Corrosion effects on the bond behaviour of steel bars in self-compacting concrete

Abstract

This paper presents an experimental investigation conducted in order to evaluate the bond strength behaviour of reinforced self-compacted concrete elements under corrosion conditions. Reinforced block and beam samples were formulated using deformed steel bars with dimensions of Ø12.5 mm and Ø25 mm. The hardened concrete samples were either cured in tap water or exposed to salt solution with concentrations similar to those available in the soil and groundwater at the southern parts of Iraq. A suitable epoxy was used for coating part of the formulated samples. The preliminary mechanical properties and the rate of corrosion were firstly measured, the pullout and flexural bond-slip tests were then carried out. A comparison was also made with the relevant code of practice.The results obtained showed that both of compressive strength and density features exhibited notable increase at early ages when the samples are exposed to salt solution. The adverse effect of such curing condition appeared at the later ages when the corrosion rate became more intensive. The highest decrease in the value of pullout strength was observed for the reinforced concrete block samples containing epoxy coating reaching to 44.5% less than those cured in tap water. Identical behaviour was also noted for the flexural bond-slip aspect. An appreciable improvement was suggested for the expression of bond strength proposed by the CEB-FIP (CEB-FIP, 2010).