Fire Resistance Tests Research Articles

Palm Kernel Ash and Eggshell Ash as Partial Replacement of Cement in Interlocking Brick Production

This research uses eggshell ash and palm kernel shell ash as a partial replacement for cement in brick production. Previous researchers have used different materials as a replacement for cement. This research seeks to determine the best eggshell ash and palm kernel ash ratio as a partial replacement for cement in brick production. The experiment uses 5, 10, 15, and 20% eggshell ash and palm kernel shell ash for a partial replacement of cement. This research performs the compressive strength, water absorption, efflorescence, fire resistance, colour, sound and size tests to determine the quality of the brick containing eggshell ash and palm kernel shell ash as a partial replacement for cement. The results show that the best ratio for replacing cement in brick production is 15% eggshell ash and palm kernel shell.

Diatomaceous earth aggregates based composite masonry blocks for bushfire resistance

PurposeThis paper presents the details of a research study on developing composite masonry blocks using two types of mixes, conventional and lightweight mix, to enhance their fire/bushfire resistance and residual compressive strength.Design/methodology/approachComposite masonry blocks (390 × 190 × 90 mm) were fabricated using conventional cement–sand mix as the outer layer and lightweight cement–sand–diatomite mix as the inner layer. Material properties were determined, and all the mixes were proportioned by the absolute volume method. After 28 days of curing, density tests, compression tests before and after fire exposure and fire resistance tests of the developed blocks were conducted, and the results were compared with those of conventional cement–sand and cement–sand–diatomite blocks.FindingsDeveloped composite blocks satisfy density and compressive strength requirements for loadbearing lightweight solid masonry units. Fire resistance of the composite block is –/120/120, and no cracks appeared on the ambient side surface of the block after 3 h of fire exposure. Residual strength of the composite block is higher compared to cement–sand and cement–sand–diatomite blocks and satisfies the loadbearing solid masonry unit strength requirements.Practical implicationsComposite block developed in this research can be suggested as a suitable loadbearing lightweight solid masonry block for several applications in buildings in bushfire prone areas.Originality/valueLimited studies are available for composite masonry blocks in relation to their fire resistance and residual strength.

In-situ preparation and performance of cold resistant K2O·5SiO2 based anti-fire glass

We describe a method for the synthesis of cold resistant K2O·5SiO2 based anti-fire material using a new high content and low viscosity SiO2 core–shell emulsion (HSLVCS SiO2 emulsion). The anti-fire glass which wasn’t frozen at −71 ± 1 °C was prepared by the in-situ reaction. The onion-shaped core–shell structure was clearly shown in scanning electron microscopy (SEM) micrographs, the viscosity of HSLVCS SiO2 emulsion (50 wt%) was 431.4 ± 12.1 mPa·s(48 rpm). Its in-situ reaction process for preparation of the K2O·5SiO2 followed a first-order reaction, the reaction rate constant kn = 1.774 × 108 exp (−Ea/RT) with the apparent activation energy Ea = 79.80 kJ/mol. The low-temperature-withstanding capability was tested at extreme-cold environment (−71 ± 1 °C), and the reasons for this were found by the thermogravimetric analysis (TG). The weather resistance capacity was more than 1000 h through ultraviolet (UV) test and the sponge-like microporous insulation layer can increase the fire insulation time by the fire-resistant test. This work provided a new routine toward the synthesis of the high quality anti-fire glass with various shapes, including curved surface structures.

Characterisation and properties of class C-fly ash based geopolymer foams: Effects of foaming agent content, aggregates, and surfactant

In this study, GFs were first prepared in two forms; foamed mortars using the graded (GS-) and the river (RS-) sand as aggregates, and a foamed paste (P-). Aluminum (Al) powder, used as the foaming agent, had effects on porosity, pore morphology, and pore size distribution. When the amount of Al was increased, there cracks had formed in the P-GFs so the strength reduction was more drastic than that of the foamed mortars of both types. The sand aggregates acted as the skeletal structure of the GFs strengthening the materials. The attempt to improve the porosity characteristics of the foamed mortars by the addition of the dishwashing liquid surfactant was successful. The pore size of the GS-GFs became smaller and the distribution was more uniform. However, the compressive strength had degraded. Assessment on initial and final setting times, phase formation, and microstructure showed that the geopolymerisation and the C-S-H phase (tobermorite) formation had been retarded when this surfactant was incorporated. This GF also showed the most severe strength degradation in the thermal exposure test. Although all GFs mortars did not show disintegration or spalling of the pieces, microcracks appeared after exposure at 800 °C, and became more remarkable after 1000 °C. The fire resistance test on the 10 mm thick-GF mortar panels showed that the reversed-side temperature remained around 400–450 °C after 30 min of exposure without spalling or catastrophic cracks.

Fire Resistance of Steel Connectors of Precast Lightweight Concrete Walls

In this study the fire test was performed to investigate the mechanic behaviors and failure patterns of precast normal weight concrete (NWC) and lightweight concrete (LWC) walls with three types of commonly used steel connectors, namely dry (61), wet (81), and bearing (56E) connectors. For the LWC wall specimens, on lateral application of tension, the cracking load values of the dry, wet, and bearing-type connectors were 95.1%, 86.3%, and 83.0%, respectively, of the original loads, and their ultimate load values were 81.6%, 90.7%, and 85.0%, respectively, of the original. In the shearing test after the fire resistance test, the cracking load value of the bearing-type connector was 88.2% of the original load. Moreover, all specimens exhibited a considerable loss in the ductility ratio after the fire resistance test. However, the hysteresis energy that can be absorbed and the seismic resistance of the LWC wall were superior to those of the NWC wall. Therefore, alt-hough the LWC and NWC walls exhibited similar failure patterns, steel connectors exhibited superior fire resistance for precast LWC walls.

Bench-scale fire stability testing – Assessment of protective systems on carbon fibre reinforced polymer composites

Fire resistance testing of components made of carbon fibre reinforced polymers (CFRP) usually demands intermediate-scale or full-scale testing. A bench-scale test is presented as a practicable and efficient method to assess how different fire protective systems improve the structural integrity of CFRPs during fire. The direct flame of a fully developed fire was applied to one side of the CFRP specimen, which was simultaneously loaded with compressive force. Three different approaches (film, non-woven, and coatings) were applied: paper with a thickness in the range of μm consisting of cellulose nanofibre (CNF)/clay nanocomposite, nonwoven mats with thickness in the range of cm and intumescent coatings with a thickness in the range of mm. The uncoated specimen failed after just 17 s. Protection by these systems provides fire stability, as they multiply the time to failure by as much as up to 43 times. The reduced heating rates of the protected specimens demonstrate the reduced heat penetration, indicating the coatings’ excellent heat shielding properties. Bench-scale fire stability testing is shown to be suitable tool to identify, compare and assess different approaches to fire protection.

Fire resistance evaluation and minimum reinforcement ratio for hybrid fibre-reinforced RPC beams under fire exposure

Reactive powder concrete (RPC) structural members are faced with the problem of fire resistance evaluation in fire safety design. In this study, the fire resistance of hybrid fibre-reinforced RPC beams evaluated through the existing design methods was compared with those measured in standard fire tests. The results showed that the existing design methods cannot provide satisfactory fire resistance evaluation for hybrid fibre-reinforced RPC beams, which highlights the need to propose a new prediction method. To fill this gap, an existing macroscopic finite-element model was extended to simulate the fire response of hybrid fibre-reinforced RPC beams. Based on the developed FE model, an extensive parametric study was conducted to study the effects of structural parameters such as the RPC cover thickness, load ratio, reinforcement ratio, span-depth ratio, beam width and compressive strength of RPC on the fire resistance of hybrid fibre-reinforced RPC beams. Then, through the regression analysis of the 663 FE simulation results, an equation, which is expressed in the form of continuous multiplication, was proposed to predict the fire resistance of hybrid fibre-reinforced RPC beams under standard fire exposure. The validity of the proposed equation was established through comparisons with the results from FE simulation and existing fire resistance tests. Additionally, the minimum reinforcement ratio required for RPC beams to achieve a specified fire resistance was proposed to prevent the brittle failure caused by the insufficiency of reinforcement under fire.

Experimental analysis of cross-laminated timber rib panels at normal temperature and in fire

The results of an experimental programme on the structural behaviour, fire behaviour, and fire resistance of CLT rib panels are presented. The floor system consists of cross-laminated timber (CLT) plates rigidly bonded to glued-laminated timber ribs by means of screw-press gluing.The experimental programme comprised ultimate-load tests at normal temperature as reference tests and full-scale fire resistance tests on four cross-sections. In addition to the reference tests, shear tests of the glue line between CLT plate and glued-laminated timber rib were performed for analysis of the cross-sections’ composite action.The results of the reference tests show good agreement with results based on the simplified method according to EN 1995-1-1 [1] and its final draft of CLT design [2]. The importance of the glue line’s quality was confirmed. The fire resistance tests show results on the safe side compared to predictions of the fire behaviour according to EN 1995-1-2 [3] and its actual draft [4]. However, the fire resistance was underestimated due to conservative assumptions about the composite cross-section’s structural behaviour.The experimental programme addressed the fire behaviour and fire resistance of CLT rib panels currently not covered in standards. The project’s overall aim is the development of design rules in fire for EN 1995-1-2.

Characterization and fire protection properties of rubberwood biomass ash formulated intumescent coatings for steel

Rubberwood biomass ash (RWA), which was derived from the combustion of rubberwood biomass in a fuel factory, was obtained for reuse as a natural mineral filler substitute in water-based intumescent coatings. The specific surface area of the RWA was 3.10 m 2 /g, with the particle's surface areas predominant composed of mesopores, which was justified using the Brunauer–Emmett–Teller Test (BET). Rubberwood ash coatings (RWAC) formulated with 3.0 wt% RWA exerted the most homogenous and durable surface matrix in the Accelerating Weathering Test (AWT). Fire-resistant test (FRT) and thermogravimetric analysis (TGA) demonstrated the incorporation of the RWA with the intumescent flame-retardant formulation, generated positive effects in equilibrium end temperature, thermal decomposition, and weight loss reductions. These effects are most prominent in the RWAC-3, which was comprised of 3 wt% RWA, and 50/40/7 wt% vinyl acetate (VA)/intumescent flame retardant additive (IFRA)/pigment. The RWAC-3 showed the lowest equilibrium end temperature at 131.4 °C, the lowest thermal degradation at 71 wt%, and the highest carbonaceous char formation at 12.8 mm. The Surface Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX) results exhibited a dense, compact, and coherent char formation for the RWAC-3 sample. The abundant O and P crosslinking structures in the RWAC-3 contributed to the quality of the char barrier. These results are supported by the evidence from Fourier-Transform Infrared Spectroscopy (FTIR), and X-Ray Diffractometer (XRD), which revealed the stretching of the O–H, P–O–C, and P O molecular functional groups, and the presence of thermally stable phosphate compounds in the RWAC-3.

Investigation of the influence of the configuration of the fire furnace chamber on the temperature regime during the implementation of tests for fire resistance

The issue related to the conditions for creating the required temperature regime of fire when testing structures for fire resistance has not been studied in detail up to now. That necessitated determining the technical conditions under which it is possible to comply with the standard temperature regime of fire in the fire chamber of the furnace. The influence of the design parameters of the fire furnace chamber on the condition of compliance with the standard fire temperature regime when tested for fire resistance has been established. One of the most effective methods for examining such an impact is computer simulation. A computer model of the fire furnace was built on the basis of a comprehensive analysis and earlier work on the study of such furnaces, taking into consideration technical characteristics, in particular, geometrical parameters, fuel and air supply systems. The obtained research results are a prerequisite for scientific substantiation of the design parameters of fire furnaces and their engineering systems, which is necessary to comply with the standard temperature regime of fire in the furnace fire chamber. This makes it possible to provide the necessary conditions for testing building structures for fire resistance in compliance with the requirements of the relevant standards. The computer model constructed makes it possible to create the necessary temperature regime in the fire chamber of the furnace (in this study, the standard temperature of fire). As a result of the study, the technical parameters of the fuel supply and ventilation system were determined, which ensure compliance with the standard temperature regime in the fire chamber of the furnace. That makes it possible to build an automated complex of the testing process for fire resistance of building structures. In addition, the data obtained can be the basis for the design of such fire furnaces with the ability to comply with different fire temperature regimes without the intervention of the operator.

Fire resistance of post-earthquake steel beams insulated with a novel fire-resistive coating- FR-ECC

Cementitious fire-resistive materials (CFRM) of steel structures, though widely used, feature several notable disadvantages, such as low mechanical properties, susceptible to crack and delamination from the steel substrate, which reduces the resilience of steel structures. A novel ultra-high ductility fire-resistive engineered cementitious composites (FR-ECC) was developed to address those advantages. The fire resistance of post-earthquake steel beams insulated with FR-ECC was investigated. Eight steel beams with the protection of CFRM, FR-ECC and FR-ECC matrix (without fiber) were designed, among which five beams were pre-damaged by reversed cyclic loading. The damage of fireproof coatings and the hysteretic behavior of steel beams after cyclic loading were evaluated before fire exposure. The vertical displacement, the temperature distribution of steel beams and the damage of fireproof coatings under fire exposure were obtained. The FR-ECC demonstrated milder damage than those of FR-ECC matrix and CFRM after cyclic loading. The fire-resistance test results further revealed a more excellent fire-protection performance of FR-ECC as a novel fireproof material. The advantages of the newly developed fireproof coating FR-ECC have been experimentally proved, which laid the foundation for its future application.

Comparative study on fire resistance and zero strength layer thickness of CLT floor under natural fire and standard fire

A study of the fire resistance of cross-laminated timber (CLT) flooring material exposed to different fire conditions (ISO 834 standard fire and natural fire) is described, along with the value of the zero strength layer (ZSL) thickness. Experimental studies of the flexural performance of four groups of CLT floor at ambient temperature and the fire resistance of six groups of CLT floor under the action of fire were conducted. The influence of different laminate compositions (three-ply and five-ply) and different load ratios (10%, 20%, 30%) on the internal temperature field distribution, fire resistance and carbonization of the six groups of CLT floors were compared and analyzed. Subsequently, Abaqus software was used to establish a finite element temperature field heat transfer model of the shedding of the charred layer to analyze the fire resistance of the CLT floor, and to compare the key parameters in the test (charring rate, depth of charring, and shedding of the charred layer), to verify the validity of the model. Finally, the effective residual section method was used to develop a theoretical calculation model for determining the thickness of the ZSL of the CLT floor throughout the fire process. The theoretical calculated charred depth at different times during the fire resistance tests are compared and analyzed to verify the accuracy of the theoretical method.

Reduction of fire spalling of concrete with small doses of polypropylene fibres

SummaryThe addition of polypropylene (PP) fibres has been shown to reduce the fire spalling propensity of concrete. When including this type of fibres in the concrete, the concrete mix becomes less robust, and small deviations in the constitutes change the workability and properties of the concrete. So, from a manufacturing perspective as small dosages as possible of PP fibres are desirable. Very few large‐scale fire resistance tests of concrete loaded in compression exist showing the function of PP fibres at low dosages on concrete mixes sensitive to spalling if no fibres are added. In this paper, results from 26 fire tests are presented and analysed. The test results are from four different experimental campaigns, but all the mixes have in common that the water‐to‐cement ratio is 0.40. The results show that an amount of only 0.6 kg/m3 PP fibres has a significant effect on the spalling propensity and that even lower amounts reduce the spalling although they do not eliminate it entirely. During one of the fire tests on large slabs loaded in compression, unloaded small cubes of the same mixes were also included in the furnace. None of the small specimens spalled, whereas some of the corresponding large slabs spalled beyond the layer of reinforcement. This illustrates that tests on small, unloaded specimens are not relevant when assessing fire spalling of larger cross‐sections loaded in compression.

Investigation into the Lithium-Ion Battery Fire Resistance Testing Procedure for Commercial Use

Lithium-ion batteries (LIBs) have many advantages (e.g., high voltage and long-life cycle) in comparison to other energy storage technologies (e.g., lead acid), resulting in their applicability in a wide variety of structures. Simultaneously, the thermal stability of LIBs is relatively poor and can be damaged by exposure to fire. This paper presents an investigation into a fire resistance safety test for LIBs and the use of thermal sensors to evaluate exposure conditions and estimate the temperatures to which cells are subjected. Temperature distribution data and statistical analysis show significant differences of over 200 ∘C, indicating the stochastic nature of the heating curve despite following the testing procedure requirements. We concluded that the current testing procedure is inadequate for the reliable testing of LIBs, leaving an alarming loophole in the fire safety evaluation. The observed instability is mostly related to wind speed and direction, and fire source size.

Fire Resistance Tests on Prestressed Concrete Box Girder with Intumescent Fire-Retardant Coatings

Fire Resistance Tests on Prestressed Concrete Box Girder with Intumescent Fire-Retardant Coatings

Comparison of the properties of flax shives based particleboards prepared using binders of bio-based lignin and partially bio-based epoxy resin

EIn order to reduce formaldehyde emissions, an experimental investigation of lightweight flax shives based particleboards, prepared using two different binders: bio-based lignin (lignosulfonate) and partially bio-based epoxy resin (greenpoxy 56), was undertaken. The flax based particleboards (with a target density of 500 kg/m³), were elaborated by a thermo-compression process using 20 wt% of binder content. The flax shives were directly valorised as they had no pre-treatment, in order to qualify their potential as a raw material. Bending, compression and fire resistance tests showed that the mechanical and flame performances of lignosulfonate-based particleboards were high compared to those of greenpoxy56 based panels. Nevertheless, the latter were found to have an interesting dimensional stability after water immersion and good insulating properties. Moreover, both lignosulfonate and greenpoxy 56 based particleboards met the minimum EN 15197 requirements for non-load bearing flaxboards for use in dry conditions (Type FB2). Such results illustrated the competitiveness of the studied particleboards, as bio-sourced structures, compared to urea-formaldehyde based panels.

Potential of activated carbon in lime mortar plastering in term of fire resistance and thermal performance

The use of lime mortar plastering for wall construction in residential and light commercial buildings has increased significantly over the world. The unique characteristic of hydrated lime increases the strength of the tensile bond. The more considerable the amount of cement content in cement lime mortar, the low the air content; thus, the bond strength stronger. The performance of plastering under fire exposure is an item of significant importance in securing construction. Activated carbon is one known adsorbent which has a high capacity to adsorb gases and improved fire resistance ability of concrete. The purpose of conducting this study is to identify the optimum proportion of lime mortar plastering containing activated carbon with different percentages which is 0%, 10%, 30% and 50% as cement replacement. Therefore, a fire resistance test was conducted on cement plaster mixtures with variable ratio content of activated carbon to identify the optimum proportion according to the temperature reading by an infrared thermometer for 30 minutes. Based on the results obtained, the sample with 30% activated carbon as cement substitution was the most effective since it gave a relatively low initial temperature reading which was 28.2°C. The test showed only a slight increase in temperature after the first five minutes, which is 93.1% and reached 108.2°C at maximum even after 30 minutes of testing. There was no hair crack developed, and no visible of smoke observed from the sample compared to existing plaster which formed hair crack and visible of smoke at 280°C after 16 minutes of testing. Therefore, 30% of activated carbon is the optimum proportion in lime mortar plastering due to ability to resist fire and prevention from hair crack and visible smoke formation. This proportion can be applied to the interior and exterior wall of the building, especially at the compartment wall and along the escape route.

GEOPOLYMERS SYNTHESIZED FROM PHILIPPINE COAL ASH AS SUSTAINABLE ALTERNATIVE LOW HEAT TRANSMISSION AND FIRE-RESISTANT MATERIAL FOR BUILDINGS

Geopolymers are formed from alumina and silica rich materials by alkali dissolution and subsequent polycondensation into a polymeric network. Geopolymerization technology presents a great potential for positive environmental impact since many alumina- and silica- rich industrial waste materials, such as coal ashes, blast furnace slags, mine tailings, etc., can be used as its precursor materials in a process that requires less energy and gives up less emissions vis-à-vis the current conventional OPC (ordinary Portland cement) technology. In this study, geopolymer samples were prepared using an 85% coal fly ash (CFA) - 10% coal bottom ash (CBA) - 5% rice hull ash (RHA) wt/wt mix proportion and activated using an alkali solution of NaOH-Na2SiO3 at an 80%-20% wt/wt solid-to-liquid ratio. With this mix proportion, two types of specimens were used, a slab type with 50 mm thickness, and a cube type, 50 mm x 50 mm x 50 mm. The slab type specimens were used for evaluating fire resistance using ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials, and the cube type specimens were used to study the effect of foaming agents on the strength and thermal conductivity of the geopolymers formed. Two types of foaming agents, hydrogen peroxide and sodium perborate, at an amount of 0.1% to 0.4% of dry mass mixture, were used. Results from the foamed geopolymers gave compressive strength values ranging from 0.37 to 0.71 MPa and densities of 1430-1560 kg/m3 at 0.3% to 0.4% peroxide added. Values of thermal conductivity of the foamed geopolymers were within 0.033-0.037 W/m-K for all foamed geopolymer samples tested which is a significant reduction compared to the thermal conductivity of the unfoamed geopolymer sample at 0.48 W/m-K. The fire resistance tests show that the unfoamed geopolymer samples perform better than OPC concrete. However, the foamed geopolymers have very low strength compared to the unfoamed sample compressive strength of 18.1 MPa and, thus, are suitable for non-load bearing, insulation applications.

A Dual Active-Passive Coating with Intumescent and Fire-Retardant Properties Based on High Molecular Weight Tannins

In this study, the tannins extracted from the Pinus radiata bark were used to develop an active–passive dual paint scheme with intumescent (IN) and fire-resistant (FR) behaviors. The properties of the coating were observed to depend on the concentration of high-molecular-weight tannins (H-MWT) incorporated into the formulation. At high concentrations (13% w/w), the coating exhibits fire-retardant properties due to the generation of a carbonaceous layer; however, at low concentrations (2.5% w/w), it generates an intumescent effect due to the formation of a carbonaceous foam layer. The dual IN–FR scheme was evaluated against fire by flame advance tests, carbonization index, mass loss, and intumescent effect, and was also compared to a commercial coating. The dual scheme presented good mechanical properties with a pull-off adhesion value of 0.76 MPa and an abrasion index of 54.7% at 1000 cycles, when using a coating with a high solid content (>60%) and the same thickness as those of the commercial coatings. The results of the fire resistance test indicate that the dual scheme generates a protective effect for wood and metal, with an excellent performance that is comparable to that of a commercial intumescent coating.

Structural response of fire-exposed laminated glass beams under sustained loads; exploratory experiments and FE-Simulations

This paper investigates the structural response of laminated glass beams under combined fire-exposure and sustained in-plane loading. This is done by means of experimental testing and Finite Element (FE) numerical modelling. Firstly, small-scale (1 m long) laminated glass beams are tested under thermal exposure and in-plane loading on a small fire resistance test furnace. From the test results it can be seen that laminated glass beams are able to sustain an imposed in-plane load for a time of 34–51 min before failing according to the limiting rate of deflection as defined in EN 1363–1:2012. It should be noted, however, that the observed failure times are strictly related to the boundary conditions applied in the test, i.e. the magnitude of mechanical loads (in this study a relatively small load of P = 1.15 kN was applied) and the presence of an inherent top zone protection, which may have positively affected the results. Secondly, additional FE thermo-mechanical simulations are performed to further investigate the mechanical response of the laminated glass beams under thermal exposure, with a focus on the effects of the top zone protection and the load magnitude on the performance of the examined laminated glass beams. From the FE study it can be seen that reducing the top zone protection (from 40 mm to 0 mm) results in a reduction in failure time from 45 min to 20 min, while increasing the load with a factor 5 (taking 30 mm top zone protection as a reference) results in a reduction of failure time from 32 to 18 min.