Expansion behavior and microstructure change of alkali-activated slag grouting material in sulfate environment

Liu, Leping; Xie, Maojia; He, Yan; Li, Yuanyuan; Huang, Xiaoqing; Cui, Xuemin; Shi, Caijun

doi:10.1016/j.conbuildmat.2020.119909

Cited by 22 publications

(9 citation statements)

References 41 publications

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“…It is noted that being independent of Al 2 O 3 content and type of alkaline activator, sulfate‐intercalated hydrotalcite is not predicted to form despite the presence of hydroxylated hydrotalcite. This, from the viewpoint of thermodynamics, further confirms the experimental observation that sodium sulfate attack on alkali‐activated slag cement does not result in the formation of sulfate‐intercalated hydrotalcite 15,16 . The factor γ , compared to the solid phase volume before sulfate salt attack as shown in Figure 8A, varies with Al 2 O 3 content of slag, but within the ranges of 5.01%–8.32% for sodium hydroxide–activated slag cement and 6.64%–14.49% for sodium silicate–activated slag cement.…”

Section: Resultssupporting

confidence: 84%

“…19 These experimental observations confirm the thermodynamic modeling results in this study. It is noted that in many other experimental studies, [14][15][16][17]20 however, ettringite and monosulfate were absent in alkali-activated slag cement after sodium sulfate attack. In those experimental studies, the concentration of sodium sulfate solution used for sulfate attack was mostly around 5%, approximately corresponding to a 1.4-g addition of SO 4…”

Section: F I G U R Ementioning

confidence: 83%

“…thermodynamics, further confirms the experimental observation that sodium sulfate attack on alkali-activated slag cement does not result in the formation of sulfateintercalated hydrotalcite. 15,16 The factor γ, compared to the solid phase volume before sulfate salt attack as shown in Figure 8A, varies with Al 2 O 3 content of slag, but within the ranges of 5.01%-8.32% for sodium hydroxide-activated slag cement and 6.64%-14.49% for sodium silicate-activated slag cement. This suggests that slag chemistry exhibits a larger effect on the solid phase expansion of sodium silicate-activated slag cement while upon sodium sulfate attack.…”

Section: The Effect Of Slag Chemistrymentioning

confidence: 99%

“…13,14 Komljenović et al 15 studied the effects of sulfate attack on mechanical and microstructural properties of alkaliactivated slag cement and reported significantly higher resistance to sodium sulfate attack for alkali-activated slag cement than for benchmark PC. By examining the linear expansion, mass change, mechanical properties, and microstructure of alkali-activated slag cement after immersion in sodium sulfate solutions, Liu et al 16 also found good anti-sulfate corrosion performance of alkali-activated slag cement. Regarding magnesium sulfate attack, an agreement has been reached that it caused a severer degradation of alkali-activated slag cement than sodium sulfate attack.…”

Section: Introductionmentioning

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: Resultssupporting

confidence: 84%

Section: F I G U R Ementioning

confidence: 83%

Section: The Effect Of Slag Chemistrymentioning

confidence: 99%

Section: Introductionmentioning

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 stability of the grouting materials is essential for the security of water‐rich engineering, among which ions erosion and dry–wet cycles are the vital elements governing the strength of the grouting materials 1,2 . The damage of engineering materials exposed to sulfate under dry–wet cycles is a complex problem that has been the focus of more and more scholars.…”

Section: Introductionmentioning

confidence: 99%

Stratified damage characteristics of high‐water quick‐setting material exposed to sulfate under dry–wet cycles

Zhou

Chen

Kang

et al. 2022

Int J Applied Ceramic Tech

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The stability of the grouting material under the coupling effect of sulfate attack and dry–wet cycles is essential to engineering safety. As a novel grouting material, the stability research of high‐water quick‐setting material (HWQSM) under different corrosive environments is in the initial stage. Moreover, the stratified damage characteristics (SDC) of HWQSM under sulfate attack were not fully explored. To this end, the strength degradation and SDC of HWQSM exposed to three kinds of sulfate solutions (i.e., 10% MgSO4 solution, 10% Na2SO4 solution, and hybrid solution of 5% Na2SO4 and 5% MgSO4) and dry–wet cycles were analyzed by using ETM‐C mechanical testing machine, scanning electron microscopy (SEM), XRD, and AFM. The results show that the strength reduction rate, the thickness of the corrosion layer, and roughness between the corrosion layer and the transition layer of HWQSM are all positively correlated with the concentration of Mg2+ in the erosion solution for the increase in dry–wet cycles. Under the combined action of ion erosion and carbonization, the pores and cracks of the corrosion layer expand, which would reduce the permeability resistance but increase the erosion damage rate. This research furnishes new views into the SDC of HWQSM under sulfate attack and dry–wet cycles, which would deeper our understanding to this special material undoubtedly; the research results are expected to furnish theoretical guidance of HWQSM resistance to different sulfate solutions.

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A review on corrosion of cement-based materials in CO2-rich karst groundwater

Zhang,

Liu,

Liu

et al. 2024

Cement and Concrete Composites

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Expansion behavior and microstructure change of alkali-activated slag grouting material in sulfate environment

Cited by 22 publications

References 41 publications

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

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

Stratified damage characteristics of high‐water quick‐setting material exposed to sulfate under dry–wet cycles

A review on corrosion of cement-based materials in CO2-rich karst groundwater

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