The bond strength of self-compacting concrete exposed to elevated temperature

Self-compacting concrete (SCC) is a flowable concrete that can flow, fill and pass through congested area of reinforcement without segregation. As a material used in massive constructions, understanding of the effects of elevated temperature exposure on the properties of SCC is vital. The bond between concrete and embedded steel, which degrades with an increase in temperature, influences the load-carrying capacity and thus the fire resistance of reinforced concrete elements. The objective of this study was to evaluate the bond strength of SCC specimens made with fly ash, ground granulated blast-furnace slag (GGBFS) and expanded perlite aggregate (EPA) under elevated temperature exposure. EPA was introduced to enhance the fire endurance of the SCC. Slump flow, J-ring and V-funnel tests were conducted as per EFNARC guidelines to check the rheological characteristics of SCC. Specimens were exposed to elevated temperature following the ISO 834 standard fire curve. Pull-out tests were carried out to determine the bond strength of reference SCC specimens and specimens exposed to elevated temperature. Data from the tests showed that the SCC specimens made with a combination of GGBFS and EPA exhibited improved bond strength, both at room and elevated temperatures.