Chloride Ion Erosion in Concrete under Sustained Axial Pressure

2016 ◽  
Vol 680 ◽  
pp. 402-405
Author(s):  
Zong Ming Yang ◽  
Wei Hong Li ◽  
Yi Han Wang
Keyword(s):  
Axial Compression ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Reinforcement Corrosion ◽  
Compression Load ◽  
Durability Design ◽  
Chloride Ion Penetration ◽  
Chloride Environment ◽  
Ion Erosion

As one of the leading causes of influencing the durability of concrete structure, reinforcement corrosion has been a central issue. Erosion of chloride ions on the concrete structure is influenced by many factors. This is not only concerned with its own structural properties, but also to its environment, to withstand the load and other factors. This article has carried on an experiment which researches on the rules of chloride ion penetration in the sustained axial compression after different corrosive time, when the concrete is corroded under the joint action of axial compression load and chlorine salt circulation. The results prove that, with the increase of Intensity of load and the cycle time of chlorine salt, the number of Chloride ion ingress in concrete continues to increase. The experimental results may provide a reference to the durability design of concrete in chloride environment.

scholarly journals Influence of Fly Ash Additive on the Properties of Concrete with Slag Cement

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3265 ◽  
Author(s):  
Anna Szcześniak ◽  
Jacek Zychowicz ◽  
Adam Stolarski
Keyword(s):  
Fly Ash ◽  
Chloride Ion ◽  
High Strength ◽  
Experimental Tests ◽  
Chloride Ions ◽  
Strength Increase ◽  
Slag Cement ◽  
Initial Strength ◽  
Chloride Ion Penetration ◽  
The Impact

This paper presents research on the impact of fly ash addition on selected physical and mechanical parameters of concrete made with slag cement. Experimental tests were carried out to measure the migration of chloride ions in concrete, the tightness of concrete exposed to water under pressure, and the compressive strength and tensile strength of concrete during splitting. Six series of concrete mixes made with CEM IIIA 42.5 and 32.5 cement were tested. The base concrete mix was modified by adding fly ash as a partial cement substitute in the amounts of 25% and 33%. A comparative analysis of the obtained results indicates a significant improvement in tightness, especially in concrete based on CEM IIIA 32.5 cement and resistance to chloride ion penetration for the concretes containing fly ash additive. In the concretes containing fly ash additive, a slower rate of initial strength increase and high strength over a long period of maturation are shown. In accordance with the presented research results, it is suggested that changes to the European standardization system be considered, to allow the use of fly ash additive in concrete made with CEM IIIA 42.5 or 32.5 cement classes. Such a solution is not currently acceptable in standards in some European Countries.

Effect of Metakaolin-Based Modifier on the Permeability of Concrete Structure in the Marine Environment

2013 ◽  
Vol 438-439 ◽  
pp. 117-120
Author(s):  
Jun Tao Ma ◽  
Liang Yan ◽  
Yu Ping Tong ◽  
Hui Xian Wang
Keyword(s):  
Fly Ash ◽  
Marine Environment ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Chloride Ion Penetration ◽  
Working Performance ◽  
Electric Flux ◽  
Penetration Behavior ◽  
Strength And Durability

Corrosion of the steel reinforcement in the concrete structure caused by chloride ion penetration becomes more serious in the marine environment. Metakaolin has been widely used in the concrete structure to improve the strength and durability. The combination of metakaolin (MK) and fine fly ash (FA) was studied in the article and the penetration behavior of concrete with various contents of metakaolin-based modifier is investigated. The penetration resistance of concrete was tested in combination of electric flux test. The improving mechanism was studied with mercury intrusion porosimetry analysis (MIP). The experiment results indicate that metakaolin-based modifier improved the penetration resistance of concrete obviously. The combination of fine fly ash weakened the water sucking action of metakaolin and preserved the working performance of concrete. The pore size distribution of concrete containing metakaolin-based modifier has been optimized to improve the microstructure and enhance the penetration resistance of concrete.

The Experimental Research on the Anti-Corrosion Performance of Concrete with Different Mineral Admixtures under Sulfate and Chloride Environment

2014 ◽  
Vol 638-640 ◽  
pp. 1431-1435
Author(s):  
Wen Xun Qian ◽  
Yan Chi Zhang ◽  
Xun Jie Chen ◽  
You Lin Ouyang
Keyword(s):  
Loss Rate ◽  
Chloride Ion ◽  
Strength Loss ◽  
Sulfate Attack ◽  
Mineral Admixtures ◽  
Corrosion Performance ◽  
Chloride Ion Penetration ◽  
Initial Stage ◽  
Chloride Environment ◽  
Permeability Of Chloride Ion

The performance of resistance to sulfate attack and permeability of chloride ion on concrete with different mineral admixtures (fly ash, slag single or both adding) under sulfate and chloride environment were discussed. The results indicated the performance of resistance to salt attack on concrete with appropriate mineral admixtures was improved. Under chloride environment, the resistance to sulfate attack coefficient of testing mortars descended, and compressive strength loss rate of concrete was raised after dry-wet cycles. Therefore, the performance of resistance to salt attack on concrete was decreased in this environment. Besides, on the initial stage of corrosion, the ability to resist chloride ion penetration of concrete was improved under sulfate environment, while the penetrating of chloride ion was accelerated on the later stage.

Experimental Study on Mix Design of Chloride Resistant Cementitious Spacers

2014 ◽  
Vol 629-630 ◽  
pp. 351-357
Author(s):  
Chen Huang ◽  
Wen Ying Guo ◽  
Yi Bo Yang ◽  
Hui Zhao ◽  
Zhen Jie Li ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Design Method ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Mix Design ◽  
Easy Access ◽  
Ion Diffusion ◽  
Electric Flux ◽  
Chloride Environment ◽  
Chloride Ion Diffusion

Chloride resistant HPC and protective cover are two basic measurements to improve the durability of concrete in chloride environment. Though it provides crucial cover for concrete to resist chloride ions, spacer has limited chloride resistant ability, which is overlooked by past researchers. Cementitious spacers are easy access for chloride ions to penetrate into concrete resulting in reduction of structural durability. To improve cementitious spacers’ performance, a systematic study was conducted. Test results showed that there was major difference between mortar and concrete in terms of chloride coulomb electric flux but minor difference in terms of chloride ion diffusion coefficient, which implied using chloride ion diffusion coefficient as spacer’s durability indicator was preferable; parameters of mix design had a similar influence on mortar and concrete and, with the same mixing parameters, the strength and chloride resistant ability of mortar were weaker than concrete’s; it was feasible to develop the mix design of chloride resistant cementitious spacers based on concrete’s design method with certain adjustments, such as using stricter mix proportion, adding small-size coarse aggregate, lowering water-binder ratio and optimizing the binder proportion, to achieve higher strength and durability.

scholarly journals Prediction of Chloride Penetration into Hardening Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wei-Jie Fan ◽  
Xiao-Yong Wang
Keyword(s):  
Cement Hydration ◽  
Binding Capacity ◽  
Numerical Procedure ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Experimental Investigations ◽  
Hydration Reaction ◽  
Degree Of Hydration ◽  
Chloride Diffusivity ◽  
Chloride Ion Penetration

In marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. Currently, most of experimental investigations about submerged penetration of chloride ions are started after the four-week standard curing of concrete. The further hydration of cement and reduction of chloride diffusivity during submerged penetration period are ignored. To overcome this weak point, this paper presents a numerical procedure to analyze simultaneously cement hydration reaction and chloride ion penetration process. First, using a cement hydration model, degree of hydration and phase volume fractions of hardening concrete are determined. Second, the dependences of chloride diffusivity and chloride binding capacity on age of concrete are clarified. Third, chloride profiles in hardening concrete are calculated. The proposed numerical procedure is verified by using chloride submerged penetration test results of concrete with different mixing proportions.

scholarly journals Preliminary Assessment of 22Cr and 15Cr Materials Selection for CO2 Enhanced Oil Recovery Program

2019 ◽  
Vol 269 ◽  
pp. 03014
Author(s):  
Harris Prabowo ◽  
Yudha Pratesa ◽  
Reza M. Ulum ◽  
Badrul Munir ◽  
Johny W. Soedarsono
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Material Selection ◽  
Selection Process ◽  
Oil Production ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Materials Selection ◽  
Fluid Analysis ◽  
Chloride Environment

Enhanced Oil Recovery (EOR) program to increase oil production from mature fields are now being implemented in Indonesia amid concern over the continuous decrease of oil production level. The mature fields and EOR process have the tendency to carry relatively high impurities components (CO2, H2S, chloride ions) that results in early corrosion occurrence, creating damages in the subsurface equipment (wellhead, tubing, Xmas tree, etc). In Java area with 0.09 TSCF potential gas reserves, 49.3 MMSTB oil and + 23% CO2 content, such amount of CO2 gas and possibility of H2S and chloride from the reservoir will require a higher grade material than the conventional carbon steel. This paper discuss the preliminary materials selection process in the program plan based on the existing condition. The material selection based on the evaluation of closest field data, literature review as a comparison, material, and fluid analysis test. Duplex 22Cr-15 Cr materials are the main study in the paper as the candidate for the tubing material in high CO2, high H2S and chloride environment. The polarization result in 27°C and 50°C showed that the chrome 22 %Cr material had pitting tendency in chloride ion 25,000 ppm, while at high temperature (80 °C) the pitting tendency shifted to 5,000 ppm of chloride ion.

scholarly journals Damage Mechanism of Mineral Admixture Concrete under Marine Corrosion and Freezing-Thawing Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yan Li ◽  
Lianying Zhang ◽  
Chao Ma ◽  
Bing Li ◽  
Jiong Zhu
Keyword(s):  
Fly Ash ◽  
Chloride Ion ◽  
Damage Mechanism ◽  
Chloride Ions ◽  
Mineral Admixture ◽  
Ion Concentration ◽  
Dominant Factor ◽  
Marine Corrosion ◽  
Chloride Ion Penetration ◽  
Mineral Powder

Understanding the performance of concrete in the marine environment is significant for preventing the corrosion of chloride ion for marine buildings. In this study, the uniaxial compressive strength (UCS), chloride ion concentration (CIC), microstructure, and pore structure of admixture concretes were tested to study the mechanical properties and microscopic characteristics under the single marine corrosion, the single freezing-thawing, and the coupled marine corrosion and freezing-thawing conditions. The results indicate that the concrete mixed with both fly ash and mineral powder has better UCS, chloride ion penetration resistance, and freezing-thawing resistance than the concrete with the single fly ash or mineral powder. Under the marine corrosion environment and coupled corrosion and freezing-thawing environment, the UCS of the concrete with both fly ash and mineral powder increases firstly and then decreases with the increase of the corrosion time. This is because the pore of the filling body is filled by large crystalline salts generated by the reaction of chloride ions and concrete; then, cementation of the cement is increased in the early corrosion; meanwhile, the increase of crystal salt in the subsequent corrosion process leads to the growth of microcracks and the formation of macrocracks in concrete specimens. In addition, a freezing-thawing-corrosion composite strength impact factor is introduced to describe the effect of coupled corrosion and freezing-thawing on the mechanical property of the concrete. The results show that the corrosion is the dominant factor after 0, 30, and 60 freezing-thawing cycles, while the freezing-thawing is the dominant factor after 90 freezing-thawing cycles.

Research on Durability Design of Concrete Structure under Chloride Environment

2014 ◽  
Vol 926-930 ◽  
pp. 623-626
Author(s):  
Ke Feng Zhang
Keyword(s):  
Concrete Structure ◽  
Design Theory ◽  
Design Method ◽  
Theory Model ◽  
Concrete Cover ◽  
Carbonation Depth ◽  
Durability Design ◽  
Chloride Environment ◽  
Cover Thickness ◽  
Chlorine Ion

For concrete structure durability increasingly highlight of problem, focus description has chlorine ion on concrete structure of erosion mechanism, and invaded model and effects factors, derivation out integrated consider concrete of chlorine ion combines capacity, and chlorine ion proliferation coefficient of time dependence, and concrete structure micro-defects effects and the mixed coagulation s performance of practical proliferation equation, established has for forecast concrete using life of chlorine ion proliferation theory model, made intends built structure in chlorine ion environment Xia durability design thought and design method, Perfected design theory of durability of concrete and carbonation model design based on Carbonation depth of concrete during the period, compared with the concrete cover thickness, for engineering design and revision of the specification reference.

Experiment Study on Concrete Resistance to Chloride Ion Penetration

2014 ◽  
Vol 716-717 ◽  
pp. 236-239
Author(s):  
Wei Hong Li ◽  
Ying Ying Xu ◽  
Yi Han Wang
Keyword(s):  
Chloride Ion ◽  
Concrete Block ◽  
Load Level ◽  
Diffusion Method ◽  
Environment Interaction ◽  
Ion Content ◽  
Chloride Ion Penetration ◽  
Conservation Condition ◽  
Ion Erosion ◽  
Permeability Of Chloride Ion

The influence law of permeability of chloride ion in concrete of load level, curing condition under the sustained pressure load and the corrosion environment interaction is researched in this article, which is through natural diffusion method. Experimental results show that as the load level increases, there is a tendency of the chloride ion content after the first increase and then decrease, the turning point in the middle remains to be further studied. Good conservation condition reduces large holes and harmful holes in concrete block, thereby reduce the porosity and improve resistance to chloride ion erosion.

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