Influence of quality of fly ash on fresh properties of self-compacting concrete incorporating large volume of fly ash

This paper presents the results of the influence of four different kinds of fly ashes on the fresh properties of self-compacting concrete incorporating large volume fly ash. The fresh concrete properties, the flowability, the viscosity and the self-compactability were determined by slump flow test, V-shaped funnel test and U-type filling test, respectively. The slump flow was influenced by the kind of fly ash, but could be almost equalized by changing the amount of added superplasticizer. However, the concrete viscosity expressed with the V-funnel efflux time varied depending on the quality of fly ash although the slump flow was about the same. The fly ash influenced strongly the self-compacting ability of concrete and there was a high correlation between the bulk specific density of fly ash and the minimum water to binder ratio for concrete to satisfy both self-compactability and workability Comparing the effect of fly ash on the self-compactability with that of the superplasticizer, it was found that the fly ash having high bulk specific density played the similar role with respect to lowing the minimum water to binder ratio at which concrete satisfied both the self-compactability and the workability.