Types Of Fly Ash Research Articles

Investigation of Microstructure and Performance of Ultra-High-Performance Concrete for Transportation Infrastructure

This study examines the engineering properties of ultra-high-performance concrete (UHPC) for use in construction and transportation infrastructure. The UHPC investigated in this study consists of three types of pozzolan, microsilica, nanosilica, and fly ash. It also contains two types of aggregate, garnet and basalt. In addition, it contains steel fibers. The study investigated the properties of fresh UHPC (slump flow, slump flow T50, L-box, and V-funnel), the mechanical properties of UHPC, including compressive and tensile strength, and its durability by analyzing volumetric water absorption, special electrical resistance, and performing the rapid chloride permeability test using scanning electron microscopy to examine the microstructure of UHPC. The results show that UHPC exhibits exceptional mechanical properties, such as high compressive and tensile strengths and remarkable durability, including reduced water absorption, increased special electrical resistance, decreased permeability to chlorine ions, and a negligible permeability range. In conclusion, the study demonstrates that UHPC is a unique material with excellent performance in various engineering applications, making it an ideal choice for construction projects and transportation infrastructures where high strength and long-lasting durability are required.

A multi-perspective study on the influence of physical and chemical properties of 5 types of fly ash on the performance of high-volume blended fly ash cementitious slurry

The study has investigated the influence of the physical and chemical properties of five types of fly ash on the performance of high volume blended fly ash cementitious (HFC) materials. The study found that the vitreous element composition of fly ash exhibits a superior correlation with compressive strength as compared to the overall element composition. Moreover, the cumulative heat displays a stronger correlation with compressive strength than the heat flow. Besides, the packing density has a significant effect on the compressive strength of HFC materials. Whereas, the slurry flowability largely depends on the water film thickness. In practical engineering, the slurry compressive strength can be predicted by testing the fly ash vitreous content, cumulative heat data and the packing density of mixed particles in concert. The findings are significant as in practical projects, the performance of cementitious materials is often unstable due to different sources and batches of fly ash. The study provides insights into the factors affecting the rheological properties of the slurry and the hydration behaviour of different fly ash blended slurries.

Machine Learning Based Reactivity Prediction of Fly Ash Type F Produced from South Korea

Fly ash (FA) is the most commonly used supplementary cementitious material in the world. However, the reactivity of FA varies substantially. In this study, new machine learning (ML) model has been developed to efficiently predict the amorphous content in FA type F. Compared to the existing ML model using types F and C of FA from different countries, this study more focused on the improved prediction of FA type F only produced from South Korea. It was found that the contents of CaO and SiO2 impact high in predicting the amount of aluminosilicate glass. However, the contribution of Al2O3 and Fe2O3 are ranked differently. The improved model algorithm was proposed as a combination of three ensemble techniques of bagging, boosting, and stacking. As a result of the test, the final model shows {R}^{2} of 0.80 in predicting the amount of aluminosilicate glass in FA type F.

Developing FA-based cementless binder composite by opting sustainable technology: Application of brick and paving block

Cementless binders are made possible by the invention of geopolymers, which utilize alkaline activators to activate alumina-silicate materials. Alkaline activators, however, are corrosive and hazardous. Its minimal usage combined with advanced technology can make it sustainable. Therefore, this work was designed to develop alkali-activated binders (AABs) through mechano-chemical activation. Initially, three types of fly ashes (FAs) were activated, and their performance was evaluated using the strength activity index. The best-performing FA was used in the second group of experiments. Slag was coupled with FA, and dune sand (DS) was coupled in the third group. The physico-mechanical performance of each group was evaluated and the geopolymerization mechanism was assessed through FTIR analysis. By using DS, it was observed that the compressive strength has been significantly enhanced with an increase of 100 % compared to the FA-based binder, while the bulk density of both cases is almost the same (i.e., 1,650 kg/m3). Based on the multi-criteria analysis for three scenarios, it is revealed that the key performances of the high strength and durability, the lightweight and insulation, and the strength requirement are optimized by alkali-activated binders of FA + DS, FA-3, and FA + GGBS (Slag), respectively.

The Emission of Volatile Components during Laboratory Vitrification When Using Fly Ash and Other Waste to Obtain Ceramic Coatings

For decades, a significant amount of research has been conducted on the vitrification of mixtures of all kinds of industrial wastes, especially fly ash, both from thermal power plants and municipal waste incinerators. Although the possibility of creating glass from all types of fly ash has been proven through such research, these studies barely focused on the emission of volatile components that takes place during vitrification processes at high temperatures. This is why, after identifying the types of volatilisation that can occur, we characterised the gasses that are emitted during the vitrification of some types of fly ash and other waste in a laboratory furnace. In order to do so, we analysed the Cl2 and SO2 gasses emitted using the DTA/TG/FTIR techniques, as well as the losses of H2O and CO2. The authors also measured the volatilizations directly from the mouth of the furnace using gas chromatography syringes and analysed the possible emission of dioxins. This study is the first analysis of volatile elements of this kind, after numerous vitrifications in recent decades which ignored the volatilisations that occur when using fly ashes. Although the various types of fly ash used generate emissions of Cl2 and SO2, their use as a by-product on an industrial level could be recommended if previous thermal and washing treatments are conducted. These would minimise the above emissions, enabling the use of said fly ash in the production of glasses for commercial frits, even if an efficient industrial-scale gas cleaning system would apply. Furthermore, an appropriate optimised design of its formulation would make it possible to structurally link some of these gaseous components to the glass structure. These types of results will make it possible to calculate the volatilization when vitrifying certain types of industrial waste on an industrial level, although these studies would require prior assessment in a pilot plant.

Cracking Resistance of Steam-Cured Precast Concrete Using High Alite Cement with Modified Fly Ash

Cement with fly ash has rarely been used in Japan, mainly because its strength development is slower than ordinary Portland cement. In this research, the effect of the new type of fly ash (which was modified by the electrostatic belt separation method) with high alite (C3S) cement on cracking resistance of precast concrete prepared by steam curing was studied. The mechanical and shrinkage properties of the proposed fly ash concrete were compared with those of concrete made using OPC cement without fly ash. In order to study the cracking tendency of precast concrete with the proposed cement with fly ash, thermal stress analysis was conducted, taking into consideration the experimental data of concrete properties with the different concrete mix proportions. A standard precast concrete box culvert model was used in this 3D FEM analysis, and the distribution of temperature and relative humidity in the cross-section and induced restraint stress during and after steam curing were discussed. Steam-cured concrete with fly ash and high alite cement developed higher compressive strength on the first day of age than concrete with OPC. The proposed fly ash concrete developed high cracking resistance in the early days. On the other hand, the results showed that the drying shrinkage at later ages was the main cause of cracking.

INFLUENCE OF BINDERS, MIX PROPORTIONS, AND FABRICATION METHOD ON THE CHARACTERISTICS OF FLY ASH AGGREGATE

In this paper, two types of lightweight fly ash (FA) aggregates: cold bonded fly ash (CFA) and sintered fly ash (SFA) aggregates were prepared through the cold bonding and sintering method. During the pelletization process, different ratios of binders to fly ash were used, i.e., 10:90, 15:85, 17:83, and 20:80 with a set amount of water. Cement, metakaolin, sodium silicate, urea-formaldehyde resin, bentonite powder, and phenol-formaldehyde resin were employed as binders. A comparative study on physicochemical, mechanical, phase identification, microstructure, and optical analysis of CFA and SFA was performed. The results showed that CFA (an alkali binder) had a higher water absorption (WA) value of 9,50 % with a crushing strength (CS) value of 6,30 MPa than SFA (sodium silicate binder) with a CS value of 5,80 MPa and a WA value of 10,28 %. Experimental observations also demonstrated that the leaching ability of SFA was considerably lower than that of CFA. Most notably, SFA can be used as a substitute for construction material and structural applications along with solving FA waste disposal and related problems to a considerable extent.

Study on preparation of ADP composite colloid by the effective component from activated fly ash and its fire prevention mechanism

The application of industrial solid waste fly ash (FA) to fire prevention material is an effective way to realize its large-scale resource utilization. How to improve the performance and application range of FA type fire-fighting materials has become an engineering roadblock. In this study, the activation technology was introduced to extract effective component from FA, and the Ash-Diatomite-Polyacrylamide (ADP) colloid with double-aggregate was prepared mainly by activated modified FA. The ICP data of active substance in liquid phase indicates that acid-base combined excitation can release a large number of active components through chemical activation of FA. The physical properties of ADP colloids were tested by measuring the colloid permeability, water retention, and thermal stability. Meanwhile, the chemical flame retardancy of colloids was also determined by the inhibition experiment and thermogravimetric analysis. Experiments results indicate that Al3+ and Fe3+ released by excitation can be acted as cross-linking agents in the formation of colloids, and Ca2+ and Mg2+ released can be used as inhibitors for coal spontaneous combustion. ADP colloid can still inhibit the release of CO and CO2 at 220 °C with higher inhibition rates. The values of activation energy prove that ADP composite colloid can effectively increase the energy required by the interaction between coal and oxygen. Moreover, the multi-component cooperative fire-prevention mechanism of ADP was explored based on the effective composition, gelling mechanism, and fire-retarding action sequence of composite colloid.

Stabilization effect of chelating agents on heavy metals in two types of municipal solid waste incineration fly ash

Municipal solid waste incineration (MSWI) fly ash is complex in composition and contains large amounts of heavy metals. To investigate the effects of different passivating agents on Cd, Pb, Cr, Ni and Zn in different types of fly ash, 7 reagents were selected as passivating agents, including 3 inorganic reagents (Na2S, Na3PO4, NaH2PO4) and 4 organic reagents (SDD, DDTC, TMT, thiourea). The results showed that at low addition levels, sulfur-containing organic chemicals and phosphates were more effective in chelating these metals in both grate furnace incineration fly ash (GF FA) and circulating fluidised bed incineration fly ash (CFB FA), while Na2S was more effective in chelating heavy metals in CFB FA. In addition, agents containing -N-CS groups showed better chelation of heavy metals in GF FA, while heavy metals in CFB FA were more affinity to agents containing -SH groups. The ternary compound TMT-NaH2PO4-SDD (m1:m2:m3 = 2:3:1) was an excellent chelating agent for Pb, Cd in the GF FA, and TMT-Na2S-thiourea (m1:m2:m3 = 2:1:3) was a suitable chelating agent for these metals in CFB FA. The chelation rate of Cd and Pb after the treatments mixed ternary reagents was above 99%, and the leaching amount was much lower than the limit value of pollution control standards for domestic landfills. Moreover, under different pH leaching conditions, the leaching concentrations of Cd and Pb in the fly ashes treated with the ternary mixture were lower than the standard limits. In general, the ternary compound can effectively chelate heavy metals in fly ash, which provides a reference for selecting a suitable stabilizer combination for heavy metal in fly ash.

Synergic effect of polyester fiber and nano silica on chemical resistance of geopolymer mortar.

The aim of this study is to evaluate the synergistic effect of polyester fiber-reinforced and nanoslica on the technical performance and durability of geopolymer mortar in terms of the chemical resistance. The study examined how the addition of polyester fiber and nanosilica affects the short-term severe durability of geopolymer mortar specimens made with fly ash (type F). The specimens were cured under ambient conditions. Different percentages (0.6%, 1.2%, and 1.8%) of polyester fiber were used, both with and without nanosilica. Additionally, a reference mixture containing only nanosilica was prepared.All mixtures had a liquid to binder ratio of 0.50, and the ratio of NaOH to Na2SiO3 solution was kept at 2.5:1 by weight. The produced mixes, after 28 days of ambient curing, were immersed for another 28 days in solutions containing 3.5%, 5%, and 5% of sodium chloride, magnesium sulphate and sulfuric acid, respectively. For comparison, control specimens which were not exposed to chemical attacks were tested at the same age of 56 days. Moreover, water absorption and sorptivity tests were conducted to explain the durability performance in a more detailed way. The test results express that the combination of both materials showed a synergistic effect and resulted in greater improvements in compressive and flexural strengths. Both materials can reduce the reduction in compressive strength caused by sulfuric acid exposure, but polyester fiber can increase mass loss. The presence of magnesium sulfate and sodium chloride can lead to a reduction in strength, but the addition of both polyester fiber and nanosilica can mitigate these effects. The addition of fibers creates a network of pores that can limit water absorption, and nanosilica can further enhance the microstructure and reduce water absorption. However, using polyester fiber beyond 1.2 percent can adversely affect the rate of water absorption.

Using perforated cenospheres to improve the engineering performance of limestone-calcined clay-cement (LC3) high performance concrete: Autogenous shrinkage, strength, and microstructure

Limestone-calcined clay-cement (LC3) is a novel ternary cementitious material. Cenospheres (CS) are a type of fly ash with a smooth surface and hollow center. The chemical etching of the CS creates perforated CS (PCS) with pores through with water can be transported to achieve internal curing of LC3. In this study, experiments were performed to determine the effect of PCS on the performance of LC3 high-performance concrete. The dosage of PCS was 4% and 8%, and the dosage of CS was 8%. The autogenous shrinkage of samples with 4% and 8% PCS was reduced by 31.1% and 61.8%, respectively. This means PCS reduces the autogenous shrinkage of LC3. The strength of the sample with 4% PCS increased by 7.01 and 12.06 MPa compared with the control sample at 7 and 28 days of age, respectively, due to the internal curing of PCS and its volcanic ash This achieves the dual impact of low shrinkage and high strength. Furthermore, the experimental X-ray diffraction and Fourier transform infrared spectroscopy results showed that PCS can undergo pozzolanic reactions with calcium hydroxide. In addition, the heat of hydration and thermogravimetric analysis experiments showed that the internal curing of PCS promotes the hydration of LC3. Scanning electron microscopy images showed that the sample with 8% PCS had a high-quality dense bond between the PCS and matrix. Therefore, PCS can be used as a reactive internal curing material and the microscopic reaction of PCS can improve the macroscopic properties of concrete.

The early hydration and rheological characteristics of cement paste containing co-combustion fly ash

In this study, the early hydration and rheological characteristics of cement paste containing co-combustion fly ash (CCFA) were studied by using isothermal calorimetry, low-field NMR (LF-NMR), and rheological tests, and the differences between CCFA/cement system and the traditional binding system made with coal fly ash (CFA) were analyzed. The results indicate that co-combustion fly ash has a retarding effect on the early hydration of the cement. This effect becomes more pronounced as the dosage of fly ash increases from 10% to 30%. Additionally, the early hydration rate of samples containing CCFA was found to be faster compared to samples with CFA, even when the same admixture was used. The T2 spectrum analysis reveals that fly ashes primarily influence the early hydration characteristics by affecting the consumption of capillary water. As the admixture of fly ash increases, there is a reduction in moisture loss. The pattern of moisture evolution exhibits a strong correlation with the heat of hydration. At 72 h, the relaxation characteristics of both CCFA and CFA samples were found to be similar. Moreover, the rheological properties of the cement paste are influenced by factors such as the type and admixture amount of fly ash, as well as the degree of hydration. With an increase in the amount of fly ash blending, the rheological properties exhibit an increase as well. Specifically, CCFA samples display higher plasticity compared to CFA samples, even when the same admixture amount is used. The results of different analytical methods in the study were consistent.

Fly ash degree of reaction in hypersaline NaCl and CaCl2 brines: Effects of calcium-based additives

The pozzolanic reaction of fly ashes with calcium-based additives can be effectively used to solidify and chemically stabilize (S&S process) highly concentrated brines inside a cementitious matrix. However, complex interactions between the fly ash, the additive, and the brine typically affect the phases formed at equilibrium, and the resulting solid capacity to successfully encapsulate the brine and its contaminants. Here, the performances of two types of fly ash (a Class C and Class F fly ash) are assessed when combined with different additives (two types of cement, or lime with and without NaAlO2), and two types of brine (NaCl or CaCl2) over a range of concentrations (0 ≤ [Cl−] ≤ 2 M). The best performing matrices – i.e., the matrices with the highest Cl-containing phases content – were identified using XRD and TGA. The experimental results were then combined with thermodynamic modeling to dissociate the contribution of the fly ash from that of the additives. All results were implemented in a machine learning model that showed good accuracy at predicting the fly ash degree of reaction, allowing for the robust prediction of extended systems performance when combined with thermodynamic modeling.

Biotransformation of coal fly ash with high carbon content; behavior and release patterns of coal fly ash constituents under the influence of allochtonic Pseudomonas stutzer MT1

The aim of this study was to analyze the influence of Pseudomonas stutzeri MT1 on the weathering of CFA, with particular emphasis on the transformation of unburnt carbon. Batch experiment with two common types of coal fly ash (one with high carbon content) showed that microbial transformation leads to metal (loid)s and organic compounds release. The concentrations of metal (loid)s leached from CFA were the highest for As and Al, reaching 951 μg/L and 1353 μg/L respectively, in the presence of bacteria. It was shown that some metal (loid)s (Al, Fe, Cr, As) leached in higher quantities when bacteria used CFA as a sole carbon source as compared to variants where external carbon source was provided. Anthracene or phenanthrene were present in every leachate variant. The addition of bacteria resulted in a higher presence of short-chain carboxylic acids as well as 9,10-anthracenedione, which is assumed to be a product of the bacterial oxidation of anthracene. Based on the performed experiments we noticed that the microbial consumption of carbon contained within CFA was crucial to increasing the leaching rate of metal (loid)s, which may have consequences for the long-term storage of CFA.

Mechanical Behaviour of Geopolymer Concrete Using Steel Fibers

This investigation inspects the concurrent influence of steel fibers with different materials such as Fly Ash(FA), Silica Fume(SF) and aggregates on the mechanical behaviour of geopolymer concrete (GPC) mixes. A range of 8 to 16 molar NaOH molarities variation was observed in the experimental work. Sodium hydroxide molar (NaOH) and sodium silicate solution (NaOH) were utilised as alkaline activators in proportions of 1, 1.5, and 2 (Na2SiO3/NaOH). Steel crimped fibers having aspect ratio of 60 were added in the geopolymer concrete. Geopolymer concrete properties considering type of fly ash, the quantity of fly ash, silica fume, the content of fine aggregate and coarse aggregate, effect of sodium hydroxide concentration, content of sodium silicate solution and inclusion of 0.2% of steel fibers in the geopolymer concrete are analyzed.

Interaction state and element leaching of waste incineration fly ash-asphalt mortar based on fillerization

Fly ash from diverse sources had various physical and chemical properties, resulting in different modified asphalt properties. Therefore, this paper aimed to investigate the interaction between fly ash and asphalt from different sources and the performance of fly ash-asphalt mortar and further sought the best-replaced amount of fly ash. The fillers included limestone, Dongguan fly ash, and Guangzhou fly ash. First, the filler's physical and chemical properties and microstructure were evaluated. Secondly, asphalt mortar was prepared according to the replaced amount (0%, 25%, 50%, 75%, 100%) and powder binder ratio (0.7). Then, the basic performance test, micro test, high-temperature rheological test, and low-temperature rheological test were conducted on asphalt mortar to investigate the interaction between fly ash and asphalt, as well as the high-temperature performance, elastic recovery ability, and low-temperature crack resistance of asphalt mortar. Finally, the segregation and heavy metal leaching of fly ash-asphalt mortar (FA-AM) were evaluated by the segregation and ICP test. The results indicate that fly ash had a small particle size, a rugged surface, well-developed porosity, abundant mineral components including potassium salt, sodium salt, and calcium carbonate, strong interaction with bitumen, and excellent compatibility. Adding fly ash and increasing the replacement amount improved the high-temperature performance of asphalt and enhanced the elastic recovery ability, but the low-temperature performance was weakened. The enhancement of Dongguan fly ash's high-temperature performance was more significant, while the low-temperature performance of Guangzhou fly ash was marginally superior to that of Dongguan fly ash. However, there was no discernible difference between the two types of fly ash in terms of elastic recovery ability. Segregation had no noticeable effect on the heavy metal absorption concentration of FA-AM, and the storage stability was excellent. Asphalt had the best stabilization effect on Zn, Cu, and Pb in FA-AM (Dongguan) and Pb and Cr in FA-AM (Guangzhou). The recommended replacement amount of Dongguan fly ash and Guangzhou fly ash was 25%∼50%.

Comparative environmental assessment of low and high CaO fly ash in mass concrete mixtures for enhanced sustainability: Impact of fly ash type and transportation

The effect of fly ash type on the sustainability of concrete mixtures has yet to be quantified. This study aims to assess the environmental impacts of low calcium oxide (CaO) and high CaO fly ash in mass concrete mixtures from Thailand. The study analyzed 27 concrete mixtures with varying percentages of fly ash as a cement replacement (0%, 25%, and 50%) for 30 MPa, 35 MPa, and 40 MPa compressive strengths at specified design ages of 28 and 56 days. Sources of fly ash have been located between 190 km and 600 km away from batching plants. The environmental impacts were assessed using SimaPro 9.3 software. The global warming potential of concrete is reduced by 22–30.6% and 44–51.4% when fly ash, regardless of type, is used at 25% and 50%, respectively, in comparison with pure cement concrete. High CaO fly ash has more environmental benefits than low CaO fly ash when utilized as a cement substitute. The reduction in environmental burden was most significant for the midpoint categories of mineral resource scarcity (10.2%), global warming potential (8.8%), and water consumption (8.2%) for the 40 MPa, 56-day design with 50% fly ash replacement. The longer design age (56 days) for fly ash concrete showed better environmental performance. However, long-distance transport significantly affects ionizing radiation and ecotoxicity indicators for terrestrial, marine, and freshwater environments. Furthermore, the results show that a high cement replacement level (50%) may not always have a reduced environmental impact on mass concrete when considering long-distance transportation. The critical distance calculated based on ecotoxicity indicators was shorter than those calculated using global warming potential. The results of this study can provide insights for developing policies to increase concrete sustainability using different types of fly ash.

STUDY THE EFFECT OF DIFFERENT REINFORCEMENT RATIOS ON THE EXPANDED LIGHTWEIGHT GEOPOLYMER MORTAR PROPERTIES

Nowadays, the demand for the production of lightweight construction materials is increasing in order to reduce the cost, which is economically beneficial, as well as reducing the weight of the building as a whole. In this work, a lightweight geopolymer based on fly ash (type F) was developed using an alkaline activator at a concentration of 12 M and the ratio of the activator to the binder was (0.6). The natural sand was partially replaced with expanded perlite (EP), at replacement rates of 10, 30, and 50% by weight. Then the lightweight geopolymer (50% by volume of perlite) was reinforced with polypropylene fiber (PPF) with an addition ratio of (0.25, 0.5, 0.75, and 1%) of the total volume. Laboratory tests were carried out on the produced samples to determine the extent of the properties change after the addition of perlite. The density, insulating and absorbent properties of the lightweight geopolymer composite, which showed a decrease in unit weight with increased porosity and absorbency due to increased interstitial pores, were improved. A clear improvement in flexural strength was also observed when adding 1% polypropylene fibers. As for compressive strength, the improvement was slight. The lower density of the fibers also supports the weight of the unit.

Correlation between dissolubilities of Si, Al, and Fe from aluminosilicate precursor and strength of fly ash-based geopolymer

Fly ash (FA) is the most used aluminosilicate precursor to synthesize geopolymer. However, as a coal-combustion by-product, the inherent characteristics of FA can be significantly altered by multiple factors such as coal sources, combustion temperatures, particle size, and impurity level. Thus, unstable performances of FA-based geopolymer due to extremely varied reactivity of FA have been widely reported in the literature and are limiting the further valorization of FA. To offset the inconsistent characteristics of FA, this study provides a universal index to quantify and evaluate its reactivity to be used as aluminosilicate precursor feedstock. Alkali leaching tests were conducted on seven types of FA sourced from six different coal power plants in the Southeast Queensland region to determine the dissolubilities and dissolution efficiencies of reactive Si and Al within 2 h. The dissolubility and dissolution efficiency demonstrated decent correlations with the mechanical properties of the resultant FA-based geopolymer, especially 7-day strength. Moreover, bulk and reactive Si/Al molar ratios were derived to distinguish each type of FA further and verified by scanning electron microscopy / energy-dispersive X-ray spectroscopy. Lastly, a reactivity index considering the dissolution efficiency of Si, Al, and Fe and reactive Si/Al molar ratios was developed and correlated to the mechanical properties of FA-based geopolymer. Dissolubility at a leaching time of 30 min best reflected the reactivity of FA, having the highest correlation coefficient of 0.82.

Enhancement of geopolymerisation reactivity and thermal resistance using mixed types of fly ash

Geopolymers prepared with class C fly ash (FA) often suffer from a flash geopolymerisation rate, making it difficult to work. Class F FA, however, may have low reactivity, so an admixture must be added to solve this problem. This research highlighted the use of mixed class C and class F FA as a precursor for geopolymer preparation to alleviate such problems. Optimisation of the precursor recipe and the solid-to-liquid ratio (S/L) was assessed. The highest compressive strength (30.54 MPa) and a suitable initial (136 min) and final (240 min) setting times were obtained with S/L = 2.00, and 50 : 50 proportions of class C to class F FA. The fire resistance test on a 10 mm thick geopolymer panel at 1000°C for 180 min showed a maximum temperature of ∼570–580°C on the reverse side without catastrophic failure, suggesting it can be applied for use in fire retardation.