Papers by Keyword: Fire Performance

Abstract: There are concerns towards the vulnerability of geopolymer concrete towards fire. High-temperature conditions instigate physical alterations and chemical reactions in concrete, which progressively breaks down the gel structure of cement. Consequently, the breakdown leads to an increase in tendency of drying shrinkage, changes to colors of aggregates and losses in load-bearing capacity and durability. In the present study, geopolymer concrete samples were exposed to fire at 1000°C at varying heating duration to investigate the effects on mass loss, residual strength and its microstructure properties. Samples with three grades of strength, GEO20, GEO40 and GEO60, were prepared. Six heating durations ranging from 30 to 180 minutes were adopted. Overall, mass losses were less than 3%, ranging from 1.65% as obtained by the low-strength concrete to 2.93% as obtained by the high-strength concrete. For the most part, as heating duration increased, residual strengths decreased, except for when residual strengths of low and medium-strength concrete initially increased at the heating duration of 30–60 minutes, where the exposure to fire facilitated geopolymerization. Analysis of the microstructure reveals that structural integrity of the matrix at high-temperature conditions is adequate. The study investigated the geopolymer concrete is able to resist the exposure to fire and must be seriously considered as an alternative to ordinary-Portland-cement-based concrete for the future of sustainable construction.

Abstract: Abstract. This studies discuss the synergistic effects of titanium dioxide (TiO₂) and zinc borate on thermal stability and water resistance of intumescent fire retardant coatings. TiO₂ in association with a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine/ zinc borate (APP–EG–MEL-ZB) was introduced to epoxy based coatings to improve the fire resistance. The influences of TiO₂ on the properties of the coatings were investigated in detail by using Bunsen burner fire test, thermogravimetric analysis (TGA), scanning electron microscope (SEM) and water immersion test. Bunsen burner test revealed that incorporation of titanium dioxide in intumescent formulation reduced the steel substrate temperature from 240 °C to 116 °C. The TGA results proved that addition of TiO₂ could enhance the anti-oxidation of the char layers and increase the residue weights of the coatings. The FESEM images demonstrated that addition of TiO₂ could improve the foam structure of the char residue. Sea water resistance test demonstrated that the optimum mass % age of TiO₂ (6%) exhibited great synergism with natural anti-corrosion agent, zinc borate, and improved corrosion resistance performance of intumescent coating formulations.

Abstract: Failure temperatures of composite cellular beams subject to a standard fire condition were investigated thoroughly by the Finite Element Method. A finite element model was developed for the fire performance analysis of composite cellular beams. Practical design guidance on the fire design of composite cellular beams is presented concerning the failure temperature.

Abstract: This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

Abstract: Energy-saving and emission-reducing must be achieved based on the reliable performance of fire safety. External thermal insulation material is the main component of external thermal insulation system, and also the main combustion participants when a fire occurs; the combustion performance is an important factor affecting the fire scale of external thermal insulation system. The main material and heat release principle was introduced in this paper, tests were carried out, and fire hazard was analyzed based on large amount of test data. The research will provide theoretical support for external insulation material choice, system construction, fire prevention and rescue.

Abstract: Material strength is one of the most important factors in designing a building. For this reason, many structural steel manufacturers have been trying to develop it. In Korea, SM 570 is one high structural steel that has many merits such as longer span and reduction of construction cost for steel works. However, the fire resistance performance of H-section made of SM 570 has not been evaluated. Especially, in high-rise steel building that can be built with various joint systems like hinged to hinge, hinge to fixed, and fixed to fixed. However, the performance of fire resistant is limited. In this paper, to evaluate the fire resistance of H-section made of SM 570, the advanced fire design was conducted using regressive equation of the mechanical and thermal properties at high temperature, compared with those made of an ordinary structural steel, SS 400. The facts show that hinge to hinge had the lowest load bearing capacity at high temperature. Therefore, to keep the same fire resistance with other types boundary conditions, the more passive fire materials are required.

Abstract: Structural columns are very important members in steel buildings. An evaluation of fire resistance performance of the column is essential to sustain the structural stability in a fire situation. However, the length of columns is dependent on various architectural design variations. Therefore, the fire resistance can be different according to the length of column. In this study, to suggest the adequate fire resistance performance of structural columns by difference of length, an analysis was done based on an ordinary structural steels, SS 400, and hinge to hinge boundary condition. The result showed that the longer the column was, the less the fire resistance.

Abstract: The numerical model of analysis of fire performance of a spatial pre-stressed steel structure with large span was established based on the software Marc. The thermal response and structural response of the pre-stressed steel structure was computed for some nodes of the structure in fire. The different fire scenes were considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed steel structure.It is concluded that the temperature rise of the nodes of the structure is far behind that of air near the nodes, however they are quite close as the fire lasted for 3600s and almost the same after 7200s.The results show that the displacement of the node right above the inner cable is the maximum and the node above the outer cable has the smallest value of displacement and the maximum value is about two and half times as large as the minimum.The results show that the reason why the cables are out of work is that the equilibrium between the cables and the rods of the structure is lost, but not that the stress relaxation caused by thermal expansion make the cables out of work.

Abstract: In this article, a series of novel phenolic resin modified with cardanol were synthesized. The influence of reaction condition and cardanol content on the structure and properties of phenolic resin was evaluated. The nanocomposite phenolic foam was then prepared by infusing the organo-modified montmorillonite (OMMT) in the synthesis step of cardanol phenolic resin to produce nanocomposite phenolic foams. These phenolic foams were characterized by FTIR, XRD, SEM and TGA. And the mechanical properties and fire performance of these nanocomposite foams were also measured. The results showed that the cardanol component could reduce the crosslink density of phenolic foam and thus improve the mechanical properties; the OMMT platelets were 3~10μm in diameter and 40~50nm in thick. These platelets can exfoliated and dispersed well in the nanocomposite due to the hydrogen-bonding between organo-modifier and phenolic matrix and improve the thermal stability, fire resistance and also the mechanical properties of nanocomposite foam.

Abstract: A fire performance finite element (FE) model of space grid structures in fire and after fire is proposed, and deformation, stress redistribution, failure modes of grid structures are also studied. The result shows that tensile membrane action arises when the grid is loaded after fire, and the load bearing capacity after fire is reduced by fire damage.