Performance of Magnesia Cement Using MgCO3 and Serpentine

Abstract

The amount of carbon dioxide (CO2) released while producing building materials is substantial and has been targeted as a leading contributor to global climate change. One of the most typical methods of reducing CO2 in building materials is the addition of slag and fly ash, like pozzolan material another method is to reduce CO2 production by developing carbon negative cement. MgO-based cement from the low-temperature calcination of magnesite required less energy and emitted less CO2 than the manufacturing of Portland cements. It is also believed that adding reactive MgO to Portland-pozzolan cements can improve their performance and also increase their capacity to absorb atmospheric CO2. In this study, basic research on magnesia cement using MgCO3 and magnesium silicate ore (serpentine) as the main starting materials, as well as blast furnace slag for the mineral admixture, was carried out for industrial waste material recycling. In order to increase the overall hydration activity, MgCl2 was also added. In the case of the addition of MgCl2 as accelerating admixture, there was a promoting effect on the compressive strength. This was found to be due to the production of needle-like dense Mg-Cl hydrates. Mgnesia cement has a high viscosity due to its high specific surface area therefore, when the PC-based dispersing agent was added at a level of more than 1.0%, it had the effect of improving fluidity. In particular, the addition of MgCl2 in magnesia cement using MgCO3 and magnesium silicate ore (serpentine) as main starting materials led to a lower expansion ratio and an increase in the freeze-thaw resistance finally, the addition of MgCl2 as accelerating admixture led to good overall durability. Key words: Magnesia cement, Carbon dioxide, Hydration activity, Blast furnace slag, MgCl2