EFFECTS OF STARCH ADDITIONS IN CONCRETE ON THE PASSIVATION OF STEEL IN REINFORCED CONCRETE EXPOSED TO AGGRESSIVE ENVIRONMENTS

Alhassan, A. Yunusa

Department of Civil Engineering,

Federal Polytechnic Idah, Idah, Nigeria

Email: alhassanay@gmail.com

ABSTRACT: Corrosion of steel reinforcement embedded in concrete is a major cause of deterioration of reinforced concrete structure. Corrosion agents penetrate concrete due to its porous nature. This study examines the effects of cassava starch in concrete as corrosion inhibitor of reinforcement steel embedded in concrete. Starch enhances the protection of reinforcement by forming a protective film of gamma ferric oxide around the steel as well as reducing the pore spaces in concrete thereby impeding the ingress of corrosion agents. The effects of cassava starch addition, different curing types and varying concrete cover to reinforcement on the rate of corrosion of embedded reinforcing steel were investigated in the study. The result of the study shows that the use of 15% cassava starch in concrete mixtures, curing of reinforced concrete samples by sprinkling with water and a concrete cover of 40 mm improves the passivation potential of the embedded steel in concrete exposed to either chloride or sulphate environments.