The Research of Influence on the Freezing Resistance and the Permeation Resistance of Concrete With Spraying Silane

2014 ◽  
Vol 629-630 ◽  
pp. 213-217
Author(s):  
Xin Ge ◽  
Xian Hui Song ◽  
Yong Ge ◽  
Xiao Ping Cai
Keyword(s):  
Diffusion Coefficient ◽  
Water Absorption ◽  
Penetration Depth ◽  
Frost Resistance ◽  
Absorption Rate ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Water Absorption Rate ◽  
Liquid Absorption ◽  
Chloride Ion Diffusion

Silane, as an extremely hydrophobic material, changes concrete surface from hydrophilic state to hydrophobic state by spraying on the surface of concrete. It has the ability to block the external corrosive medium to improve the durability of concrete. Three types of strength grade of concrete (C30, C40, C50) were designed, after spraying with silane on the surface of concrete, to measure the penetration depth of silane and the influence on water-absorption rate, liquid-absorption rate, chloride ion diffusion coefficient and salt frost resistance. The test result shows that: by spraying silane on the surface of concrete,the one hour water-absorption rate of concrete was reduced by more than 98%, the 48 hours water-absorption rate was cut down above 91%, and the 48 hours liquid-absorption (3% NaCl solution) rate was decreased above 94%. The penetration depth for C30 and C50 has the maximum value (6.3mm) and minimum value (3.9mm) respectively. Absorption reduction rate of chloride ion overall was decreased by above 93%, and chloride ion diffusion coefficient was reduced by 42% ~ 48%. The freeze-thaw resistance was improved by 5 times. Key words: silane, the salt frost resistance, liquid-absorption rate, chloride ion diffusion coefficient

Research on Chloride Ion Diffusion of Concrete Water-Based Capillary Crystalline Waterproofer and its Penetration Depth by Using Electron Microscope

2013 ◽  
Vol 857 ◽  
pp. 27-34 ◽  
Author(s):  
Xin Xiao ◽  
Qi Sen Zhang ◽  
Xiao Ye Liang ◽  
Xiao Ning Zhang
Keyword(s):  
Diffusion Coefficient ◽  
Electron Microscope ◽  
Penetration Depth ◽  
Good Condition ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Diffusion ◽  
Strength Concrete ◽  
Water Based ◽  
Chloride Ion Diffusion

In order to improve the durability of concrete structure, studying reduction effect that water-based capillary crystalline waterproofer has on chloride ion diffusion coefficient in the concrete; analyse the inner microstructure of concrete by using electron microscope, and observe the penetration depth of waterproof agent in concrete directly. Research shows that: the water permeable crystalline waterproof agent can significantly reduce the diffusion coefficient of chloride ions in concrete, after concrete forms, the earlier brush waterproof agent, the longer it cure and its improving effect is more prominent after brushing waterproof agent , reduction rate of chloride ion diffusion coefficient in low strength concrete is higher than high-strength concrete;in good condition of water percolation, by detecting of electron microscope, it proved waterproofing agent can penetrate into internal concrete 6cm at least , the gel produced can be filled with pore and micro crack of concrete, so it can significantly improve the compactness of the whole structure.

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 Evaluation of Chloride-Ion Diffusion Characteristics of Wave Power Marine Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5675
Author(s):  
Changhyuck Lim ◽  
Gyuyong Kim ◽  
Gyeongtae Kim ◽  
Bokyeong Lee ◽  
Youngduck Kim ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Atmospheric Pressure ◽  
Concrete Structures ◽  
Chloride Ion ◽  
Wave Power ◽  
Ion Diffusion ◽  
Chloride Ion Penetration ◽  
Chloride Attack ◽  
Marine Concrete ◽  
Chloride Ion Diffusion

Wave power marine concrete structures generate electrical energy using waves. They are exposed to a multi-deterioration environment because of air and hydrostatic pressure and chloride attack. In this study, the effect of air pressure repeatedly generated by water level change of wave power marine concrete structures on the chloride-ion diffusion of marine concrete was analyzed. The chloride-ion diffusion of wave power marine concrete structures was evaluated. The results show that the air chamber and bypass room, which were subjected to repetitive air pressures caused by water level changes, showed a higher water-soluble chloride-ion content compared to the generator room and docking facility, which were subjected to atmospheric pressure. Field exposure tests and indoor chloride attack tests were performed using fabricated specimens to analyze the effect of pressure on chloride-ion penetration. It was confirmed that Portland blast furnace slag had a greater inhibitory effect on chloride-ion penetration than ordinary Portland cement. The concrete specimens subjected to pressure showed increased capillary pores and micro-cracks. We devised an equation for calculating the diffusion coefficient based on measured data and estimating the diffusion coefficient for the location receiving repeated air pressure by using the diffusion coefficient of the location receiving general atmospheric pressure.

scholarly journals Experimental Study on Chloride Ion Diffusion in Concrete under Uniaxial and Biaxial Sustained Stress

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5717
Author(s):  
Xiaokang Cheng ◽  
Jianxin Peng ◽  
C.S. Cai ◽  
Jianren Zhang
Keyword(s):  
Diffusion Coefficient ◽  
Compressive Stress ◽  
Stress Level ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Ion Diffusion ◽  
Chloride Ion Diffusion

The existence of axial and lateral compressive stress affect the diffusion of chloride ions in concrete will lead to the performance degradation of concrete structure. This paper experimentally studied the chloride diffusivity properties of uniaxial and biaxial sustained compressive stress under one-dimensional chloride solution erosion. The influence of different sustained compressive stress states on chloride ion diffusivity is evaluated by testing chloride concentration in concrete. The experiment results show that the existence of sustained compressive stress does not always inhibit the diffusion of chloride ions in concrete, and the numerical value of sustained compressive stress level can affect the diffusion law of chloride ions in concrete. It is found that the chloride concentration decreases most when the lateral compressive stress level is close to 0.15 times the compressive strength of concrete. In addition, the sustained compressive stress has a significant effect on chloride ion diffusion of concrete with high water/cement ratio. Then, the chloride diffusion coefficient model under uniaxial and biaxial sustained compressive stress is established based on the apparent chloride diffusion coefficient. Finally, the results demonstrate that the chloride diffusion coefficient model is reasonable and feasible by comparing the experimental data in the opening literature with the calculated values from the developed model.

Influence of Concrete with Lithium-Slag and Steel Slag by early Curing Conditions

2014 ◽  
Vol 599 ◽  
pp. 52-55 ◽  
Author(s):  
Fu Fei Wu ◽  
Ke Bin Shi ◽  
Shuang Kuai Dong
Keyword(s):  
Diffusion Coefficient ◽  
Water Conservation ◽  
Water Solution ◽  
Steel Slag ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Lithium Slag ◽  
Chloride Ion Diffusion

Using industrial waste (lithium-slag and steel-slag) for the preparation of high-performance concrete, and the same mix proportion’s concrete are cured using six kinds method, which is cured to the required age later and tests its chloride ion diffusion coefficient by RCM method. The results show that: the chloride ion diffusion coefficient of 28d and 84d decreases with the lower water-binder ratio. It can achieve RCM-Ⅴ grade when the water to binder ratio is 0.27. The admixtures total of 275-350kg/m3 is appropriate when the water to binder ratio is constant.The diffusion of water conservation,water solution with 5% Nacl after 7d water conservation,water solution with 5% Nacl after 14d water conservation,water solution with 5% Nacl after 7d in water conservation and water solution with 5% Nacl after 14d in water conservation is 1.5, 3.1, 2.5, 2.8 and 2.3 times than standard conservation , so the effect of early different curing ways to HPC can not be ignored.

scholarly journals Evaluation of Relationship between Water Absorption and Durability of Concrete Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. P. Zhang ◽  
L. Zong
Keyword(s):  
Compressive Strength ◽  
Surface Water ◽  
Water Absorption ◽  
Chloride Ion ◽  
Sulfate Attack ◽  
Ion Diffusion ◽  
Curing Conditions ◽  
Concrete Materials ◽  
Chloride Ion Diffusion ◽  
Durability Of Concrete

Environment has significant effects on the water absorption of concrete materials. This paper presents an experimental study of the influence of water absorption on the durability of concrete materials. A detailed analysis is also presented in order to establish useful relationship between them. Concrete specimens of different water absorption were prepared through different curing conditions, and results indicated that curing condition can significantly affect the surface water absorption. SEM photos also showed that different curing conditions caused different microstructure. After 28-days curing, compressive strength, permeability, sulfate attack, and chloride ion diffusion of concrete samples were investigated. As a result, both of surface sorptivity and internal sorptivity have no clear relationship with compressive strength. Results obtained also showed that only surface water absorption related to the performance of concrete including permeability, sulfate attack, and chloride ion diffusion. In addition, both impermeability and resistance to sulfate attack were linearly associated with surface sorptivity, and both correlation coefficients were not less than 0.9. Furthermore, chloride ion diffusion coefficient has exponent relation to surface water absorption with higher correlation coefficient. However, no apparent relationship was found between internal water absorption and durability like impermeability, resistance to sulfate attack, and chloride ion diffusion.

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