Assessment of statistical variations in experimental impact resistance and mechanical properties of silica fume concrete

Silica fume as a new supplementary cement has several eects on initial mechanical characteristics and long term improvements. In this paper, the impact resistance and mechanical properties of concrete mixed with silica fume are statistically investigated by selecting 288 specimens in three mix designs. Zero, 7% and 14% of Portland cement by weight were replaced by silica fume in silica-fume mixtures. Twenty 100  100  100 mm cubic specimens, twenty 100  200 mm cylindrical specimens, twenty 60  80  320 mm specimens and thirty-six 150  64-mm discs were cast from each batch to prepare specimens for dierent test purposes. Cubic and cylindrical specimens were used to determine compressive strength, and prismatic specimens were tested to obtain tensile rupturing. Also, cylindrical cutting specimens were subjected to a drop-weight test, following ACI committee 544, to determine the impact strength of mixed concrete. Experimental data on the mechanical properties of the dierent mixes indicated that silica fume improves mechanical properties and impact resistance, while statistical analysis undertaken based on these experimental tests showed a reduction in the coecient of variation values. In other words, adding silica fume improves the statistical dispersion of data