Effect of Silica Fume and Ground Granulated Blast Furnace Slag on Mechanical Properties in Concrete Repair

Reinforced concrete structures are widely constructed in Persian Gulf region for infrastructures of ports and oil exploration. Deterioration of concrete structures in this hot marine area, which is mainly due to chloride induced corrosion of embedded steel bars, requires hundreds of million dollars of repair cost every year. Accordingly, good quality concretes are used, under these extreme ambient conditions, to enhance the design life and durability of concrete constructions and infrastructures and finally, reduce the cost of repair and rehabilitation of these structures in this harsh environment. In this study, four different mixture proportions with water to cement ratio of 0.38 and constant cement content of 420 kg/m3 are used to investigate the effect of silica fume, slag and combined effect of these two materials (silica fume and slag) on mechanical specifications (compressive, bending and shear strengths and module of elasticity) of repair concretes. It can be deducted from results of this study that mixture with combined of silica fume and slag improves the mechanical specification of concrete better than other mixtures. In addition,concrete mixture with slag increases the plasticity of repair concretes. Results show that all of repair mixtures represent better plasticity than base concrete and finally, increase the strength of repair concretes against cracking.

Keywords:

concrete repair , shear strength module of elasticity , silica fume , slag