Microstructural and morphological evolution of fly ash based geopolymers

Nath, S.K.; Maitra, Saikat; Mukherjee, Shaswata; Kumar, Sanjay

doi:10.1016/j.conbuildmat.2016.02.106

Cited by 207 publications

(84 citation statements)

References 47 publications

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“…Carbonation affects mechanical strength adversely [28], therefore the fact of the strength reduction with the addition of sodium hydroxide (decrease of Al/Na ratio) in the case of "B" series should not surprise. At the same time, the amount of reaction products (as sodalite) crystallizing in the regular system increases (Fig.…”

Section: The Results Of Research and Discussionmentioning

confidence: 99%

Synthesis of the Sodalite by Geopolymerization Process Using Coal Fly Ash

Król¹,

Rożek²,

Mozgawa³

2017

Pol. J. Environ. Stud.

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IntroductionGeopolymers, also called inorganic polymers, are classified as synthetic aluminosilicate materials characterized by many interesting properties. This group of materials has gained a lot of attention in the past 10 years (measured by increasing number of publications) and raised high expectations concerning their applicability. Geopolymers are usually hard, mechanically resistant materials, therefore many attempts to substitute Portland cement in the construction industry have been taken [1]. Despite the huge number of publications devoted to this family and hundreds of new examples of these materials, researching them is still pioneering [2]. Attempts to systematize their structures and properties are just beginning to appear.Geopolymers are considered as zeolite precursors, thus zeolites are often detected in geopolymer gels. Activation of metakaolinite with sodium silicate and sodium hydroxide solutions at various temperatures (20-100ºC) can lead to the geopolymer-zeolite hybrid materials containing zeolite A, sodalite, and zeolite Y [3]. During hydrothermal treatment at low temperature, depending on the synthesis conditions, metakaolin-based geopolymeric gel transforms into zeolite ZSM-20, zeolite Na-P1, faujasite, sodalite, and analcime [4]. Metakaolin-based geopolymeric gel was also used for hydrothermal preparation of a faujasite zeolite membrane for alcohol/water separation [5]. On the other hand, non-hydrothermal preparation of Na-A zeolite membranes from chemosynthetic Al 2 O 3 -SiO 2 powder and sodium silicate solution by the geopolymer gel thermal conversion at 60ºC is possible [6].Pol. J. Environ. Stud. Vol. 26, No. 6 (2017), 2611-2617 AbstractThis study investigated the influence of alkali activation process conditions on the amount and types of zeolites in the resultant geopolymers. The products were formed during the alkaline activation of coal fly ash with the use of aluminium and sodium hydroxide solution. Geopolymers were cured at 80ºC for 24 h. The effects of reaction systems' constitution (expressed as SiO 2 /Al 2 O 3 and Al 2 O 3 /Na 2 O molar ratios) on the phase composition and structure of obtained products were determined. The results indicated that the products obtained from such hydrothermal treatment demonstrated the characteristics of zeolite-like materials -sodalite. By using the appropriate composition of the initial solution (sufficiently high concentration of NaOH and aluminum carrier), it is possible to synthesize the sodalite phase efficiently in an amorphous matrix.

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Section: The Results Of Research and Discussionmentioning

confidence: 99%

Synthesis of the Sodalite by Geopolymerization Process Using Coal Fly Ash

Król¹,

Rożek²,

Mozgawa³

2017

Pol. J. Environ. Stud.

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“…A number of researchers explored the geopolymer as a repair material. The bond strength of the geopolymer is reported higher bonding strength than comparable portland cement based repair [4], commercial repair products [5,6] and repair epoxies [7]. Moreover, geopolymeric binders had very high bond strength even at early ages.…”

Section: Geopolymer Repair Materialsmentioning

confidence: 97%

“…In addition, the interface zones between between substrate and geopolymer were homogenous at contact zone. Instead of engineering properties is comparable to the existing repair material, the cost of the geopolymer is also reported to be the cheapest [5].…”

Section: Geopolymer Repair Materialsmentioning

confidence: 99%

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Review on Potential of Geopolymer for Concrete Repair and Rehabilitation

et al. 2016

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Abstract. Cracking, spalling, surface deterioration, seepage and other concrete damage of the existing infrastructure have raised concern among residents, local authorities and developers. Dealing with concrete infrastructure rehabilitation is an important issue due to most of infrastructures today are concrete based. To simply patch up the spalling concrete as temporary solution and sooner or later, the cracks will return to haunt. This paper reviewed the current research and studies on concrete repair materials, highlighting the properties of geopolymer. It covers geopolymer repair materials which addressed in the field of concrete infrastructure rehabilitation. Geopolymer had good repair characteristics and displays the potential as an excellent repair material.

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“…This reflects the fact that the range of 1600-4000 cm -1 geopolymer product containing free water absorbed from the environment and water molecules bound in the structure of geopolymer network of the crystallization process and the absorption of the reaction product [8] [9] [10]. Peaks at 1300-1600 cm -1 related to the absorption band which is owned by carbonate units [11] [12] [13] [14].…”

Section: A Mineralogical and Structure Of Geopolymer Materialsmentioning

confidence: 99%

The Effect of Si/Al Ratio to Compressive Strength and Water Absorption of Ferronickel Slag-based Geopolymer

Mustofa

Pintowantoro

2017

IJPS

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Abstract Geopolymer material is inorganic polymers that are generally synthesized from aluminosilicate materials, such as ferronickel slag. In this study, synthesis of geopolymer material using NaOH 7 molar and Na2SiO3 solutions with different Si/Al ratio to make paste. Paste is molded in a metal mold with dimensions of 5x5x5 cm 3 , then released from the mold and heated in an oven at 80 °C for 24 hours. The specimens that have been heated further left at room temperature for 28 days and then tested for compressive strengthand water absorption. The results indicate a trend compressive strength increases and water absorption decreases with increasing the Si/Al ratio. The optimum condition is obtained when Si/Al ratio is 3.5. Keywordsferronikelslag, inorganic polymer, aluminosilicate material.

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Microstructural and morphological evolution of fly ash based geopolymers

Cited by 207 publications

References 47 publications

Synthesis of the Sodalite by Geopolymerization Process Using Coal Fly Ash

Synthesis of the Sodalite by Geopolymerization Process Using Coal Fly Ash

Review on Potential of Geopolymer for Concrete Repair and Rehabilitation

The Effect of Si/Al Ratio to Compressive Strength and Water Absorption of Ferronickel Slag-based Geopolymer

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