research of interaction between caustic magnesite and a microsilica additive

The authors argue that a dry mixture composed of caustic magnesite and a microsilica additive represents a binding material which contributes to formation of a durable and water resistant artificial stone. The results of the research of the artificial stone performed through the application of the Fourier IR spectroscopy method are provided. Interaction between magnesium oxide (MgO) as the basic oxide and microsilica as an acidic oxide is proposed. This interaction makes it possible to add water to Sorel cement instead of the magnesium chloride (MgCl2) solution. Compressive strength of the dry mix containing 10 % of microsilica has been measured. In the event of hydraulic hardening, the compressive strength of the dry mix is 11.5 MPa, while the compressive strength of the water-saturated mix is equal to 12.0 MPa. In the aftermath of the air-setting procedure, the compressive strength of the dry mix is 10.0 MPa, while the compressive strength of the water-saturated mix is 21.0 MPa. The IR spectra of the specimen exhibit vibrations at 1100-400 cm-1 that correspond to the area of Si-O and Si-O-Me stretching vibrations, a peak at 1121-1119 cm-1 that can be assigned to Si-O-Si bond vibrations, and a peak at 474-472 characteristic of Si-O-Mg stretching vibrations. The areas of 3700-3000 cm-1 and 1650-1600 cm-1 are assigned to stretching and deformational vibrations of OH groups, respectively.