Mortar cracking was investigated by impressing a constant anodic current density onto steel reinforcements. The time and the corrosion penetration required for crack onset was determined. Tests were carried out in calcium hydroxide (Ca[OH]2)-saturated solutions and in mortar with and without chloride (Cl–) addition. Data reproductibility was poor and could be ascribed to current efficiencies much > 100%, corroded surface area fractions much < 100%, and occasional diffusion of corrosion products via macropores to the mortar surface. Notwithstanding potential effects of these uncertainties, results showed penetrations of a few tens of micrometers (25.4 μm = 1 mil) could give rise to cracking. Fairly low corrosion rates of ~ 1 μA/cm2 (6.45 μA/in.2) could result in hazardous damage during short service periods (5 y to 10 y).

Subject
Current efficiency, Corrosion rate, Mortar, Corrosion cracking, Anode surfaces, Stress cracking, Density, Corrosion products, Penetration, Anodic current, Rust, Concrete, Reinforcement
Keywords:
calcium hydroxide, chloride, concrete, current efficiency, durability, imposed current, mortar, nitrite, reinforcing steel
NACE International
1997
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