Effects of colloidal nanoSiO 2 on fly ash hydration

Pengkun Hou; Kejin Wang; Jueshi Qian; Shiho Kawashima; Deyu Kong; Surendra P. Shah

doi:10.1016/j.cemconcomp.2012.06.013

Effects of colloidal nanoSiO ₂ on fly ash hydration

Pengkun Hou, Kejin Wang, Jueshi Qian^*, Shiho Kawashima, Deyu Kong, Surendra P. Shah

^*Corresponding author for this work

Civil and Environmental Engineering

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

191 Scopus citations

Abstract

The influences of colloidal nanoSiO ₂ (CNS) addition on fly ash hydration and microstructure development of cement-fly ash pastes were investigated. The results revealed that fly ash hydration is accelerated by CNS at early age thus enhancing the early age strength of the materials. However, the pozzolanic reaction of fly ash at later age is significantly hindered due to the reduced CH content resulting from CNS hydration and the hindered cement hydration, as well as due to a layer of dense, low Ca/Si hydrate coating around fly ash particles. The results and discussions explain why the cementitious materials containing nanoSiO ₂ had a lower strength gain at later ages. Methods of mitigating the adverse effect of nanoSiO ₂ on cement/FA hydration at later ages were proposed.

Original language	English (US)
Pages (from-to)	1095-1103
Number of pages	9
Journal	Cement and Concrete Composites
Volume	34
Issue number	10
DOIs	https://doi.org/10.1016/j.cemconcomp.2012.06.013
State	Published - Nov 2012

Keywords

Coating
Fly ash
Hydration
Morphology
Nanosio

ASJC Scopus subject areas

Building and Construction
Materials Science(all)

Access to Document

10.1016/j.cemconcomp.2012.06.013

Cite this

@article{00bc0c0298c14402b814aa45521dbc8b,

title = "Effects of colloidal nanoSiO 2 on fly ash hydration",

abstract = "The influences of colloidal nanoSiO 2 (CNS) addition on fly ash hydration and microstructure development of cement-fly ash pastes were investigated. The results revealed that fly ash hydration is accelerated by CNS at early age thus enhancing the early age strength of the materials. However, the pozzolanic reaction of fly ash at later age is significantly hindered due to the reduced CH content resulting from CNS hydration and the hindered cement hydration, as well as due to a layer of dense, low Ca/Si hydrate coating around fly ash particles. The results and discussions explain why the cementitious materials containing nanoSiO 2 had a lower strength gain at later ages. Methods of mitigating the adverse effect of nanoSiO 2 on cement/FA hydration at later ages were proposed.",

keywords = "Coating, Fly ash, Hydration, Morphology, Nanosio",

author = "Pengkun Hou and Kejin Wang and Jueshi Qian and Shiho Kawashima and Deyu Kong and Shah, {Surendra P.}",

note = "Funding Information: The authors would like to acknowledge the financial support from Infrastructure Technology Institute at Northwestern University under Grant DTRT06-G-0015 and Tennessee Valley Authority (TVA) and Oak Ridge Associated Universities (ORAUs) (Award 105866). The first author would also like to thank China Scholarship Council for its financial support during his study at Northwestern University. ",

year = "2012",

month = nov,

doi = "10.1016/j.cemconcomp.2012.06.013",

language = "English (US)",

volume = "34",

pages = "1095--1103",

journal = "Cement and Concrete Composites",

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T1 - Effects of colloidal nanoSiO 2 on fly ash hydration

AU - Hou, Pengkun

AU - Wang, Kejin

AU - Qian, Jueshi

AU - Kawashima, Shiho

AU - Kong, Deyu

AU - Shah, Surendra P.

N1 - Funding Information: The authors would like to acknowledge the financial support from Infrastructure Technology Institute at Northwestern University under Grant DTRT06-G-0015 and Tennessee Valley Authority (TVA) and Oak Ridge Associated Universities (ORAUs) (Award 105866). The first author would also like to thank China Scholarship Council for its financial support during his study at Northwestern University.

PY - 2012/11

Y1 - 2012/11

N2 - The influences of colloidal nanoSiO 2 (CNS) addition on fly ash hydration and microstructure development of cement-fly ash pastes were investigated. The results revealed that fly ash hydration is accelerated by CNS at early age thus enhancing the early age strength of the materials. However, the pozzolanic reaction of fly ash at later age is significantly hindered due to the reduced CH content resulting from CNS hydration and the hindered cement hydration, as well as due to a layer of dense, low Ca/Si hydrate coating around fly ash particles. The results and discussions explain why the cementitious materials containing nanoSiO 2 had a lower strength gain at later ages. Methods of mitigating the adverse effect of nanoSiO 2 on cement/FA hydration at later ages were proposed.

AB - The influences of colloidal nanoSiO 2 (CNS) addition on fly ash hydration and microstructure development of cement-fly ash pastes were investigated. The results revealed that fly ash hydration is accelerated by CNS at early age thus enhancing the early age strength of the materials. However, the pozzolanic reaction of fly ash at later age is significantly hindered due to the reduced CH content resulting from CNS hydration and the hindered cement hydration, as well as due to a layer of dense, low Ca/Si hydrate coating around fly ash particles. The results and discussions explain why the cementitious materials containing nanoSiO 2 had a lower strength gain at later ages. Methods of mitigating the adverse effect of nanoSiO 2 on cement/FA hydration at later ages were proposed.

KW - Coating

KW - Fly ash

KW - Hydration

KW - Morphology

KW - Nanosio

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