Corrosion Investigation of Rock Anchors Served over 10 Years in Underground Powerhouse of a Hydropower Station

Table 8

Description of corrosion ratings of the anchor head structures.

Rating	Rating standard
0	No rust or cannot find rust
1	Slight rust, local rust spots on the surface
2	Obvious rust, rust spots on the whole surface
3	Severe rust, with uneven surface because of rust
4	Severe rust, with layered or peeling rust products