Shear repairing of reinforced concrete beams exposed to high temperature using basalt fiber reinforcing bars and CFRP ropes and strips

Abstract

In this research, the shear behavior of reinforced concrete (RC) beams subjected to high temperatures and then repaired using Basalt Fiber Reinforcing (BFRP) bars and Carbon Fiber Reinforced Polymer (CFRP) ropes and strips was investigated experimentally. Eleven reinforced concrete beams with shear deficiency were cast with dimensions 200mmx300mmx1800mm in width, depth, and span length, respectively. Then, after 28 days, ten beams were heated in an electric furnace for three hours at a temperature of 650 °C. Later, nine of the heated beams were repaired using near surface mounted technique (NSM) with different configurations of BFRP bars and CFRP ropes and strips, and one beam was left unrepaired to serve as a control heated sample. The behavior of the beams was evaluated under two-point loading. The experimental results showed that using NSM CFRP or BFRP efficiently enhances the shear capacity of heat damaged beams. Using NSM rope increased the ultimate loads by 40 % to 95 % compared to control heat beams. The highest improvement in maximum load capacity was achieved by using an inclined rope positioned at 150 mm. While, using BFRP bar increased the maximum load by 37 % to 63 % compared to control heat beams depending on the configuration and spacing between bars. Also, it has been found that the overall effectiveness of CFRP rope in increasing the shear capacity is 32 % higher than that of the BFRP bars.