Structural behavior of reinforced concrete columns retrofitting with CFRP exposure to high temperature

Total of six reinforced concrete columns were tested included two column specimens with 10 and 17mm concrete cover were considered in present study to estimate the ultimate capacity of column. The remaining four specimens tested under temperature of 500 and 800 °C to find out the reduction in strength carrying capacity under these temperature loads. Rehabilitation of the four tested columns specimens by Carbon Fiber Reinforced Polymer were applied around the heated zone of tested columns. The compressive strength 28 MPa (the cylinders exposed to same applied temperatures to investigate the residual compressive strength under these two different temperatures). The cross-sectional dimensions of reinforced concrete column are 200x200x1200 mm. Mode of failure, ductility and stiffness for the repaired tested specimens under static was discussed. As results, the strength carrying capacity of tested specimens influenced by column cover in cases of static and under temperature load. Increase in the temperature lead to reduce in the strength carrying capacity of the tested columns with an increase in the axial and lateral displacements. Presence of CFRP reduce the displacements as axial and later, enhance the concrete ductility and delays the failure of the tested specimens. As an example, the strength carrying capacity of the tested specimens increase when compared with specimens heated but not retrofitting. The ultimate load capacity of specimen under 500 °C with 10 mm cover is 69.4% from the control specimen and enhance as strength capacity by 112% when compared with specimen without retrofitting.