Effect and Mechanism of Steel Slag on Performance of Magnesium Phosphate Cements

Abstract:

This work investigated the feasibility of reusing steel slag as raw materials in preparing magnesium phosphate cement (MPC). The effect of steel slag on the setting time, hydration process, mechanical properties and microstructure of prepared cements was determined. The results show that the influence of steel slag on the performance of magnesium phosphate cement exhibits a similar trend as that of fly ash. The addition of 10% steel slag would accelerate the hardening of prepared cement due to the presence of CaO and the formed calcium hydroxide. The hardness of steel slag would also increase the compressive strength. With increasing the steel slag substitutional level, the content of hydration products would decreases, while the porosity increases and micorstructure become loose as a result. The hydration of f-CaO would do a detrimental effect on the mechanical properties of MPC. The hydration products detected in X-ray diffraction(XRD) patterns of steel slag blended MPC is the same as those of reference. However, there is more microcrack present in the hardened paste containing 40% of steel slag.

Key words:magnesium phosphate cement; steel slag; fly ash; performance; mechanism