Bond-slip relationships of full scaled reinforced concrete columns subjected to corrosion

Corrosion in reinforced concrete structures is of great importance due to the many problems that it causes in the building sector. The negative results of the existing building elements as a result of corrosion lead to many problems such as cracking of concrete, pouring of rust share, decrease of cross section of reinforcement and loss of adherence between concrete and reinforcement. In recent years, many different models have been developed to evaluate the seismic performance of reinforced concrete buildings. In the evaluation made with these models, the effect of corrosion on the structural elements is evaluated only due to the decrease in the reinforcement area. The loss of adherence between concrete and reinforcement due to corrosion is not taken into account and the additional increase in structural displacement due to slippage of reinforcement is not taken into consideration. The most important notion that expresses the relationship between concrete and reinforcement in reinforced concrete structures is adherence and related slip of reinforcement. In this study carried out within the scope of TÜBİTAK 3501 (116M162) project, reinforced concrete column reinforcement was controlled by using accelerated corrosion method. 5 full-scale reinforced concrete column samples with C30 concrete compressive strength were produced. The produced concrete column samples were corroded in four different corrosion rates as 2.00%, 2.79%, 5.65% and 8.52%. Constant axial load (0.20) and lateral load were applied to the test specimens. After loading tests, the corroded concrete column samples were broken and all reinforcements removed from the concrete were shear to the specified dimensions and actual corrosion rates were obtained. Mechanical properties of corrugated longitudinal reinforcement at different corrosion rates were obtained by applying tensile test to each shear longitudinal reinforcement. By applying constant axial and reversible lateral loads to the reinforced concrete columns, load-displacement results, ductility ratios, energy absorption capacities and adherence-slip values were obtained in relation to these corrosion rates. Using the obtained results, an experimental study was conducted to estimate the effects of sliding on the structure depending on different corrosion rates and concrete compressive strength.