Diffusion Behavior of Chloride Ions in Concrete Box Girder under the Influence of Load and Carbonation.

Yinglong Liu,Pengzhen Lin,Junjun Ma

doi:10.3390/ma13092117

Abstract

In order to study the durability degradation characteristics of concrete box girder under load and carbonation and chloride ion erosion, a scale model of concrete box girder was made for experimental research. According to the test results, the diffusion characteristics of chloride ions in the concrete box girder under the coupling effect of load and carbon dioxide were analyzed. By revising the calculation formula of the existing chloride ion concentration considering multiple factors, a calculation model of chloride ion concentration considering the influence of carbonation was proposed, and the test results were verified. The results show that the chloride concentration of the box girder on the same cross section is non-uniformly distributed due to the shear lag effect and the spatial structure. After considering the effect of carbonation, the difference rate of the improved model proposed in this paper is generally within 10%. Compared with the original model, the difference rate is reduced by a maximum of 19%.

Highlights

The durability of concrete structures involves structural safety, which has become a key issue in the engineering community [1]
The most prominent problem affecting the durability of concrete structures is the corrosion of steel bars [2], and concrete carbonation and chloride ion erosion are the main causes [2,3]
Once the steel bars in the concrete corrode, will the effective area of the steel bars be reduced, but the resulting corrosion products will expand the volume of the steel bars, which will cause the concrete protective layer to crack or even fall off, which will eventually lead to a decrease in the durability and bearing capacity of the concrete structure [4,5]

Summary

Introduction

The durability of concrete structures involves structural safety, which has become a key issue in the engineering community [1]. The most prominent problem affecting the durability of concrete structures is the corrosion of steel bars [2], and concrete carbonation and chloride ion erosion are the main causes [2,3]. CO2 and Cl− erosion are the most common and coupling corrosion types of concrete bridges [3]. J. et al [6] have shown that the life of concrete structures under the combined action of carbonation and chloride ions has been reduced by nearly 20 years. In 2004, Germany spent about 300 million euros on highway maintenance and repairs, of which 40% was used to repair concrete bridge damage caused by chloride salt corrosion and steel bar corrosion [7]

Methods

Discussion

Conclusion