| KONG Xiangqing,ZHANG Ning,SHEN Yidan,ZHANG Ruixiang,CHANG Yahui,DING Xiaoxuan.Preparation of Durable Superhydrophobic Concrete Coating and Its Anti-corrosive Property[J],54(10):116-127 |
| Preparation of Durable Superhydrophobic Concrete Coating and Its Anti-corrosive Property |
| Received:August 18, 2024 Revised:December 18, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.10.009 |
| KeyWord:one-step method spray superhydrophobic concrete corrosion resistance mechanical durability |
| Author | Institution |
| KONG Xiangqing |
School of Civil Engineering, Liaoning University of Technology, Liaoning Jinzhou , China;College of Pipeline and Civil Engineering, China University of Petroleum East China, Shandong Qingdao , China |
| ZHANG Ning |
School of Civil Engineering, Liaoning University of Technology, Liaoning Jinzhou , China |
| SHEN Yidan |
School of Civil Engineering, Liaoning University of Technology, Liaoning Jinzhou , China |
| ZHANG Ruixiang |
Songshan Lake Material Laboratory, Guangdong Dongguan , China |
| CHANG Yahui |
School of Civil Engineering, Liaoning University of Technology, Liaoning Jinzhou , China |
| DING Xiaoxuan |
College of Pipeline and Civil Engineering, China University of Petroleum East China, Shandong Qingdao , China |
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| Abstract: |
| Concrete is widely used in the field of civil engineering because of its excellent mechanical properties and low price. However, concrete is inherently porous and hydrophilic, and is susceptible to corrosion by corrosive ions in seawater when exposed to moisture or marine environments for a long time. These corrosive ions will not only erode the surface of the concrete, but also corrode the internal steel bars. Therefore, in marine structural engineering, it is very important to improve the corrosion resistance of concrete by inhibiting the entry of external corrosive ions into concrete. In recent years, inspired by the lotus leaf effect, superhydrophobic materials have attracted widespread attention and become a research hotspot in the field of building materials due to their excellent hydrophobicity, corrosion resistance, and self-cleaning properties. Applying superhydrophobic materials to concrete structures can effectively prevent direct contact between concrete and corrosive ions in seawater, thereby preventing corrosion of internal steel bars. However, there is still a challenge in large-scale preparation of stable superhydrophobic anti-corrosion coatings. The work aims to propose a superhydrophobic concrete coating with simple process and excellent corrosion resistance and durability. The tannic acid (TA) was used as the binding substance and the superhydrophobic surface roughness structure with high-strength nano-SiO2 particles was co-constructed, while the non-fluorine low surface energy substance n-octyltriethoxysilane (OTES) was introduced for hydrophobic modification to obtain the superhydrophobic solution. Then, TA/SiO2@OTES superhydrophobic coating was successfully prepared by spraying the mixture on the surface of concrete with a one-step method. By studying the effects of different concentrations of TA/SiO2 on the microstructure and wettability of concrete coatings, the optimal doping concentration was determined. In addition, X-ray diffractometer (XRD) and Fourier infrared spectrometer (FT-IR) were used to characterize the material composition and chemical bonding on the surface of the concrete material, and experimental studies were carried out on water absorption, chloride ion erosion, surface friction and water droplet impact to comprehensively evaluate the corrosion resistance and mechanical durability of the superhydrophobic concrete coating. The results of the study showed that when the concentration of TA/SiO2 was 4 mg/mL, the coating formed the best microscopic morphology, with a contact angle as high as (156.8±1.6)° and a low sliding angle as low as (5.8±1.1)°. In the water absorption test, after soaking for 15 days, the water absorption of ordinary concrete was about 2.15 mm, while that of TA/SiO2@OTES superhydrophobic concrete was 0.42 mm, which was reduced by 80.5% compared with that of ordinary concrete, showing good impermeability and durability; In the corrosion resistance test, when ordinary concrete and TA/SiO2@OTES superhydrophobic concrete were immersed in 7wt.% NaCl solution for 28 days respectively, the depth of erosion of TA/SiO2@OTES superhydrophobic concrete was only one-fourth of that of the ordinary concrete at the same location on the cutting surface. Moreover, the quantitative analysis test also showed that the resistance of the concrete with coating to chloride ion erosion increased by more than 60%. In the mechanical durability test, TA/SiO2@OTES superhydrophobic concrete coating still had superhydrophobic properties (contact angle was greater than 150.0° and slide angle was less than 10.0°) after 50 times of sandpaper linear friction test and 50 minutes of water drop impact test, respectively. The above tests indicate that the prepared TA/SiO2@OTES superhydrophobic concrete coating has excellent corrosion resistance and mechanical strength, effectively protecting concrete components from corrosive ions and maintaining their superhydrophobic performance even under various physical attacks during long-term use. Furthermore, the one-step spraying method proposed in this study for preparing superhydrophobic concrete coatings is simple and produces no harmful substances, solving the problems of complex coating process and insufficient environmental protection. It is suitable for large-scale production and has broad application prospects in civil engineering structures. |
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