Good Fire Resistance Research Articles

Seismic Performance Analysis of PEC Structures

Partially-Encased Composite Steel and Concrete Members (PEC members for short) consists of H-shaped cross-section of the main steel and concrete filling between the flange and the web, compared with the pure steel structure, the PEC structure has the advantages of high stiffness, high bearing capacity, good fire resistance and so on. The arrival of an earthquake may cause damage to building structures. The use of PEC structures can effectively improve their bearing capacity and seismic performance, and the method of post earthquake repair is relatively easier and more economical. In recent years, PEC components have been gradually popularized and applied in building structures.

From waste to resource: Exploring the recyclability and performance of gypsum-graphene nanofiber composites

Gypsum is a widely used building material with a variety of benefits, including good fire resistance, sound insulation, and environmental friendliness. However, gypsum disposal is commonly associated with significant environmental risks, including unhealthy gas emissions and land degradation. Gypsum recycling can help to reduce these impacts, but it can also lead to a decrease in the performance of the recycled gypsum products. This study investigated the effects of graphene nanofibers (GNFs) on the recyclability and properties of gypsum plasters. The results showed that test samples containing 1 % of GNFs exhibited improved mechanical response, with flexural and compressive strength exceeding those of neat gypsum by 30 % and 60 % respectively. This improvement is attributed to the retained functional properties of GNFs during the recycling process. Recycled gypsum pastes containing GNFs presented a more uniform and denser matrix with longer crystals, enhanced bonding, and reduced porosity. These findings suggest that GNFs can be used to facilitate the recycling of gypsum waste and to produce recycled gypsum components with improved properties. Overall, this study demonstrates the potential of GNFs to improve the sustainability and performance of recycled gypsum plasters.

Convert bamboo into high-performance, long-time durability, and fire-retardant with hyperbranched polyethylene glycol and boron

Despite renewable bamboo globally available and has been applied in industry, the bamboo modification still absents for achieving long-term anti-mildew, stability and desirable toughness, owing to its inherent hierarchical porous structures, that cannot fully insert and retain ideal drugs/polymers. Hence, a hyperbranched polymer (HPB) with polyether as backbone and phenylboronic acid as binding groups via epoxy ring-opening reactions with amino was designed, and subsequently in situ synthesized in the multi-scaled cellular structures in bamboo. It was demonstrated that the hyperbranched polyether chains filled and swollen the hierarchical bamboo cell walls, which could efficiently replace the inner hydroscopic water in bamboo and greatly improved the bamboo stability, resulted in the wet swelling and dry shrinkage rates reduced by 20.3 % and 14.8 %, respectively. Both the side groups of phenylboronic acid and epoxy on HPB outer layers could generate covalent bonding with bamboo cell walls, which twisted the easy-losing facts of boron and gained a 60.6 % retention rate, surpassed most reported modified bamboo literatures and conferred bamboo with good fire resistance and long-time anti-mildew performance. Importantly, with the cavitation effect of HPB to help stress transmission, the modified bamboo had not expensed bamboo strength, instead of reaching satisfied bending strength and toughness at 154.1 MPa of flexure strength and 10.8 % of bending strain, respectively. That expand the industrial application of bamboo.

Ultra-stable foam enabled by nano silica engineering for foam concrete improvement

Foam concrete is increasingly applied in construction due to its lightweight, good thermal insulation and fire resistance, and environmental sustainability, while its low strength limits its further popularization and applications. To enhance the stability and performance of foam concrete, amphiphilic nano silica (ANS) was employed in this study to modify the sodium dodecyl sulphate (SDS) based foaming agent. Then, the designed foam was utilized to fabricate foam concrete, of which the micro/macro performance was analysed in detail. The results showed that ANS-modified foam exhibited superior stability with a thicker foam wall thickness, contributing to the enhancement of foam stability within the cement matrix. The foam concrete with ANS exhibited higher strength compared to the control groups. The analysis of pore structures revealed that the ANS modification led to a more rounded and homogeneous pore configuration, characterized by an increased proportion of small and medium-sized pores and a decreased average pore size. The increase in pore roundness was accompanied by a reduction in the number of sharp edges of the pores and therefore a reduction in the stress concentration factor, while the moderately sized pore also was more conducive to increasing strength due to its lower stress concentration. As a result, the strength of the concrete is significantly increased. These findings demonstrate the potential of ANS as an effective foam stabilizer for foam concrete production, leading to enhanced foam stability and improved mechanical properties of concrete.

Comparison between Waterproofing Sheets Membrane and Polyurea Waterproofing Coating Methods

This research aims to compare between Waterproofing Sheets Membrane and Polyurea Waterproofing Coating Methods, and know the waterproofing methods applying time, cost, weight, materials durability, and the waterproofing methods materials fire resistance properties. The research used qualitative analysis techniques to compare the two waterproofing methods objectively, Through lab testing, researchers found that: the polyurea waterproofing coating method usually takes between 1 to 2 working days to apply while the traditional sheet membrane waterproofing method takes between 5 to 7 working days applying time, and the polyurea waterproofing coating method can be more expensive than the traditional waterproofing sheet membranes method. Applying polyurea requires specialized equipment and trained personnel for proper handling and application, Both methods' materials weight are considered relatively light but the polyurea coating method materials are lighter, the polyurea waterproofing coating system lasts up to 30 years. Rather than the traditional system which durability is up to 20 years, the polyurea waterproofing coating system is considered a good fire resistance system rather than traditional sheet membrane system. It is recommended to clean and clear the surface before the commence of the waterproofing process. and the surface needs to be tested for at least 3 full days to confirm that the waterproofing system was applied successfully and without missing any openings.

Behaviour of glass and sisal incorporated gypsum based composite panels under axial compression–experimental and numerical study

Gypsum based composite (GBC) Wall panels are being used in precast concrete industry as the panels are low cost, energy consumption, good habitability, and good fire resistance. This paper presents the studies related to gypsum based composite panels incorporated with glass and sisal fibers. The main objective of the research is to investigate the capacity of gypsum based composite wall panel subjected to axial compression with and without eccentricity. The panels were loaded in axial compression with and without eccentricity. Gypsum, white cement, fibres (glass fibers or sisal fibers) are used to prepare composite panels of size 1000 (length) × 500 (width) × 125 (thickness) mm. Total four panels (two with glass fibers and two with sisal fibers) were tested under axial compression (two panels without eccentricity and two panels with eccentricity) were tested under load control. From the tests, it was observed that the eccentric load application on the panels is very significant compared to normal load application. Significant decrease in the ultimate load is observed for the case of panels subjected to eccentric loading. Nonlinear finite element analysis for the fibre incorporated (E-glass and sisal) gypsum based composite panels under axial compression has been carried out by using the general purpose finite element software.

Desirable Strong and Tough Adhesive Inspired by Dragonfly Wings and Plant Cell Walls.

The production of wood-based panels has a significant demand for mechanically strong and flexible biomass adhesives, serving as alternatives to nonrenewable and toxic formaldehyde-based adhesives. Nonetheless, plywood usually exhibits brittle fracture due to the inherent trade-off between rigidity and toughness, and it is susceptible to damage and deformation defects in production applications. Herein, inspired by the microstructure of dragonfly wings and the cross-linking structure of plant cell walls, a soybean meal (SM) adhesive with great strength and toughness was developed. The strategy was combined with a multiple assembly system based on the tannic acid (TA) stripping/modification of molybdenum disulfide (MoS2@TA) hybrids, phenylboronic acid/quaternary ammonium doubly functionalized chitosan (QCP), and SM. Motivated by the microstructure of dragonfly wings, MoS2@TA was tightly bonded with the SM framework through Schiff base and strong hydrogen bonding to dissipate stress energy through crack deflection, bridging, and immobilization. QCP imitated borate chemistry in plant cell walls to optimize interfacial interactions within the adhesive by borate ester bonds, boron-nitrogen coordination bonds, and electrostatic interactions and dissipate energy through sacrificial bonding. The shear strength and fracture toughness of the SM/QCP/MoS2@TA adhesive were 1.58 MPa and 0.87 J, respectively, which were 409.7% and 866.7% higher than those of the pure SM adhesive. In addition, MoS2@TA and QCP gave the adhesive good mildew resistance, durability, weatherability, and fire resistance. This bioinspired design strategy offers a viable and sustainable approach for creating multifunctional strong and tough biobased materials.

INFLUENCE OF THE ADDITION OF LIME ON A MATRIX EARTH REINFORCED WITH COCONUT FIBER

The present research is based on improving the stability, resistance to moisture degradation and fire resistance of molded soil blocks for use in housing construction. The main objective was to include fibers obtained from the shell of the coconut fruit and slaked lime. The methodology includes a prior characterization of the materials using the Eades and Grim method (ASTM D6276), density test, Atterberg limits and granulometric study; and then combine the fiber and lime into a local soil matrix. It is then subjected to water absorption and erosion tests, and is also subjected to direct fire. The results reveal that the additions of 0.5% fiber and 7% lime showed changes in the weight of the blocks, at the same time improvements in the resistance to water absorption and also good fire resistance. Finally, the results are compared with the scientific literature consulted, in order to correlate them with each other.

Post-Fire Behavior of Modified SIFCON One-Way Plates with Waste Tire Rubber under Flexural Load: Experimental and Numerical Study

In this research, an experimental and numerical investigation was conducted to study the flexural behavior of modified slurry-infiltrated fiber concrete slurry-infiltrated fibrous concrete (SIFCON) one-way plates after being subjected to a high temperature. The first part is an experimental work to ensure that the model developed is adequate, while the second part is a 3D finite element modeling of the SIFCON plates with the program ABAQUS using a sequentially coupled thermal displacement analysis. The experimental program included testing eight modified SIFCON plates containing waste powder rubber as a partial substitute for natural sand (0%, 5%, 10%, and 15%). All adopted specimens had identical dimensions (1,000 mm length, 300 mm width, and 50 mm thickness). Four specimens were exposed to fire for 2 hr at a constant temperature of 600°C, after which they were rapidly cooled by spraying them with water. Test results showed that increasing the powder rubber content of burned and unburned modified SIFCON specimens decreased the failure load and increased the specimens’ ductility factor, as well as the ultimate and service deflections. During the test, the failure of SIFCON was observed to be gradual, and the plates remained in contact even after the ultimate load was attained, whereas the failure of the reference mix (without wasted rubber) was observed to be more rapid than that of other SIFCON mixtures. For the flexural test, it gives desirable strength and good fire resistance. This study provides guidance for the study of SIFCON with waste rubber. Overall, the percentage of error between the experimental and numerical results for the load capacity and midspan displacement was about 5.05% and 8.65%, respectively.

Experimental and numerical study on seismic behavior of special shaped steel truss and concrete composite shear wall

A steel truss-concrete composite (STCC) shear wall is fabricated by replacing the reinforcement of the shear wall by steel truss, which has high bearing capacity, good fire resistance, good seismic performance, and an easy construction. In order to investigate the seismic performance of special shaped composite shear wall, a quasi-static test was carried out on four T-shaped and two L-shaped composite shear walls. The results showed that the change of diagonal bracing form from strip steel to channel steel can improve the ductility and energy dissipation capacity of the shear wall and delay the strength degradation. Increasing the thickness of steel vertical supports can effectively improve the initial stiffness, while decreasing the thickness of diagonal braces will reduce the bearing capacity of the wall. The strength and stiffness of shear walls loaded along the web in the positive direction (flange in tension) is high, but the ductility is relatively poor when compared with walls loaded in the negative direction (flange in compression). Numerical models were established by ABAQUS, in which the steel hysteretic constitutive model was adjusted to simulate the influence of bond-slip effect. The influence of shear span ratio, axial load ratio, steel ratio of vertical support, volumetric ratio of diagonal brace, tilt angle of diagonal brace and horizontal force direction on the seismic performance of T & L shaped composite shear walls were analyzed. Finally, a design method was proposed, and the calculated results by the design method were in good agreement with the test.

Fire research of joint between special-shaped CFST column and U-shaped composite beam

The steel-concrete composite joint plays an important role in the building structure of transmitting load and maintaining structural stability, and the research on fire performance of composite joints is significant. The special-shaped concrete-filled steel tube (SCFST) column and U-shaped steel-concrete composite beam (USCB) have good fire resistance which is proved by authors' previous fire tests. Therefore, the fire performance of the joint between SCFST column and USCB, the temperature distribution, failure mode, fire resistance, and internal force distribution of the joint under fire are investigated based on the fire tests results of column and beam component. The results showed that the temperature of the joint zone is lower than that of the non-joint zone, which ensured that the strength and stiffness of the joint zone are higher than that of the non-joint zone (beam and column). Then the two failure modes including beam failure and column failure occurred in the composite joint in fire conditions. Furthermore, the internal force analysis indicated that internal force redistribution happens during the elevated temperature. The parameter analysis expressed that fire resistance decreases with the increase of load ratio and the beam-column moment ratio and increases with the increase of the beam-column stiffness ratio and the fire protection layer thickness. Finally, the high-temperature calculation formula for the bearing capacity of beam-column joint was proposed.

Possibilities of Using Geopolymers in Welding Processes and Protection against High Temperatures

Geopolymer materials have long been known for their competitive properties against traditional construction materials. Their special features include high resistance to elevated temperatures and good fire resistance. They are typically used as insulating materials at temperatures not exceeding 100 °C (because they can achieve a thermal conductivity coefficient of 0.060 W/m × K or less under these conditions). Still, they can also be used as thermal insulation at temperatures exceeding 1000 °C. One technology that uses very high temperatures is metal welding technology, where temperatures often exceed as many as 3000 °C. Geopolymers, due to their properties, can also be an interesting new alternative in various welding applications. This paper presents the preliminary results of pot-proofing the resistance of geopolymers to temperatures exceeding 3000 °C. Test results of a foamed geopolymer insulating a steel substrate are presented, and a geopolymer mold for thermite rail welding was made and realistically tested. The results confirmed the feasibility of using cast geopolymer molds for thermite welding of railroad rails. The geopolymer material performed well during the test and no cracks or other damage occurred. The following article presents the potential of using geopolymer materials for welding applications.

Fire-resistant polyimide-silica aerogel composite aerogels with low shrinkage, low density and high hydrophobicity for aerospace applications

Polyimide (PI)-silica aerogel composite aerogels with low shrinkage (3.7%), low density (0.061 g/cm3), low thermal conductivity (0.0216 W m−1 K−1), high hydrophobicity (146°) and good fire resistance were prepared by incorporating silica aerogel powders into PI matrix. The properties of the aerogels are affected by the type and content of silica aerogel powders. The samples show high compressibility, and the stress at 80% strain increases with the increase of silica aerogel powder content. The addition of inorganic silica aerogel powders (ISAp) can improve the thermal stability of the aerogel and the fire resistance and structural integrity of the sample under flame, but has adverse effect on moisture resistance. While the addition of polyvinylpolymethylsiloxane aerogel powders (PAp) improves the moisture resistance of the aerogel but weakens the thermal stability and fire resistance. The introduction of both ISAp and PAp can reduce the thermal conductivity of the aerogel, and the samples exhibit good thermal insulation performance. Furthermore, ground equivalent simulation tests were carried out to verify the adaptability of these aerogels in the space environment. The sample meets the standard requirements and shows stable structure and performance during the tests, which proves its potential application in the aerospace field.

I-section stainless steel portal frames: Loading tests and numerical modelling

Austenitic stainless steel is an attractive structural material due to its high ductility, appropriate toughness, significant strain hardening and good fire resistance. Also the laser welding technology for fabrication of structural stainless steel profiles has recently become increasingly popular. However, there is still only a limited amount of experimental data on laser-welded stainless steel members. And loading tests of whole structures made of these sections have still not been published. Therefore, loading tests were performed on two austenitic stainless steel frames made of laser-welded I-sections. The frames had pinned columns and were loaded both vertically and horizontally. The objective of the loading tests was to capture the effects of material nonlinearity on the global sway behaviour of the stainless steel frames. In fact, material nonlinearity leads to a gradual loss of stiffness, which results in higher deformations and thus a higher second-order effect. The resulting load-displacement diagrams of the experiment are tabulated, allowing their further use. A numerical model of the studied frames was developed and validated on the basis of the performed experiments. Based on the elastic buckling load factor and the modified elastic buckling load factor, a large influence of material nonlinearity on second-order effect has been demonstrated.

Research on the Concrete-Filled Double Skin steel Tubular (CFDST) columns subjected to axial force after fire

This article investigates the structural performance of Concrete-Filled Double Skin Steel Tubular (CFDST) columns after fire under the axial compress. 13 experiments were conducted on the residual bearing capacity of CFDST columns under axial compression after different fire duration time. The variation parameters included the hollow ratio, fire duration time and strength of concrete. The effect of different parameters on the axial load and displacement changes after fire was revealed. The experimental and finite element simulation results were compared and analyzed, and they were in good agreement. The results indicate that CFDST columns have good fire resistance, and the strength of concrete has little effect on the residual bearing capacity of CFDST columns after the fire. With the increase of hollow ratio from 0 to 0.72, the axial residual bearing capacity of CFDST columns increases first and then decreases after the same fire duration time. Compared with the column without initial load, the residual bearing capacity of CFDST columns will increase with an initial load before fire, but different initial loads have no significant impact on the ultimate bearing capacity after fire.

Experimental and Numerical Investigation of the Mechanical Properties of a Fiber-Reinforced Geopolymer Mortar Blast Resistant Panel.

Geopolymer materials have excellent properties such as high strength, low thermal conductivity, fire resistance, acid and alkali resistance, and low carbon emissions. They can be used as protective engineering materials in places with explosion risks. At present, the common composite blast resistant panel is in the form of a sandwich: the outer layer isgalvanized steel plate, and fiber cement board or calcium carbonate board is used as the inner layer material, as these boards have the advantages of easy installation, good fire resistance, and explosion resistance. This study investigates the effect of adding different types of fibers to geopolymer mortar on the mortar's basic mechanical properties, such as compression strength, bending strength, and impact resistance. The explosive resistance of the fiber-reinforced geopolymer mortar blast resistant panels was evaluated through free-air explosion. In this paper, experimental procedures and numerical simulation have been performed to study the failure modes, maximum deflection, and dynamic response of the fiber-reinforced geopolymer mortar blast resistant panel under free-air explosion. The research results can provide a reference for the design and production of blast resistant panels.

Effect of Lignin or Lignosulfonate Addition on the Fire Resistance of Areca (Areca catechu) Particleboards Bonded with Ultra-Low-Emitting Urea-Formaldehyde Resin

As a way to accommodate the rising demand for “green” wood-based products, agricultural waste from Areca (Areca catechu) nut farms, which is generally burned on-site, can be used to raise the value of alternative lignocellulosic raw materials. This research aimed to investigate and evaluate the effect of technical lignin (kraft lignin or lignosulfonate) addition on particleboard properties from areca bonded with ultra-low-emitting urea formaldehyde (UF) resin. The physical properties, mechanical properties, and fire resistance of the laboratory-made particleboards were tested and evaluated in accordance with the applicable Japanese industrial standards (JIS). The highest density of 0.84 g/cm3 was determined for the laboratory boards, bonded with an adhesive mixture of UF resin and kraft lignin with three washing treatments. The lowest moisture content of 9.06%, thickness swelling of 71.16%, and water absorption of 129.17% were determined for the boards bonded with lignosulfonate with three washing treatments, with commercial lignin, and with lignosulfonate with five washing treatments, respectively. The highest MOR and MOE values, i.e., 113.49 kg/cm2 and 10,663 kg/cm2, respectively, were obtained for the particleboards bonded with lignosulfonate with five washing treatments. Interestingly, all laboratory boards exhibited good fire resistance following the UL-94 standard. Based on the gas torch test, the lowest weight loss of 16.7% was determined in the boards fabricated with lignosulfonate with five washing treatments. This study demonstrated that adding lignin-based fire retardants represents a viable approach to producing lignocellulosic composites with enhanced fire resistance and a lower carbon footprint.

Flammability and morphology of Agel leaf fibre- epoxy composite modified with carbon powder for fishing boat applications

Fibre Reinforced Polymer Composites have been extensively developed to construct fishing vessels. This study reports on the successful development of the Agel Leaf Fibre (ALF)-Epoxy composite reinforced with carbon powder and fabricated using the Vacuum Infusion method.The composites were prepared by varying the carbon powder filler content at volumes of 0%, 10%, and 30%. The fire resistance of the composites was investigated using a burning test according to ASTM D-3014 standards. The morphology of the composites was observed through SEM analysis and analysed using ImageJ software.The research findings reveal that adding 30% carbon powder in the HCP composite reduced the burning rate by 42.624 mm/sec and the time to ignition by 17.33 seconds, indicating improved fire resistance properties. The carbon powder inhibited flame propagation and reduced the combustion rate by 0.49%. The SEM examination confirmed that the fibre porosity decreased, resulting in a denser composite with enhanced fibre-matrix adhesion. Therefore, the implementation of fire-resistant composite materials in fishing vessel construction can be realised.The present study primarily examined the immediate effects of carbon powder additions on the morphology of the composites. However, it is crucial to consider these composites’ long-term stability and durability. Future research should investigate the ageing behaviour, considering environmental factors such as humidity, temperature, and UV radiation, to assess their impact on the morphology and flammability resistance of the composites. Additionally, it is essential to acknowledge that other factors, including fibre orientation, fibre length, and matrix properties, can significantly influence the overall performance of the composites.The enhanced flammability resistance of Agel Leaf Fibre-Epoxy composites with carbon powder additions holds significant benefits for fishing boat applications. In marine environments, the risk of fire incidents on fishing boats is high, making materials with good fire resistance highly desirable. Therefore, implementing fire-resistant composite materials in fishing boat construction can be realised to reduce the risk of fire incidents in high-seas fishing vessels.Composites with added carbon powder exhibited smaller flames, slower burning rates, and a lack of significant flame propagation. This suggests that adding carbon powder acts as an oxygen barrier and reduces the availability of fuel within the composite.

Difference analysis of dissolved gas in natural ester insulating fluids under typical electrical and thermal faults: An experimental study

AbstractNatural ester insulating oil is widely used in transformers due to its good fire resistance and biodegradability. It is mainly composed of triglycerides, and there are some differences in fatty acid composition and content among natural esters. Therefore, the fault diagnosis methods based on dissolved gas analysis are different. Three kinds of natural ester insulating oils are used to study the dissolved gas in oil under typical electrical and thermal faults of power transformers. Thermal faults from 200°C to 800°C and electrical faults with different discharge energies, which include partial discharge, breakdown discharge, and arc discharge, are simulated. The characteristic gases and their variation trends of natural esters under thermal and electrical faults are obtained through the experimental results. The gas generation characteristics of the three natural ester insulating oils under typical electrical and thermal faults are almost similar, but the relative percentages of characteristic gases have certain differences. Natural ester insulating oil with a higher unsaturation degree tends to produce more H2 and less C2H4. Finally, the fault diagnosis methods are used to determine the fault gas data, and the Duval pentagon is modified and improved according to the gas generation characteristics of natural esters.

Mechanical Properties, Durability, and Structural Applications of Rubber Concrete: A State-of-the-Art-Review

Substituting rubber particles for a portion of the standard coarse aggregates in concrete is regarded as a sustainable solution for tackling the issue of waste-tires disposal. In order to assess the structural performance of rubber concrete (RC), many studies have been conducted on the proportions, mechanical properties, curing conditions, usages, and serviceability performance of the material over the decades. This review systematically summarizes the mechanical properties (e.g., static and dynamic), testing method, and durability of RC, emphasizing its dynamic characteristics from the perspectives of material and component. The inclusion of rubber particles weakens the static properties of the concrete, while the low module of inherent rubbers improves the concrete dynamic properties, such as low stiffness degradation, high strain-rate sensitivity, excellent energy dissipations, and good ductility. With the increase in the strain rate, the improvement in energy absorption and ductility of the RC (0 to 30%) can increase to 110% and 80%, respectively. Concrete with a rubber volume fraction of less than 30% enhances both mechanical and long-term environmental performances. Moreover, RC shows good fire resistance, permeability, and freeze–thaw behavior; however, further research is needed to understand its constitutive model and the synergistic effects of additional materials.