Concrete Corrosion Cracking and Transverse Bar Strain Behavior in a Reinforced Concrete Column under Simulated Marine Conditions

Gyeongcheol Choe,Euibae Lee,Sangkyu Lee,Gyuyong Kim,Jeongsoo Nam,Yasuji Shinohara

doi:10.3390/app10051794

Abstract

This study performed accelerated corrosion tests on reinforced concrete (RC) specimens reinforced with transverse steel bars to evaluate the concrete cracking and rebar strain behaviors caused by rebar corrosion. Seven RC specimens were created with variable compressive strengths, rebar diameters, and concrete cover thicknesses. To mimic in-situ conditions, the accelerated corrosion tests applied a current to the longitudinal bar and transverse bar for different periods of time to create an unbalanced chloride ion distribution. These tests evaluated the amount of rebar corrosion, corrosion cracking properties, and transverse bar strain behavior. The corrosion rate of the transverse bar was faster than that of the longitudinal bar, and cracking first occurred in the concreate around the transverse bar in the specimens with low concrete compressive strength and thin concrete cover. Corrosion cracking and rebar strain were greatly affected by the behavior of the corrosion products that resulted from the pore volume and cracking properties of the cement paste.

Highlights

Rebar corrosion from chloride attack is a major cause of reduced performance in reinforced concrete (RC) structures [1,2]
The amount of longitudinal bar corrosion was compared between the corner and intermediate bar of each specimen, and the amount of transverse bar corrosion was shown as the average of three different bars
F40-D38-C40), the largest longitudinal bar diameter was associated with higher transverse bar strain

Summary

Introduction

Rebar corrosion from chloride attack is a major cause of reduced performance in reinforced concrete (RC) structures [1,2]. Rebar corrosion causes section loss and creates corrosion by-products that expand to two–six times the volume of the steel [3]. These corrosion by-products lead to expansion pressures around the rebar, which cause tensile stresses in the rebar’s circumferential direction. If corrosion cracking within the member propagates to the surface, the risk of spalling increases because the integrity of the concrete cover is reduced. When the corrosion cracking affects transverse bar, the tensile strain increases and the yield strength is reduced [5,6]

Methods

Results

Conclusion