Laboratory Study of Mechanical Properties and Durability of ConcreteContaining Silica fume and Barchip Fibers

In recent years corrosion of steel reinforcement in concrete has been recognized as one of the most important reasons for early damage in reinforced concrete structures. In marine environments, the release of ion chloride and ion sulfate into concrete resulted in corrosion, are the major cause of dameges and shortening the useful life of reinforced concrete structures. Because concrete is weak in tension and it is cracked due to the operation loads, chlorine ions can easily enter concrete through these cracks, causing corrosion of the rebars. Therefore, the fibers can reduce the corrosion of the bars in concrete by delaying of cracking or reducing the crack width as well as silica fume Pozzolan can decrease the rebars corrosion through reduction of  penetration of liquids. Accordingly, in the present study 5 concrete compositions were made. Silica fume pozzolan was added to the concrete mixtures by replacing 10 wt.% of the cement and Barchip fibers with values ​​of 2.5, 3.5 and 5 kg/m3 were added to the concrete mixtures. In order to evaluate the mechanical properties, compressive and flexural strength tests, and for concrete durability, special electrical resistance and half-hour water absorption tests were performed. The results show that silica fume is effective in decreasing of half-hour water absorption and increasing of the specific electrical, compressive and flexural strength of concrete, and the combined application of silica fume and Barchip fibers enhances the flexural strength of concrete up to 65%. There is also a decrease in electrical resistance and an increase in compressive strength and half-hour water absorption by the addition of Barchip fibers to the concrete composition containing silica fume