混凝土用硅灰粒度分布参数检测条件的研究

Research on Size Distribution Measurement Condition of Silica Fume Particle Used in Concrete

为了准确快速测量混凝土用硅灰的粒度分布,以中位径（D50）和粒度分布曲线为评价指标,采用激光粒度仪系统研究了分散剂种类、分散剂浓度、硅灰在介质中浓度、超声分散时间、分散温度以及超声分散频率对硅灰检测结果的影响。结果表明,激光粒度分析仪适用于硅灰粒度分布的检测,且具有高度重复性。六偏磷酸钠和十二烷基苯磺酸钠对硅灰具有显著的分散效果,六偏磷酸钠作为硅灰分散剂的最佳浓度为0.5-1.1g/L。未使用分散剂时,硅灰最佳分散条件为5-15g/L分散浓度、10min分散时间、40℃分散温度和40kHz分散频率;六偏磷酸钠加入后,硅灰最佳分散条件为5-30g/L分散浓度、5min分散时间、20℃分散温度和32kHz分散频率。

In order to measure particle size distribution of silica fume accurately and quickly,the effects of dispersant type,dispersant concentration,solution concentration of silica fume,ultrasonic dispersing time,ultrasonic dispersing temperature and ultrasonic frequency on particle size measurement of silica fume were investigated using median particle diameters（ D50） and particle size distribution curve as evaluation indicator. The results indicate that the laser particle size analyzer applies to particle size measurement of silica fume and it has high degree of reproducibility. The dispersion effects are increased significantly by sodium hexametaphosphate and sodium dodecyl benzene sulfonate and the optimal concentration of sodium hexametaphosphate as dispersant of silica fume is 0. 5-1. 1 g / L. The optimized operating dispersing factors of silica fume without dispersant are dispersion concentration 5-15 g / L,dispersion time 10 min,dispersion temperature 40 ℃ and dispersion frequency 40 k Hz. The optimized operating dispersing factors of silica fume with sodium hexametaphosphate dispersant are dispersion concentration 5-30 g / L,dispersion time 5 min,dispersion temperature 20 ℃ and dispersion frequency 32 k Hz.