The influences of ultra-fine powders on the compatibility of cement and superplasticiser with very low water/binder ratio

The effects of ultra-fine powders such as pulverised fly ash (PFA), granulated blast furnace slag (GBFS) and silica fume (SF) on the compatibility of grade 525 ordinary Portland cement and superplasticiser (DFS-2) are studied in detail. The results indicate that the addition of PFA or GBFS into cement mixture with water/binder ratio of 0·22 can improve compatibility of mixtures and superplasticiser (DFS-2), while adding a large amount of SF into cement mixture will degrade it. At the same time, the influence of PFA, GBFS and SF on the fluidity of paste, as well as on the compactness of paste with very low water/binder ratio, is also investigated.