Experimental Study Of Strength And Workability Of Magnesium Silicate Hydrate

1486 Words May 13th, 2016 6 Pages
Experimental Study of Strength and Workability of Magnesium Silicate Hydrate Binder System
H.M. Tran, A. Scott
Abstract—The novel binder system of magnesium silicate hydrate has the advantage of low-CO2 production and potential use for structures and nuclear waste immobilisation. This paper discusses the experimental study to optimize proportions of cement paste and mortar for compressive strength and workability using magnesium silicate hydrate system. Binary systems containing magnesium oxide and amorphous silica (silica fume) were studied in which amount of each constituent accounted for 40-60% by mass of the binder. It is found that magnesium silicate hydrate binder system requires very high water demand compared to Portland cement due to high microfine content of silica fume and light specific gravity. It is only possible to produce workable mixes in use of suitable superplasticizers. Use of polymer-based superplasticizer is more effective than inorganic superplasticizer to reduce water to cementitious materials ratio to 0.40. The optimal binder composition for strength and workability is found to contain 60% magnesium oxide and 40% silica fume (Mg/Si molar ratio equals 2.25) at which the proportions are not fully dependent on stoichiometry for formation of magnesium silicate hydrate gel but in line with high packing density mixtures to reduce water content. Testing of samples resulting in the highest compressive strength of over 40 MPa confirms cementing properties and…

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