分选与磨细粉煤灰对水泥胶砂性能的影响

研究了分选与磨细粉煤灰的颗粒分布与形貌的差异及对水泥胶砂性能的影响。研究结果表明:当勃氏比表面积相近,磨细粉煤灰的中位粒径大于分选细粉煤灰,其圆珠状颗粒较少,表面较为粗糙。在相同水胶比的条件下,掺分选粗粉煤灰的水泥胶砂流动度及强度均低;分选粗粉煤灰磨细后,不仅减少了颗粒的粘连,增加了比表面积,而且提高了粉煤灰的反应活性和水泥胶砂流动度及强度,虽其水泥胶砂流动度仍小于掺分选细粉煤灰的水泥,3d水泥胶砂强度也略低,但其28d水泥胶砂强度略高于掺分选细粉煤灰的水泥;在相同水泥胶砂流动度的条件下,掺磨细粉煤灰配制的水泥胶砂3d强度低于掺分选细粉煤灰的水泥,但随着水化龄期的增长,其差距逐步缩小,至60d时可超过后者。

Comparation of effect of classificated and ground fly ash on mortar properties of Port-land fly ash cement

The difference between the particle size distribution and configuration of classificated and ground fly ash and their effects on the cement mortar properties were studied.The results showed that with similar specific surface area,the median diameter of the ground fly ash was larger than that of the classified fly ash.The former consist of lesser orbicular granule and rough surface.At the equal w/c ratio,the fluidity and the cement mortar strength of the coarser separated fly ash were low.After being ground,the coherent particles in the coarse fly ash was reduced,its specific surface area,fluidity and strength of the cement mortar were greatly improved.Its cement mortar fluidity and 3d strength were lesser than those of the fine separated fly ash,but its 28d strength was a little higher.With a same fluidity,the 28d and early cement mortar strengths of the size reduction fly ash was lower,but the strengths increased.After 60d,the cement mortar strength of the size reduction fly ash exceeded that of the separated fine fly ash.