Research on Composite Cement of Phosphoaluminate-Portland Clinkers by Orthogonal Test

The composite cement that is composed of phosphoaluminate-portland clinkers, gypsum and additive is prepared. Mechanical performances of the composite cement have been tested and the techniques of x-ray diffraction and scanning electron microscope have been employed to analyze the hydration products. The results show that, basically same to Portland cement, the hydration products of the composed cement are mostly C-S-H gel,Ca(OH)_2 and Aft. The hydration rate and the amount of hydration products of the composite cement are higher than that of Portland cement, and high mechanical performances have been achieved because of the change of the crystalline size and its morphology.