Title of Paper:Formation of magnesium silicate hydrate (M-S-H) cement pastes using sodium hexametaphosphate

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Date of Publication:2014-11-01

Journal:CEMENT AND CONCRETE RESEARCH

Included Journals:SCIE、EI

Volume:65

Page Number:8-14

ISSN No.:0008-8846

Key Words:Dispersion; Hydration products; Compressive strength; MgO; Silica fume

Abstract:Magnesium silicate hydrate (M-S-H) gel is formed by the reaction of brucite with amorphous silica during sulphate attack in concrete and M-S-H is therefore regarded as having limited cementing properties. The aim of this work was to form M-S-H pastes, characterise the hydration reactions and assess the resulting properties. It is shown that M-S-H pastes can be prepared by reacting magnesium oxide (MgO) and silica fume (SF) at low water to solid ratio using sodium hexametaphosphate (NaHMP) as a dispersant. Characterisation of the hydration reactions by x-ray diffraction and thermogravimetric analysis shows that brucite and M-S-H gel are formed and that for samples containing 60 wt.% SF and 40 wt.% MgO all of the brucites react with SF to form M-S-H gel. These M-S-H cement pastes were found to have compressive strengths in excess of 70 MPa. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).