Investigation on the Degree of Reaction and Strength Performance of Fly Ash Based Geopolymer Binder with Alternative Chemical Reagents

The existence of high calcium contents in fly ash will contribute to the rapid stiffening and low workability of geopolymer paste. This study reports the feasibility of sodium nitrate and citric acid as the alternative admixtures for geopolymer binder. The effects of sodium nitrate and citric acid were independently evaluated at 0.5%, 1.5% and 2.5% of fly ash weight in geopolymer mixture. The effect of these admixtures on fresh geopolymer characteristic was evaluated through series of setting time and flow table workability tests, while degree of hydration, compressive strength and porosity tests were conducted to provide fundamental information on the hardened properties of geopolymer paste. Based on the result of degree of reaction, the inclusion of sodium nitrate in fly ash based geopolymer will increase the level of degree of hydration. Nevertheless, this result is in contrast with citric acid inclusion where degree of hydration decreased along with the increasing dosage of citric acid in the mixture. Strength development of geopolymer paste, particularly during the early age, appears to be affected by various geopolymerization rate presented by these admixtures.

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Interrelationship Analysis of Geopolymer Components Using Pearson Correlation Technique

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.567.417 ◽

2014 ◽

Vol 567 ◽

pp. 417-421 ◽

Cited By ~ 1

Author(s):

Andri Kusbiantoro ◽

Norbaizurah Rahman ◽

Noor Fifinatasha Shahedan

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Elemental Composition ◽

Setting Time ◽

Source Material ◽

Curing Temperature ◽

Strength Development ◽

Correlation Technique ◽

High Calcium ◽

Geopolymer Binder

Performance of geopolymer based specimens is significantly affected by internal and external aspects. Curing temperature and air humidity are among the prominent external factors that contribute to the alteration of geopolymer properties. Nevertheless, internal component of geopolymer binder also carries essential effect to the hardened geopolymer binder produced. In this research, the study was concentrated on the elemental composition of source material components and their interrelation to the performance of geopolymer binder produced. Different types of fly ash were used as the source material in this research. Low calcium (class-F) fly ash was combined with high calcium (class-C) fly ash to determine the elemental composition effect, particularly SiO2, Al2O3, and CaO to the geopolymer properties. Analysis using SYSTAT statistical software indicated the importance of oxide composition of source material to the geopolymer specimens produced. Initial setting time of geopolymer paste was also possibly important to the compressive strength of geopolymer specimens produced. Nevertheless, final setting time indicated less importance to the compressive strength development of geopolymer binder.

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Influence of Chemical Additives on the Properties of Composite Materials Based on Fine-Dispersed High-Calcium Fly Ash

Journal of Siberian Federal University Chemistry ◽

10.17516/1998-2836-0192 ◽

2020 ◽

pp. 395-407

Author(s):

Olga M. Sharonova ◽

Valerii M. Kirilets ◽

Leonid A. Solovyov ◽

Alexander G. Anshits

Keyword(s):

Composite Materials ◽

Fly Ash ◽

Citric Acid ◽

Sodium Sulfate ◽

Setting Time ◽

Strength Properties ◽

Sodium Tetraborate ◽

Chemical Additives ◽

High Calcium ◽

High Calcium Fly Ash

Composite materials (CM) were obtained on the basis of fine- dispersed high-calcium fly ash (HCFA), selected from the 4th field of electrostatic precipitators of Krasnoyarsk TPP-2, with the addition of Melflux 5581F superplasticizer at the water: binder ratio W/B = 0.25. The influence of the concentration of superplasticizer in the range 0.06-0.6 wt. % on the strength properties of composite materials was studied. The effect of the addition of sodium sulfate as an accelerator of hydration hardening and additives-retarders of sodium phosphate, sodium tetraborate and citric acid, were studied. The optimal concentration of superplasticizer was established (0.3 wt. %). It was determined that sodium sulfate helps to improve the strength of CM, and the addition of sodium tetraborate and citric acid can effectively regulate the setting time

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The effect of water binder ratio on strength development of class C fly ash geopolymer mortar prepared by dry geopolymer powder

MATEC Web of Conferences ◽

10.1051/matecconf/201925805032 ◽

2019 ◽

Vol 258 ◽

pp. 05032 ◽

Cited By ~ 1

Author(s):

Arie Wardhono

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Calcium Content ◽

Strength Properties ◽

Strength Development ◽

Effect Of Water ◽

High Calcium ◽

Binder Ratio ◽

Geopolymer Binder ◽

Water Binder Ratio

The use of geopolymer binder as cement replacement material can reduce the amount of carbon dioxide gas produced during the Portland Cement manufacturing process. However, the main issue of geopolymer binder is in the mixing process of sodium silicate and NaOH which requires specialized knowledge and strict supervision. This paper reports the effect of water binder ratio on strength development of fly ash geopolymer mortar using dry geopolymer powder. Fly ash with high calcium content was used as primary material. The dry geopolymer powder was prepared by wet mixing method which was made by drying a mixture of NaOH solution and limestone for 24 hours. The variations of water to binder ratio were 0.30, 0.35, 0.40, 0.45, and 0.50. Strength properties were measured by compressive strength at the age of 7, 14 and 28 days. The results showed that the water binder ratio significantly affect the strength development of geopolymer mortar prepared by dry geopolymer powder. The water binder ratio of 0.40 gives the highest compressive strength of 10.3 MPa at 28 days. This suggests that the use of dry geopolymer powder on geopolymer mortar production can overcome the difficulties of geopolymer mortar mixing on site.

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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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The Effect on Cement Mortar and Concrete by Admixture of Spray Drying Absorption Products

MRS Proceedings ◽

10.1557/proc-178-267 ◽

1989 ◽

Vol 178 ◽

Author(s):

Kirsten G. Jeppesen

Keyword(s):

Grain Size ◽

Fly Ash ◽

Cement Mortar ◽

Setting Time ◽

Mineralogical Composition ◽

Cement Clinker ◽

Strength Development ◽

Fall Meeting ◽

Freeze Thaw ◽

Spray Dried

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported

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Hydration and strength development of binder based on high-calcium oil shale fly ash

Cement and Concrete Research ◽

10.1016/s0008-8846(99)00139-8 ◽

1999 ◽

Vol 29 (11) ◽

pp. 1713-1719 ◽

Cited By ~ 6

Author(s):

C Freidin

Keyword(s):

Fly Ash ◽

Oil Shale ◽

Strength Development ◽

High Calcium

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Influence of Particle Size Distribution of High Calcium Fly Ash on HVFA Mortar Properties

Civil Engineering Dimension ◽

10.9744/ced.20.2.51-56 ◽

2018 ◽

Vol 20 (2) ◽

pp. 51

Author(s):

Antoni . ◽

Hendra Surya Wibawa ◽

Djwantoro Hardjito

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Fly Ash ◽

Particle Size Distribution ◽

Size Distribution ◽

Setting Time ◽

High Volume ◽

High Volume Fly Ash ◽

High Calcium ◽

High Calcium Fly Ash

This study evaluates the effect of particle size distribution (PSD) of high calcium fly ash on high volume fly ash (HVFA) mortar characteristics. Four PSD variations of high calcium fly ash used were: unclassified fly ash and fly ash passing sieve No. 200, No. 325 and No. 400, respectively. The fly ash replacement ratio of the cementitious material ranged between 50-70%. The results show that with smaller fly ash particles size and higher levels of fly ash replacement, the workability of the mixture was increased with longer setting time. There was an increase in mortar compressive strength with finer fly ash particle size, compared to those with unclassified ones, with the highest strength was found at those with fly ash passing mesh No. 325. The increase was found due to better compactability of the mixture. Higher fly ash replacement reduced the mortar’s compressive strength, however, the rate was reduced when finer fly ash particles was used.

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