Influence of nano-silica agglomeration on fresh properties of cement pastes

Deyu Kong; Yong Su; Xiangfei Du; Yang Yang; Su Wei; Surendra P. Shah

doi:10.1016/j.conbuildmat.2013.02.066

Influence of nano-silica agglomeration on fresh properties of cement pastes

Deyu Kong^*, Yong Su, Xiangfei Du, Yang Yang, Su Wei, Surendra P. Shah

^*Corresponding author for this work

Civil and Environmental Engineering

Research output: Contribution to journal › Article › peer-review

181 Scopus citations

Abstract

The influence of nano-silica agglomeration on fresh properties of the cement paste was investigated by using precipitated nano-silica (PS) with very large agglomerates and fumed nano-silica (FS) with much smaller ones as nano-strengthening admixtures. The rheologic tests revealed that addition of PS showed a greater influence on rheological behavior of the paste than that of FS, because the very large agglomerates in PS cannot act as fillers to release free water in the void space originally contributing to fluidity, but absorb free water originally contributing to fluidity in paste. Through monitoring the heat evolution, it is interestingly found that addition of PS accelerated cement hydration more significantly than that of FS though the latter provides much more seeds than the former, implying that the acceleration may have nothing to do with the so-called seeding effect. The calcium-adsorption tests confirmed that the accelerating effect is probably caused by the rapid calcium adsorption of nano-silica, which can keep a low under-saturation of calcium ions in paste, enabling a higher dissolution rate of calcium and thus an increase of heat evolution.

Original language	English (US)
Pages (from-to)	557-562
Number of pages	6
Journal	Construction and Building Materials
Volume	43
DOIs	https://doi.org/10.1016/j.conbuildmat.2013.02.066
State	Published - 2013

Keywords

Accelerating effect
Fumed nano-silica
Precipitated nano-silica
Seeding effect

ASJC Scopus subject areas

Civil and Structural Engineering
Building and Construction
General Materials Science

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10.1016/j.conbuildmat.2013.02.066

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title = "Influence of nano-silica agglomeration on fresh properties of cement pastes",

abstract = "The influence of nano-silica agglomeration on fresh properties of the cement paste was investigated by using precipitated nano-silica (PS) with very large agglomerates and fumed nano-silica (FS) with much smaller ones as nano-strengthening admixtures. The rheologic tests revealed that addition of PS showed a greater influence on rheological behavior of the paste than that of FS, because the very large agglomerates in PS cannot act as fillers to release free water in the void space originally contributing to fluidity, but absorb free water originally contributing to fluidity in paste. Through monitoring the heat evolution, it is interestingly found that addition of PS accelerated cement hydration more significantly than that of FS though the latter provides much more seeds than the former, implying that the acceleration may have nothing to do with the so-called seeding effect. The calcium-adsorption tests confirmed that the accelerating effect is probably caused by the rapid calcium adsorption of nano-silica, which can keep a low under-saturation of calcium ions in paste, enabling a higher dissolution rate of calcium and thus an increase of heat evolution.",

keywords = "Accelerating effect, Fumed nano-silica, Precipitated nano-silica, Seeding effect",

author = "Deyu Kong and Yong Su and Xiangfei Du and Yang Yang and Su Wei and Shah, {Surendra P.}",

note = "Funding Information: The authors gratefully acknowledge the financial support from Scientific Bureau of Zhejiang Province , China under Grant 2009R50022 and Infrastructure Technology Institute at Northwestern University under Grant DTRT06-G-0015 . The first author would also like to thank China Scholarship Council (CSC) for its financial support during his stay as a visiting scholar at Northwestern University.",

year = "2013",

doi = "10.1016/j.conbuildmat.2013.02.066",

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T1 - Influence of nano-silica agglomeration on fresh properties of cement pastes

AU - Kong, Deyu

AU - Su, Yong

AU - Du, Xiangfei

AU - Yang, Yang

AU - Wei, Su

AU - Shah, Surendra P.

N1 - Funding Information: The authors gratefully acknowledge the financial support from Scientific Bureau of Zhejiang Province , China under Grant 2009R50022 and Infrastructure Technology Institute at Northwestern University under Grant DTRT06-G-0015 . The first author would also like to thank China Scholarship Council (CSC) for its financial support during his stay as a visiting scholar at Northwestern University.

PY - 2013

Y1 - 2013

N2 - The influence of nano-silica agglomeration on fresh properties of the cement paste was investigated by using precipitated nano-silica (PS) with very large agglomerates and fumed nano-silica (FS) with much smaller ones as nano-strengthening admixtures. The rheologic tests revealed that addition of PS showed a greater influence on rheological behavior of the paste than that of FS, because the very large agglomerates in PS cannot act as fillers to release free water in the void space originally contributing to fluidity, but absorb free water originally contributing to fluidity in paste. Through monitoring the heat evolution, it is interestingly found that addition of PS accelerated cement hydration more significantly than that of FS though the latter provides much more seeds than the former, implying that the acceleration may have nothing to do with the so-called seeding effect. The calcium-adsorption tests confirmed that the accelerating effect is probably caused by the rapid calcium adsorption of nano-silica, which can keep a low under-saturation of calcium ions in paste, enabling a higher dissolution rate of calcium and thus an increase of heat evolution.

AB - The influence of nano-silica agglomeration on fresh properties of the cement paste was investigated by using precipitated nano-silica (PS) with very large agglomerates and fumed nano-silica (FS) with much smaller ones as nano-strengthening admixtures. The rheologic tests revealed that addition of PS showed a greater influence on rheological behavior of the paste than that of FS, because the very large agglomerates in PS cannot act as fillers to release free water in the void space originally contributing to fluidity, but absorb free water originally contributing to fluidity in paste. Through monitoring the heat evolution, it is interestingly found that addition of PS accelerated cement hydration more significantly than that of FS though the latter provides much more seeds than the former, implying that the acceleration may have nothing to do with the so-called seeding effect. The calcium-adsorption tests confirmed that the accelerating effect is probably caused by the rapid calcium adsorption of nano-silica, which can keep a low under-saturation of calcium ions in paste, enabling a higher dissolution rate of calcium and thus an increase of heat evolution.

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KW - Seeding effect

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Influence of nano-silica agglomeration on fresh properties of cement pastes

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Keywords

ASJC Scopus subject areas

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