NOVELS PATTERNS OF HYDRATION AND NEW COMPOUNDS IN THE TERNARY-SYSTEM OF CAO-AL2O3-P2O5

The patterns of hydrating and solidifying with the compositional varia tion of phosphorus-rich, phosphorus-calcium-rich and aluminum-calcium rich regions in ternary system CaO-Al2O3-P2O5 has been studied in deta il, and two new ternary compounds L and H have been synthesized here. The results indicate that the region of 48-56% P2O5 doesn't present ce mentitiousness, which contains mainly crystal phases of beta-C2P(2CaO . P2O5), alpha-C3P(3CaO . P2O5) and AIPO(4); the phosphorus-calcium-ri ch region of 21-35% P2O5 exhibits substantial cementitiousness, which contains mainly crystal phase of alpha-C3P and certain amount of CA(Ca O . Al2O3) and new phases L/H; and the aluminum-calcium-rich region of 8-18% P2O5 is full of promise for cementitiousness. It contains mainl y new crystal phase I, and certain amount of alpha-C3P and CA. The hyd ration and solidification mechanisms have been preliminarily analyzed by means of XRD, XPS and DTA. It appears that crystal phase CA might h ydrate directly to the stable phase of C(3)A . 6H(2)O in the phosphoru s-rich case of 21-35% P2O5; new phase H has the behavior of rapid sett ing; and L, being a dominant phase, can prevent cement pastes from sig nificant: strength loss in long curing cycles.