Durability of Prestressed Piles in a Leachate Environment

Area of Science:

• Civil Engineering
• Materials Science
• Environmental Engineering

Background:

• Prestressed pipe piles are vital for coastal soft soil foundations due to their robust concrete structure and mechanical properties.
• The long-term durability of these piles in aggressive environments, such as landfill leachate, requires further investigation.
• Understanding corrosion mechanisms is crucial for ensuring the structural integrity and longevity of coastal infrastructure.

Purpose of the Study:

• To evaluate the durability of prestressed pipe piles exposed to landfill leachate under accelerated corrosion conditions.
• To investigate the impact of drying-wetting cycles and epoxy resin protection on pile corrosion.
• To quantify chloride ion penetration and assess the overall corrosion resistance of the piles.

Main Methods:

• Leachate from a Chinese landfill was used as the corrosive medium.
• Accelerated corrosion was induced by electrifying prestressed pipe piles.
• Experiments simulated immersion, epoxy resin protection, and drying-wetting cycle conditions.
• Chloride ion concentration, corrosion potential, and corrosion depth were measured.

Main Results:

• Chloride ion concentration in the concrete increased with corrosion time.
• Drying-wetting cycles resulted in the most severe corrosion.
• Epoxy resin coating significantly inhibited chloride ion diffusion.
• Theoretical corrosion amounts were 1.55 kg (immersion), 1.20 kg (epoxy), and 1.64 kg (drying-wetting).
• Epoxy resin reduced penetration by 22.6%; drying-wetting increased it by 5.8%.

Conclusions:

• Prestressed pipe piles demonstrate good durability in landfill leachate environments.
• Epoxy resin coating is an effective protective measure against chloride ingress.
• Drying-wetting cycles pose a significant risk to pile durability.
• Despite corrosion, the piles maintained a sufficient corrosion allowance for their ultimate bending moment.