Protective Mechanism of Silane on Concrete upon Marine Exposure
Abstract
:1. Introduction
2. Experimental
2.1. Concrete Preparation
2.2. Raw Materials and Preparation Technology of the Compound Gel
2.3. Marine Exposure Test
2.4. Contact Angle Determination Test
2.5. Surface Morphology Observation (SEM)
2.6. Infrared Spectrum Analysis
3. Marine Exposure Experiment Results
3.1. Results and Analysis in the Full Immersion Zone
3.1.1. Variation of the Chloride Ion Content in the Concrete
3.1.2. Fitting Results of the Chloride Diffusion Coefficients in the Concrete
3.2. Results and Analysis in the Tidal Zone
3.2.1. Variation in the Chloride Ion Content in the Concrete
3.2.2. Fitting Results of the Natural Permeability Coefficient in the Concrete
3.3. Results and Analysis in the Splash Zone
3.3.1. Variation of Chloride Ion Content in the Concrete
3.3.2. Fit Results of the Chloride Diffusion Coefficients in the Concrete
3.4. Contact Angle Determination Test
3.5. SEM and Infrared Spectrum Analysis
3.6. Infrared Spectrum Analysis
4. Conclusions
- In the early stage of marine exposure, the three kinds of protective materials had a good ability to resist the chloride ion erosion. With an extension in exposure time, the protective effect of the three protective materials showed a downward trend, to some extent. The compound gel displayed the best stability. Under marine exposure durations, the chloride diffusion coefficients of the concrete test blocks coated with the compound gel were reduced to about 50%. This confirms its excellent ability to resist chloride ion erosion;
- Via the contact angle determination tests, it can be found that the use of coating protective materials on the coupon surface can effectively reduce the coupon surface tension and increase the contact angle. This makes the coupon surface transform from a hydrophilic surface to anhydrophobic surface. Therefore, coating the coupon surface with protective materials can effectively inhibit the transportation of water molecules into the concrete and reduce the content of chloride ions that are carried by the water molecules into the concrete;
- According to the microscopic test results of the SEM and infrared spectrum analysis, the protective coatings can react with the cement-based materials when they are coated on the surface of cement-based material, and drive the hydrophobic alkyl to form a lamellar protective layer on the coupon surface. This fills the capillary pores and effectively inhibits the entrance of water molecules and ions into the capillary channels of the concrete.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Material | Dosage/(kg·m−3) | Habitat |
---|---|---|
Cement | 380 | ShanLv Co., Ltd., Qingdao, China |
Sand | 579 | River sand in Qingdao, China |
Macadam | 1269 | Yuanping Stone Co., Qingdao, China |
Water | 152 | Qingdao, China |
Water reducer | 54.9 | Sobute New Materials Co., Ltd., Nanjing, China |
Raw Materials | Molecular Formulas | Manufacturer |
---|---|---|
Isobutyl triethoxysilane (ITES) | (CH3)2CHCH2Si(OC2H5)3 | QuanzhouSicong Chemical Co., Ltd., Quanzhou, China |
Tetraethoxysilane (TEOS) | Si(OC2H5)4 | Shanghai Aibi Chemistry Preparation Co., Ltd., Shanghai, China |
Peregal O (PPG O) | RO-(CH2CH2O)n-HR | Shanghai Aibi Chemistry Preparation Co., Ltd., Shanghai, China |
Polyethylene glycol (PEG 2000) | HO(C2H4O)nH | Tianjin Guangfu Fine Chemical Research Institute, Tianjin, China |
Span80 | C24H44O6 | Tianjin Ruijinte Chemical Co., Ltd., Tianjin, China |
Distilled water | H2O | Qingdao University of Technology, Qingdao, China |
Exposure Time (Month) | Chloride Diffusion Coefficients/(×10−12 m2·s−1) | |||
---|---|---|---|---|
Blank | Silane Emulsion | ST Compound Emulsion * | ST Compound Gel | |
3 | 7.85 | 3.35 | 3.15 | 1.62 |
6 | 3.56 | 2.01 | 1.85 | 1.32 |
9 | 2.75 | 2.12 | 1.69 | 1.42 |
12 | 2.50 | 2.06 | 1.62 | 1.21 |
Exposure Time (Month) | Chloride Diffusion Coefficients/(×10−12 m2·s−1) | |||
---|---|---|---|---|
Blank | Silane Emulsion | ST Compound Emulsion * | ST Compound Gel | |
3 | 8.52 | 3.92 | 2.72 | 1.89 |
6 | 5.82 | 3.12 | 3.01 | 1.51 |
9 | 3.72 | 3.31 | 1.82 | 1.41 |
12 | 2.72 | 1.98 | 1.92 | 1.35 |
Exposure Time (Month) | Chloride Diffusion Coefficients/(×10−12 m2·s−1) | |||
---|---|---|---|---|
Blank | Silane Emulsion | ST Compound Emulsion * | ST Compound Gel | |
3 | 13.99 | 5.82 | 5.62 | 3.01 |
6 | 6.45 | 4.36 | 3.03 | 2.32 |
9 | 4.95 | 3.35 | 2.96 | 2.45 |
12 | 4.56 | 3.06 | 2.82 | 1.99 |
Coating Method | Silicon Content (at.%) | |
---|---|---|
Spot Scanning | Map Scanning | |
Blank | 3.98 | 4.75 |
Silane emulsion | 9.56 | 9.23 |
Compound emulsion | 12.65 | 11.78 |
Compound gel | 14.26 | 13.58 |
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Li, S.; Zhang, W.; Liu, J.; Hou, D.; Geng, Y.; Chen, X.; Gao, Y.; Jin, Z.; Yin, B. Protective Mechanism of Silane on Concrete upon Marine Exposure. Coatings 2019, 9, 558. https://doi.org/10.3390/coatings9090558
Li S, Zhang W, Liu J, Hou D, Geng Y, Chen X, Gao Y, Jin Z, Yin B. Protective Mechanism of Silane on Concrete upon Marine Exposure. Coatings. 2019; 9(9):558. https://doi.org/10.3390/coatings9090558
Chicago/Turabian StyleLi, Shaochun, Wenjuan Zhang, Jun Liu, Dongshuai Hou, Yongjuan Geng, Xu Chen, Yan Gao, Zuquan Jin, and Bing Yin. 2019. "Protective Mechanism of Silane on Concrete upon Marine Exposure" Coatings 9, no. 9: 558. https://doi.org/10.3390/coatings9090558