Role of microwave radiation in curing the fly ash geopolymer

Chindaprasirt, Prinya; Rattanasak, Ubolluk; Taebuanhuad, Sompop

doi:10.1016/j.apt.2012.12.005

Cited by 139 publications

(44 citation statements)

References 18 publications

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“…Somaratna et al (2010) showed that volumetric heating provided by microwave curing results in faster property development of NaOH activated fly ash mortars as compared to conventional heat curing. Chindaprasirt et al (2013) also confirmed that short microwave curing accelerates reaction in AAFA cement resulting in improved compressive strength. Diop and Grutzeck (2008) showed that solar radiation can be used to produce bricks made of alkali-activated material.…”

Section: Introductionsupporting

confidence: 63%

Direct electric curing of alkali-activated fly ash concretes: a tool for wider utilization of fly ashes

Kovtun

Shekhovtsova

Kearsley

2016

Journal of Cleaner Production

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Utilization of the fly ashes is a major problem in many developing countries and in South Africa only about 7% of the fly ash produced annually by coal-fired power stations, has being utilized. Although, fly ashes can be used as an alternative binder in alkali-activated concretes, strength development of these concretes at room temperature is slow limiting application of the material. Direct electric curing is proposed for heat curing of alkali-activated fly ash concrete which will open new opportunities for in-situ applications of these concretes in the construction industry thus increasing the amount of beneficially utilized fly ash. Alkaliactivated fly ash concretes containing unclassified low calcium fly ash, sodium hydroxide and sodium silicate solutions were cured at 60 ºC by means of direct electric curing. The electric resistivity and compressive strength development of the concretes were investigated. The resistivity strongly depends on the type of activator used. Compressive strength up to 33.8 MPa and 48.5 MPa at 2 and 28 days respectively, can be achieved after a short period of 2 direct electric curing. This opens new opportunities for wider application of alkali-activated fly ash concretes and for more extensive utilization of fly ash.

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Section: Introductionsupporting

confidence: 63%

Direct electric curing of alkali-activated fly ash concretes: a tool for wider utilization of fly ashes

Kovtun

Shekhovtsova

Kearsley

2016

Journal of Cleaner Production

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“…In modern geopolymer, the AAS geopolymer denotes the alkali activation of aluminosilicate precursors such as the calciumcontaining sources (e.g., alkali-activated GGBS binder), the lowimpurity aluminosilicates (e.g., alkali-activated FA/MK binder), or their blends (e.g., alkali-activated GGBS/FA blends), while the SAP geopolymer implies that the aluminosilicate sources are pre-mixed with some metals and activated by the acid phosphate or other phosphates. It is good to mention that the activation methods assisted by external energies [e.g., microwave (Chindaprasirt et al, 2013a), autoclaved (Rashad et al, 2012), and mechanical activation (Kumar and Kumar, 2011)] are not involved in this review.…”

Section: Terminology and Classificationmentioning

confidence: 99%

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

2019

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Chemically activated materials (often termed as geopolymer) have received attracting attentions in civil, material and environmental research fields as a toolkit alternative to traditional Portland cement in specific applications. This paper presents a comparative review on silico-aluminophosphate (SAP) geopolymers in terms of definition, chemistries involved during geopolymerization, mechanical performance, durability, environmental impacts, and their potentials in applications relative to conventional alkali-aluminosilicate (AAS) geopolymers. Recommendations for future applications are also highlighted. It is found that S-A-P gels with six-coordinated aluminum environment dominate in SAP geopolymers, while the aluminum in N-A-S-H gels formed in the AAS geopolymers is characterized by four-coordinated features. Besides, the slow performance development of SAP geopolymer matrix under ambient temperature curing can be compensated through incorporating additional countermeasures (e.g., metal sources) which allow the tailored design of such geopolymers for certain in-situ applications. Generally, the calcium-bearing C-(A)-S-H gels co-existing with N-A-S-H gels are dominant in AAS geopolymers, while the S-A-P gels enhanced by phosphate-containing crystalline/amorphous phases are the main products in SAP geopolymers. The SAP geopolymers show their environmental friendliness relative to the AAS geopolymers due to the utilization of phosphate activators that require lower production energy relative to silicate-containing activators. However, the higher cost of phosphate activators may confine the applications of SAP geopolymers in some exquisite or special fields.

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“…Most of the research works on fly ash based geopolymer are on the mix proportion and strength variation of geopolymer concrete cured at different temperature range of 45-80°C for about 2-3 h [7][8][9][10][11][12][13]. It is noted that the strength of such geopolymer mortar is more at 60°C compared to 80°C for a given molar concentration [14,15].…”

Section: Introductionmentioning

confidence: 99%

Effect of nano-silica on strength and durability of fly ash based geopolymer mortar

Adak

Sarkar

2014

Construction and Building Materials

316

100

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Role of microwave radiation in curing the fly ash geopolymer

Cited by 139 publications

References 18 publications

Direct electric curing of alkali-activated fly ash concretes: a tool for wider utilization of fly ashes

Direct electric curing of alkali-activated fly ash concretes: a tool for wider utilization of fly ashes

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

Effect of nano-silica on strength and durability of fly ash based geopolymer mortar

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