矿粉对水泥水化特性的影响及其相关性的研究

Study on Effect of Slag on Hydration Characteristics of Cement and Their Correlations

为研究矿粉对水泥早期水化特性的影响,采用非接触式电阻率和水化热等方法进行表征。利用不同活性矿粉水泥复合浆体水化热测量结果定量计算矿粉对水泥水化的作用和复合浆体的水化度;结合水化度和水化动力学模型计算复合浆体固体体积分数;并研究了3 d电阻率与抗压强度间的相关性。结果表明:与其它掺量的样品相比,矿粉质量分数为20%的复合浆体样品在3、7和28 d的抗压强度均最大。提出了一个参数K值来表示矿粉对复合浆体中水泥水化的促进作用大小,参数K随复合浆体中矿粉质量分数的增加而增大。电阻率微分曲线与水化放热速率曲线有相似的变化规律且有相对应特征点。电阻率与固体体积分数遵行指数函数关系,3 d的电阻率与3 d的抗压强度呈现良好的线性关系。由此,利用电阻率法可以表征矿粉对水泥浆体水化过程的影响,并预测样品中固体体积分数和样品的抗压强度。

The non-contact electrical resistivity and hydration heat methods were used to study the influence of slag on early hydration characteristics of cement. The hydration heat test results of different active slagcement composite pastes were used to quantitatively calculate the effect of slag on cement hydration and the hydration degree of the composite pastes. The solid volume fraction of the composite pastes was calculated based on the hydration degree results and hydration kinetics model. The correlation between the compressive strength and the electrical resistivity at 3 d was studied. Compared with the other samples,the compressive strength of the samples with slag mass fraction of 20% was the highest at each age of 3,7 and 28 d. A parameter K was proposed to represent the promotion effect of slag on cement hydration in composite pastes,and the parameter K value increases with the increase of slag mass fraction in the composite pastes. The electrical resistivity differential curves have similar development trend and characteristic points to the hydration heat release rate curves. The relationship of the electrical resistivity and solid volume fraction follows an exponential function,and the electrical resistivity shows a good linear relationship with the compressive strength at 3 d. Therefore,the resistivity method can be used to characterize the influence of slag on the hydration process of cement pastes and to predict solid volume fraction and compressive strength of cement based materials.