钢渣-水泥复合胶凝材料的水化放热和动力学研究

通过测定钢渣掺量（质量分数）分别为0、20%、30%、40%的水泥基复合胶凝材料的水化放热速率，根据Krstulovi?-Dabi?动力学模型得到几何晶体生长指数n、反应速率常数K、各阶段转换时的水化度α，进而研究钢渣掺量对钢渣水泥复合胶凝材料水化放热与动力学的影响。结果表明：随着钢渣掺量的增加，各阶段水化放热速率变化趋势不同，钢渣掺量30%和40%时，出现第3放热峰，水化放热量随着钢渣掺量的增加而降低；钢渣掺量0、20%、30%时，水化历程由结晶成核与晶体生长(NG)到相边界反应(I)再到扩散过程(D)；钢渣掺量40%时，模拟曲线偏离实际水化速率曲线，水化过程不符合Krstulovi?-Dabi?动力学模型；钢渣掺量0~30%范围内KNG、KI、KD均随着钢渣掺量的增加而降低；相对于钢渣掺量20%试样而言，纯水泥与钢渣掺量30%试样的I过程水化度范围较大；钢渣掺量0~30%的试样，水化12h已经成型，然而相同条件下，钢渣掺量40%的试样仍然不能硬化成型。为避免水化速率过低，钢渣最大掺量应为30%。

Study of hydration exotherms and kinetics of steel slag-cement composite binder

Hydration heat emission rates of cementitious composite binders containing 0, 20%, 30%, 40% steel slag have been measured. According to theKrstulovi?-Dabi? kinetic model, the reaction rate constant K, geometrical crystal growth exponent n and hydration degrees αfor the conversion between the various stages were obtained. The impact of adding different contents of steel slag on the hydration heat release and kinetics for the slag-cement composite binder was investigated. The results showed that, with the increase of steel slag content, the hydration heat emission rates of each stage had different trends. The third exothermic peak could be observed clearly when the content of steel slag was more than 30%. The hydration heat of each stage decreased when the content of steel slag increased. When the steel slag amounts were 0, 20% and 30%, the order of the hydration approach was nucleation and crystal growth(NG), interactions at phase boundaries(I) and diffusion(D). The simulation curves deviated greatly from theactual hydration rate curve, and the hydration process did not meet theKrstulovi?-Dabi? kinetic model when the steel slag content was 40%. When 0-30% cements was replaced by steel slag, the reaction rate constants KNG, KI, KDof the cementitious composite binder all decreased. Compared with the composite binder containing 20% steel slag, the pure cement and sample with 30% steel slag experienced a longer process I. When the steel slag content was 0-30%, paste samples had hardened after hydration for 12 h, while the paste sample of the cement-based composite binder mixed with 40% steel slag had still not hardened into shape. Therefore to avoid low hydration rates, the maximum dosage of steel slag should be 30%. 