Evaluating composite nanomaterials to control corrosion of reinforcing steel using different tests

Abstract

There is limited research on the utilization of composite nanomaterials to control corrosion of reinforcing steel in concrete. Therefore, this work was initiated to evaluate the composite nanomaterials (zinc oxide and titanium dioxide) to control corrosion deterioration in reinforced concrete using different tests. The composite nanomaterials were utilized as coating cover over the reinforcing steel surface using two methods of nanofilms and nanoparticles. Fourteen reinforced concrete prisms (100 ×100×300 mm) with central reinforcing steel coated with nanocomposite were casted using w/c ratio of 0.45. After 28 days of moist curing, the prisms were exposed to an accelerated corrosion process using an electrical current supply. The ability of nanocomposite to control corrosion was evaluated using different tests including crack width, ultrasonic pulse velocity (UPV), half-cell potential (HCP) and pullout test. The experimental results showed that nanocomposite materials coated over the reinforcing steel surface significantly reduced the corrosion level of the reinforcing steel in concrete. The non-destructive tests (UPV and HCP) showed significant difference between the nanocoated and uncoated specimens. The damage index of the UPV of the corroded uncoated prisms showed higher values than those of the corroded coated prisms. The HCP values of the nanocoated prisms after corrosion showed significantly lower negative values than those of the control uncoated prisms. Moreover, prisms coated with nanocomposite revealed less corrosion crack width and attained higher ultimate bond load compared to the uncoated prisms. The composite nanolayer coated on the reinforcing steel surface showed higher performance to control corrosion compared to the single nanolayer coated on the reinforcing steel surface. Scanning electron microscopy images showed more homogeneous filling layers of the composite nanolayer coating compared to the single nanolayer coating.