Determination of Optimum Substitute Rate for Silica Fume in Fiber Concrete

In this study, in order to ensure maximum complexity in fiber concrete production, different amounts of silica fume (SF) were substituted by keeping the amount of fiber and super plasticizer (SP) constant. The amount of cement was replaced by SF at 0% (RC): 2.5%, 5%, 7.5%, 10% and 12.5% by weight, respectively. Six 100 x 100 x 100 mm cube test samples were produced with these mixtures. Slump and Ve-Be tests were carried out on processability tests on fresh concrete. 28, 90 and 120 days compressive strength tests were performed on hardened concrete samples. In all mixtures, it was found that there was an inverse relationship between SF ratio and workability. SF ratio was effective on the processability of fresh concrete. As the SF content of the mixtures increased, the precipitation decreased and the Ve-Be duration was extended time. In all mixtures, there was a certain increase in compressive strength naturally depending on the age of the concrete. In fiberless samples, the compressive strength increased as the ratio of SF to RC’ increased. The highest compressive strength of all ages was obtained with 7.5% SF. In fiber samples (FC): compressive strength increased as SF ratio increased. The highest compressive strength increase at all ages was obtained in samples produced with 10% SF rati