Experimental Analysis for Corrosion in Reinforced Concrete Structures

Ahmed Ashour Rhouma, Waled Farj Alnaas, Mokhtar Abdusalam Alaaib

Abstract: Corrosion of Structural reinforcement is becoming an issue for constructions that are exposed to environmental conditions. The bond strength between concrete and the reinforcement can be affected by corrosion due to loss of the reinforcement area. This can lead to safety issues in terms of sudden collapse without warning signals. Therefore, it is important to study the effects of corrosion on concrete and the period of bond strength loss in order to take into account safety precautions. The effect of corrosion on bond strength has been studied in several experiments. In this paper, an electrical current with voltage of 24V was used in order to accelerate the corrosion of an embedded rebar within three hours in concrete cubes of 15*15*15. Pull out tests were applied on the specimens after 14 days of casting of the concrete, with compressive strength C30. The specimens have different levels of corrosion (0%, 5% and 10%) and different applied loads pulling the rebar. The applied force on the samples was at 100%, 90% and 80% of the failure load and bond slip relations were compared under different levels of corrosion. This provides a period during the test to monitor the level of cycling before specimen failure. The results showed that a corroded rebar with 5% of corrosion level has higher bond strength and less slip than the other specimens that have different levels of corrosion, which slightly differs from the theories espoused in previous researches. It was remarkable how a slight difference in cycling between corroded and uncorroded rebars indicates that specimens with similar levels of corrosion and the same properties of concrete can affect bond strength under slight impacts. It was also noticed that uncorroded samples cannot be affected by cracks even though the rebar was pulled out by applied force.

Keywords: Bond Strength, Corrosion, Pull Out test, Bond Slip, Reinforced Concrete