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Effective Bio-Slime Coating Technique for Concrete Surfaces under Sulfate Attack.
Keun-Hyeok Yang1, Hee-Seob Lim2, Seung-Jun Kwon2
1Department of Plant Architectural Engineering, Kyonggi University, Suwon 16227, Korea.
Materials (Basel, Switzerland)
|April 1, 2020
Summary
This study demonstrates that bio-slime coating layers significantly extend concrete service life against sulfate attack. These eco-friendly layers improve concrete durability by reducing sulfate diffusion.
Area of Science:
- Materials Science
- Civil Engineering
- Environmental Science
Background:
- Sulfate attack degrades concrete, reducing its service life due to ettringite and gypsum formation.
- Aerobic bacteria-based repair coatings show promise in mitigating sulfate attack on concrete structures.
Purpose of the Study:
- To fabricate bio-slime repair coating layers using bacteria.
- To evaluate the effectiveness of these coatings in extending concrete service life under sulfate attack.
- To analyze chloride and sulfate diffusion through the coating layers.
Main Methods:
- Fabrication of bio-slime repair coating layers using bacteria.
- Chloride diffusion experiments were conducted.
- Service life evaluation using time-dependent diffusivity and a multi-layer technique.
- Comparison of chloride and sulfate diffusivity based on literature.
Main Results:
- Concrete service life increased from 38.5 years to 41.5-54.3 years with bio-slime coating.
- A 2.0 mm thick bio-slime layer can increase service life 1.31-2.15 times.
- Controlling the sulfate diffusion coefficient of the layer to 0.1–0.3 × 10-12 m2/s is crucial for enhanced durability.
Conclusions:
- Eco-friendly, aerobic bio-slime coating layers effectively enhance concrete resistance to sulfate attack.
- The application of bio-slime coatings offers a viable strategy for extending the service life of concrete infrastructure.
- Optimizing coating thickness and sulfate diffusion properties is key for maximum performance.
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