Title: Corrosion-Induced Cracking Time in Steel Fiber-Reinforced Concrete: Experiment and Finite Element Method
Author(s): Nattapong Paewchompoo, Wanchai Yodsudjai, and Prinya Chindaprasirt
Publication: Materials Journal
Appears on pages(s): 3-12
Keywords: concrete cover cracking time; corrosion; corrosion current density; experimental study; fiber-reinforced concrete; finite element analysis
The objective of this research was to clarify the mechanism of concrete cover cracking time due to reinforcement corrosion in steel fiber-reinforced concrete. An experimental study and analytical study were conducted. For the experimental study, 3 in. (76.2 mm) diameter and 6 in. (152.4 mm) length cylindrical concrete specimens with reinforcement placed in the middle were prepared. Conventional and steel fiber-reinforced concrete with three levels of compressive strength were used in the study. A strain gauge was installed along the specimen’s circumference and the corrosion of reinforcement was accelerated using anodic DC current. Concrete surface strain and impressed anodic current were recorded via a data logger and a multimeter, respectively. Concrete cover cracking time was also investigated. After corrosion acceleration, reinforcement weight loss was evaluated and internal pressure due to the reinforcement corrosion product was calculated. The analytical study was conducted using finite element with four-node bilinear plane strain in a two-dimensional (2-D) model. In the finite
element method (FEM) model, the reinforcement was removed and the internal pressure result from the expansion of corrosion products was applied, similar to the problem of cylinder under constant internal pressure. The relationship between concrete surface strain and internal pressure from the analytical study was compared with the experimental study. It was found that corrosion current density of the reinforcement embedded in the fiber-reinforced concrete was higher than that of conventional concrete. Concrete cover cracking time increased with increase of concrete tensile strength. In addition, the relationship between concrete surface strain and the internal pressure could be predicted by the FEM results within an acceptable margin of error.