1. By L. Shi, J. Ye, C.C. Chen, Y. Wu and J.Z. Liu
Analysis of the influence of organic corrosion inhibitors on corrosion of reinforcement in concrete bridge structure under simulated field service environment
By L. Shi, J. Ye, C.C. Chen, Y. Wu and J.Z. Liu

2. Outline Introduction Experimental
Influences of corrosion inhibitors on reinforcement corrosion behaviors considered protective layer thickness changed, chloride intrusion form difference and environmental temperature difference
Recommendations for organic corrosion inhibitors applications technology

3. Introduction

4. Huge destruction and waste!
Reinforcement corrosion problems
It has to spend 100 million yuan per year on concrete bridge structures repairing and strengthening.
Huge destruction and waste!

5. Qingdao Wanda East Hollywood Organic corrosion inhibitors
The way to solve corrosion problems
Qingdao Wanda East Hollywood
Organic corrosion inhibitors
Hangzhou Bay Bridge
Chong Kai Bridge

6. Concrete structure change
Organic corrosion inhibitors effect evaluation
Firstly, the concrete protective layer thickness of different parts of bridge structure is different and protective layer may change due to the external corrosion medium attack or physical damage.
Secondly, chloride salt directly mixes and intrudes from outside both existence in concrete bridge structure.
Thirdly, some concrete projects service in cold area and freeze-thaw cycles must be considered.
Service environment change
Concrete structure change
corrosion inhibitors loss
wetting-drying cycles
negative temperature range
concrete protective layer thickness change
Do not consistent with the actual project situation !

7. ‘Guan He Bridge’ Corrosion risk 5 km 167.5m
The experiment work of this paper was conducted relying on a coastal bridge named “Guan He Bridge” in China.
Research considered the conditions of concrete protective layer change, chloride intrusion form difference and various environments through laboratory simulations.

8. Experimental

9. C-cement, FA-fly ash, SL-slag, S-sand, G-coarse aggregate, W-water
Materials and concrete mix proportions
Sample NO.
Mix proportion (kg/m3)
PCA ZX CN C FA SL S G W
C50-control
322 46 92
721
1081
138  -
C50-ZX
C50-CN
C-cement, FA-fly ash, SL-slag, S-sand, G-coarse aggregate, W-water
Concrete without corrosion inhibitors (C50-control), concrete with small molecule alcohol amine (C50-ZX) and concrete with calcium nitrite (C50-CN)
All the experiments in this study were focus on C50 concrete tower.
In the mix proportion, mineral admixtures were used to enhance the durability of concrete.
When the concrete specimens with reinforcement were casted, the fresh concrete needed to have the same slump and air content.

10. Reinforcement corrosion behaviors experiment1# 2# 3# 4#
Influences of corrosion inhibitors on reinforcement corrosion behaviors when protective layer thickness changed.
Influences of corrosion inhibitors on reinforcement corrosion behaviors when protective layer thickness changed.
Chloride intrusion form was different.
Environmental temperature was different.
Influences of corrosion inhibitors on reinforcement corrosion behaviors when protective layer thickness changed.
Chloride intrusion form was different.
Test equipment of corrosion status of the internal reinforcement in specimen
Electrochemical workstation!
Corrosion current density was the key indicator to characterize the reinforcement corrosion behaviour and the corrosion inhibitors effect.

11. Influences of corrosion inhibitors on reinforcement corrosion behaviors considered protective layer thickness changed

12. [Cl-]/[NO2] values OH- ions “filming” function “plug holes” function
When corrosion inhibitors were added into concrete the corrosion current density of reinforcement decreased.
There was a significant impact of wetting-drying cycles on corrosion current density of reinforcement in concrete when the protective layer thickness decreased.
For reinforcement in concrete with organic corrosion inhibitors, the corrosion current density increment did not significantly impact by protective layer thickness changed.
[Cl-]/[NO2] values
OH- ions
“filming” function
“plug holes” function

13. Influences of corrosion inhibitors on reinforcement corrosion behaviors considered chloride intrusion form difference

14. “chemical-physical combination film”
For chloride salt mixed directly situation, the corrosion current density increment of reinforcement in concrete did not have significantly change at the age synchronous with wetting-drying cycles.
Mineral admixtures have a great adsorption of chloride ions.
[Cl-]/[NO2] values
“chemical-physical combination film”

15. Influences of corrosion inhibitors on reinforcement corrosion behaviors considered environmental temperature difference

16. Solution may not frozen
Positive and negative temperature had no significant effect on the corrosion current density of reinforcement in concrete without corrosion inhibitors and with organic corrosion inhibitors.
0.13μA/cm2
0.04μA/cm2
The corrosion current density increment of reinforcement in concrete with inorganic corrosion inhibitors increased significantly in negative temperature range.
Temperature decreases
CN diffusion rate reduce
Solution may not frozen
Wet-dry
[Cl-]/[NO2] values
Solution may freeze
Migrate by vapor

17. Recommendations for organic corrosion inhibitors applications technology

18. Recommendations for organic corrosion inhibitors applications
technology in “Guan He Bridge”
Organic corrosion inhibitors should be used in concrete structure which protective layer is thin or the protective layer easily damaged during service.
Organic corrosion inhibitors should be used to protect the reinforcement in the concrete structure which may suffer from wetting-drying and freeze-thaw cycles.
Organic and other kinds of corrosion inhibitors can be used in the concrete structure which service in water for a long time if the water is stationary instead of flow.

19. Recommendations for organic corrosion inhibitors applications
technology in “Guan He Bridge”
Organic corrosion inhibitors has been used in concrete tower of “Guan He Bridge”

20. THANK YOU
for your attention!
Questions?