Influence of inorganic additives on the water resistance of a magnesium binder

Magnesium-based binders are widely used worldwide. Magnesia cements are employed in the production of xylolite, fibrolite, various structural elements, artificial marble, bases for finished floors, plasters, heat-insulating foamed and gas concretes, refractory ramming masses, grindstones, and more. They are characterized by several advantageous properties, including high mechanical strength at the initial stages of hardening; increased flexural strength compared to other types of binders; a compact structure of the hardened cement combined with low true density; low thermal conductivity; high adhesion strength to aggregates in magnesia concretes and mortars; and relatively high resistance to corrosive media. Furthermore, the relatively low energy costs for firing (unlike lime and Portland cement production) make the use of magnesite and dolomite particularly appealing. A distinguishing feature of magnesia binders compared to traditional ones is the use of magnesium chloride solutions (instead of water) in combination with caustic magnesite or dolomite. This study investigates inorganic additives capable of stabilizing the phase composition of hardening magnesium cements through the incorporation of mineral bischofite brine into the magnesium mixture. The research identifies specific inorganic additives that enhance frost and water resistance, thereby broadening the application range of magnesium-based binders formulated with bischofite mineral brine.