Thermal properties of novel binary geopolymers based on metakaolin and alternative silica sources

Villaquirán-Caicedo, Mónica A.; Gutiérrez, Ruby Mejía de; Sulekar, Soumitra; Davis, Calvin; Nino, Juan C.

doi:10.1016/j.clay.2015.10.005

Cited by 89 publications

(36 citation statements)

References 30 publications

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“…The geopolymeric materials (GP) were prepared using the molar ratios SiO2/Al2O3 = 2.5 and K2O/SiO2 = 0.28 based on results from previous research [14]. A potassium hydroxide (KOH) analytical-grade reagent and commercial potassium silicate (K2SiO3) distributed by Pan American Chemicals (SiO2 = 26.38%, K2O = 13.06%, H2O = 60.56%) were dosed to obtain the activator solution module (Ms: SiO2/K2O = 0.76) required in the geopolymer mixture.…”

Section: Preparation Of Geopolymeric Mixturesmentioning

confidence: 99%

Metakaolin-Based Geopolymer with Added TiO2 Particles: Physicomechanical Characteristics

2017

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Abstract:The effect of the TiO 2 addition on the physicomechanical properties of a geopolymer system based on metakaolin (MK) and hydroxide and potassium silicate as activators is presented in this article. Three different liquid-solid systems (0.35, 0.40, and 0.45) and two titanium additions were investigated (5% and 10% of the cement content). The flowability, setting time, and mechanical strength of the geopolymer mixtures and their microstructural characteristics were evaluated using techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). It was concluded that a percentage of up to 10% TiO 2 does not affect the mechanical properties of the geopolymer, although it does reduce the fluidity and setting times of the mixture.

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Section: Preparation Of Geopolymeric Mixturesmentioning

confidence: 99%

Metakaolin-Based Geopolymer with Added TiO2 Particles: Physicomechanical Characteristics

2017

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“…The densities for KS and G matrix are similar regardless of the silica source used. Comparing the different silica sources (G and KS) the open porosity was found to be higher in G, this is due to the higher hydration energy associated with the smaller particles of RHA (9,57).…”

Section: Physical and Mechanical Propertiesmentioning

confidence: 89%

“…An onset of initial and rapid shrinkage occurs in region I. A high strain, between 2.2 to 3.2% shrinkage occurred for all samples up to 300 °C due to the capillary contraction created when free or weakly bound water evaporated from the micro-and nano-pores of the geopolymer (9,48). Consequently, pore solution is released from the gel causing the microstructure and nanostructure of the gel to rearrange (region II).…”

Section: Thermophysical Propertiesmentioning

confidence: 99%

“…The production of commercial silicate solutions (Na 2 SiO 3 ·nH 2 O and K 2 SiO 3 ·nH 2 O) involves a high energy demand (temperatures close to 1000 °C-1400 °C) and the emission of greenhouse gases (7,8). In recent years there has been great interest for the use of alternative sources of amorphous reactive silica for producing alkaline activators: rice husk ash (3,4,(9)(10)(11)(12)(13)(14)(15)(16)(17), silica fume (2,3,(18)(19)(20)(21) and waste glasses (1,(22)(23)(24)(25) have been used and have shown similar microstructure and mechanical performance to geopolymers produced with commercial soluble silicate solutions (3,9,18,26,27).…”

Section: Introductionmentioning

confidence: 99%

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A Novel MK-based Geopolymer Composite Activated with Rice Husk Ash and KOH: Performance at High Temperature

2017

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Geopolymers were produced using an environmentally friendly alkali activator (based on Rice Husk Ash and potassium hydroxide). Aluminosilicates particles, carbon and ceramic fibres were used as reinforcement materials. The effects of reinforcement materials on the flexural strength, linear-shrinkage, thermophysical properties and microstructure of the geopolymers at room and high temperature (1200 °C) were studied. The results indicated that the toughness of the composites is increased 110.4% for geopolymer reinforced by ceramic fibres (G-AF) at room temperature. The presence of particles improved the flexural behaviour 265% for geopolymer reinforced by carbon fibres and particles after exposure to 1200 ºC. Linear-shrinkage for geopolymer reinforced by ceramic fibres and particles and the geopolymer G-AF compared with reference sample (without fibres and particles) is improved by 27.88% and 7.88% respectively at 900 °C. The geopolymer materials developed in this work are porous materials with low thermal conductivity and good mechanical properties with potential thermal insulation applications for building applications.

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“…Heat resistant properties of alkali activated fly ash were investigated by several workers [10][11][12][13][14][15] and geopolymeric paste indicated high shrinkage as well as large changes in compressive strength at elevated temperature in the range 800-1200°C. To improve thermal resistance, alternate GSMs such as mine tailings, waste ceramics were tried and satisfactory thermo stable geopolymeric paste was obtained [16][17].…”

Section: Introductionmentioning

confidence: 99%

Fire Related Temperature Resistance of Fly Ash Based Geopolymer Mortar

et al. 2017

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Abstract. The study presented in this paper is on the effect of heat treatment on fly ash based geopolymer mortar synthesized from fly ash (Class F -Low lime) using alkaline binary activator solution containing sodium hydroxide (18 M) and sodium silicate solution (MR 2.0), cured at 80oC for 24 h. 7 days aged specimen heated at elevated temperature (200°C, 400°C, 600°C and 800°C) for the sustained period of 2hrs. The TGA/DTA analysis and thermal conductivity measurement as per ASTM C113 were carried out besides the compressive strengths. The thermal stability of the fly ash mortar at elevated temperature was found to be high as reflected in the observed value of f800°C/f30°C being more than 1 and this ratio was raised to about 1.3 with the addition of 2% Zirconium di oxide (ZrO 2 ). No visible cracks were found on the specimens with and without ZrO 2 when 800°C was sustained for 4 hrs in smaller specimens of size: 50 mm diameter x 100 mm height and in also bigger size specimens: 22 cm x 11 cm x 7 cm) specimens. TGA/DTA analysis of the geopolymer paste showed that the retention of mass was around 90%. The addition of ZrO2 improved thermal resistance. The micro structure of the matrix found to be intact even at elevated temperature that was evident from the FESEM studies.

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Thermal properties of novel binary geopolymers based on metakaolin and alternative silica sources

Cited by 89 publications

References 30 publications

Metakaolin-Based Geopolymer with Added TiO2 Particles: Physicomechanical Characteristics

Metakaolin-Based Geopolymer with Added TiO2 Particles: Physicomechanical Characteristics

A Novel MK-based Geopolymer Composite Activated with Rice Husk Ash and KOH: Performance at High Temperature

Fire Related Temperature Resistance of Fly Ash Based Geopolymer Mortar

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