Development of greener alkali-activated cement: utilisation of sodium carbonate for activating slag and fly ash mixtures

Abdalqader, Ahmed; Jin, Fei; Al‐Tabbaa, Abir

doi:10.1016/j.jclepro.2015.12.010

Cited by 335 publications

(103 citation statements)

References 51 publications

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“…Figure 6 presents the TG-DTG results of mixtures at the curing ages of 7, 28 and 180 days, and all samples [23]. It should be noted that there are several other small separate peaks shown in the low temperature range of 20-200°C, while in the previous researches only one broad peak centred at around 105°C is shown [23,42]. Considering the XRD results, these peaks can potentially be attributed to the dehydration of sodium carbonate salts.…”

Section: Xrdmentioning

confidence: 88%

“…The sharp peak at around 946 cm -1 is generally observed for sodium carbonate activated slags of the generated C-(A)-S-H [25,42], while for the waterglass activated slags the position of this peak shifts to a higher wavenumber between 950 and 1000 cm -1 [52][53][54], pointing to a different chemical proportion (Si/Ca ratio) [51,55,56]. Nevertheless, the LP incorporation does not affect the peak position, indicating that the gel structure of C-(A)-S-H remains the same regardless of the LP dosages.…”

Section: Ft-irmentioning

confidence: 93%

“…providing extra specific surface area acting as nuclei sites. Abdalqader et al [42] characterized the mixtures of sodium carbonate activated slag-fly ash blenders, and found that the effect of fly ash on the strength development at the early ages is not prominent. Gao et al [18] studied the properties of alkali activated slag-fly ash blends with limestone addition using waterglass as activators, and found that increasing the LP content with a constant slag content leads to a slightly better strength development.…”

Section: Compressive Strengthmentioning

confidence: 99%

See 2 more Smart Citations

Assessing the chemical involvement of limestone powder in sodium carbonate activated slag

Yuan

Brouwers

2017

Mater Struct

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This study aims to investigate the effect of limestone powder (LP) on the reaction of sodium carbonate activated slag. The results show that the incorporated LP up to 30% improves the strength development, especially at advanced curing ages. A slightly accelerated reaction is observed for samples containing low amount of LP (B5%), while mixture with 10% LP shows the optimized results with respect to the heat release and strength development. Chemical effect of incorporating LP is observed at high replacement levels (C15%), indicated by the formation of a new phase, natron (Na 2 CO 3 Á10H 2 O). Besides, relatively high contents of hydrotalcite-like phases are generated when increasing the dosage of limestone powder. The chemical changes, including the volume changes of generating natron and the transformation of natron to calcite, is potentially responsible for the enhanced mechanical properties.

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Section: Xrdmentioning

confidence: 88%

Section: Ft-irmentioning

confidence: 93%

Section: Compressive Strengthmentioning

confidence: 99%

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Assessing the chemical involvement of limestone powder in sodium carbonate activated slag

Yuan

Brouwers

2017

Mater Struct

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“…The gels, not significantly affected by exposure to elevated temperatures, also protect the materials from acid corrosion [6,7]. The utilization of industrial by-products to produce alkali-activated cement decreases the negative impacts on environment [8]. Slag and fly ash are the industrial by-products most frequently used to manufacture AAC.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Effects of Starches on the Properties of Alkali-Activated Cement and the Potential of Starch as a Self-Degradable Additive

Tan¹,

Zheng²,

Ma³

et al. 2017

Energies

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An urgent problem of geothermal energy source development is how to cut down the production costs. The use of temporary sealing materials can reduce the costs associated with the circulation lost by plugging, and increase the production by self-degradation. Based on the utilization of starches as self-degradable additives in the medical field, this paper investigated the effects of three kinds of starches, namely corn starch (CS), hydroxypropyl starch (HPS) and carboxymethyl starch (CMS) on the properties of alkali-activated cement (AAC). In addition, the thermal properties of starch, the compressive strength and microstructures of the cement with starch were tested, to evaluate the potentiality of starch as self-degradable additive for geothermal cement. The analysis showed that: (1) all the starches have the effect of increasing the apparent viscosity, prolonging the setting time and reducing the static fluid loss of alkali-activated cement; (2) the addition of starch increased the number of pores in 200 • C-heated cement, facilitated the leaching process, and thus promoted the self-degradation; and (3) among the three starches, CMS has the most potential as a self-degradable additive.

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“…Heath et al (2014) believe that the use of multiple initial aluminosilicate sources and complex mix design of alkali-activated materials has the potential to reduce the global warming effect compared to Portland cement. Alkaliactivated cements utilize different raw materials including fly ashes (Torres-Carrasco and Puertas, 2015), slags (Abdalqader et al, 2015), kaolin (Longhi et al, 2015), rice husk ash and different soils (He et al, 2013;Mejía et al, 2016;Nimwinya et al, 2016). Alkali-activated cements based on fly ash probably have the greatest opportunity for commercial utilisation due to the worldwide presence of coal-fired power plants, as well as the more favourable rheological properties and lower water demand when compared to mixes based on calcined clays (van Deventer et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Direct electric curing of alkali-activated fly ash concretes: a tool for wider utilization of fly ashes

Kovtun

Shekhovtsova

Kearsley

2016

Journal of Cleaner Production

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Utilization of the fly ashes is a major problem in many developing countries and in South Africa only about 7% of the fly ash produced annually by coal-fired power stations, has being utilized. Although, fly ashes can be used as an alternative binder in alkali-activated concretes, strength development of these concretes at room temperature is slow limiting application of the material. Direct electric curing is proposed for heat curing of alkali-activated fly ash concrete which will open new opportunities for in-situ applications of these concretes in the construction industry thus increasing the amount of beneficially utilized fly ash. Alkaliactivated fly ash concretes containing unclassified low calcium fly ash, sodium hydroxide and sodium silicate solutions were cured at 60 ºC by means of direct electric curing. The electric resistivity and compressive strength development of the concretes were investigated. The resistivity strongly depends on the type of activator used. Compressive strength up to 33.8 MPa and 48.5 MPa at 2 and 28 days respectively, can be achieved after a short period of 2 direct electric curing. This opens new opportunities for wider application of alkali-activated fly ash concretes and for more extensive utilization of fly ash.

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Development of greener alkali-activated cement: utilisation of sodium carbonate for activating slag and fly ash mixtures

Cited by 335 publications

References 51 publications

Assessing the chemical involvement of limestone powder in sodium carbonate activated slag

Assessing the chemical involvement of limestone powder in sodium carbonate activated slag

A Study on the Effects of Starches on the Properties of Alkali-Activated Cement and the Potential of Starch as a Self-Degradable Additive

Direct electric curing of alkali-activated fly ash concretes: a tool for wider utilization of fly ashes

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