Effect of volcanic pumice powder on the fresh properties of self-compacting concretes with and without silica fume

The current study presents an experimental study conducted on the effectiveness of volcanic pumice powder (VP) on the fresh properties of self-compacting concretes (SCCs) with and without silica fume (SF). In the first group, SCCs without SF were produced with 0, 5, 10, and 20 % replacement levels of VP. However, for the second group, SF incorporation was achieved by a constant SF replacement level of 8 %. All of the replacement levels assigned were substitution of cement with the supplementary cementing materials on the basis of weight of total binder. Therefore, totally eight different SCCs were produced. The investigated fresh characteristics of the concretes were slump flow diameter, T (500mm) slump flow time, V-funnel flow time, and L-box height ratio. The compressive strength of concretes was also evaluated to indicate the mechanical performance. Moreover, a statistical study, namely general linear model analysis of variance, was performed in order to examine the significance of the critical parameters such as inclusion of SF and replacement level of VP on the properties of SCCs. The results have revealed that increasing the replacement level of VP generally resulted in the increase of fluidity of SCCs without loss of uniformity and with no segregation. Moreover, incorporation of SF provided significant increase in compressive strength while VP caused a systematic decrease.