Interfacial Transition Zone of Alkali-Activated Slag Concrete

Ji, Tao; Gao, Qiaoling; Zheng, Wenyuan; Lin, Xian; Wu, Hejun

doi:10.14359/51689473

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…However, the ITZ formed in alkali-activated concrete has totally different features compared to that in PC concrete [20,21]. A few studies have discussed the microstructure and properties of ITZ in alkali-activated fly ash (AAF) concrete and alkali-activated slag (AAS) concrete [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

The evolution of interfacial transition zone in alkali-activated fly ash-slag concrete

Fang

Zhang

2020

Cement and Concrete Research

109

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This paper investigates the mechanisms of microstructure evolution of interfacial transition zone (ITZ) in alkali-activated fly ash-slag (AAFS) concrete using scanning electron microscope. Results indicate that the formation of original ITZ depends on the so-called "wall effect", leading to a deficit of large grains and a higher effective alkaline activator/precursor ratio compared to paste matrix. The alkaline reaction process is correspondingly accelerated, which promotes the formation of low Ca C-(N)-AS -H gels and reduces the porosity in the ITZ. Afterwards, the high Ca C-(N)-AS -H gels are generated due to the release of more Ca from slag, resulting in the continuous refinement of pores. The C-(N)-AS -H gels with rich Si and Al are then produced at 7 d, attributing to the species diffusion from paste matrix to ITZ. Consequently, a compact and dense microstructure is formed in the ITZ at 28 d, which would be beneficial to the long-term performance of concrete.

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Section: Introductionmentioning

confidence: 99%

The evolution of interfacial transition zone in alkali-activated fly ash-slag concrete

Fang

Zhang

2020

Cement and Concrete Research

109

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“…The ITZ in AAC seems to play an entirely different role in governing the macroscopic properties of AAC [25][26][27][28]. The ITZ in AAF concrete has comparable micromechanical properties to paste matrix, attributing to the dense microstructure formed in this region [21].…”

Section: Introductionmentioning

confidence: 99%

“…This is mainly because of the formation of N-A-S-H gels instead of the CH crystals formed in PC concrete, which would help to produce a strong bonding between aggregate and paste [25] and contribute to the improvement of mechanical properties of AAF concrete [26]. Additionally, AAS concrete activated by Na2SiO3 exhibits superior interfacial properties, in which ITZ has low porosity and high strength [27,[29][30][31].…”

Section: Introductionmentioning

confidence: 99%