An Experimental Study On The Crossion-Induced Cracking And Stiffness Degradation Of Reinforced Concrete Beams

Through an electric-chemical experiment on reinforced concrete beams located in a chloride-laden environment, the effects of the water/cement ratio, cover depth, and corrosion current density on the time to surface cracking, crack width, and corrosion rate are studied. The relationship between the crack width and mechanical property degradation of reinforced concrete beams is analyzed.The experimental results showed that the time to surface cracking increases as the water/cement ratio and cover depth increase and/or the corrosion current density decreases. Although the water/cement ratio has a little influence on the time to surface cracking and time to structural failure, increasing the ratio between the tensile strength and elastic modulus of concrete can increase the time to surface cracking. The cover depth influences concrete surface cracking mainly in the early stages. In the stage of cracking development, the cover depth has little influence on the crack width. The corrosion current density is the most important influential factor that affects surface cracking, but its effect is restricted by the oxygen content around steel bars.There is a critical value in the relationship between the surface crack width and stiffness degradation of reinforced concrete beams. When the crack width is smaller than0.3mm, increasing the crack width can increase the stiffness of concrete beams. When the crack width is greater than0.3mm, however, the stiffness of concrete beams decreases with an increase in crack width.This study not only enriches the test data of corroded concrete beams but also provides a certain evidence for the durability design of reinforced concrete structures.