Effect of heat treatment on reactivity-strength of alkali-activated natural pozzolans

Bondar, Dali; Lynsdale, C.J.; Milestone, Neil B.; Hassani, N.; Ramezanianpour, Ali Akbar

doi:10.1016/j.conbuildmat.2011.04.044

Cited by 69 publications

(36 citation statements)

References 11 publications

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“…The compressive strength of geopolymers with Na 2 SiO 3 /NaOH ratios of 2 and 3 exhibits nearly the same behavior except for the 7 days curing. These geopolymers have good mechanical strengths, which is able to fulfil the strength requirement of typical construction materials for performance applications (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40). The maximum compressive strength (42 MPa) was obtained for geopolymer cured at 50°C for 56 days with a Na 2 SiO 3 /NaOH ratio of 2.…”

Section: Characteristics Of Zeolite Bearing Tuffsmentioning

confidence: 88%

“…However, the studies on the synthesis of geopolymer by the alkali-activation of natural zeolites are limited [31,32]. The majority of published papers on natural zeolite-based geopolymers have focused on the effect of variables.…”

Section: Introductionmentioning

confidence: 99%

“…The majority of published papers on natural zeolite-based geopolymers have focused on the effect of variables. In general the methods of analysis have been limited to investigation of compressive strength analysis [32,33,34]. Meantime, microstructural characteristics of resulting products has been less intensely examined [31].…”

Section: Introductionmentioning

confidence: 99%

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Compressive Strength and Microstructural Characteristics of Natural Zeolite-based Geopolymer

Özen

Alam

2017

Period. Polytech. Civil Eng.

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IntroductionThe manufacturing of Portland cement causes CO 2 emission through the calcination of the raw materials during clinker production. One ton of Portland cement production results in the release of approximately one ton of CO 2 emissions into the atmosphere. Global CO 2 emission from cement production is now 5-8% and it is estimated to be about 17% in a few years due to the fast growing industry [1]. The development of new binding materials with low CO 2 impact is essential for future global warming solutions since many scientists predict that level of CO 2 in the atmosphere already go beyond the safe limit [2].Blended cements obtained by mixing Portland cement with mineral admixtures are widely used in building industry in order to reduce the use of Portland cement. The use of such materials may lead not only to a significant reduction in CO 2 emission but also to an improvement in workability and sulphate resistance, low-cost, reduced energy consumption, lower heat of hydration, enhanced long-term mechanical strength and so on [3][4][5][6][7][8][9][10][11]. Nevertheless, there are some disadvantage of using blended cement. The main one in general is that they have an early strength development lower than Portland cement [4,12,13]. Besides, only a portion of the cement in concrete is replaced by supplementary cementing materials.Nowadays, new binding material seen as an alternative to Portland cement is being developed. This new technology could release 80-90% less CO 2 emission related to the manufacturing of cement, while at the same time it provides high early strength, freeze-thaw resistance, corrosion resistance and suphate resistance [14,15] [21], they all designate the same mechanism, which involves an alkali activation of natural or artificial aluminosilicate materials such as fly ash [22,23,24,25], blast furnace slag [26,27], kaoline [28] and natural pozzolans [29,30].

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Section: Characteristics Of Zeolite Bearing Tuffsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Compressive Strength and Microstructural Characteristics of Natural Zeolite-based Geopolymer

Özen

Alam

2017

Period. Polytech. Civil Eng.

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“…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%

“…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. However, other researchers have noted the need for thermal curing treatments or the addition of secondary CaO and Al 2 O 3 sources such as granulated blast furnace slag (GBFS) and metakaolin (MK) to achieve good mechanical performance in a short amount of time due to the semi-crystalline nature and the deficiencies in the reactivity of CaO and Al 2 O 3 in these materials (10,(12)(13)(14). According to Rodríguez et al (15) and Li et al (16), the addition of GBFS as a source of Ca 2+ cations allows the curing and hardening of alkaline activation blends at ambient temperature, which contributes to the formation of calcium silicate hydrate gels (C-S-H) and hydrated calcium silicoaluminates (C-A-S-H) (6,17).…”

Section: Introductionmentioning

confidence: 99%

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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Investigation of sulfates effects in perlite‐based geopolymer

Mohabbi

2019

Structural Concrete

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Condition deterioration of the concrete, especially in corrosive environments, is one of the most common imperfection and disadvantages of reinforced concrete structures. Sulfates' main damages are expansion and loss of strength. Geopolymers are one of the newest structural materials that have been widely developed in recent years for use in sustainable designs. Geopolymers are environmentally friendly and considered as green materials since they are effective in sustainable and eco‐friendly material design concept. One of the most important matters in the sustainability of structural materials is their resistance against sulfates. So far, the durability of perlite‐based geopolymers against sulfates and acids has not been investigated. In this research, the fineness influence, curing conditions, duration of maintaining in the sulfate environment at different weight percentage in solution (i.e., 2.5, 5, 7.5, and 10%) have been investigated. Compressive strength and microstructure changes of geopolymer samples have been assessed in this research. As a result, optimum increase in perlite fineness causes increase in compressive strength and durability of samples against sulfate attack. Also, samples that have been cured by autoclave method have better mechanical properties and better durability. It is hoped that by filling these deficiencies and gaps, a positive step can be taken to accelerate attempts for finding a suitable replacement for ordinary Portland cement.

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Effect of heat treatment on reactivity-strength of alkali-activated natural pozzolans

Cited by 69 publications

References 11 publications

Compressive Strength and Microstructural Characteristics of Natural Zeolite-based Geopolymer

Compressive Strength and Microstructural Characteristics of Natural Zeolite-based Geopolymer

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

Investigation of sulfates effects in perlite‐based geopolymer

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