research trends and methodological approaches. The review indicates that fiber reinforcement primarily improves flexural strength and thermal performance, while binders significantly enhance compressive strength and erosion resistance. The findings also demonstrate that selected waste materials can partially replace natural soil, provided minimum material and performance standards are satisfied. The study highlights the need for standardized manufacturing guidelines and testing protocols to improve the reliability, scalability, and wider adoption of CSEBs in sustainable building applications. Full article

Masonry bricks and blocks are among the most widely used construction materials worldwide; however, their conventional production relies on energy-intensive firing processes and virgin raw materials, leading to significant environmental impacts. In response to increasing sustainability and decarbonization demands in the construction sector, numerous novel ceramic and refractory materials have been proposed for masonry applications. This systematic review provides a comprehensive assessment of recent advances in ceramic and refractory materials for masonry bricks and blocks, focusing on material classification, processing routes, microstructure–property relationships, and sustainability performance. Following the PRISMA 2020 guidelines, the peer-reviewed literature published between 2018 and 2025 was systematically identified, screened, and analyzed. An analytical framework based on well-established relationships from ceramic science was adopted to support consistent comparison of mechanical, thermal, acoustic, durability, and sustainability-related properties across heterogeneous material systems. Conventional fired ceramics, waste-derived ceramics, lightweight and porous systems, alkali-activated and unfired materials, and advanced engineered ceramics were comparatively evaluated. The results reveal a clear shift from dense traditional fired ceramics toward materials incorporating industrial and agricultural residues, engineered porosity, and low-temperature or unfired processing routes. Waste-derived and geopolymer-based systems demonstrate significant potential for reducing CO₂ emissions and energy consumption while maintaining functional performance suitable for masonry applications. Lightweight and porous ceramics exhibit enhanced thermal and acoustic behavior, often accompanied by reduced mechanical strength, highlighting application-dependent trade-offs. Overall, this review provides an integrated perspective linking composition, processing, microstructure, performance, and environmental impact, identifying key research trends and knowledge gaps relevant to sustainable masonry construction. Full article

Elevated temperatures are frequently encountered in numerous occupational settings such as iron and steel foundries, non-ferrous metal foundries, brick and ceramic manufacturing plants, glass production facilities, rubber factories, electrical power plants, bakeries, laundries, chemical processing sites, mining operations, smelting plants, and steam tunnels. Employees working in these environments are at risk of developing various health issues and injuries, including ocular complications, due to prolonged exposure to heat and the physical demands of handling heavy materials. This study focuses on examining the pressure within the eye’s anterior chamber, referred to as Intraocular Pressure (IOP), and its association with the cornea’s biomechanical characteristics, with particular attention to corneal temperature. Our methodology is grounded in the principles of the first law of thermodynamics. The findings reveal a link between the temperature of the eye’s anterior chamber and the biomechanical behaviour of the cornea. Specifically, IOP serves as an indicator of the cornea’s elasticity and its optical properties as influenced by temperature variations. We investigated how the cornea’s elastic energy, or the work it performs, varies with temperature changes. The results show that an increase in temperature corresponds to a reduction in the work exerted by the cornea. The corneal temperature is affected by both the ambient environment and the temperature of the aqueous humour within the anterior chamber. This indicates a relationship between the mechanical work done by the cornea and the pressure exerted by the fluid in the eye’s front segment. Furthermore, our study identified a correlation between corneal thickness and IOP, which our modelling approach successfully quantifies. Utilizing the first law of thermodynamics, we calculated the work performed by the anterior chamber against the cornea’s internal surface. Temperature fluctuations influence the secretion, drainage, and flow characteristics of the aqueous humour, thereby impacting IOP and associated ocular conditions. These insights are valuable for devising strategies aimed at preventing eye injuries among workers exposed to high-temperature environments. Full article

Bamboo is widely available and renewable. Using bamboo blocks to partially replace coarse aggregates in the production of concrete solid bricks shows promising application prospects in areas such as nonload-bearing wall materials. However, as a natural biomass material, bamboo squares have disadvantages such as susceptibility to decay, water absorption, swelling, and drying shrinkage, necessitating modification when used as concrete coarse aggregate. This study subjected raw bamboo squares to high-temperature carbonization. The compressive performance of concrete made with these carbonized bamboo squares was first tested and compared with concrete containing raw bamboo squares. Subsequently, both raw and carbonized bamboo squares were modified using conventional methods: polyvinyl alcohol (PVA) treatment, epoxy mortar (EM) treatment, epoxy resin (EPR) treatment, water glass (WG) treatment, and glutinous rice glue treatment. Modified bamboo block concrete specimens were prepared, and their compressive strengths were tested and compared. The results indicated that the compressive mechanical performance of carbonized bamboo block concrete consistently outperformed that of raw bamboo block concrete across all substitution rates. Specifically, the optimal modification method—using epoxy mortar (EM) encapsulation—significantly enhanced the mechanical properties. At a high volumetric replacement rate of 30%, the EM-modified carbonized bamboo concrete achieved a compressive strength of 27.79 MPa, which is 15.1% higher than that of identically treated raw bamboo concrete and far exceeds the standard MU7.5 grade requirements. These quantitative findings provide a solid experimental and theoretical basis for the high-value application of bamboo squares in sustainable concrete solid bricks. Full article