Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure

Efflorescence is an inevitable phenomenon in all cementitious materials, particularly for Portland cement (PC) - based materials. Considering the relations between ion availability and crystallization, the factors influencing efflorescence involve the compositions of binders, pore structure of the h...

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Main Authors: Zhenghong Yang, Nannan Xue, Linglin Xu, Long Yu, Liming Huang, Kai Wu
Format: Article
Language:English
Published: Elsevier 2023-01-01
Series:Journal of Materials Research and Technology
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2238785422019512
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author Zhenghong Yang
Nannan Xue
Linglin Xu
Long Yu
Liming Huang
Kai Wu
author_facet Zhenghong Yang
Nannan Xue
Linglin Xu
Long Yu
Liming Huang
Kai Wu
author_sort Zhenghong Yang
collection DOAJ
description Efflorescence is an inevitable phenomenon in all cementitious materials, particularly for Portland cement (PC) - based materials. Considering the relations between ion availability and crystallization, the factors influencing efflorescence involve the compositions of binders, pore structure of the hardened matrix, and so on. This study investigated the efflorescence of calcium sulfoaluminate cement (SAC) mortar at 5–40 °C from perspectives of carbonation potential and pore structure, while PC mortar was chosen as a reference. The microstructure of the efflorescence substances, such as phase assemblage and distribution, was systematically unraveled using optical microscope, in-situ Raman spectroscopy, SEM and EDS at multi scale-level. Water absorption test and XCT were employed for the pore structure characterization. Additionally, an outdoor exposure was carried out to compare with the results from the indoor accelerated experiments. Results reveal that a lower temperature has a limited effect on the efflorescence potential. The dominant efflorescence ingredient for SAC and PC mortars cured at 5–40 °C is CaCO3, with varied polymorphs. However, both primary and secondary efflorescence of SAC mortar is much slighter than that of PC mortar. The volume of fine pores (less than 0.1 mm3) in SAC mortar is higher than that of PC, accompanied by higher capillary absorption coefficient and water absorption rate. However, the low carbonation potential of ettringite tends to be more effective in reducing efflorescence risk for SAC mortar in both lab tests and outdoor exposure. The understanding of the relationship between efflorescence and carbonation provides important insights into the inhibition of efflorescence in cementitious materials.
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spelling doaj.art-2e3d6b33ed5c4e43b21d7c6faf1fbd072023-01-26T04:46:13ZengElsevierJournal of Materials Research and Technology2238-78542023-01-012224472461Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposureZhenghong Yang0Nannan Xue1Linglin Xu2Long Yu3Liming Huang4Kai Wu5Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, ChinaKey Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, ChinaCorresponding author.; Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, ChinaKey Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, ChinaKey Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, ChinaKey Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 201804, ChinaEfflorescence is an inevitable phenomenon in all cementitious materials, particularly for Portland cement (PC) - based materials. Considering the relations between ion availability and crystallization, the factors influencing efflorescence involve the compositions of binders, pore structure of the hardened matrix, and so on. This study investigated the efflorescence of calcium sulfoaluminate cement (SAC) mortar at 5–40 °C from perspectives of carbonation potential and pore structure, while PC mortar was chosen as a reference. The microstructure of the efflorescence substances, such as phase assemblage and distribution, was systematically unraveled using optical microscope, in-situ Raman spectroscopy, SEM and EDS at multi scale-level. Water absorption test and XCT were employed for the pore structure characterization. Additionally, an outdoor exposure was carried out to compare with the results from the indoor accelerated experiments. Results reveal that a lower temperature has a limited effect on the efflorescence potential. The dominant efflorescence ingredient for SAC and PC mortars cured at 5–40 °C is CaCO3, with varied polymorphs. However, both primary and secondary efflorescence of SAC mortar is much slighter than that of PC mortar. The volume of fine pores (less than 0.1 mm3) in SAC mortar is higher than that of PC, accompanied by higher capillary absorption coefficient and water absorption rate. However, the low carbonation potential of ettringite tends to be more effective in reducing efflorescence risk for SAC mortar in both lab tests and outdoor exposure. The understanding of the relationship between efflorescence and carbonation provides important insights into the inhibition of efflorescence in cementitious materials.http://www.sciencedirect.com/science/article/pii/S2238785422019512EfflorescenceCalcium sulfoaluminate cement (SAC)Outdoor exposureCarbonationPore structure
spellingShingle Zhenghong Yang
Nannan Xue
Linglin Xu
Long Yu
Liming Huang
Kai Wu
Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure
Journal of Materials Research and Technology
Efflorescence
Calcium sulfoaluminate cement (SAC)
Outdoor exposure
Carbonation
Pore structure
title Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure
title_full Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure
title_fullStr Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure
title_full_unstemmed Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure
title_short Evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar: from indoor accelerated testing to outdoor exposure
title_sort evaluation of the efflorescence resistance of calcium sulfoaluminate cement mortar from indoor accelerated testing to outdoor exposure
topic Efflorescence
Calcium sulfoaluminate cement (SAC)
Outdoor exposure
Carbonation
Pore structure
url http://www.sciencedirect.com/science/article/pii/S2238785422019512
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