氯化钙激发粉煤灰基充填材料水化的机理及动力学特征

HYDRATION MECHANISM AND KINETIC CHARACTERISTICS OF CaCl_(2) EXCITING FLY ASH PASTE FILLING MATERIALS

胶结充填材料的早期水化动力学特征是合理设计配比的重要前提。采用等温量热法测量了不同CaCl_(2)浓度激发粉煤灰膏体充填材料(FPFM)的早期水化放热情况,基于Krstulovic-Dabic水化动力学模型对不同FPFM早期水化放热进行拟合,计算其水化动力学参数,对水化动力过程各阶段的变化特征进行分析,并对CaCl_(2)的激发机理做出解释。结果表明:随着CaCl_(2)浓度增加,FPFM水化热量从1.1 mW/g增大至2.9 mW/g,总累计放热量从16.4 J/g增大至29.6 J/g,诱导阶段和加速阶段持续时间缩短,使其水化反应速率加快,水化反应程度加深。CaCl_(2)激发FPFM的水化机理均为成核和晶体生长(NG)→扩散(I)→相边界作用(D),随着CaCl_(2)浓度增加,FPFM动力学参数均增大,I阶段持续时间延长,促进了粉煤灰的火山灰反应,产生了更多的水化产物。因此,通过对CaCl_(2)激发FPFM早期水化动力学特征的研究,揭示了其结构演化的规律,对FPFM的现场应用提供理论参考。

The early hydration kinetics of cementitious filling materials is an important prerequisite for reasonable designed ratios.In this paper,the early hydration exothermic condition of fly ash paste filling materials(FPFM)with different CaCl_(2)concentration excitation was measured by isothermal calorimetry,and the early hydration exothermic heat of different FPFM was fitted based on the Krstulovic-Dabic hydration kinetic model.The hydration kinetic parameters were calculated,the variation characteristics of each stage of the hydration dynamic process were analyzed,and the excitation mechanism of CaCl_(2)was explained.The results showed that with the increase of CaCl_(2)concentration,the hydration heat of FPFM increased from 1.1 mW/g to 2.9 mW/g,and the total cumulative heat release increased from 16.4 J/g to 29.6 J/g,so that the hydration reaction rate was accelerated and the degree of hydration reaction was deepened.The hydration mechanism of FPFM stimulated by CaCl_(2)was NG→I→D,and with the increase of CaCl_(2)concentration,the kinetic parameters of FPFM were increased,and the duration of phase I was prolonged,which promoted the pozzarash reaction of fly ash and produced more hydration products.Therefore,through the study of the early hydration kinetic characteristics of CaCl_(2)exciting FPFM,the law of its structural evolution is revealed,which provides a certain guide for the application of FPFM.