The effect of corrosion on shear behaviour of self-consolidating concrete beams

The objectives of this research are to compare the effect of corrosion on shear behavior in particular, and the overall structural response in both NC and SCC beams in general. Twenty reinforced concrete beams were used, with ten specimens cast using normal concrete (NC), and the other ten were cast using self-consolidating concrete (SCC). The dimensions for each beam were 150mm x 220mm x 1400mm. Using accelerated corrosion through the application of a constant current of one ampere, four stages of corrosion were established at 5%, 10%, and 20% of mass loss. Simply supported beams were loaded with two concentrated loads, and a four-point loading test was applied to the reinforced concrete (RC) beams. If (a) is the distance from the concentrated load to the reaction, and (d) is the distance from the center of the tensile flexural rebars to the top of the concrete beam, then a/d=2.5 was applied to assure the highest probability of shear failure mode. The data collected from load cell, LVDTs, corrosion crack patterns and loading cracks patterns were used to study the effects of multiple stages of corrosion on the shear behaviour of reinforced NC and SCC concrete beams. The corroded rebars were then retrieved and cleaned to compare the calculated mass loss with real mass loss. The results showed high correlation between the calculated mass loss (according to Faraday law) and real mass loss. The accelerated corrosion resulted in a corrosion crack pattern, which was documented and analyzed. In this research, the use of NC and SCC showed minor influences on failure mode, while the different states of corrosion showed a higher degree of influence on failure mode and the structural capacity of beams made from both types of concrete. The apparent changes in failure mode were associated with the increased corrosion stage.