A comparative study of two methods to produce geopolymer composites from volcanic scoria and the role of structural water contained in the volcanic scoria on its reactivity

Tchakouté, Hervé K.; Kong, Sakéo; Djobo, Jean Noël Yankwa; Tchadjié, Léonel N.; Njopwouo, D.

doi:10.1016/j.ceramint.2015.06.073

Cited by 61 publications

(15 citation statements)

References 21 publications

(33 reference statements)

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“…3(a)] and corresponding to the out-of-plane bending vibrations of the CO 3 2À group can be related to the reaction between excess of NaOH and atmospheric CO 2 . A similar reaction was observed by Tchakoute et al 32 during geopolymer synthesis from alkali fusion of VA. For alkaliactivated oyster shell-VA, this band (864 cm À1 ) might be due to the carbonation of free sodium ion and the presence of remaining oyster shell that has not reacted. This is supported by the presence of a band at 714 cm À1 [ Fig.…”

Section: ) Characterization Techniquessupporting

confidence: 81%

“…The bands observed at 1625–1644 and 3350–3480 cm −1 are characteristic of bending and stretching vibrations, respectively, of O–H bond of water molecules contained in alkali‐activated VA. The bands at 650–666 cm −1 and 750 cm −1 are attributed to the Si–O–Al IV stretching of tetrahedral network from aluminosilicate gel . The main difference on these figures are the bands at 714, 864, and 1400–1494 cm −1 corresponding to the presence of carbonate ions (CO 3 2− ).…”

Section: Resultsmentioning

confidence: 96%

“…The bands at 650-666 cm À1 and 750 cm À1 are attributed to the Si-O-Al IV stretching of tetrahedral network from aluminosilicate gel. 32 The main difference on these figures are the bands at 714, 864, and 1400-1494 cm À1 corresponding to the presence of carbonate ions (CO 3 2À ). The band at 864 cm À1 on reference samples [ Fig.…”

Section: ) Characterization Techniquesmentioning

confidence: 93%

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Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions

et al. 2016

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The gel composition and mechanical properties of alkali‐activated oyster shell‐volcanic ash were investigated at different NaOH concentrations (8, 12, and 15M) and curing temperatures (60°C and 80°C) in wet and dry conditions. XRD, FTIR, SEM‐EDS, and TGA‐DSC were used for microstructural characterization of the binder. The gel composition of the system was found to be influenced by NaOH concentration and was not affected when curing temperature was varied from 60°C to 80°C. The main phase was N,C–A–S–H for all alkali‐activated oyster shell‐volcanic ash, with C–S–H as secondary phase for some samples and contains high percentage of iron. The splitting at υ3 = 1400–1494 cm−1 on FTIR spectra corresponded to the elimination of the degeneracy due to the distortion of CO32− group. The high degree of splitting indicated that this carbonate group is linked to Ca2+. The compressive strength was influenced by curing temperature and the formation of a secondary phase. The compressive strength in dry condition increased roughly between 28 and 180 d for some samples, while in wet condition, the partial dissolution of Si–O–Si bonds of some silicate phases resulted in a reduction of strength.

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Section: ) Characterization Techniquessupporting

confidence: 81%

Section: Resultsmentioning

confidence: 96%

Section: ) Characterization Techniquesmentioning

confidence: 93%

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Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions

et al. 2016

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“…Both spectra exhibited the bond characteristic of the asymmetric stretching vibrations of Si-O-T (T = Si or Al) with peaks at around 1030 and 1161 cm −1 for VA and MSWI-FA, respectively [26,27]. The peaks center at 579 (VA) and 675 cm −1 (MSWI-FA) and correspond to Si-O bending vibration of quartz [28] and the peak at 472 cm −1 for VA represents the vibration of Si-O-Fe bond [29]. The characteristic bonds of silanol group and water molecules are situated at 3421 and 1643 cm −1 for VA and at 3436 cm −1 and 1621 cm −1 for MSWI-FA, respectively.…”

Section: Methodsmentioning

confidence: 99%

Characterization and Leachability Behaviour of Geopolymer Cement Synthesised from Municipal Solid Waste Incinerator Fly Ash and Volcanic Ash Blends

et al. 2018

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Municipal solid waste incinerator fly ash (MSWI-FA) was used synergistically with volcanic ash (VA) to synthesize Geopolymer cement. The effects of the incorporation of 0%, 30%, and 50% of VA and the alkalinity of activating solution on the structure and properties were studied by using the X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), field emission gun scanning electron microscopy (FEG-SEM), and mechanical testing. The encapsulation efficiency of the cements was carried out by using a toxicity characteristic leaching procedure (TCLP). The geopolymerization of MSWI-FA promoted the formation of new minerals such as Thernadite (Na 2 SO 4 ), Hydrocalumite (Ca 4 Al 2 O 6 (CO 3 ) 0.67 (SO 3 ) 0.33 ), C-S-H, and Faujasite-Na(Na 2 Ca) 0.075 (Al 0.3 Si 0.7 )O 2 (H 2 O) 0.22 . The Geopolymer cement synthesized with the addition of 50% of VA at 6M NaOH concentration, which exhibited the most compact microstructure. This was the highest strength with the best encapsulation ability. The microstructure analysis of the MSWI-FA-VA system revealed the coexistence of C-S-H and N-A-S-H phases as the main cementitious binders. The TCLP results of cement vis a vis raw MSWI-FA showed the leaching of metals reduced to a great extent. This was much lower than the permissible limit fixed by the United States Environmental Protection Agency (USEPA) for the toxicity characteristic. Furthermore, an attempt was made to correlate the microstructure with mechanical properties.Recycling 2018, 3, 50 2 of 14 of heavy metals content. Therefore, MSWI-FA is classified as a hazardous waste [3,4]. Owing to its chemistry, fine particle size, and pozzolanic behavior, MSWI-FA has the potential to be used as a mineral additive in cement. However, its high chlorine content restricts its application in construction material. Although the cement paste is not much affected by chloride except for increased solubilization of cement solids, chlorine is detrimental to the passivation of embedded steel [5]. To avoid this problem, some pre-treatment methods such as water washing and thermal treatment have been proposed [3,6,7]. These pre-treatments certainly eliminate the chlorides and inorganic salts in MSWI-FA but generate other wastes and increase the quantity of energy required for the synthesis and the total cost of the product. The efficient way to valorize MSWI-FA in construction is its use in the process, which displays limited signs of heavy metals leaching and the formation of the corrosion product in the presence of chlorine such as geopolymerization [8][9][10].Geopolymer cement are considered eco-friendly binder materials and potential alternative to Portland cement (OPC) in specific applications since they produce around 80% less CO 2 than Portland cement [11]. It has the potential to use alumina-silicate materials either from natural occurring waste, synthetic waste, or from industrial waste. Thus, varieties of alumina-silicate and industrial waste used for Geopolymer cement synthesis involve volcanic ash, glass powder,...

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“…Many previous works have reported the formation of geopolymer materials from calcined clays [9] [10], granulated blast furnace slag and fly ash as industrial by-products or wastes [11] [12], volcanic ashes [13] [14] [15], ground perlite [16], ground aplite rock [17], granite waste [18], Taftan and esite and Shahindej [19], alkali-feldspars [20] [21], a pumice-type natural pozzolan [22], basaltic ash [23].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Study of Alkali Activation of Basalt: Effect of NaOH Concentration on Geopolymerization of Basalt

Saraya¹,

El-Fadaly²

2017

MSCE

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The main objective of this study is to examine the possibility of using fresh basalt powder in the preparation of geopolymer pastes. Four NaOH concentrations of 2.5, 5, 7.5 and 10 M were used to alkali activation of basalt. In addition, effect of curing temperature at ambient, 45˚C and 65˚C were studied. The geopolymer pastes were investigated using FTIR, XRD and SEM-EDS techniques as well as compressive strength up to 90 days. The results were shown the compressive strength of prepared geopolymer increased with concentration of alkali activator up to 90 days. On the other hand, the compressive strength of prepared geopolymer pastes were improved with increased curing temperature. The results showed that there was a change in the chemical and mineral structure, due to the reaction of the sodium hydroxide with the different minerals of the basalt. In addition, the Na/Al and Si/Al ratios were completely different from that of the raw basalt. The geopolymerization reactions occurred at the surface basalt and the unreacted basalt particles actually play a supporting role in the geopolymer properties.

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A comparative study of two methods to produce geopolymer composites from volcanic scoria and the role of structural water contained in the volcanic scoria on its reactivity

Cited by 61 publications

References 21 publications

Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions

Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions

Characterization and Leachability Behaviour of Geopolymer Cement Synthesised from Municipal Solid Waste Incinerator Fly Ash and Volcanic Ash Blends

Preliminary Study of Alkali Activation of Basalt: Effect of NaOH Concentration on Geopolymerization of Basalt

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