الفهرس 
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Abstract
Repairing and strengthening of reinforced concrete columns are very sensitive topics. Many retrofitting techniques have been studied in an attempt to increase the load carrying capacity in addition to increase the ductility behavior of RC columns. Steel fiber reinforced concrete (SFRC) jacketing can remarkably improve ductility, and energy absorption (toughness) through the action of crack bridging, that allows RC column to sustain more deformability without occurring of crushing brittle failure. Moreover, it can increase the load carrying capacity and overall durability. It is advisable to use SFRC with self-consolidating behavior to enhance the distribution and dispersion of steel fibers throughout overall the concrete mixture in all directions.
The main objective of this study is to investigate the axial behavior of the repaired RC columns with such repairing technique. For this objective, phase 1 of the experimental program included mixing and testing thirty-one concrete mixes to produce an optimized SFR-SCC mix to be used in the repairing process. The effects of varied types of sands, coarse aggregates, and superplasticizers on producing self-consolidating concrete were considered. In addition, ratio of sand/coarse aggregate and the amount of superplasticizer were involved in the study as well. The achieved optimized sand/coarse aggregate ratio and volume fraction of crimped steel fibers were 0.90, and 1.25%, respectively, for the specified properties of the studied materials.