Simplified model for corrosion-induced bond degradation between steel strand and concrete

The corrosion-induced bond degradation between corroded steel strands and concrete is investigated in the present study. Ten pull-out specimens with different corrosion levels were tested to study corrosion's effects on concrete splitting, strand twisting, failure mode, and global force-displacement behavior. The local bond characteristics are discussed and derived based on the test results. Experimental results show that the bond behavior depends on the corrosion loss level and does not have a monotonic trend. Strand corrosion had beneficial effects on the bond strength when the corrosion loss is less than 6.24% in the current study. The corrosion loss significantly decreased the bond strength when the corrosion loss is greater than 9.26% or the corrosion-induced crack is wider than 0.67 mm. The strand will be pulled out instead of fracturing when the corrosion loss exceeds 8%. Corrosion affects the bond strength more significantly than the tension strength for severe corrosion conditions. A simplified model is proposed to predict the residual bond strength between corroded strands and concrete. The proposed model's predictions are validated with experimental data. Several conclusions and suggestions for future work are drawn based on the conducted study.