Effects of steel slag on the microstructure and mechanical properties of magnesium phosphate cement

The effects of steel slag (SS) addition on the strength and water resistance of magnesium phosphate cement (MPC) are investigated, and the hydration mechanism is proposed in this paper. With the addition of SS, the strength and water resistance of MPC were significantly enhanced. The compressive strength of MPC with 10 wt% SS (SS 10) cured in air for 60 d reached 56.7 +/- 4.2 MPa. Interestingly, the strength loss rate of the sample cured in water for 14 d was only 6.6%. In addition, the microstructure and hydration products of MPC specimens were investigated via Xray diffraction and scanning electron microscopy. There was a significant amount of unreacted MgO after MPC curing, and the main hydration product was struvite-K. The amount of struvite-K (KMgPO4.6H(2)O) of MPC with 0 wt% SS decreased after curing in water. However, no significant changes in the amount of hydration products was evident for SS 10, and the compactness was enhanced. This work provides a new approach for the resource utilization of SS.

Automated summary

This paper investigates the effects of steel slag addition on the strength and water resistance of magnesium phosphate cement (MPC), and proposes a hydration mechanism. The results show that with the addition of steel slag, the strength and water resistance of MPC are significantly enhanced. The steel slag also improves the compactness and stability of the cement.