Effects of Aluminum Hydroxide and Layered Double Hydroxide on Asphalt Fire Resistance

Li, Menglin; Pang, Ling; Chen, Meizhu; Xie, Jun; Liu, Quantao

doi:10.3390/ma11101939

Cited by 33 publications

(22 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their fire retardance mechanisms are to reduce the combustion temperature by dehydration during the combustion process, thus limiting the combustion speed. Because they can catalyze and oxidize the gas, the amount and the escape rate of the smoke can be reduced [23,24]. Furthermore, the MgO and Al 2 O 3 generated by aluminum hydroxide and magnesium hydroxide can absorb the smoke and precipitate it into ash [25].…”

Section: Experimental Materials and Methodsmentioning

confidence: 99%

Evaluation of Asphalt with Different Combinations of Fire Retardants

Chen

Zhu

et al. 2019

Materials

View full text Add to dashboard Cite

When a fire takes place in a tunnel, the surface of the asphalt pavement will burn and release a large amount of smoke, which is toxic to human health. Thus, in order to prevent the combustion of the asphalt pavement under fire, it is necessary to propose some methods to retard its physical and chemical reaction under the high temperature. In this study, ten different combinations of fire retardants and a control case where no fire retardant was applied were prepared for evaluation. The thermogravimetric (TG)–mass spectrometry (MS) tests were used to evaluate their effect on the fire retardance from mass and energy perspectives and the Fire Dynamics Simulator (FDS) software was used to evaluate the fire retardance from temperature and smoke distribution perspectives. In experimental analysis, the TG (thermogravimetric) and DTG (differential thermogravimetric) curves were used to analyze the mass loss rate and residual mass of the asphalt and the activation energy was calculated and analyzed as well. In addition, decay rate of mass loss rate and increasing rate of activation energy were proposed to evaluate the ease of combustion of the asphalt with and without fire retardants. The results show that in laboratory experiments, the fire retardant combination which includes 48% aluminum hydroxide, 32% magnesium hydroxide, 5% expanded graphite, and 15% encapsulated red phosphorous would lead to an improved effect of fire retardance. In numerical modeling, the temperature and smoke height distribution over time were adopted to evaluate the fire retardance effect. The temperature distribution was found to be symmetrical on both sides of the combustion point and the same combination as proposed in experimental analysis was found to have the best effect on fire retardance due to the largest decrease in temperature. Additionally, because of the highest smoke height distribution, an improved effect on smoke suppression was also found when this combination was applied.

show abstract

Section: Experimental Materials and Methodsmentioning

confidence: 99%

Evaluation of Asphalt with Different Combinations of Fire Retardants

Chen

Zhu

et al. 2019

Materials

View full text Add to dashboard Cite

show abstract

“…The results show that the synergistic effect of OEVMT was more obvious compared with OMMT. Besides, it has been reported that nano-layered hydroxides (LDHs) [ 25 , 26 ] and expanded graphite (EG) [ 27 , 28 ] show excellent synergistic effects with CFR. To a certain extent, the nanolayered flame retardant system has overcome some deficiencies of CFR, and the flame retardancy effect is significantly improved with a small amount of admixture.…”

Section: Introductionmentioning

confidence: 99%

Research on the Flame Retardancy Properties and Mechanism of Modified Asphalt with Halloysite Nanotubes and Conventional Flame Retardant

Tan

et al. 2020

Materials

View full text Add to dashboard Cite

The inflammability of asphalt road will promote fire spread in the tunnel and produce lots of toxic smoke. To improve the fire resistance of asphalt pavement, mineral powder flame retardants are generally replaced by flame retardants in equal amounts. In this study, the effects of the synergistic flame retardancy system of halloysite nanotubes (HNTs) and conventional flame retardants (CFR) on the flame retardancy performance and mechanism of asphalt were investigated. Firstly, the flame retardancy properties of the HNTs and CFR composite modified asphalt were investigated based on the Cleveland open cup method (COC), Limiting oxygen index meter (LOI), and Cone calorimeter tests (CCTs). Then, the flame retardancy mechanism of the modified asphalt was studied based on Thermogravimetric analyzer (TGA), Fourier-transform infrared (FTIR), and Scanning electron microscopy (SEM). The results show that adding HNTs could improve the flame retardancy of the CFR modified asphalt binder. When 1 wt % HNTs and 8 wt % CFR were used, the limiting oxygen index of asphalt increased by 40.1%, the ignition temperature increased by 40 °C, while the heat release rate, total heat release, the smoke production rate, total smoke release, and other parameters decreased with varying degrees. Based on TG, FTIR, and SEM, the targeted flame retardancy mechanism and synergistic effect of HNTs/CFR flame retardancy system were revealed and summarized as three stages: (1) Stage 1, aluminum hydroxide (ATH) absorbs heat through thermal decomposition and inhibits the decomposition of lightweight components in asphalt; (2) Stage 2, aluminum diethyl phosphate (ADP) decomposes and produces organic phosphoric acid, which catalyzes crosslinking and ring thickening of asphalt and the quenching effect of phosphorus free radicals to block the combustion; and (3) Stage 3, HNTs plays an important role in increasing the integrity and density of the barrier layer. In addition, the Al2O3 produced by the decomposition of ATH, the carbon layer formed by the ADP catalyzed pitch, and HNTs play a significant synergistic effect in the formation of the barrier layer. Thus, the combination of HNTs and CFR has been proved to be a prospective flame retardancy system for asphalt.

show abstract

“…Therefore, the energy conversion characteristics, nonisothermal kinetic properties, and emitted volatiles of bitumen have been studied. 9 , 10 …”

Section: Introductionmentioning

confidence: 99%

Thermal Characteristics, Kinetic Models, and Volatile Constituents during the Energy Conversion of Bituminous SARA Fractions in Air

Xia

2020

ACS Omega

View full text Add to dashboard Cite

To understand the thermal characteristics, nonisothermal kinetic models, and volatile constituents during the energy conversion of bituminous materials at the fraction level, differential scanning calorimetry–mass spectrometry tests were performed on bituminous four fractions, including saturates, aromatics, resins, and asphaltenes (SARA). Then, three-dimensional (3D) nonisothermal kinetic models of SARA fractions were established and volatile constituents of SARA fractions were discussed. Results indicate that when the heating rate is increased, the decomposition temperature ranges in each stage increase and the initial decomposition, peak, and burn-out temperatures of each SARA fraction all shift to high temperatures. Also, the whole energy conversion processes of SARA fractions are mainly exothermic reactions. Additionally, the energy conversion mechanism in each stage of saturates and aromatics accords with different nonisothermal kinetic models. However, the energy conversion mechanisms of resins and asphaltenes are similar and both accord with the 3D diffusion models. Further, the established nonisothermal kinetic models in each decomposition stage of SARA fractions are feasible to describe the energy conversion processes of SARA fractions. The released small molecular volatiles from saturates and aromatics increase when the heating rate is increased, but the macromolecular volatiles are decreased. The opposite is true for resins, but all volatiles emitted from asphaltenes are increased. Finally, the heating rate has little influence on the constituents of emitted gaseous products from SARA fractions but shows an effect on the release amount of volatiles from SARA fractions. The main common volatiles of SARA fractions are CO 2 , H 2 O, methanol, hydrazine, propyne, acetaldehyde, and propane. This study contributes to further reveal the energy conversion mechanisms of bituminous materials.

show abstract

Effects of Aluminum Hydroxide and Layered Double Hydroxide on Asphalt Fire Resistance

Cited by 33 publications

References 26 publications

Evaluation of Asphalt with Different Combinations of Fire Retardants

Evaluation of Asphalt with Different Combinations of Fire Retardants

Research on the Flame Retardancy Properties and Mechanism of Modified Asphalt with Halloysite Nanotubes and Conventional Flame Retardant

Thermal Characteristics, Kinetic Models, and Volatile Constituents during the Energy Conversion of Bituminous SARA Fractions in Air

Contact Info

Product

Resources

About