Papers by Author: Chung Kong Chau

Abstract: The recent development of two types of environmental friendly cementitious materials, magnesium oxychloride cement and magnesium phosphate cement, at HKUST are presented. Both of them can develop high strength without heat treatment under elevated temperature, i.e. the bonding of these cementitious materials can be achieved at low temperature through chemical reaction, as opposed to fusion or sintering at high temperature. The preparation process of the two cements can not only save a lot of energy but also emit no carbon dioxide. For magnesium oxychloride cement, our research includes parametric study of the formulation, strength development, water resistance, and also identification of phase composition in the cement paste. Magnesium phosphate cement is mainly applied as rapid repair material in civil engineering. In this paper, the formulation, mechanical properties and performance in patch repair of mortar specimen including strength, bond ability to old concrete substrate, volume stability are studied.

Abstract: Magnesium Oxychloride Cement (MOC) is an air-hardened material with chemical reaction between magnesium oxide and magnesium chloride solution. It has many properties superior to Portland cement. It does not need wet curing, has very good fire resistance, low thermal conductivity. In this study, wood composites were developed by using MOC as binder and wood powders as filler. It was demonstrated that MOC was suitable for binding wood particles in large quantities. In order to ensure smooth extrusion process, additives and rheological modifiers were used to modify the rheology behaviors and properties of the mixture and the rheology behaviors of fresh materials were also investigated with upsetting and relaxation tests simultaneously. Then MOC-based panels with different cross-sections were produced by using extrusion technology and mechanical properties of them were investigated.