Physico-Mechanical and thermal behavior of prolong heat Cured geopolymer blocks

Raut, Ashwin; Murmu, Anant Lal; Alomayri, Thamer

doi:10.1016/j.conbuildmat.2023.130309

Cited by 18 publications

(4 citation statements)

References 27 publications

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“…The active calcium contained in slag is prone to transforming into a Ca-containing binder, while the spherical FA also improves the mobility of slurry and the cost effectiveness. Therefore, binary slag/FA geopolymers are very promising for developing solid-waste-based pastes without heat curing at about 60 • C [6] due to the as-formed sodium alumino-silicate hydrate (N-A-S-H) networks from reactive calcium involved in slag. Investigations and…”

Section: Introductionmentioning

confidence: 99%

Silica Fume Enhances the Mechanical Strength of Alkali-Activated Slag/Fly Ash Pastes Subjected to Elevated Temperatures

Dai¹,

Wang

2023

Fire

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The fireproof design of geopolymers through adjusting multi-component metallurgical solid wastes has attracted increasing attention, due to their potential low carbon emission, cost effectiveness, and role in environmental conservation. Herein, the effects of silica fume (SF) on the microstructure and mechanical properties of alkali-activated slag/FA (fly ash) pastes subjected to elevated temperatures (150, 500, 850, and 1200 °C) are investigated to clarify whether or not SF has a positive role in the mechanical strength of the slag/FA (slag/FA = 30:70, wt.%) geopolymer during building fires. The results show that the replacement of FA with 10 wt.% SF (silica fume) promotes the increasing pore volume with a diameter of 0.2~3 μm, leading to an increase in the compressive or flexural strength below 850 °C, “right shifts” of the endothermic peak, and uniform and compact fracture surfaces. Meanwhile, gehlenite and labradorite are generated after exposure above 850 °C. The bloating effect of the SF-containing sample occurs at 1200 °C, leading to a greater deformation due to the further restructuring of the amorphous geopolymer chain N–A–S–H or N–(Ca)–A–S–H composed of [SiO4]4− and [AlO4]5−. This paper explores an effective approach to improving geopolymers’ fireproof performance by adjusting the formulation of solid waste.

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Section: Introductionmentioning

confidence: 99%

Silica Fume Enhances the Mechanical Strength of Alkali-Activated Slag/Fly Ash Pastes Subjected to Elevated Temperatures

Dai¹,

Wang

2023

Fire

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show abstract

“…Currently, the global perspective on burgeoning sustainability boosts the development of converting industrial by-products slag derived from blast furnace iron making and fly ash (FA) from coal-fired power plants into cementitious materials, which is very promising to develop solid wastebased pastes without heating curing at about 60 • C [4], due to the reactive calcium involved in slag. Investigations and wide applications of alkali-activated slag/FA geopolymers [5][6][7] have been hotspots to realize the recycling economy and environmental protection.…”

Section: Introductionmentioning

confidence: 99%

Silica Fume Improves the Mechanical Properties of Alkali-Activated Slag/Fly Ash Pastes Subjected to Elevated Temperatures

Wang¹,

Liu²,

Mo³

et al. 2023

Preprint

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Recycling of metallurgical solid waste has intriguing increasing attention for fabricating cementitious materials, due to its low-carbon emission, cost-effectiveness, and environmental conservation. Herein, the effects of silica fume (SF) on the microstructure and mechanical properties of alkali-activated slag/FA (fly ash) pastes subjected to elevated temperatures (150, 500, 850, and 1200℃) are investigated, to clarify the fact that whether or not the SF generates positive roles in mechanical properties of slag/FA geopolymers. The results show that the replacement with 10 wt% SF (silica fume) promotes the increasing pore volume with a diameter of 0.2~3 μm at room temperature, leading to an increase in the compressive or flexural strength, “right shifts” of endothermic peak and the initial-final temperature of mass loss, presenting a denser and compact fracture surface. Meanwhile, the mineral phase of gehlenite and labradorite emerges after exposure above 850℃ from the XRD results. Furthermore, the bloating effect of the incorporated SF occurs due to the formation of a liquid phase altogether with the amorphous silicates after exposure to 1200℃, leading to a greater deformation and enhancement of restructuring involved in the [SiO4]4− and [AlO4]5−. It explores an effective recycling approach for fabricating paste binders using metallurgical solid wastes.

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“…Geopolymerization could convert a wide range of metallurgical waste alumino-silicate materials including fly ash (FA), slag, and steel slag into cementitious materials, such as pastes and binders. Nevertheless, the multifunctional design of geopolymer has intriguing increasing attention by adjusting multi-component metallurgical solid wastes [3][4][5], such as fire protection, thermal stability, and ultra-high toughness, as well as the freezing-thawing resistance.…”

Section: Introductionmentioning

confidence: 99%

Silica Fume Improves the Frost Resistance of Alkali-activated Slag/fly Ash Geopolymer Binder

Wang¹,

Liu²,

Mo³

et al. 2023

Preprint

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Benign design of alkali-activated slag/FA geopolymer paste has intriguing increasing attention for optimizing its service performance. Therefore, the replacement of fly ash (FA) with 10 wt% silica fume (SF) is investigated by mechanical strength after freeze-thawing cycles and microstructure characterization. The results show that an appropriate dosage (30 wt%) of slag is necessary to attain alkali-activated slag/FA geopolymer paste with excellent mechanical performance, and the SF/slag/FA (SF: slag: FA= 10:30:60, wt%) geopolymer paste exerts the compressive and flexural strength of 95.2 and 3.2 MPa, respectively. Meanwhile, the doped 10 wt% SF facilitates the propagation of (N, C)-A–S–H chains, rather than the formation of C-S-H gels, evidenced by the absent exothermic peak at about 861oC from the differential scanning calorimetry (DSC) curves, leading to the increases in the pores volume with a pore diameter<20 nm and tortuosity by mercury intrusion porosimeter (MIP) results, corresponding to an improved freezing-thawing resistance with the residual compressive strength of 52.8 MPa and the weight loss of 10.5% after 300 freeze-thawing cycles. It explores a cost-effective and benign facile approach to designing heating curing-free alkali-activated slag/FA geopolymer paste with good freezing-thawing resistance.

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Physico-Mechanical and thermal behavior of prolong heat Cured geopolymer blocks

Cited by 18 publications

References 27 publications

Silica Fume Enhances the Mechanical Strength of Alkali-Activated Slag/Fly Ash Pastes Subjected to Elevated Temperatures

Silica Fume Enhances the Mechanical Strength of Alkali-Activated Slag/Fly Ash Pastes Subjected to Elevated Temperatures

Silica Fume Improves the Mechanical Properties of Alkali-Activated Slag/Fly Ash Pastes Subjected to Elevated Temperatures

Silica Fume Improves the Frost Resistance of Alkali-activated Slag/fly Ash Geopolymer Binder

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