Fire Conditions Research Articles

Performance of Seismically-Compatible Fin Plate Joints under Fire Conditions

AbstractThis paper compares the performance of fin plate joints designed with and without seismic considerations under gravity loading and fire conditions. The non-seismic design, following British detailing provisions, has a thicker fin plate located higher on the beam web and it positions the beam web closer to the column face compared to the seismic design detail based on New Zealand provisions. Finite elements in ABAQUS are used to model the subassembly, which is subjected to the ISO 834 fire with and without a cooling phase. The analyses indicate the same failure mode in both subassemblies, with yielding at the beam web top bolt hole in bearing and fracture of the top bolt in shear. However, under the same fire regime, peak compressive and moment demands of the seismic detail were approximately 25% less than those for the non-seismic detail. When subjected to heating only, time to runaway failure was similar for the seismic and non-seismic detail, occurring at 15.0 and 14.8 min into the analyses respectively. When a cooling phase was included, beginning 10 min after initial fire exposure, both subassemblies recovered without failure. A parametric study showed a larger gap between the beam end and column face decreased compression in the beam but did not significantly affect the failure characteristics of the joint. Use of thicker fin plates was also found to increase the time to failure. The results show that the seismic detailing provides limited improvement over the non-seismic detail for the analysed fin plates.

Development and Characterization of Thermal Protection Gels for Steel Pipelines Transporting Combustible Materials

Due to low costs, pipelines are commonly used for transporting hazardous substances such as combustible liquids and gasses. Currently, chemical industrial parks and gas production stations have dense pipeline networks. In the case of a pipeline leakage and subsequent fire accident, the adjacent pipelines could be directly impinged by the flame or engulfed in hot smoke, with the potential to result in a chain of accidents and catastrophic consequences. It is thus of practical importance to develop an efficient thermal protection material for pipelines. In this study, a new type of bio-based gel material was prepared for pipeline thermal protection, using guar gum (GG) as the gelling agent, sodium tetraborate (B) as the crosslinking agent and magnesium chloride (MgCl2) as the fire retardant. Firstly, orthogonal experiments were conducted to examine the gelling time of the gel and determine the optimal formulations that meet the protection requirements. Subsequently, water retention, thermal stability and the microstructure of these formulations were analyzed. Finally, the thermal protection performance of the gel formulations was evaluated under the direct impingement of flames or high-temperature smoke. The results indicated that the best performance was achieved by the formulation with GG, B and MgCl2 mass fractions of 2.5, 0.6 and 0.5 wt%, respectively. This formulation also exhibited the best water retention capacity and thermal stability. In the pipeline thermal protection experiments, this formulation achieved effective protection times of 216 s (for a 90 mm diameter) and 312 s (for a 120 mm diameter) for the lower part of the pipeline under direct flame impingement. Under high-temperature smoke impingement, this formulation also showed excellent performance. These research and findings can provide an important foundation for the further development of thermal protection materials for pipelines under fire conditions.

Performance of photovoltaic panels with different inclinations under uniform thermal loading

Integrating photovoltaic (PV) panels with different tilt angles in building envelopes or roofs is widely employed for environmental sustainability. However, little is known about the influence of different tilt angles on the thermal failure of the photovoltaic façades or roofs in fire conditions. A total of 15 four-edge shielded PV panels (300 × 300 × 4.7 mm3), with five different inclinations of 0°, 15°, 30°, 45° and 60°, were heated to fail using a uniform radiant panel. Measurements were taken to track glass thermal breakage, surface temperatures, incident heat flux and failure characteristics. The glass fracture and pyrolysis of the internal thermoplastic materials were observed under thermal radiation. The average breakage time of glass in PV panels showed an increasing trend with increasing inclination of the PV panels. Moreover, when the PV panels were tilted beyond 30°, the time to failure increased more significantly. The maximum temperature difference and heat flux that the PV panels can withstand were primarily measured within the range of 61–84 °C and 8–15 kW/m2, respectively. Finally, the test results were simulated by a finite element method (FEM) model, calculating the heat transfer and thermal stress of PV panels: the average errors concerning temperature distributions and failure times were smaller than 15 % compared with the experimental results.

Underground rescue path planning based on a comprehensive risk assessment approach

Fire incidents in underground environments, such as subway stations and shopping malls, pose significant hazards due to restricted ventilation and confined spaces. These conditions complicate rescue operations, particularly given the unpredictable nature of fires. Effective integration of fire risk assessment into rescue path planning is essential for ensuring both safety and operational efficiency. However, fire risk is inherently complex, varying across both temporal and spatial dimensions, and accurate assessment depends on precise fire situation inference. Despite advancements in fire simulation technologies, inconsistencies in geometric structures between computational units limit seamless integration with path planning models. Consequently, many existing studies rely on simplistic and less reliable linear fire inference models, compromising the safety of rescue operations. This paper addresses these challenges by proposing an underground rescue path planning method based on a comprehensive fire risk assessment, aimed at enhancing both safety and operational efficiency. A fire risk assessment approach, driven by fire situation inference, is introduced, employing a novel grid-matching transformation to capture the spatio-temporal dynamics of fire conditions using high-precision simulation software. Additionally, an improved A* algorithm is developed for real-time rescue path optimization, minimizing path risk based on the results of the risk assessment. The proposed method is validated through a detailed case study, demonstrating its effectiveness and reliability.

Stoichiometric and bacterial eco-physiological insights into microbial resource availability in karst regions affected by clipping-and-burning

Despite growing interest in soil microbial resource limitation (MRL), the impacts of clipping-and-burning on bacterial resource acquisition and its soil carbon, nitrogen, and phosphorous stoichiometry (C:N:P) remain unclear, yet are critical for nutrient cycling and SOC accumulation in vegetation restoration. We examined the soil C:N:P and eco-enzymatic stoichiometry, bacterial life-history strategies, and bacterial resource limitation under the influence of clipping-and-burning management practices: high-intensity fire (HIF), low-intensity fire (LIF), clipping-and-fire (CF), clipping (CP), and an undisturbed control (CK) in a Karst site in southwest China. The results showed that SOC, TN, and TP in HIF and LIF were significantly (p < 0.05) reduced (by 64%, 97%, and 99%) compared to CK. However, soil C:N, C:P, and N:P ratios were surprisingly higher (18.1, 56, and 3.08) in CF than in CK. The ratios of soil microbial biomass carbon (MBC) and nitrogen (MBN) were higher (4.8) under clipping. In contrast, their ratios with microbial biomass phosphorus (MBP) were observed to be higher (22.3 and 6.4) under high-intensity fire compared to CK. Moreover, results show that there is a higher percentage of species linked with oligotroph bacteria of Rickettsiales in CF treatments than CK. Soil bacterial communities in CF treatments exhibited co-limitation by C and P, whereas N limitation was more pronounced under low-intensity fire conditions. In conclusion, the evidence links MRL to soil C:N:P stoichiometry, underscoring the critical role of oligotrophic bacteria in mediating soil nutrient dynamics under clipping-and-burning disturbances. These findings improve our understanding of MRL over the Karst region under clipping-and-burning treatments, shedding light on its relationship with soil C:N:P, eco-enzymatic stoichiometry, and bacterial life-history strategies.

Flexural behaviour and shear capacity of RC flat plate sections during fire exposure

PurposeFire safety is a pivotal requirement in building codes. Prescribed design criteria have been the norm to achieve it, which imposes limitations on engineers, including the inability to accommodate new solutions/materials. The shift towards performance-based design offers the potential to address shortcomings of the prescribed design. However, this shift also significantly increases the workload on structural engineers without a corresponding increase in their engineering fees. Simplified design tools are needed to assist engineers in this transition.Design/methodology/approachThe paper is divided into sections investigating equivalent standard fire duration, thermal deformations, flexural behaviour and shear capacity of flat slabs when exposed to fire. The first section conducts a parametric study correlating equivalent and realistic fire durations using the average internal temperature profile (AITP) method, resulting in statistical equations estimating equivalent fire duration. The second section evaluates thermal deformations and flexural behaviour through a parametric study considering various parameters. This section results in statistical equations estimating thermal deformations and flexural behaviour of flat slab sections during fire exposure. The final section focuses on shear capacity, developing simplified heat transfer formulas and statistical equations predicting compression zone depth reduction. The section presents methodologies predicting flat slab sections' one-way and two-way shear capacities during fire exposure.FindingsStructural engineers can use the proposed methods for daily design work without applying complex heat transfer calculations. When the equivalent standard fire duration is utilized, a flat slab’s thermal deformations, flexural behaviour and shear capacity under an actual fire condition can be calculated. As such, the methods would be highly beneficial in assessing the structural integrity of a building during an active fire incident.Originality/valueThe paper provides engineers with the tools required to evaluate the safety of flat slab sections during fire exposure. The methodologies presented in the paper enable engineers to use performance-based design for slab sections by (1) converting any real fire scenario to a standard fire with an equivalent duration, (2) assessing their thermal behaviour, (3) evaluating their flexural behaviour and (4) evaluating their flexural and shear capacities. The paper concludes with a case study example demonstrating the detailed application of the developed methods.

Application and Research of Intelligent Multi-source Information Fusion Technology in Firefighting Equipment

As modern firefighting environments become increasingly complex, traditional firefighter equipment and operational methods are no longer adequate to address the high-risk challenges of fire rescue operations. Fire scenes are characterized by complex and hazardous environmental factors, with firefighters facing multiple threats such as extreme temperatures, dense smoke, and toxic gases. Therefore, ensuring the safety and efficiency of firefighters is of paramount importance. This study integrates multiple sensor technologies to enable real-time monitoring of firefighters' physiological status, posture changes, and fire scene conditions. The system incorporates ErgoLAB wireless ECG and PPG sensors, the BWT61CL posture sensor, and the MAG14mini infrared camera, which are capable of simultaneously capturing key physiological data and heat distribution in the fire scene. To ensure data accuracy and real-time performance, the study employs efficient signal preprocessing techniques, including noise reduction, baseline correction, and time synchronization. In addition, wireless transmission technology and multimodal data fusion algorithms are utilized to comprehensively analyze the firefighters' status and fire scene conditions. This approach significantly enhances the precision of firefighter safety monitoring and operational efficiency, demonstrating substantial innovation and practical value.

Pottery Production Changes During the Transition from Byzantine to Umayyad Rule

Pottery is the most affected tool by the changes in human societies; this is due to its flexibility during forming. In order to estimate the effect of the transition of inhabitants of the urban center of Umm Qais (Gadara), north Jordan, from Byzantine (Christianity) to Umayyad (Islam) rule on pottery production traditions, a total of 29 cooking pots and sherds of pottery jars were selected. The samples were dated according to stratigraphy, archaeological context, and parallel examples to the proposed periods. The samples were investigated following the typological and archaeometric approaches. The raw materials and firing technology of the pottery during the two periods were determined following chemical and mineralogical methods using petrography, XRD, ED-XRF, and EDX-SEM techniques. The results revealed that many styles and forms of pottery continued to be produced and some new styles emerged at the urban center of Gadara. Technically, the potters inherited the knowledge of selecting the available raw materials and firing conditions of pottery during the Byzantine and Umayyad periods. During these periods, Umm Qais potters used the local raw materials—non-calcareous ferruginous illite clays mixed with medium to high amounts of coarse quartz grains and fired at temperatures around 1000° in an oxidizing atmosphere to produce cooking pots. They used the available medium to highcalcareous ferruginous illite clays and fired them at temperatures between 850° and 950° in an oxidizing atmosphere to produce the jars. Importing fine fabric jars and cooking pots during the seventh century from Jarash are indicated too. Thus, the types and forms of everyday use pottery were more affected by the political and religious changes than the technical aspects.

METHODOLOGY FOR NUMERICAL MODELING OF DETERMINING THE VALUES OF CONDITIONAL PROBABILITIES OF HITTING AIR TARGETS WHEN FIRING A MISSILE WITH A TELEVISION OPTICAL SIGHT OF A COMBAT VEHICLE

The article presents a methodology for numerical modeling of determining the values of conditional probabilities of hitting air targets when firing a missile with a combat vehicle's television optical sight. The conditional probabilities of hitting air targets are associated with the sloping range to the far limit of the kill zone of an anti-aircraft missile system. The effectiveness of the use of an anti-aircraft missile system with a television optical sight depends on the plane of air targets, the picture plane of firing, and the conditions of missile firing. The following factors were taken into account in the modeling: the color of air targets, the meteorological range of atmospheric visibility, the quality of combat performance of the combat vehicle personnel, and sunlight. The calculations take into account the technical characteristics of the stations and systems of the combat vehicle and missile. The values of the first kind of missile firing errors are presented, namely, the systematic components of the first kind of missile firing errors and their standard deviations of errors depending on the far limit of the kill zone of the anti-aircraft missile system. It is shown that the systematic component of the dynamic first-order missile firing errors increases due to the maneuvering of air targets, provided that the standard deviation of the first-order missile firing errors during the maneuvering of air targets remains unchanged. The values of the standard deviations of the first kind of missile firing errors depending on the far limit of the kill zone of the anti-aircraft missile system are given, taking into account the influence of interference on the combat vehicle's reconnaissance radar station and optical interference on the channel of the combat vehicle's television optical sight. The parameters of the first kind of missile firing errors, i.e., the values of the probabilities of the missile passing through the “tube” of the required radius of operation of the missile's radio fuse, were found. The values of the second kind of missile firing errors, namely the conditional probabilities of the missile's radio fuse, are considered. The mathematical expectation of the random value of the radius of the missile's radio fuse, which corresponds to air targets under the specified conditions, is established. The values of conditional probabilities of hitting various air targets under various conditions of firing at the far edge of the kill zone of the anti- aircraft missile system are analyzed and calculated. The obtained analytical expressions for the numerical modeling technique and the corresponding graphical material are presented.

Insights into Boreal Forest Disturbance from Canopy Stability Index

The world’s forests are being increasingly disturbed from exposure to the compounding impacts of land use and climate change, in addition to natural disturbance regimes. Boreal forests have a lower level of deforestation compared to tropical forests, and while they have higher levels of natural disturbances, the accumulated impact of forest management for commodity production coupled with worsening fire weather conditions and other climate-related stressors is resulting in ecosystem degradation and loss of biodiversity. We used satellite-based time-series analysis of two canopy indices—canopy photosynthesis and canopy water stress—to calculate an index that maps the relative stability of forest canopies in the Canadian provinces of Ontario and Quebec. By drawing upon available spatial time-series data on logging, wildfire, and insect infestation impacts, we were able to attribute the causal determinants of areas identified as having unstable forest canopy. The slope of the two indices that comprise the stability index also provided information as to where the forest is recovering from prior disturbances. The stability analyses and associated spatial datasets are available in an interactive web-based mapping app. that can be used to map disturbed forest canopies and the attribution of disturbances to human or natural causes. This information can assist decision-makers in identifying areas that are potentially ecologically degraded and in need of restoration and those stable areas that are a priority for protection.

Study on the Configuration and Fire-Resistant Property of Cable Tunnel Fireproof Clapboard Based on Equivalent Fire Condition Testing

At present, the selection criteria and configuration methods for fireproof clapboards in cable tunnels are not yet perfect, making it difficult to achieve effective fire protection. Therefore, an equivalent fire condition testing method is proposed to analyze the fire-resistant property of fireproof clapboards of different materials. Firstly, a tunnel fire experiment platform was built to carry out the combustion experiment of the high-voltage cable intermediate joint. The cable combustion equivalent fire source device is developed based on the temperature rise characteristics under different combustion conditions. However, the temperature rise characteristics of the equivalent fire source and the actual cable combustion error are within 10%. Then, four typical fireproof clapboards were tested under equivalent fire sources. The results indicate that the organic molded board has the best performance. In addition, factors such as the thickness, side panel height, and installation method of the fireproof clapboards were tested and analyzed. The results indicate that a minimum thickness of 5 mm for the fireproof clapboard and a height of 200 mm for the side panel of the clapboard are necessary to ensure effective protection. The installation method of hoisting fireproof clapboards can effectively extend the protection time by about 30% compared to the flat method.

Intelligent System for Artillery Mount Autonomous Guidance And Firing Adjustment

The article presents mathematical models, numerical algorithms and a software package for an intelligent system for artillery mount autonomous guidance and adjustment of firing. The software package includes the following components: a module for solving the direct problem of external ballistics, a neural network training module, and a firing guidance and adjustment module. The first module is designed to form a database of computational experiments by repeatedly solving the direct problem of external ballistics under varying firing conditions. In the second module, a neural network is trained to solve the inverse problem of external ballistics using the database generated from computational experiments. The third module implements algorithms for calculating the artillery mount launching angles on a target using a trained neural network and calculating corrections to launching angles based on data on the projectile impact point deviation from the target. Having received data on the artillery mount readiness to fire, the coordinates of the target position and projectile’s impact point received from a digital observer, the software package calculates the necessary launching angles or corrections to them. Launching angles are transferred via text files to the control system of the artillery mount drives, then a shot is fired and the conditions for hitting the target are assessed. The algorithm is then repeated for the next shot or new target. Testing of the developed algorithms for autonomous guidance and shooting correction was carried out using modeling of external ballistics processes in the software package, as well as carrying out experimental testing on a working simulation device of an artillery mount. The developed software package allows visualization of the obtained results and saving the history of the performed operations.

Systematic review of the use of phase change material (PCM) in concrete and the fire performance of PCM in concrete

ABSTRACT The Mechanical properties of concrete significantly deteriorate when exposed to fire, with explosive spalling posing a major threat to structural integrity. This highlights the need for effective insulation systems to protect concrete structures in fire conditions. However, current insulation solutions are typically installed externally, requiring additional labour and materials. This review explores the potential of incorporating Phase Change Materials (PCMs) directly into concrete as an embedded insulation system. As a latent heat storage material, PCM offers promising fire-resistant properties, reducing the need for external insulation while improving the fire performance of concrete. This paper presents a bibliometric analysis and a systematic review of recent publications on the use of PCMs in concrete and their fire performance applications. One thousand two hundred and four publications retrieved from Scopus© and Web of Science databases were passed through the PRISMA flowchart to obtain a database of recent literature on the study area. The current trend of research shows a shift towards inorganic PCMs in concrete. There is a significant lack of studies on using inorganic and eutectic PCM in concrete for fire applications and existing studies show inorganic PCM can be a viable solution. Commercial availability and lack of synthesised encapsulated PCM were found to be barriers to research.

Community perceptions on wildfires in Mount Kenya forest: implications for fire preparedness and community wildfire management

BackgroundNatural ecosystems provide beneficial goods and services to adjacent communities. However, these benefits also come with societal risks, among them wildfires. Kenyan ecosystems have faced increased wildfire risk due to human activities and a warming earth that causes dangerous fire weather conditions. Mount Kenya is one such ecosystem that experiences annual fires; however, there is limited information on the level of knowledge or preparedness of the local community towards wildfires and fire management across the entire ecosystem. Here, we used questionnaires and interviews to randomly and purposively survey 55 respondents across 11 villages that surround Mt Kenya forest, majority of whom were Community Forest Association (CFA) members. We investigated the perceived extent to which the communities contribute to wildfires; their opinions on some aspects of fire management; and what individual and collective actions are required to improve fire preparedness.ResultsThe most perceived causes of wildfires were honey harvesting (56%) and poaching (40%). A minority of the respondents (35%) were aware of the belief that setting forests on fire brings about rainfall, with 56% of that group reporting that the belief contributed to wildfire ignitions by a large extent. This scientifically inconclusive belief was not specific to certain tribes around Mt Kenya, as previously expected. The community strongly rejected the use of prescribed burning in fire management. They were against clearing of forest or farm debris to reduce fuel hazards, and preferred converting debris into compost.ConclusionsTo improve fire preparedness, firefighting training, resourcing, firebreak creation, and sharing of wildfire warnings with the local community need to be enhanced. Despite limited community involvement in fire-management decisions, we recommend a greater involvement of the local community in forest and/or fire management to promote ownership and sustainability.

Enhanced Pacific Northwest heat extremes and wildfire risks induced by the boreal summer intraseasonal oscillation

The occurrence of extreme hot and dry summer conditions in the Pacific Northwest region of North America (PNW) has been known to be influenced by climate modes of variability such as the El Niño-Southern Oscillation and other variations in tropospheric circulation such as stationary waves and blocking. However, the extent to which the subseasonal remote tropical driver influences summer heat extremes and fire weather conditions across the PNW remains elusive. Our investigation reveals that the occurrence of heat extremes and associated fire-conducive weather conditions in the PNW is significantly heightened during the boreal summer intraseasonal oscillation (BSISO) phases 6-7, by ~50–120% relative to the seasonal probability. The promotion of these heat extremes is primarily attributed to the enhanced diabatic heating over the tropical central-to-eastern North Pacific, which generates a wave train traveling downstream toward North America, resulting in a prominent high-pressure system over the PNW. The ridge, subsequently, promotes surface warming over the region primarily through increased surface radiative heating and enhanced adiabatic warming. The results suggest a potential pathway to improving subseasonal-to-seasonal predictions of heatwaves and wildfire risks in the PNW by improving the representation of BSISO heating over the tropical-to-eastern North Pacific.

Synergistically creolization of rubber system for fire safety cable by sepiolite functionalized with boron-based nanoparticles

In this research, a novel ethylene propylene diene monomer rubber (EPDM) formulation for cable with high ceramization efficiency was prepared by the addition of functionalized sepiolite with boron fluxing compound nanoparticles (SEPTB) obtained by precipitation route. Non-functionalized sepiolite (SEP) has been incorporated to the system for reference. EPDM materials were characterized by standardized tests measuring their behavior against fire and important improvements were observed, especially in terms of smoke production (25% reduction of the smoke production compared with the formulation using SEP) presenting a remarkable behaviour against dripping and self-extinction when a flame is directly applied. The mechanism of ceramization under fire conditions was discussed. It was found that EPDM system with SEPTB additive transformed into a rigid ceramic after treating at 1000°C. In this particular case, the ceramization was more efficient due to the sepiolite transformation to enstatite at lower temperatures (∼750 vs ∼850°C) combined with the “in situ” formation of a glassy phase which notably enhances the reinforcement of the char layer by forming a reinforcing 3D ensatite fibers net structure that reduces smoke production and even totally avoids the dripping of melted polymer by the action of the heat in a fire event. This work provides new insights for the preparation of high-performance synergist additive based on sepiolite for the enhancement of fire retardance of EPDM system for cable applications.

Study the impact of spacer at thermal degradation process of MLI-based insulation in fire condition

To reduce CO2 emissions, energy carriers such as hydrogen are considered to be a solution. Consumption of hydrogen as a fuel meets several limitations such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquified phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Different studies have been addressed the vulnerability of such insulation against high thermal loads e.g., in an accident engaging fire. Some of research works have highlighted the importance of considering the MLI thermal degradation focusing on its reflective layer. However, limited number of studies addressed the thermal degradation of spacer material and its effect on the overall heat flux.In this study, through systematic experimental measurements, the effect of thermal loads on glass fleece, glass paper as well as polyester spacers are investigated. The results are reported in various temperature and heat flux profiles. Interpreting the temperature profiles revealed that, as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Each individual spacer contributes to mitigating the radiative energy received by the measurement plate. Stacks of 20–50 spacers (this is the number of layers in commercial MLI systems applied for liquid hydrogen applications) can potentially reduce the thermal radiation by 1–2 orders of magnitude.An empirical correlation to predict a heat flux attenuation factor is proposed, which is useful for further numerical and analytical studies in the temperature range from ambient to 300 °C.

Deterioration of fire resistance of ultra-high-performance polypropylene-fibre-reinforced concrete (UHPPFRC) under long-term acid rain corrosion action

The application of ultra-high-performance polypropylene-fibre-reinforced concrete (UHPPFRC) has become widespread due to its superior mechanical properties and non-flammable characteristic. Compared to UHPC, the fire resistance of UHPPFRC, which is crucial in ensuring structural integrity and safety during fire incident, has been improved by the addition of PP fibres. In recent years, the escalation of industrial emission has resulted in a more pronounced pollution of acid rain, a major type of sulphate attack on outdoor concrete structures, leading to the aging of UHPPFRC. Given the long service life of civil engineering structures, the fire performance of aging UHPPFRC should be given significant consideration, yet few studies have taken it into account. This study, for the first time, analyses the deterioration of fire resistance of acid-rain-induced aging UHPPFRCs and compares their probability of failure under fire condition across different corrosion durations, providing guidance for the maintenance of UHPPFRC in acid-rain-prone areas. A novel coupled chemo-thermal-mechanical model is developed, which is employed to investigate the sulphate penetration process and internal stress development within UHPPFRC during the corrosion stage, and to predict temperature and internal stress distribution during the subsequent heating stage. The effects of sulphate concentration, heating rate and fibre dosage on the probability of failure of aging UHPPFRC are then studied. The results obtained from the numerical investigation indicate that the aging effect can significantly compromise the fire resistance of UHPPFRC and augment the probability of failure at elevated temperature. Also, the probability of failure of aging UHPPFRC is more sensitive to changes in sulphate concentration than changes in heating rate.

Experimental investigation into the effect of transparent fireproof coatings on charring behavior of glued laminated timber exposed to fire

As timber structures evolve towards greater heights and longer spans for buildings, there is a pressing need to enhance the fire resistance of timber structures. Considering the charring behavior of timber is crucial to the fire resistance of timber structures, it is a promising way to retard the charring behavior of timber and further enhance the fire resistance by applying transparent fireproof coatings. In this study, a series of fire tests were conducted to investigate the effect of transparent fireproof coatings on the charring behavior of Douglas fir glued laminated timber (Glulam) under small-scale ISO 834 standard fire conditions. Different coating types, coating quantities, exposed time to fire and member sizes were considered in the experiments. The experimental results including temperature profiles, maximum temperature, and charring rates for uncoated and coated Glulam specimens were carefully recorded and analyzed. Then, the effect of transparent fireproof coatings was quantified by the proposed ratio of delayed charring. The main mechanism of the delayed charring in fire was finally discussed. This study demonstrated that two transparent fireproof coatings can both effectively lower the temperature at different depths and delay the charring behavior of timber. The reduction in charring rates increased with the increase of coating quantity and decreased as the fire exposure time progressed. The ratio of delayed charring for two coatings can be over 30% in the initial stage of fire and over 20% for one-hour standard fire exposure. This study can provide technical support for enhancing the fire resistance of timber structures using transparent coatings.

Thermal insulation and fire protection plaster for FRP systems incorporating aerogel nanoparticles and phyllosilicates

Fiber Reinforced Polymers (FRP) Systems are the most advanced systems in structural repair and strengthening field for their minimal time of application, limited space needed, and high durability. However, FRP systems still have a major drawback that limits their utilization in many projects, namely low fire-resistance. A novel material that was introduced lately with a substantial thermal performance is Aerogel, which has been widely utilized in other fields. This study attempted to develop fire-protective plaster incorporating nano silica-aerogel particles and phyllosilicates. During the experimental process, different surfactants were assessed as wetting agents, and their impact on both cement and mineral matrices. Finally, the selected plaster was evaluated under fire conditions. The results reveal that aerogel incorporation in mineral (gypsum) matrix was successfully achieved using various types of surfactants. The mechanical and thermal performance of the developed plasters were promising, with a fire-rating performance reaching 82 minutes for FRP system.