Effect of coral filler on the hydration and properties of calcium sulfoaluminate cement based materials

In this research, the feasibility of using coral filler in Calcium sulfoaluminate (CSA) cements based materials is investigated, targeting at reducing transportation cost for the marine construction. Properties including setting time, mechanical properties and hydration kinetics are investigated. Two blended materials groups with and without anhydrite are tested. Then, their properties are compared with the plain CSA cement clinker samples (with and without quartz filler). The obtained results indicate that coral filler decreases the hydration heat and generates hemicarbonate instead of monosulfate. Moreover, the replacement of CSA cement clinker by coral filler can slightly decrease the setting time and improve the strength development of sulpho-aluminous cement based materials with limited anhydrite. However, the activity of coral filler decreases with the addition of anhydrite. In the group with sufficient anhydrite, the replacement of CSA cement clinker by coral filler has limited effect on the CSA cement hydration, and can decline the long-term mechanical properties of CSA cement based materials.