Why hot-dip galvanized reinforcing steel works

Nov. 8, 2004

No corrosion creeping under the zinc coating;
No holidays in the zinc coating; the hot-dip galvanizing process ensures complete coating coverage;
Zinc corrosion products are less dense than black steel corrosion products and migrate away from the bar into the voids of the concrete and thus no cracking or spalling forces are exerted;
Zinc corrosion products passivate the rebar, elevating the corrosion threshold to a range between five and 10 times that of bare rebar;
Zinc corrosion products block the progress of chloride ions to the rebar;

No corrosion creeping under the zinc coating;
No holidays in the zinc coating; the hot-dip galvanizing process ensures complete coating coverage;
Zinc corrosion products are less dense than black steel corrosion products and migrate away from the bar into the voids of the concrete and thus no cracking or spalling forces are exerted;
Zinc corrosion products passivate the rebar, elevating the corrosion threshold to a range between five and 10 times that of bare rebar;
Zinc corrosion products block the progress of chloride ions to the rebar;
Zinc corrosion rate is very low in dried concrete, where the pH is usually within the range of 5-12.5;
The bond strength of hot-dip galvanized rebar is about 600 psi, i.e., as high or higher than plain bar; and
Zinc is a galvanic and barrier protection system, sacrificially corroding to protect the substrate steel and also providing a metal barrier to electrolytes.

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