Reactive magnesium oxide as alternative secondary binder for Portland cement

Reactive magnesium oxide which is produced using low oxidation temperatures is characterized by higher reactivity in comparison with regular magnesium oxide. Its hydration rate is claimed to be similar to Portland cement. The test results showed that the addition of a moderate amount of up to 20 wt% of cement resulted in the enhancement of the compressive strength by 20%. No micro cracking was observed. The hydration products appeared to contain in addition to CSH, Portlandite also Brucide which is directly related to the reaction between magnesium oxide and water. No hybrid phases have been detected. The microstructure of the binder matrix was densfied by formation of brucide.