A chemo-damage-transport model for chloride ions diffusion in cement-based materials: Combined effects of sulfate attack and temperature

2021 ◽  
Vol 288 ◽  
pp. 123121
Author(s):  
Penggang Wang ◽  
Rui Mo ◽  
Sen Li ◽  
Jun Xu ◽  
Zuquan Jin ◽  
...  
Keyword(s):  
Transport Model ◽  
Sulfate Attack ◽  
Chloride Ions ◽  
Combined Effects ◽  
Cement Based Materials ◽  
Chloride Ions Diffusion

Molecular Dynamics Study of the Interaction of C-S-H and Chloride Ions

2016 ◽  
Vol 711 ◽  
pp. 1061-1068
Author(s):  
Yang Zhou ◽  
Guo Dong Xu
Keyword(s):  
Molecular Dynamics ◽  
Calcium Silicate Hydrate ◽  
Chloride Concentration ◽  
Sorption Isotherms ◽  
Hydration Product ◽  
Chloride Ions ◽  
Dynamics Modeling ◽  
Solution Interface ◽  
Molecular Dynamics Modeling ◽  
Cement Based Materials

Molecular Dynamics was employed to investigate the interaction of calcium silicate hydrate (C-S-H), the primary hydration product of cement based materials, and chloride, causing severe durable problems of concrete. The 11Å tobermorite structure was chosen to describe the C-S-H structure and the CLAYFF force field was used. It is observed in the simulation that there are no bound chlorides at 303K, while a fraction of chlorides appear in the adsorption district of tobermorite/solution interface at 323K indicating the temperature increase can improve chloride sorption capacity of C-S-H. The formation of Ca-Cl cluster is found on the surface of tobermorite, which is assumed to promote the chloride sorption. The experimental results of sorption isotherms of C-S-H in CaCl2 and NaCl aqueous solutions with the same chloride concentration have proved this point. Other researchers have made the same conclusion by means of molecular dynamics modeling, NMR tests or zeta potential experiments.

Pitting Corrosion Behaviour of Boron Added Modified 9Cr–1Mo Steel: Combined Effects of Alkali and Chloride Ions

2014 ◽  
Vol 68 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Namrata Upadhyay ◽  
M. G. Pujar ◽  
C. R. Das ◽  
Nanda Gopal Krishna ◽  
C. Mallika ◽  
...  
Keyword(s):  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
Chloride Ions ◽  
Combined Effects

scholarly journals Low Stress Abrasion-Corrosion of High-Cr White Cast Iron: Combined Effects of Particle Angularity and Chloride Ions

2019 ◽  
Vol 166 (13) ◽  
pp. C382-C393
Author(s):  
Mobin Salasi ◽  
Mariano Iannuzzi ◽  
William Rickard ◽  
Zakaria Quadir
Keyword(s):  
Cast Iron ◽  
White Cast Iron ◽  
Chloride Ions ◽  
Combined Effects

scholarly journals Cement-based materials destruction under the action of deicing salts

2019 ◽  
Vol 298 ◽  
pp. 00053 ◽  
Author(s):  
Ekaterina Potapova ◽  
Ivan Korchunov
Keyword(s):  
Aqueous Solution ◽  
Pore Solution ◽  
Colorimetric Method ◽  
Chloride Ions ◽  
Cement Matrix ◽  
Chloride Solutions ◽  
Deicing Salts ◽  
Cement Based Materials ◽  
Destructive Processes

The results of chloride ions with aqueous solution penetrating into the cement structure were determined with the colorimetric method. Some tendencies of chloride solutions migration in different conditions were established. The article suggests the possible ways of the prevention of destructive processes occur during the excessive pore solution saturation in cement matrix with chloride ions.

Quantitative Analysis of Cement-Based Materials and Sulfate Attack Products by XRD-Rietveld Analysis

2013 ◽  
Vol 357-360 ◽  
pp. 1362-1369 ◽  
Author(s):  
Hua Li ◽  
Jia Ping Liu ◽  
Wei Sun
Keyword(s):  
Quantitative Analysis ◽  
Calcium Hydroxide ◽  
Rietveld Method ◽  
Internal Standard ◽  
Rietveld Analysis ◽  
Sulfate Attack ◽  
Practical Significance ◽  
Cement Pastes ◽  
Cement Based Materials ◽  
Mixed Samples

XRD-Rietveld method has been adopted for quantitative analysis of phases in cement powder, phases in mixed samples of cement and pure calcium hydroxide, and sulfate attack products in cement pastes, based on the TOPAS software. The results show that, Rietveld analysis values show good agreement with the actual levels of mixed samples, and the accuracy degree of Rietveld method is at least as well as that of TG/DSC method which is commonly used in quantitative analysis of calcium hydroxide. By adding appropriate internal standard substance, XRD-Rietveld analysis method can be effectively used in quantitative analysis of sulfate attack products in cement-based materials. This work has practical significance on the study of sulfate attack of cement-based material.

Experiment Study on the Durability of Dry-Mixing Self-Compacting Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 493-496 ◽  
Author(s):  
Lan Zong ◽  
Shi Ping Zhang ◽  
Pei Xin Liang
Keyword(s):  
Pore Structure ◽  
Frost Resistance ◽  
Chloride Ions ◽  
Experiment Study ◽  
Self Compacting Concrete ◽  
Freeze Thaw ◽  
Coarse Aggregates ◽  
Carbonation Resistance ◽  
Dry Mixing ◽  
Chloride Ions Diffusion

Durability of dry-mixing self-compacting concrete was evaluated through carbonation testing, freeze-thaw testing and chloride ions diffusion testing. The results indicate that carbonation resistance, frost resistance and chloride ions diffusion of durability of dry-mixing self-compacting concrete are excellent, compared with normally vibrated concrete (NVC). Durability of dry-mixing self-compacting concrete shows a better pore structure. Furthermore, the more the content of coarse aggregates is, the poorer the pore structure becomes.

Accelerate Thaumasite Formation in Cement-Limestone Powder Paste by Internal Adding Method

2011 ◽  
Vol 250-253 ◽  
pp. 22-27 ◽  
Author(s):  
Chang Cheng Li ◽  
Yan Yao ◽  
Ling Wang
Keyword(s):  
Magnesium Sulfate ◽  
Sodium Sulfate ◽  
Calcium Sulfate ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cement Based Materials ◽  
Internal Sulfate Attack

Cement-limestone powder pastes added with 10% magnesium sulfate, sodium sulfate, and calcium sulfate respectively were stored in water at (5±2) °C to accelerate thaumasite formation. The pastes were inspected visually at intervals. And the formation of thaumasite was identified and confirmed by X-ray diffraction (XRD), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The results show that internal adding sulfate in cement-limestone powder paste is an efficient way to accelerate thaumasite formation, and the accelerated effect is magnesium sulfate> sodium sulfate> calcium sulfate. Cement-limestone paste containing 10% magnesium sulfate totally turns into grey-white mushy materials after 6 months immersion, and products are mainly thaumasite and gypsum. In addition, the amount of thaumasite increases along with time of internal sulfate attack in 15 months. XRD, IR, and NMR are powerful and reliable tools for identification of thaumasite in cement-based materials.

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