Effect of high temperatures on the behaviour of RCC columns in compression

Abstract

Fire has become one of the most serious hazards to structures. Concrete constructions that are exposed to fire or high temperatures degrade and lose their strength as a result. The current research investigates the effect of high temperatures on columns built of reinforced cement concrete that are subjected to compressive loading. With a water binder ratio of 0.53, seven columns are cast, six of which are intended for fire exposure and one of which serves as a companion column. Specimens are heated to temperatures ranging from 100°C to 700°C in 100°C increments after 28 days of cure. After being exposed to high temperatures, the specimens were cooled to room temperature using an air-cooling method before being evaluated for loads at the first crack and ultimate failure loads. The variation of load at first crack, failure loads, and variation of residual strengths of RCC columns with an increase in temperature has been studied and presented. The heated columns have a lower load-carrying capability than the companion column, and the color of the heated columns changes when exposed to temperatures exceeding 300°C. The residual strength of the companion column was found to be 97.52%, 99.17%, 95.60%, 94.50%, 81.04%, 57.69%, and 49.86% for the columns exposed to temperatures of 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, and 700°C, respectively.