Bond Deterioration of Corroded-Damaged Reinforced Concrete Structures Exposed to Severe Aggressive Marine Environment
Cecielle N. Dacuan, Virgilio Y. Abellana
Abstract
Cracks lead to a reduction of the bond between concrete and reinforcing steel rebars. A considerable decrease in the bond strength is more dangerous to a structural element’s safety than the loss of the cross-sectional steel reinforcement area. The purpose of this study is to evaluate the bond strength of corroded-damaged structures exposed to severely aggressive marine environments. Eighteen (18) cube specimens with dimensions of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mn>200</a:mn> <a:mtext> </a:mtext> <a:mtext>mm</a:mtext> <a:mtext> </a:mtext> <a:mtext>x</a:mtext> <a:mtext> </a:mtext> <a:mn>200</a:mn> <a:mtext> </a:mtext> <a:mtext>mm</a:mtext> </a:math> were cast. They were reinforced with three (3) different diameters of deformed steel and were grouped as unconfined and confined. The specimen was accelerated under a simulated corrosive environment. The experiment results reveal that the bond strength of concrete and steel reinforcement is susceptible to corrosion levels. The degree of corrosion significantly affects the bond strength of concrete and steel. The bond strength and the average crack width have a strong correlation; a minimal amount of corrosion with a minimum crack width of 0.03 mm after cracking reduces the bond strength to an unacceptable level. Stirrups confinement has a significant influence on the bond strength; it provides an excellent means to counteract bond loss. The loss of bond directly affects the serviceability and ultimate strength of reinforced concrete structures. There is an exponential relationship between cement and steel reinforcement’s bond strength with the serviceability and residual strength of reinforced concrete structures.