Effect of chloride salt on the phase evolution in alkali-activated slag cements through thermodynamic modelling

Zuo, Yibing

doi:10.1016/j.apgeochem.2021.105169

Cited by 6 publications

(21 citation statements)

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“…It is known that the chemical composition of GGBFS differs from source to source as shown in Figure 1, where 68 different slags were summarized from 49 literature studies. The summarized data can be found in a previous publication 54 . As a baseline in this study, the chemical composition marked with cross‐circle symbols in Figure 1 was adopted to represent the slag for thermodynamic modeling.…”

Section: Methods and Model Descriptionmentioning

confidence: 99%

“…The summarized data can be found in a previous publication. 54 As a baseline in this study, the chemical composition marked with cross-circle symbols in Figure 1 was adopted to represent the slag for thermodynamic modeling. This adopted chemical composition is 40.6-wt% CaO, 35.4-wt% SiO 2 , 12.1-wt% Al 2 O 3 , 7.3-wt% MgO, 0.5-wt% K 2 O, 0.2-wt% Na 2 O, and 1.7-wt% SO 3 .…”

Section: Input Parametersmentioning

confidence: 99%

“…37 Similar to the chemical composition of slag, the density of slag also varies from source to source. According to a survey based on 20 different slags, 54 the density of the unreacted slag in thermodynamic modeling was taken as the median value of 2.9 g/cm 3 in this study. Sodium hydroxide (NaOH) and sodium silicate (Na 2 O⋅SiO 2 ) were used as alkaline activators in the activation of slag.…”

Section: Input Parametersmentioning

confidence: 99%

“…More details on the summarized data can be referred to a previous publication. 54 in alkali activator solution and then mixed with slag. In this situation, sulfate salt would probably react with an alkali activator and as a result the previously calculated mol/L is not any more the actual concentration of sulfate salt.…”

Section: Modeling the Effect Of Sulfate Salt Attackmentioning

confidence: 99%

“…It is known that sodium sulfate can be used as an alkali activator that increases solution alkalinity for F I G U R E 4 Simulated element concentrations in comparison with the experimental results at zero addition of sodium sulfate salt. The simulated data were obtained through thermodynamic modeling in this study and the experimental data were from the literature study 54 where the same mixtures with a similar chemical composition of slag were used.…”

Section: F I G U R Ementioning

confidence: 99%

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Thermodynamic modeling of the phase evolution in alkali‐activated slag cements with sulfate salt exposure

Zuo

2022

J Am Ceram Soc.

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The phase evolutions in sodium hydroxide and sodium silicate-activated slag cements upon sulfate salt attack were investigated via thermodynamic modeling.The effects of different sulfate salts (i.e., Na 2 SO 4 and MgSO 4 ) and slag compositions were studied. In thermodynamic modeling, a solid solution model, that is, MgAl-SO 4 -LDH_ss, was proposed to describe the sulfate-intercalated hydrotalcite. The modeling results were presented and discussed in comparison with experimental observations. Upon sulfate salt attack, ettringite, gypsum, sulfateintercalated hydrotalcite, magnesium silicate hydrate, and so on were predicted to form. By quantitatively evaluating the composition change of C-(N-)A-S-H gel, solid phase expansion, and alteration in pore solution chemistry, it was found that magnesium sulfate induced severer degradation of alkali-activated slag cements compared to sodium sulfate. Upon sulfate salt attack with a fixed sulfate concentration, the ideal outcome shows that the slag with lower Al 2 O 3 content not only gave a larger content of C-(N-)A-S-H gel but also caused the reduced decalcification and dealumination of C-(N-)A-S-H gel and solid phase expansion.

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Section: Methods and Model Descriptionmentioning

confidence: 99%

Section: Input Parametersmentioning

confidence: 99%

Section: Input Parametersmentioning

confidence: 99%

Section: Modeling the Effect Of Sulfate Salt Attackmentioning

confidence: 99%

Section: F I G U R Ementioning

confidence: 99%

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