New MagnesiaPhosphate Cement Based on MgO（NH4）2HPO4K2HPO4H2O System

Abstract:

A new type of magnesiaphosphate cement（MPC）that has high strength and controllable setting time was prepared by low acidity phosphates （NH4）2HPO4 and K2HPO4 as raw materials. The results show that the new MPC has better fluidity and longer setting time with the decrease in （NH4）2HPO4/K2HPO4 molar ratio in the case of fixed mw/mc ratio and retarder dosage. Early compressive strength of the new MPC after adding K2HPO4 decreases slightly， while 28d compressive strength of the new MPC is all above 70 MPa. The main hydration products of MPC are NH4MgPO4·6H2O and KMgPO4·6H2O.