Workability of hybrid fiber reinforced self-compacting concrete

The aim of this work is to evaluate the effect of adding different types of fibers on the fresh properties of the self-compacting concrete, SCC. The used types of fibers were steel (with volume ratios of 0.75, 1.0 and 1.25 %) and polypropylene fibers (0.10 and 0.15 %) and a hybrid system of these fibers (0.65 % steel and 0.10 % polypropylene). The conducted tests in the fresh state were slump flow, T500, V-funnel and L-box. It was noticed that increasing the volume fraction of fibers would lead to decrease in the workability of SCC. According to EFNARC requirements for SCC, many test results were nonconforming. It was also concluded that polypropylene fibers have higher detrimental effect on fresh properties of SCC than steel fibers and that was attributed to the ability of polypropylene to absorb part of mixing water.