Influence of the chemical and mineralogical composition on the reactivity of volcanic ashes during alkali activation

Lemougna, Patrick N.; Melo, U. F. Chinje; Delplancke, Marie-Paule; Rahier, Hubert

doi:10.1016/j.ceramint.2013.06.072

Cited by 99 publications

(48 citation statements)

References 25 publications

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“…Thus, this phenomenon contributes to the formation of more stable and stronger structures compared with simple systems as a result of the simultaneous formation of the geopolymeric network and C-S-H gel. This finding correlates with the highest mechanical strengths that have been attained by binary blends (8,(25)(26)(27)(28). The setting times of the different geopolymer samples, which are considered an indicator of the kinetics of the geopolymerisation reactions (23), are shown in Table 5, which shows evidence that the incorporation of GBFS and its proportion in binary systems (NP+GBFS) reduces the initial and final setting times of the simple system (NP).…”

Section: Geopolymerisation Kineticsmentioning

confidence: 65%

“…Lemougna et al (8), Tchakoute et al (9), Bondar et al (10), and Kani and Allahverdi (11), among others, have used volcanic pozzolans from different sources as precursors in the production of geopolymer cements with satisfactory results. Tchakoute et al (9) report compressive strength of up to 50 MPa after 28 days of curing at ambient temperature for a volcanic pozzolan from Cameroon.…”

Section: Introductionmentioning

confidence: 99%

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Natural pozzolan-and granulated blast furnace slag-based binary geopolymers

Robayo¹,

Gutiérrez²,

Gordillo³

2016

Mater. construcc.

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This study describes the synthesis at ambient temperature (25±3 °C) of binary geopolymer systems based on natural volcanic pozzolan and granulated blast furnace slag. Na 2 SiO 3 and NaOH were used as alkaline activators. The effects of the SiO 2 /Al 2 O 3 , Na 2 O/Al 2 O 3 ratio and the amount of slag added (from 0 to 30%) on the reaction kinetics, compressive strength and microstructure of the final product were studied. To characterise the geopolymer pastes, techniques such as X-ray diffraction (XRD), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used. The results indicate the possibility of obtaining a geopolymer cement with a compressive strength of up to 48.11 MPa after 28 days of curing at ambient temperature whose characteristics are comparable to those of commercial portland cement. RESUMEN: Geopolímeros de tipo binario basados en una puzolana natural y escoria siderúrgica de alto horno.Este trabajo describe la síntesis a temperatura ambiente (25±3 °C) de sistemas geopoliméricos de tipo binario basados en una puzolana natural de origen volcánico y escoria siderúrgica de alto horno usando activadores alcalinos basados en la combinación de Na 2 SiO 3 y NaOH. Se estudió el efecto de la relación SiO 2 /Al 2 O 3 , Na 2 O/ Al 2 O 3 y la cantidad de escoria adicionada en niveles entre el 0 y 30% sobre la cinética de reacción, la resistencia a la compresión y la microestructura del producto final. Para la caracterización de las pastas geopoliméricas se utilizaron técnicas como difracción de rayos X (DRX), espectroscopia infrarroja (FTIR) y microscopia electró-nica de barrido (MEB). Los resultados conseguidos revelan la posibilidad de obtener un cementante geopolimérico con una resistencia a la compresión de hasta 48,11 MPa a los 28 días de curado a temperatura ambiente cuyas características son comparables a las de un cemento portland comercial.

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Section: Geopolymerisation Kineticsmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Natural pozzolan-and granulated blast furnace slag-based binary geopolymers

Robayo¹,

Gutiérrez²,

Gordillo³

2016

Mater. construcc.

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“…The literature shows that different researchers used moulds of various sizes made from different materials to produce samples of alkali-activated pastes and mortars (Bakharev, 2005;Chindaprasirt et al, 2009;Criado et al, 2012;Duxson et al, 2007;Ghosh and Ghosh, 2012;Görhan and Kürklü, 2014;Lemougna et al, 2014;Somna et al, 2011). In the work reported here, the effect of mould size and material on temperature development in the core of alkali-activated fly ash cement paste samples was investigated.…”

Section: Introductionmentioning

confidence: 99%

Temperature rise and initial shrinkage of alkali-activated fly ash cement pastes

Shekhovtsova¹,

Kovtun²,

Kearsley³

2015

Advances in Cement Research

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This paper reports on core temperature development and initial shrinkage of fly ash cement pastes activated with sodium hydroxide solution at different concentrations during elevated-temperature curing at 60°C. The results indicate that a high sodium hydroxide concentration might result in a substantial rise in the core temperature of samples, dependent on the mould size and ratio of paste to oven volume. An increase in alkali concentration was also found to increase the initial shrinkage of the pastes during elevated-temperature curing. Excessive initial shrinkage and temperature increase might lead to the appearance of internal stresses in the pastes, which can affect the material performance. mass of mould with sample after elevatedtemperature curing (g) m m mass of empty mould (g) T p peak temperature (°C) t p time of appearance of peak temperature after the start of elevated-temperature curing (min) Notation

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“…The incorporation of inorganic fillers in polymers is a widely used practice in industry to obtain new plastics with better properties at relatively low cost [3]. Volcanic ashes (VA) are vitreous pyroclastic materials produced by violent eruptive volcanic action [4]. VA, known as mesoporous material, usually has high specific surface area, significant porosity, and an appropriate pore structure, which enhances their ability to control the humidity in the environment.…”

Section: Introductionmentioning

confidence: 99%

Surface Modification Effect of Volcanic Ash Particles Using Silane Coupling Agent on Mechanical Properties of Polyphenylene Sulfide Composites

et al. 2016

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The surface treatment of volcanic ash particles with various concentrations (1-3-5% (v/v)) silane coupling agent (3-aminopropyltriethoxysilane (3-APTS)) having organic functional group was conducted. After surface treatment, polyphenylene sulfide (PPS) composite samples containing surface treated volcanic ash particles at two concentrations (10 and 15 wt%) were manufactured by twin screw extruder and injection molding machine. This study investigated the effect of surface modification on mechanical properties of two different concentrated volcanic ash/PPS composites. All tests were performed using a Shimadzu AG-X Universal Tester. Tensile and three point bending tests were carried out at a crosshead speed of 1 mm/min and 2 mm/min according to ISO 527-2 and ASTM D790 standards, respectively. During the experiments, the relation between the mechanical properties and surface treatment concentrations of silane agent on volcanic ash/PPS composites was determined as a function of tensile strength and modulus, flexural strength and modulus. Moreover, fracture surface morphologies of volcanic ash/PPS composite samples were observed by using a scanning electron microscopy.

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Influence of the chemical and mineralogical composition on the reactivity of volcanic ashes during alkali activation

Cited by 99 publications

References 25 publications

Natural pozzolan-and granulated blast furnace slag-based binary geopolymers

Natural pozzolan-and granulated blast furnace slag-based binary geopolymers

Temperature rise and initial shrinkage of alkali-activated fly ash cement pastes

Surface Modification Effect of Volcanic Ash Particles Using Silane Coupling Agent on Mechanical Properties of Polyphenylene Sulfide Composites

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