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Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica

Tricalcium aluminate (C(3)A) is the most reactive component of the Portland cement and its hydration has an important impact on the workability and early strength of concrete. Recently, nanomaterials such as nano-silica (nano-SiO(2)) have attracted much attention in cement-based materials because of...

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Autores principales: Zheng, Dapeng, Monasterio, Manuel, Feng, Weipeng, Tang, Waiching, Cui, Hongzhi, Dong, Zhijun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830693/
https://www.ncbi.nlm.nih.gov/pubmed/33466793
http://dx.doi.org/10.3390/nano11010199
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author Zheng, Dapeng
Monasterio, Manuel
Feng, Weipeng
Tang, Waiching
Cui, Hongzhi
Dong, Zhijun
author_facet Zheng, Dapeng
Monasterio, Manuel
Feng, Weipeng
Tang, Waiching
Cui, Hongzhi
Dong, Zhijun
author_sort Zheng, Dapeng
collection PubMed
description Tricalcium aluminate (C(3)A) is the most reactive component of the Portland cement and its hydration has an important impact on the workability and early strength of concrete. Recently, nanomaterials such as nano-silica (nano-SiO(2)) have attracted much attention in cement-based materials because of its pozzolanic reactivity and the pore-filling effect. However, its influence on the hydration of C(3)A needs to be well understood. In this study, the hydration kinetics of C(3)A mixed with different percentages of nano-SiO(2) were studied and compared with pure C(3)A. The hydration products were examined by different characterization techniques including XRD, XPS, and NMR spectroscopy and isothermal calorimetry analyses. The XRD results showed that the addition of nano-SiO(2) promoted the conversion of the intermediate product C(4)AH(13). The isothermal calorimetry results showed that the addition of nano-SiO(2) significantly reduced the hydration exotherm rate of C(3)A from 0.34 to less than 0.1 mW/g. With the presence of nano-SiO(2), the peaks for Q(1) were observed in (29)Si MAS-NMR measurements, and the content of Q(1) increased from 6.74% to 30.6% when the nano-SiO(2) content increased from 2 wt.% to 8 wt.%, whereas the proportion of Q(4) gradually decreased from 89.1% to 63.6%. These results indicated a pozzolanic reaction provoked by the nano-SiO(2) combined with aluminate structures generating C-A-S-H gel.
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spelling pubmed-78306932021-01-26 Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica Zheng, Dapeng Monasterio, Manuel Feng, Weipeng Tang, Waiching Cui, Hongzhi Dong, Zhijun Nanomaterials (Basel) Article Tricalcium aluminate (C(3)A) is the most reactive component of the Portland cement and its hydration has an important impact on the workability and early strength of concrete. Recently, nanomaterials such as nano-silica (nano-SiO(2)) have attracted much attention in cement-based materials because of its pozzolanic reactivity and the pore-filling effect. However, its influence on the hydration of C(3)A needs to be well understood. In this study, the hydration kinetics of C(3)A mixed with different percentages of nano-SiO(2) were studied and compared with pure C(3)A. The hydration products were examined by different characterization techniques including XRD, XPS, and NMR spectroscopy and isothermal calorimetry analyses. The XRD results showed that the addition of nano-SiO(2) promoted the conversion of the intermediate product C(4)AH(13). The isothermal calorimetry results showed that the addition of nano-SiO(2) significantly reduced the hydration exotherm rate of C(3)A from 0.34 to less than 0.1 mW/g. With the presence of nano-SiO(2), the peaks for Q(1) were observed in (29)Si MAS-NMR measurements, and the content of Q(1) increased from 6.74% to 30.6% when the nano-SiO(2) content increased from 2 wt.% to 8 wt.%, whereas the proportion of Q(4) gradually decreased from 89.1% to 63.6%. These results indicated a pozzolanic reaction provoked by the nano-SiO(2) combined with aluminate structures generating C-A-S-H gel. MDPI 2021-01-14 /pmc/articles/PMC7830693/ /pubmed/33466793 http://dx.doi.org/10.3390/nano11010199 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zheng, Dapeng
Monasterio, Manuel
Feng, Weipeng
Tang, Waiching
Cui, Hongzhi
Dong, Zhijun
Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica
title Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica
title_full Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica
title_fullStr Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica
title_full_unstemmed Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica
title_short Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica
title_sort hydration characteristics of tricalcium aluminate in the presence of nano-silica
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830693/
https://www.ncbi.nlm.nih.gov/pubmed/33466793
http://dx.doi.org/10.3390/nano11010199
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