Bond between deformed steel rebars and concrete at elevated temperatures

Abstract

This paper presents an experimental study on the bond behavior between deformed steel rebars and concrete at elevated temperatures, focusing on the effect of heating rate on the flexural bond strength. Most of the earlier research on this topic involved axial pull-out tests in cooled-down conditions. None of the earlier research has studied flexural bond behavior in hot conditions. Also, there is a lot of variability in the test conditions used in these studies. To overcome these challenges, a number of beam specimens whose flexural behavior was governed by bond failure were prepared and tested at elevated temperatures. Two different rebar diameters (12 mm and 20 mm), and two different rates of heating (2 °C/min and standard fire curve) were used in these tests. The results indicate that a rapid rate of heating affected the bond strength more significantly. Also, the 20 mm-diameter rebar had lower bond strength per unit surface area in comparison to the 12 mm-diameter rebar. The bond ductility reduced more rapidly than the bond strength as the interface temperature rose.