scholarly journals Study on chloride ion diffusion characteristics of reactive powder concrete under different loads

2021 ◽  
Vol 283 ◽  
pp. 01015
Author(s):  
Yan Xin-e
Keyword(s):  
Chloride Ion ◽  
High Strength ◽  
Ion Concentration ◽  
Reactive Powder Concrete ◽  
Ion Diffusion ◽  
Soaking Time ◽  
Volume Stability ◽  
Diffusion Characteristics ◽  
Reactive Powder ◽  
Chloride Ion Diffusion

Reactive powder concrete (RPC) is a new cement-based material with ultra-high strength, high durability, high toughness and good volume stability. The study of chloride corrosion behavior is of great significance to the application of RPC in complex service environment. In this paper, the chloride ion immersion experiment is carried out to investigate the change rule of chloride ion concentration on the surface of RPC with soaking time under different loads. The results show that with the extending of soaking time, the chloride ion concentration of RPC surface gradually increases and tends to be stable, and the different depths from RPC surface also show similar rules. The results also show that the chloride ion diffusion characteristics of RPC under different loads are different, and the chloride ion diffusion rate under bending stress is higher than that under compressive stress.

Research on Chloride Diffusion Model of PC with Chloride Attack in Marine Atmosphere Zone

2014 ◽  
Vol 711 ◽  
pp. 481-484
Author(s):  
Yu Chen ◽  
Jie Xu ◽  
Rong Gui Liu ◽  
Su Bi Chen ◽  
Yuan Gao
Keyword(s):  
Prestressed Concrete ◽  
Concentration Distribution ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Chloride Diffusion ◽  
Marine Atmosphere ◽  
Ion Diffusion ◽  
Chloride Ion Diffusion

Based on the existing studies about chloride ion erosion in prestressed concrete structures, this paper intends to discuss the effects of the stress level and environment factors (including temperature and humidity, etc.) on chloride ion diffusion under marine atmosphere zone. The investigation from pre-stressed concrete crossbeams which service for 39 years in Lianyungang Port shows the chloride ion concentration distribution and chloride ion diffusion. According to the chloride ion concentration distribution, it finds that chloride ion concentration values in pre-concrete structures is Cmax,1> Cmax,2. In addition, the free chloride concentration distribution values go down smoothly after the second peak. Therefore, the result shows that the improved model can be used in marine atmosphere zone.

Study on the Durability of Concrete Structure of Aviation Oil Wharf of Shenzhen Airport

2010 ◽  
Vol 163-167 ◽  
pp. 1019-1023
Author(s):  
Wei Lun Wang ◽  
Ji Hua Zhu ◽  
Feng Xing
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Ion Diffusion ◽  
Cell Potential ◽  
Shenzhen City ◽  
High Possibility ◽  
Chloride Ion Diffusion ◽  
Existing Structure

Due to the invasion of chloride ion, the reinforcement in coastal concrete structure is corroded, which causes damage to the concrete structure and becomes the major factor affecting the structure’s service life. Aiming at the existing concrete structure under the coastal environment of Shenzhen City, the durability experimental study has been implemented, discussing the main reason for the insufficient durability of the existing structure. The experiment result shows that the higher chloride ion diffusion coefficient (76.1×10-12 m2/s) in the concrete structure leads that the chloride ion concentration of the structure in the depth of 30mm surpasses one percent upon using it for two decades. The half-cell potential value also reflects the relatively high possibility of the reinforcement corrosion of the structure. Combining with the experiment result, the service life of this concrete structure has been analyzed, which is hard to be guaranteed to use for five decades under the current concrete parameters and resistance.

Service Life Prediction of Reactive Powder Concrete due to Seawater Infiltration

2012 ◽  
Vol 535-537 ◽  
pp. 1785-1789
Author(s):  
Xin Wei Ma ◽  
Yu Yan Ji
Keyword(s):  
Service Life ◽  
Life Prediction ◽  
Sea Water ◽  
Energy Dispersive Spectrometer ◽  
Chloride Ion ◽  
Service Life Prediction ◽  
Reactive Powder Concrete ◽  
Ion Diffusion ◽  
Marine Engineering ◽  
Reactive Powder

Reactive powder concrete (RPC) has a higher strengths, as well as excellent durability and corrosion resistance. So, it is expected to be increasingly used in marine engineering. In this study, After the RPC samples had been subjected to gradually increased high-pressure seawater for 30 days, the chloride contents in the samples along with the infiltration direction were calibrated on an energy dispersive spectrometer. On the basis of second Fick’s law, the chloride ion diffusion model and service life prediction model of reactive powder concrete in sea water are established. The service life of an actual reactive powder concrete structure could be predicted.

Study on Effect of Soaking Time on the Transmission of Chloride Ion in Concrete under Drying-Wetting Cycles

2011 ◽  
Vol 261-263 ◽  
pp. 61-68 ◽  
Author(s):  
Qing Zhang Zhang ◽  
Xiang Lin Gu ◽  
Wei Ping Zhang ◽  
Qing Hua Huang
Keyword(s):  
Diffusion Coefficient ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Ion Content ◽  
Tidal Zone ◽  
Soaking Time ◽  
Pure Diffusion ◽  
Severe Erosion ◽  
Shallow Area ◽  
Chloride Ion Diffusion

Acceleration penetration tests of chloride ion were conducted for typical diurnal and semidiurnal tidal types in China with consideration of various values of soaking time. It was found that the content of chloride ion from shallow area near the surface of concrete to the pure diffusion area of concrete reduced more significantly with the depth than that in the pure diffusion area of concrete. Based on Fick’s second law, the variation laws of chloride ion content at the edge of the pure diffusion area and chloride ion diffusion coefficient in the pure diffusion area under different soaking time ratios were identified by using the chloride ion content distributions that were established based on the test results of concrete in the pure diffusion area. It was found that the chloride ion content and the apparent chloride ion diffusion coefficient in pure diffusion area may be very high when the ratio of soaking time ratio is between 0.3 and 0.42 or 0.6 and 0.7 for diurnal tidal type and 0.83 for semidiurnal tidal type, which will cause severe erosion in concrete structures in tidal zone.

Chloride Ion Diffusion Behavior of Concrete after Freezing and Thawing Cycles

2013 ◽  
Vol 671-674 ◽  
pp. 1652-1656 ◽  
Author(s):  
Feng Qu ◽  
Di Tao Niu
Keyword(s):  
Chloride Transport ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Chloride Diffusion ◽  
Ion Diffusion ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Improved Model ◽  
Freezing And Thawing Cycles ◽  
Chloride Ion Diffusion

With repeated action of freeze-thaw cycles, chloride ion diffusion characteristics changed obviously in concrete structure. In the study, the chloride ion diffusion coefficient and the surface chloride ion concentration were discussed especially with the trends. Based on these facts, the chloride diffusion model and the improved model of concrete was also discussed based on its time-dependent characteristics, which indicated that the freeze-thaw damage of concrete would have a greater impact to the chloride transport course in the concrete, and so on the service life of concrete structures would be affected.

Sea Sand Concrete Chloride Ion Diffusion and Combination of Curing

2012 ◽  
Vol 174-177 ◽  
pp. 358-361
Author(s):  
Jian Bin Chen ◽  
Guo Liang Zhang ◽  
Li Wei Mo ◽  
Jun Zhe Liu ◽  
Zhi Min He
Keyword(s):  
Chloride Ion ◽  
Chloride Ions ◽  
Water Soluble ◽  
Ion Concentration ◽  
Ion Diffusion ◽  
Binding Characteristics ◽  
Fly Ash Concrete ◽  
Sea Sand ◽  
Chloride Ion Diffusion

The concentration of chloride ion in concrete has been an important part of the study of reinforcement corrosion, while the microstructure of concrete on the concentration of chloride ions play an important role, in order to evaluate the sea sand for ordinary concrete and fly ash concrete microstructure andmineral composition, we use the 28 days of age in sea sand Mohr method for the determination of the different types of water-soluble chloride ion concentration to the chloride ion binding characteristics in the study of sea sand in concrete

scholarly journals Multi-Factor Coupling Model of Concrete Chloride-Ion Diffusion Coefficient in a Salt Lake

2019 ◽  
Author(s):  
Liming Zhang ◽  
Hongfa Yu ◽  
Jia Li
Keyword(s):  
Diffusion Coefficient ◽  
Salt Lake ◽  
Accumulation Rate ◽  
Chloride Ion ◽  
Coupling Model ◽  
Calculation Model ◽  
Ion Concentration ◽  
Ion Diffusion ◽  
Binder Ratio ◽  
Chloride Ion Diffusion

Immersion in salt-lake solution was adopted to periodically test the concrete chloride-ion diffusion coefficient. The regression analysis was also completed. Also investigated was the time-dependent law of concrete chloride-ion diffusion coefficient with time. The influence of chloride-ion concentration in solution, water-to-cement ratio, and corrosion time on the largeness and accumulation rate of the concrete chloride-ion diffusion coefficient was also analyzed. Test results show that the concrete chloride-ion diffusion coefficient gradually decreased with increasing time and increased with increasing chloride-ion concentration in a salt lake . Taking into account the influence of factors such as water–binder ratio, chloride-ion concentration, and time-varying characteristics, a multi-factor calculation model for the concrete chloride-ion diffusion coefficient was established. Combining the prediction results and the measured data reported in this paper, the effectiveness and applicability of the established concrete chloride-ion diffusion coefficient calculation model were compared and verified, and the durability design and service life of a concrete structure under cool chlorine were compared. The results of analysis provide important boundary conditions.

Modeling of Chloride Ion Diffusion in Concrete under Fatigue Loading

2018 ◽  
Vol 23 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Tao Yang ◽  
Bowen Guan ◽  
Guoqiang Liu ◽  
Yanshun Jia
Keyword(s):  
Chloride Ion ◽  
Fatigue Loading ◽  
Ion Diffusion ◽  
Chloride Ion Diffusion

EFFECT OF CRUMB RUBBER ON CONCRETE STRENGTH AND CHLORIDE ION PENETRATION RESISTANCE

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nurazuwa Md Noor ◽  
H. Hamada ◽  
Y. Sagawa ◽  
D. Yamamoto
Keyword(s):  
Structural Strength ◽  
Salt Water ◽  
Chloride Ion ◽  
Crumb Rubber ◽  
Rubberized Concrete ◽  
Migration Test ◽  
Ion Diffusion ◽  
Steady State Condition ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion

This paper present the effect of crumb rubber on its ability to produce concrete with structural strength when it was used directly from the plant without any treatment process. Crumb rubber was added as fine aggregates at 0%, 10%, 15% and 20% of sand volume meanwhile silica fume was added at 10% by cement weight. Three main series of concrete namely rubberized concrete with water-to-cement ratio of 50% and 35% was design and development of compressive strength was observed from day 7 until 91 days. Also, effectiveness of crumb rubber under flexural strength and splitting tensile strength was studied at 28 days curing age. Effect of crumb rubber on durability performance was done on chloride ion penetration resistance performance by migration test and by immersion in salt water. Chloride ion diffusion in rubberized concrete by migration test was carried out under steady state condition using effective diffusion coefficient, De meanwhile, immersion test in salt water was conducted under non-steady state condition using apparent diffusion coefficient, Da. Results showed that compressive strength was decrease with the increasing of crumb rubber in the mixture.  Even though the strength were reducing with the inclusion of crumb rubber, the reduction were less than 50% and it achieved acceptable structural strength. Chloride transport characteristics were improved by increasing amount of CR and rubberized concrete with w/c = 0.35 gave better resistance against chloride ion compared to w/c = 0.50 with more than 50% difference. Silica fume provide slightly strength increment compared to normal rubberized concrete and the same behavior was observed during chloride ion diffusion test.

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