Self compacting concrete (SCC) is compacting itself alone due to its self-weight and is filled almost completely while flowing in the formwork. In structural members with high percentage of reinforcement ,it fills also completely all voids and gaps. The purpose of presented research is to investigate, the fresh properties of Steel Fiber SCC and the hardened properties. Fresh properties comprising flow ability, passing ability, and viscosity related segregation resistance. Hardened properties comprising compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, and Ultrasonic pulse velocity. The results indicated of the fresh properties of SCC with steel fiber , reduction in workability with increase of steel fiber content. Also the Steel fibers had effect on compressive & tensile strength , modulus of elasticity and ultrasonic pulse velocity of steel fiber self compacting concrete, there was an optimum content of steel fiber at which higher performance obtained at the both mentioned characteristics ,the content was(0.75-1)% . All fiber mixes demonstrated higher splitting tensile strength, and flexural strength relative to plain mix at all curing ages. The strengths increased as the fiber content increased. The fibers slightly decrease the U.P.V followed the same behavior as in compressive strength of SCC.

Chloride-induced corrosion of steel rebar embedded in concrete is one of the major concerns influencing the durability of reinforced concrete structures. It is widely recognized that the carbonation in concrete affects the chloride diffusivity and accelerates chloride-induced reinforcement corrosion. The service load related cracks also have a dominant influence on the reinforcement corrosion. This study aims to investigate the potential impact of concrete carbonation on the chloride penetration resistance, and the rate of corrosion, in RC structures subjected to service related cracks, which is not yet fully understood within the literature. The experimental programme involves casting concrete prisms (100 x 100 x 500 mm) with different water-cement ratios of 0.4, 0.5 and 0.6 and with four different crack width ranges (0, 0.05-0.15 mm, 0.15-0.25 mm and 0.25-0.35 mm), developed through flexural loading of prisms. These samples were exposed initially to accelerated carbon dioxide (CO2) environment and then exposed to the accelerated chloride environment. Carbonation depth, chloride penetration, and the degree of corrosion (using half-cell potential and linear polarization resistance) were experimentally measured. The results indicated that (i): The depth of carbonation increases with the increase in crack width and w/c ratio, (ii) chloride penetration depth and chloride concentration profile in concrete structures increases significantly due to the influence of carbonation and (iii) half-cell corrosion potential and linear polarization resistance increases significantly when carbonated concrete samples are exposed to the chloride environment relative to the uncarbonated concrete samples.

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