Effect of temperature on uni-axial compressive behavior of confined concrete

In this paper, the effects of elevated temperatures on the concentric compressive behavior of confined concrete are presented. An experimental program was designed and carried out involving testing of hoop confined concrete cylindrical specimens exposed to elevated temperatures ranging from room temperature to 800 °C. The test variables included temperature of exposure, concrete strength, amount of confining reinforcement and yield strength of transverse confining steel. A total of 84 confined and 42 unconfined cylindrical specimens of size 150 mm×450 mm were tested in this test program. The effects of various key variables of confinement were studied and quantified with respect to strength and ductility gains. The results indicate that the residual strength, strain corresponding to the peak stress and the post-peak strains of confined concrete are not affected significantly up to an exposure temperature of 400 °C. However, the peak confined stress falls and the corresponding strain increases considerably in the temperature range of 500–800 °C. An increase in the temperature of exposure makes the stress–strain curve of confined concrete flatter. It is shown that an increase in the degree of confinement reinforcement results in an increased residual strength and deformability of confined concrete.

► Effect of high temperature on confined concrete was studied experimentally.
► Study was quantified with respect to strength and ductility gains.
► Results indicated that temperature effects were not significant up to 4000 C.
► Temperature in the range of 500–800 °C has considerable effects on confined concrete.
► Strength and deformability increase with increase in degree of confinement.