Compressive Strength of CFRP Confined Concrete under Exposure to High Temperature

Abstract

Currently, in Malaysia, there has been an alarming number of fire breakouts that not only concern the lives of the residents but also the integrity of the exposed structures themselves. Exposure to high temperature may result in significant damage to reinforced concrete structures such as losses in strength, thus affecting its mechanical and physical properties. The chances of re-using the structure after the event of a fire by means of applying certain retrofitting measures are mainly dependent on the residual load-bearing capacity and an acceptable residual deflection. The structural design of buildings should be carried out so that a structure is able to maintain its stability and strength throughout its service life, including design consideration on fire resistance. This research was carried out to study the effectiveness of the carbon fiber reinforced polymer (CFRP) sheet to strengthened concrete cylinders under high temperatures (600℃ and 800℃). The study will focus on the effect of high temperature on compressive strength as well as the effect of high temperature on the CFRP concrete cylinder. Eighteen (18) concrete cylinder samples of 300 mm height and 150 mm diameter were fabricated, which consist of six (6) control samples (without CFRP), six (6) CFRP concrete cylinders and the remaining three (3) CFRP concrete cylinders were insulated with fire protection mortar. The average strength loss of the control sample (without CFRP), when exposed to 600℃, is about 28% compared to control samples. The average compressive strength of the CFRP concrete cylinder exposed to 600℃ is increased by about 9% compared to the control sample. Fire protection mortar can prevent the concrete cylinder from spalling, major cracks and combustion of CFRP at high temperature. The knowledge in this research field can be used as the basis for structural rehabilitation work.