Factors Influence on Shrinkage of High Calcium Fly Ash Geopolymer Paste

This research shows the progress of geopolymer synthesis based on high calcium fly ash. In this study, the fly ash contents of 60, 65, and 70 percents by weight and sodium hydroxide solution concentrations of 8 to 12 M were used. Alkali activators for the geopolymer synthesis consisted of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) and the weight ratio of Na2SiO3 to NaOH were 0.50, 1.00, and 1.50. Drying shrinkage deformation of geopolymer paste was investigated by longitudinal measurement in a room temperature. Generally, the drying shrinkage behavior could be divided into three groups. The minimum drying shrinkage strain below 3,000 x 10-6 mm/mm was observed. The results indicated that an increase in the fly ash to alkali solution ratio and the decease of NaOH concentration significantly decreased the drying shrinkage strain. The optimum ratio of Na2SiO3 to NaOH was 1.0. The findings show that high calcium fly ash geopolymer binder could be used for alternative construction materials with low shrinkage strain.

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Geopolymer Mortar Incorporating High Calcium Fly Ash and Silica Fume

Archives of Civil Engineering ◽

10.2478/ace-2019-0001 ◽

2019 ◽

Vol 65 (1) ◽

pp. 3-16 ◽

Cited By ~ 2

Author(s):

V.C. Prabha ◽

V. Revathi

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Sodium Hydroxide ◽

Silica Fume ◽

Sodium Hydroxide Solution ◽

Test Results ◽

Dense Microstructure ◽

High Calcium ◽

High Calcium Fly Ash ◽

Binder Ratio

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.

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Influence of Glass and Limestone Powders in High Calcium Fly Ash Geopolymer Paste on Compressive Strength and Microstructure

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.801.397 ◽

2019 ◽

Vol 801 ◽

pp. 397-403

Author(s):

Pattanapong Topark-Ngarm ◽

Tawatchai Tho-In ◽

Vanchai Sata ◽

Prinya Chindaprasirt ◽

Trinh Cao

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Glass Powder ◽

Sodium Hydroxide Solution ◽

Setting Time ◽

Limestone Powder ◽

Hydration Reaction ◽

High Calcium ◽

High Calcium Fly Ash ◽

Geopolymer Paste

The effects of replacing high calcium fly ash with containment glass powder and limestone powder in the geopolymer are investigated in this paper. The high calcium fly ash was replaced by either glass powder or limestone powder at 20% and 40% by weight. The geopolymer paste was tested for setting time and compressive strength and evaluated of its microstructure on SEM, XRD, FTIR, and MIP. The results indicated that the setting time of geopolymer paste was increased with the replacement of glass powder and reduced by replacement of limestone powder. The compressive strengths were generally higher than those of controls. The maximum increase of compressive strength was 33% when replaced fly ash with 20% of glass powder at 8 molar NaOH concentration of sodium hydroxide solution. The microstructure evaluations show the remaining particles of raw materials and the compatible of hydration reaction and polymerization when having limestone powder in the mix proportion. Furthermore, the powder acts as a filler in the gels.

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Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

Advances in Materials Science and Engineering ◽

10.1155/2015/731056 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 10

Author(s):

Ganesan Lavanya ◽

Josephraj Jegan

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Sodium Hydroxide ◽

Ordinary Portland Cement ◽

Geopolymer Concrete ◽

Portland Cement Concrete ◽

Cement Concrete ◽

High Calcium ◽

High Calcium Fly Ash ◽

Ordinary Portland Cement Concrete

This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were150×150×150 mm cubes,100×200 mm cylinders, and100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

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Effect of Mechanical Activation of Fluidized Bed Fly Ash on Geopolymer Properties

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.288.51 ◽

2019 ◽

Vol 288 ◽

pp. 51-58

Author(s):

Gendenjamts Oyun-Erdene ◽

Jadambaa Temuujin

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Mechanical Activation ◽

Sodium Hydroxide ◽

Fluidized Bed ◽

Sodium Silicate ◽

Sodium Hydroxide Solution ◽

Chemical Activation ◽

Weight Ratio ◽

Particle Size Reduction

This paper is focused on the elucidation of mechanical activation effect of circulating fluidized bed combustion fly ash (Amgalan Thermal Station, Mongolia) on mechanical properties of geopolymers. Fluidized bed fly ash was mechanically activated for 15-120 minutes with a vibratory mill. The effect of mechanical activation was quite visible on the particle size reduction and on the degree of amorphization.Geopolymer samples were prepared from the raw and milled fluidized bed fly ashes by alkaline activation. Chemical activation was performed with 10M sodium hydroxide solution, as well as solutions containing a mixture of sodium silicate and sodium hydroxide with a weight ratio of 2:1. The geopolymer cubic specimens were cured at 70°C for 24 hrs and their 7 days uniaxial compressive strength was measured. After curing and drying, the bulk density, water absorption and apparent porosity of geopolymer samples were evaluated.X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetry-differential thermal analysis (TGA-DTA) have been used for the structural characterization of the CFA and the resulting geopolymers. The highest compressive strength of 32.4 MPa was achieved for the fly ash milled for 30 minutes and activated with the solution containing the sodium silicate and 10M sodium hydroxide at a weight ratio of 2:1. Non-milled CFA based geopolymers showed the compressive strength of 16.2 MPa after activation with the same solution. Mechanical activation resulted in an increase in the reactivity of the fluidized bed fly ash and that enhances the geopolymerization reactions.

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Effect of Addition of Microsilica and Nanoalumina on Compressive Strength and Products of High Calcium Fly Ash Geopolymer with Low Concentration NaOH

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1103.29 ◽

2015 ◽

Vol 1103 ◽

pp. 29-36 ◽

Cited By ~ 1

Author(s):

Prinya Chindaprasirt ◽

Kiatsuda Somna

Keyword(s):

Compressive Strength ◽

Salicylic Acid ◽

Fly Ash ◽

Sodium Hydroxide ◽

Product Form ◽

Leaching Test ◽

Low Concentration ◽

High Calcium ◽

High Calcium Fly Ash

This research aims to study the effect of addition of microsilica and nanoalumina on compressive strength and products of high calcium fly ash geopolymer with low NaOH concentration. Microsilica and nanoalumina were added in the mixture in order to adjust the Si/Al ratios which resulted in the change of product form of geopolymer pastes. Geopolymer was synthesized using high calcium fly ash and 2 molar sodium hydroxide (NaOH). Microsilica and/or nanoalumina were added as additional sources of silica and alumina in the mixtures. Compressive strengths of pastes were investigated at the age of 7, 28 and 60 days. The products of geopolymer pastes were characterized by FTIR and salicylic acid with methanol (SAM leaching test). The results showed that the mix (2Si10Al0) with additional 10% of microsilica gave the highest compressive strength of 14 MPa at the age of 60 days. The products of geopolymer pastes were CSH gel, CASH gel, NASH gel and zeolite which were characterized by FTIR and SAM leaching test.

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Effect of sodium hydroxide and sodium silicate solutions on strengths of alkali activated high calcium fly ash containing Portland cement

KSCE Journal of Civil Engineering ◽

10.1007/s12205-016-0327-6 ◽

2016 ◽

Vol 21 (6) ◽

pp. 2202-2210 ◽

Cited By ~ 16

Author(s):

Tanakorn Phoo-ngernkham ◽

Sakonwan Hanjitsuwan ◽

Nattapong Damrongwiriyanupap ◽

Prinya Chindaprasirt

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

High Calcium ◽

High Calcium Fly Ash ◽

Alkali Activated

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Drying shrinkage, strength and microstructure of alkali-activated high-calcium fly ash using FGD-gypsum and dolomite as expansive additive

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2020.103760 ◽

2020 ◽

Vol 114 ◽

pp. 103760 ◽

Cited By ~ 1

Author(s):

Sakonwan Hanjitsuwan ◽

Borwonrak Injorhor ◽

Tanakorn Phoo-ngernkham ◽

Nattapong Damrongwiriyanupap ◽

Long-Yuan Li ◽

...

Keyword(s):

Fly Ash ◽

Drying Shrinkage ◽

Fgd Gypsum ◽

High Calcium ◽

High Calcium Fly Ash ◽

Expansive Additive ◽

Alkali Activated

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Influences of the Ratios of High-Calcium Fly Ash to Low-Calcium Fly Ash on the Strength and Drying Shrinkage of Geopolymer Mortar

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.931-932.416 ◽

2014 ◽

Vol 931-932 ◽

pp. 416-420 ◽

Cited By ~ 1

Author(s):

Ridtirud Charoenchai ◽

Prinya Chindaprasirt

Keyword(s):

Fly Ash ◽

Power Plants ◽

Setting Time ◽

Drying Shrinkage ◽

High Calcium ◽

High Calcium Fly Ash ◽

Class C ◽

Class F Fly Ash ◽

By Products ◽

Class F

New types of binders are being developed as an alternative to traditional cement. These alternatives are developed to have better properties and to be more environmentally friendly. Geopolymer is a novel binder that is produced from by-products such as fly ash, rich hushes ash and bio mass ash. In this experiment, fly ash, which was a by-product from electrical-generating power plants, was used during the synthesis of geopolymer. According to ASTM standard C168, fly ash is categorized into two types: class F and class C. This research focuses on the effects of using both types of fly ashes on mechanical properties of geopolymer. The experiment studies the changes on setting time, drying shrinkage and compressive strength of geopolymer mortar when 0, 25, 50, 75 and 100 percent of total weight of class F fly ash (LCF) is substituted with class C counterpart (HCF). The study used sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) as alkali activators. The samples were cured for 24 hours either at an ambient temperature of 25°C or at an elevated temperature of 60°C.The result showed that the setting time of pure LCF geopolymer mortar was 6 times longer than that of the pure HCF ones. In addition to setting time, the specimens with 25 percent of their total binders weight replaced by HCF appeared to have the highest strength. However, the increase in HCF also increased the drying shrinkage by 6 and 12times when the specimens were cured at25°C and at 60°C respectively

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