Search Results (102)

Ceramic tiles classified as non-biodegradable are made from fired clay, silica, and other natural materials for several construction applications. Waste ceramic tiles (WCTs) are produced from several sources, including manufacturing defects; surplus, broken, or damaged tiles resulting from handling; and construction and demolition debris. WCTs do not decompose easily, leading to long-term accumulation in landfills and occupying a significant amount of landfill space, which has substantial environmental impacts. Recycling WCTs offers several critical ecological benefits, including reducing landfill waste and pollution, conserving natural resources, lowering energy consumption, and supporting the circular economy, which in turn contributes to sustainable construction and waste management practices. In green concrete manufacturing, WCTs are widely utilized as replacements for cement, fine, and coarse aggregates, and the recycling level in the concrete industry is an increasingly explored practice aimed at promoting sustainability and reducing construction waste. From this view, this paper reports the innovative technologies, advancements in green concrete performance, and development trends in the reuse of WCTs in the production of systems. The effects of WCTs on fresh, engineering, microstructural, and durable properties, as well as their environmental performance, are reviewed. In conclusion, the use of technologies for recycling WCTs has demonstrated potential in promoting sustainability and supporting the transition toward a more environmentally friendly construction industry. This approach offers a practical contribution to sustainable development and represents significant progress in closing the recycling loop within the construction sector. Full article

In the case of strengthening building structures, the process usually involves elements that have a certain loading history and are typically subjected to loading during the strengthening process. In scientific research, on the other hand, strengthening is usually applied to elements that are not representative of real structures. This article presents a study of the effect of pre-damage on the behavior of eccentrically compressed concrete cylinders confined with PBO-FRCM (fabric-reinforced cementitious matrix with PBO fibers) composite. Concrete confinement introduces a favorable triaxial stress state, which leads to an increase in the compressive strength of concrete. FRCM systems are an alternative to FRP (fiber-reinforced polymer) composites. Replacing the polymer matrix with a mineral matrix primarily improves the fire resistance of the strengthening system. The elements were made of concrete with a compressive strength of about 40 MPa, which is typical for current reinforced concrete columns. Pre-damage was induced by loading the test elements to 80% of the average compressive strength and then fully unloading. The elements were then strengthened with three layers of PBO-FRCM composite and subjected to axial or eccentric compression with force applied at two different eccentricities. In addition to electric strain gauges, a digital image correlation system was used for measurements, to identify the initiation of PBO mesh overlap delamination. This study analyzed the elements in terms of load-bearing capacity, deformability, ductility, and failure mechanisms. In general, there was no negative effect of pre-damage on the behavior of the tested elements. Full article

Post-earthquake fires (PEFs) represent a complex, cascading hazard in which seismic damage creates ignition conditions that can overwhelm urban infrastructure and severely compromise structural integrity. Despite growing scholarly attention, the literature on PEFs remains fragmented across disciplines, lacking a consolidated understanding of structural vulnerabilities, urban-scale impacts, and response strategies. This study presents a systematic and thematic synthesis of 54 peer-reviewed articles, identified through a PRISMA-guided screening of 151 publications from the Web of Science Core Collection. By combining bibliometric mapping with thematic clustering, the review categorizes research into key methodological domains, including finite element modeling, experimental testing, probabilistic risk analysis, multi-hazard frameworks, urban simulation, and policy approaches. The findings reveal a dominant focus on structural fire resistance, particularly of seismically damaged concrete and steel systems, while highlighting emerging trends in sensor-based fire detection, AI integration, and urban resilience planning. However, critical research gaps persist in multi-hazard modeling, firefighting under partial collapse, behavioral responses, and the integration of spatial, infrastructural, and institutional factors. This study proposes an interdisciplinary research agenda that connects engineering, urban design, and disaster governance to inform adaptive, smart-city-based strategies for mitigating fire risks in seismic zones. This work contributes a comprehensive roadmap for advancing post-earthquake fire resilience in the built environment. Full article

The service status of rail, fasteners and track slabs is the key determinant of whether the ballastless track is ready for traffic after a fire. The track slab rail support bolt anchoring performance and the shoulder service performance damaged by fire were tested. Experiments of ballastless track slab concrete burned at different high temperatures were carried out to compare macro- and microstructural properties of the concrete under high-temperature burning to study the microstructure of hydration products after high-temperature burning and reveal the damage mechanism of the track slab concrete after a fire. The results show that the fire damage to the rail and fastener is mainly deformations, fractures and strength reduction. The degree of the fire damage of the mortar layer and base slab is much lower than that of the track slab. The main fire damage to the concrete is track and base slab cracks, spalling and gaps. The degree of the fire damage to the mortar layer and base slab is much lower than that of the track slab. The fire damage of the track slab concrete is mainly bursts, and the concrete cracks, spalling and deterioration occur layer by layer from the outside to inside. The shoulder injury is the most serious, the shear resistance is greatly reduced, the rail support is protected by the rail and fastener, the impact of the fire damage is small and the bolt anchoring performance was not decreased. The position of the track slab’s inside damage corresponds to the surface damage position. The steel bar inside the track slab is in good condition, and there is no obvious damage. The bulk expansion of the ballastless track concrete was caused by the expansion of aggregates under fire. When the expansion of aggregates is constrained by the shrinkage of hydration products, greater internal stress is generated, which is the main reason for the cracking or bursting of the ballastless track slab concrete under high temperatures. Full article

Recent catastrophic bridge fire incidents have highlighted the critical need for effective post-fire assessment of bridges, thereby challenging the dominant practice of complete replacement following these destructive events. This study investigates the post-fire performance of bare, isolated, and Carbon Fiber Reinforced Polymer (CFRP)-repaired Reinforced Concrete (RC) bridge columns under single-unit truck impact followed by air blast. This extreme loading scenario was deliberately selected given the increased vulnerability of bridge columns to this loading scenario in the recent few years. Three-dimensional Finite Element (FE) models of the structural system and surrounding environment were developed and validated in LS-DYNA. The effectiveness of two in-situ retrofitting schemes in mitigating damage and enhancing structural integrity of three column diameters under the selected multi-hazards was assessed. Results demonstrated that wrapping the bottom half of the column height prevents shear failure and significantly reduces the damage under the coupled impact and blast. In contrast, employing a combination of CFRP bars and externally bonded sheets showed limited enhancement on post-fire impact and blast performance. This study provides critical insights into the feasibility and efficacy of retrofitting bridge columns that have experienced fire, thus laying the groundwork for the reconsideration of current design and rehabilitation protocols. Full article

Fire is a distinctive factor in forest ecosystems. While uncontrolled wildfires can cause significant damage, prescribed burning is widely used as a management tool. However, despite the growing threat of forest water stress under climate change, there is a lack of concrete evidence on the impact of fire on water stress in forest ecosystems. This study utilized Landsat time-series remote sensing data combined with the Infrared Canopy Dryness Index (ICDI) to monitor changes in canopy dryness patterns across the eucalyptus-dominated Northern Jarrah Forest of southwestern Australia. The forest was chosen due to its exposure to a changing climate characterized by decreasing rainfall and more frequent droughts, signs of water stress in otherwise drought-resilient trees, and its well-documented fire management history. Analysis of ICDI patterns over the period from 1988 to 2024 revealed a clear overall trend of increasing water stress, coinciding with a small overall decline in annual rainfall in the 10,000 km² study area. Furthermore, by examining five prescribed burns and five wildfires, we found that NDVI-assessed canopy cover recovered rapidly in fire-affected areas, typically within one to three years, depending on fire severity. However, ICDI water stress levels were reduced for approximately 7–8 years following low-severity prescribed burns and more than 20 years after high-severity wildfires. These findings suggest the potential of prescribed burning as a tool to mitigate water stress in vulnerable forest landscapes, particularly in regions prone to drought and climate change. Additionally, the study underscores the effectiveness of the ICDI in monitoring forest water stress and its potential for broader applications in forest management and climate adaptation strategies. Full article

The increasing demand for sustainable and resilient construction solutions calls for the integration of innovative, non-conventional materials in structural retrofitting. This study investigates the use of basalt fiber-based engineered geopolymer composites (BFEGC) as a retrofitting material for fire-damaged reinforced concrete (RC) short columns. A total of 14 columns (150 mm × 150 mm × 650 mm) were cast. Two columns were used as control specimens. The remaining 12 columns were exposed to various fire conditions: 300 °C for 30 min, 600 °C for 20 min, and 900 °C for 15 min, followed by gradual (GC) or rapid cooling (RC). Among the columns, six were left unwrapped (GC-NW, RC-NW), while six others were retrofitted with BFEGC (GC-W, RC-W) and subjected to axial loading until failure. The results showed that BFEGC wrapping improved the mechanical performance of fire-damaged columns, especially at 600 °C. The 600RC-W columns exhibited 1.85 times higher ultimate load, 1.56 times greater displacement ductility, and 2.99 times higher energy ductility compared to unwrapped columns. The strength index and confinement coefficient of the 600RC-W columns increased by 2.31 times and 40.2%, respectively. Microstructural analysis confirmed the formation of salient hydration products under elevated temperatures. BFEGC shows significant reduction in carbon emissions and embodied energy, compared to conventional cement-based binders for fiber-reinforced polymer systems. Full article

Compressive strength tests of concrete using core samples are used to determine the strength of concrete elements in building structures. Due to ecology, the use of recycled aggregate in concrete is common. There are more and more concrete structures with recycled aggregate, in which the technical condition must be checked. It is difficult to find scientific studies concerning changes in compressive strength (using core samples of different sizes and using concrete with the addition of recycled aggregates) across the entire thickness of concrete elements. Therefore, studies of the compressive strength of core samples taken across the thickness (top layer, middle layer, bottom layer) of horizontally formed concrete elements with recycled aggregate and clean natural aggregate were conducted. The obtained test results allowed for the determination of the conversion coefficients that enable the compressive strength of the core samples (of different diameters: 59 mm, 74.5 mm, 114 mm, samples taken from different layers of a concrete element with a thickness of 260 mm) to be converted into the compressive strength of the core sample with a diameter of 94 mm and compared with a standard cubic sample with an edge length of 150 mm. The conversion coefficients can be used to determine the quality of the concrete produced or the technical condition of the building (mechanical damage, building reconstruction, building fire). The obtained results of the tests of the concrete samples, which had a compressive strength equal to 40 MPa and were prepared with the addition of recycled aggregate, indicate that there is a decrease of 17% in the strength value in the top layer of the concrete element when compared to its bottom layer. The concrete with a compressive strength of 20 MPa had a lower strength value of its top layer by 33% when compared to its bottom layer. Similar relationships were obtained for concrete with pure natural aggregate. Full article

When exposed to events such as fires or elevated temperatures, carbonation is an eventual outcome in cementitious building materials and can compromise the structural integrity of the material. Monitoring the pH levels in cement-based materials using color dyes, such as phenolphthalein, can offer insights into their chemical stability and the potential for early aging. These chemicals are traditionally used to detect carbonation depth in concrete, and recently, it has been suggested that they be applied to the concrete surface to determine the pH levels and the associated changes within these materials after heat treatment. This study utilizes image processing techniques to analyze the extent of fire damage by evaluating the primary color changes induced by phenolphthalein in cemented clay-based building materials. The primary color analysis can reduce the complexity in image processing, and while analyzing the color changes, it is found that the CMYK color model is superior to the RGB model for the cemented clay brick samples analyzed. The objective of this study is to develop rapid image processing techniques to automate the detection of carbonation in heat-treated cementitious materials. This study highlighted significant color transformations across different temperature exposures, providing valuable insights into the carbonation processes in burnt building materials. This study also identified the temperature range limitation (100 °C to 400 °C) of phenolphthalein indicators, which was not previously identified, and suggested the need for more robust carbonation indicators. Full article

With the improvement of building safety requirements and the need for risk assessment under extreme conditions such as earthquakes, fires, and explosions, research related to the failure of some key components has received more attention in recent years. The concrete frame is an important and complex research field in structural engineering when analyzing the chain reaction and collapse mode that may occur after the failure or removal of some columns. In order to study the influence of local damage on the stability of the residual structure of a typical frame concrete structure, the dynamic response and collapse resistance of the residual structure of a plane frame structure were analyzed by using the column removal method. Based on LS-DYNA, all working conditions of single column, double column, and multi-column in different demolition positions were designed. By studying the numerical simulation of different adjacent demolition columns and demolition positions, combined with force transmission path analysis and progressive collapse theory, the dynamic response process of damaged structures under different conditions was obtained. Based on the theory of resistance in progressive collapse, the collapse mode and response characteristics of plane frame structures were analyzed. Through the simulation verification of a multi-story frame structure, the dynamic response law under each column removal condition was obtained: with the increase in the number of columns removed, the collapse speed of the building structure and the dynamic response to the remaining structure are enhanced; as the failure column is closer to the center of the structure, the force transmission path of the surrounding structure becomes greater, the resistance provided by the structure increases, the collapse speed becomes slower, the dynamic response range increases, and the progressive collapse of the peripheral column is caused when multiple columns are removed. According to this law, the relationship between the location parameters of the failure column and the vertical displacement and horizontal displacement is established. The results show that the closer the multi-column collapse is to the central area of the structure, the greater the structural response caused by the failure column. Due to the greater constraints and force transmission paths closer to the remaining columns in the center of the structure, it is difficult for the failure structure to eventually cause collapse damage to the central members, and the failure of the secondary external columns close to the external area is more likely to lead to the progressive collapse of the edge structure. The research provides design ideas and insights for the anti-collapse design of frame structures under multi-column demolition conditions. Attention should be paid to the risk of progressive collapse caused by the sub-external area, and this part should be strengthened. Full article

Steel–concrete–steel (SCS) composite slabs are widely used in critical infrastructures such as nuclear power plants, where systematic performance evaluation through multiple criteria is crucial due to their safety functions. During their use, fires may occur due to fuel or gas leaks, leading to explosions. This article uses ABAQUS 2020 finite element software and combines the different advantages of the implicit heat transfer algorithm and explosion display algorithm to establish a numerical simulation method for dynamic analysis of SCS slab under explosion after fire. Based on different fire conditions and the propagation laws of explosion shock waves, some key dynamic indicators and failure modes of the slab were studied. The results reveal progressive damage mechanisms with increasing fire duration, characterized by expanding damage areas, significant stress fluctuations, and increasing displacement rates. Additionally, the fire surface shows greater vulnerability than the back fire surface. The results provide multiple evaluation criteria for assessing structural performance, including temperature distribution, stress evolution, and damage patterns, which can support engineering decision-making in structural safety management. Full article

Post-earthquake fires (PEFs) pose a significant secondary hazard in earthquake-prone regions, compounding the destruction caused by seismic events and threatening structural safety. This review explores the interplay between seismic damage and fire resistance, focusing on ignition sources such as damaged utility systems and overturned appliances, and their cascading effects on structural integrity. Advanced performance-based design approaches are evaluated, emphasizing the integration of probabilistic risk assessments, sequential analysis, and hybrid fire simulations to address multi-hazard scenarios. Key findings of current studies reveal that seismic damage, including spalling, cracking, and loss of fireproofing, substantially reduces the fire resistance of materials like steel and reinforced concrete, exacerbating structural vulnerabilities. Despite advancements, critical gaps persist in experimental data, probabilistic modeling, and comprehensive performance-based design guidelines for PEF scenarios. Addressing these deficiencies requires enhanced data collection, improved modeling techniques, and the integration of PEF considerations into building codes. This study provides a comprehensive review of PEF damage assessment and underscores the need for a holistic, multi-hazard design paradigm to enhance structural resilience and ensure safety in regions subject to seismic and fire risks. These insights provide a foundation for future research and practical applications aimed at mitigating the compounded effects of earthquakes and fires. Full article

Reactive powder concrete (RPC) is widely used in ultra-high-rise buildings, hydropower stations, bridges, and other important infrastructures. To study the dynamic response and damage characteristics of RPC columns and frames considering coupled fire and explosions, an analytical model of RPC columns and frames with coupled fire and explosions was established by using ABAQUS (2021) finite element software. The dynamic response and damage degree of RPC columns under coupled fire and explosions were investigated to reveal the influence laws of parameters such as cross-section size, axial compression ratio, reinforcement rate, and fire duration on the dynamic response of RPC columns at high temperatures. The dynamic response of the frame structure was analyzed when the explosion load was applied to the bottom corner columns, side columns, and top beams, respectively. The results show that the fire severely weakened the blast resistance of RPC columns; the maximum mid-span deformation and residual deformation of RPC columns decreased with the increase in cross-section size and longitudinal bar reinforcement ratio and increased with the increase in fire duration and axial compression ratio. When the explosion load was applied to the corner columns of the bottom floor of the frame, the bottom corner columns were almost completely destroyed, and there was a significant risk of the structure collapsing. Based on the results of the data analysis, a method to enhance the explosion resistance of RC frame structures using RPC materials at high temperatures is proposed. Full article

Fiber-reinforced concrete (FRC) has become increasingly important in recent decades due to its superior mechanical properties, especially flexural strength and toughness, compared to normal concrete. FRC has also received significant attention because of its superior fire resistance performance compared to non-fiber concrete. In recent years, studies on the mechanical performance, fire design, and post-fire repair of thermally damaged fibrous and non-fibrous concrete have gained importance. In particular, there are very few studies in the literature on the mechanical performance and flexural behavior of steel and basalt hybrid fiber concretes after high temperature and water re-curing. This study aims to determine the mechanical properties and toughness of concrete containing steel fiber (SF) and basalt fiber (BF) after ambient and high temperature (400 °C, 600 °C, and 800 °C). Additionally, this study aimed to examine the changes in fire-damaged FRCs as a result of water re-curing. In this context, high temperature and water re-curing were carried out on non-fibrous concrete (control) and four different fiber compositions: in the first mixture, only steel fibers were used, and in the other two mixtures, basalt fibers were substituted at 25% and 50% rates instead of steel fibers. Furthermore, in the fifth mixture, basalt fibers were replaced by polypropylene fibers (PPFs) to make a comparison with the steel and basalt hybrid fiber-reinforced mixture. This study examined the effects of different fiber compositions on the ultrasonic pulse velocity (UPV) and compressive and flexural strength of the specimens at ambient temperature and after exposure to elevated temperatures and water re-curing. Additionally, the load–deflection curves and toughness of the mixtures were determined. The study results showed that different fiber compositions varied in their healing effect at different stages. The hybrid use of SF and BF can improve the flexural strength before elevated temperature and particularly after 600 °C. However, it caused a decrease in the recovery rates, especially after re-curing with water in terms of toughness. Water re-curing provided remarkable improvement in terms of mechanical and toughness properties. This improvement was more evident in steel–polypropylene fiber-reinforced concretes. Full article

Bridge fires present unique challenges due to their potential for catastrophic structural failures, leading to extensive traffic disruptions, economic losses, and, in some cases, loss of life. In the aftermath of a fire incident, assessing the structural integrity and future viability of concrete bridges has become a paramount concern for civil engineers and safety inspectors. The critical decision to rehabilitate or demolish a fire-damaged structure hinges on accurately assessing the extent of damage incurred. Enhancing the fire resilience of concrete structures is a critical endeavor within civil engineering, necessitating accurate evaluation methods to analyze conditions after fire exposure. Focusing on concrete bridges, this study aimed to establish a comprehensive review of research on the effects of fire, providing engineers with the necessary means to develop guidelines for post-fire assessment to enhance safety and operational readiness. It proposes an in-depth examination of various methods as strategic decision-making tools. The assessment involves estimating the temperature, the extent of damage to concrete, and the reduction in the strength of both concrete and reinforcement. To achieve this, a detailed review of the existing literature on the impact of fire on concrete and its steel reinforcements is conducted. Current post-fire assessment tools have also been evaluated to improve the efficiency of the evaluation process. This study establishes a systematic post-fire assessment review framework that incorporates assessment information domains (including non-destructive testing, destructive testing, advanced computational modeling, and digital-twin technology) to provide a practical solution for accurately determining the safety and operational readiness of fire-damaged concrete bridges. Full article