Thermophysical Properties of Blended Cements

摘要

Blended cements have attracted intensive attention. The behaviour of mortars with blends consisting of sulfoaluminate - belite (SAB) cements and ordinary Portland cement (OPC) made with cement to sand ratio of 1 : 3 (weight) and w/c = 0.5 maintained for 90 days at 20℃ either at 60% relative humidity (RH) - dry air or 100% RH - wet air was studied. The results show insufficient character of hydraulic activity of SAB cements. Their quality has been improved. The replacement of 15 % SAB cement by OPC influences strength positively and elasticity modulus values as well as hydrated phase and pore structure development of SAB/OPC blends relative to pure SAB cement systems. The mortars with mixed cement show excellent protective properties against corrosion of steel comparable to that of mortars made from OPC and blastfurnace - slag Portland cement (BFSPC). Steel is depassivated in SAB cement mortars. The above statements confirm the possible making technologies, when improvements in SAB cement quality were achieved. One can easily anticipate the competition in usages between SAB/OPC and BFSPC systems in the practice. SAB cements are a great advantage from the viewpoint of energy savings and quantity of CO_2 released during their production.