EFFECT OF ORGANIC COATING ON MILD STEEL CORROSION OF REINFORCED CONCERT IN SOME GYPSEOUS IRAQI SOILS

Abstract

The present work studies the effect of different types of gypseous Iraqi soils on the corrosion rate of embedded steel in mortar, and studies the effect of coated steel and concrete on the corrosion rate. Three different types of soils were used, which were collected from different locations in Iraq, (Falluja, Kirkuk and Najif) and hydrated gypsum was also used.

Three types of organic coatings were used. Red and black oxides were used for coating the steel and asphalted bitumen for coating the mortar (concrete).

          This study shows that the corrosion potential is shifted to more positive direction (more noble) for the coated steel and mortar than the un-coated steel and mortar, whereas the corrosion current for the coated steel and mortar is lower than the un- coated steel and mortar.

Kirkuk soil solution is lower corrosive than the Falluja soil solution, the later is lower corrosive than Najaf soil solution and the gypsum is the most corrosive. The expected time to visible deterioration of uncoated structures is more than ten years with Falluja and Kirkuk soils, whereas it is between 3-10 years with Gypsum and Najaf soils