Influence of molar ratios on properties of magnesium oxychloride cement

Journal Article · Fri Jun 15 04:00:00 EDT 2007 · Cement and Concrete Research

OSTI ID:20995388

Zongjin, Li ^[1]; Chau, C K ^[1]

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1. Department of Civil Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong (China)

A parametric study has been conducted to investigate the influences of the molar ratios of MgO/MgCl{sub 2} and H{sub 2}O/MgCl{sub 2} on the properties of magnesium oxychloride (MOC) cement. By an integrated assessment of the experimental studies of strength development and X-ray diffractograms, together with application of the relevant phase diagram, it is recognized that the molar ratios of MgO/MgCl{sub 2} and H{sub 2}O/MgCl{sub 2} can significantly affect the properties of MOC cement. For a MOC cement paste possessing a dominance of 5MgO.MgCl{sub 2}.8H{sub 2}O (phase 5) crystals, the molar ratios of MgO/MgCl{sub 2} of 11-17 and H{sub 2}O/MgCl{sub 2} of 12-18 are found to be the most favorite ranges for design purpose. The choose of the molar ratio of H{sub 2}O/MgCl{sub 2} is, however, largely depends on the molar ratio of MgO/MgCl{sub 2} mainly for controlling workability of paste. Therefore, the most critical parameter to be selected in the design process is the molar ratio of MgO/MgCl{sub 2}, although the reactivity of the MgO powder is also important. Besides, the molar ratio can also be affected by the reactivity of the MgO powder to be employed. It is believed that a molar ratio of MgO/MgCl{sub 2} of 13, the most suitable one shown in this study, can be used as a starting point in the normal practice.

• OSTI ID: 20995388
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 6 Vol. 37; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CEMENTS
MAGNESIUM CHLORIDES
MAGNESIUM OXIDES
OXYCHLORIDES
PARAMETRIC ANALYSIS
PHASE DIAGRAMS
POWDERS
REACTIVITY
WATER
X-RAY DIFFRACTION