掺P2O5水泥基材料水化动力学研究

基于水化动力学模型，采用SEM、XRD和C-80Ⅱ型导热式微量热仪研究了硅酸盐水泥和掺P2O5硅酸盐水泥胶凝体系的水化特性和水化动力学，分析了P2O5对硅酸盐水泥水化机制的影响规律。研究结果表明，掺入P2O5后硅酸盐水泥的水化产物数量和尺寸显著减小。P2O5掺量为3．5％时，硅酸盐水泥熟料水化热总量降低32．6%，硅酸盐水泥的初凝和终凝分别被延缓1．10h和12．54h。掺入P2O5复合体系的水化机制与硅酸盐水泥类似，加速期由自动催化反应控制，减速期由自动催化和扩散反应双重反应控制，稳定期扩散反应占据主导。P2O5会增加硅酸盐水泥在加速期和减速期的水化反应阻力，减小稳定期的水化反应阻力。掺入P2O5后，水泥在加速期和减速期的表观活化能增加，稳定期表观活化能略有降低P2O5溶液环境有利于水泥熟料C3A的水化，延缓C3S和C2S的水化。

Hydration Kinetics of Cement-based Materials With P2O5 Incorporated

By means of SEM, XRD and calorimeter C-80Ⅱ , the hydration kinetics of cement-based materials with and without P2O5 incorporated were characteristics and hydration investigated. It is found that the amount and size of hydration products incorporated with P2O5 were decreased dramatically. When 3.5% P2O5 was added in cement, total amount of hydration heat was decreased by 32.6% and initial and final setting were delayed by 1.10 h and 12.54 h respectively. In terms of mechanism analysis, P2O5 had little impact on cement hydration mechanism, and accelerating stage was controlled by chemical reaction, decreasing stage controlled by both chemical and diffusion reaction while stabilizing stage controlled by diffusion alone. The hydration resistance in both accelerating and decreasing stage was elevated while decreased in stabilizing stage. The activation energy in both accelerating and decreasing stage were reduced and increased in stabilizing stage. P2O5 was favorable to hydration of C3A yet retarded hydration of C3S and C2S.