We know corrosion is very important factor for subsurface construction and sometimes becomes governing factors in pile construction depending on ground condition. Dear reader we have already discussed about measures to be taken for corrosion protection of micropile.
Corrosion inhibition, if required, the compounds used for this purposes in free length and should be of organic say wax or grease.
The inhibiting compounds should have
• Inhibiting additives
• Appropriate method for displacing polar moisture
• Nonreactive with
- Prestressing steel
- Anchor grout
- Sheathing materials
• Chemically stable
• Can permanently retain its viscosity
When bond breaker is required, smooth plastic pipe or tube should be used for fabrication of it. The expected properties of pipe or tube are as follows:
• Should have resistance against chemical attack; the aggressive environment, corrosion inhibition or grout are considered to produce chemical attack.
• Should have resistance against aging from UV-light
• Not harmful to any type of reinforcement
• Should have ability to withstand
- Bending while handling & installation
Regarding application of bond breaker, we can include, it allows elongation of prestressing steel while testing and also stressing. The tube or pipe discussed above should be made from polyethylene of medium-high density and should conform
• ASTM D1248
• AASHTO M252
Sometimes of polyvinyl chloride (PVC) tubes/pipes are uses which should comply with ASTM D1784, class 13463-B having wall thickness of at least 0.04 in or equivalent materials can be used.