Experimental Study on Bond Behavior between Plain Reinforcing Bars and Concrete

Abstract

To evaluate the bond behavior between the reinforcing bar and surrounding concrete, a total of six-group pullout specimens with plain steel bars and two-group specimens with deformed steel bars, serving as a reference, are experimentally investigated and presented in this study. The main test parameters of this investigation include embedment length, surface type of reinforcing bars, and bar diameter. In particular, the bond mechanism of plain steel reinforcing bars against the surrounding concrete was analyzed by comparing with six-group pullout specimens with aluminium alloy bars. The results indicated that the bond stress experienced by plain bars is quite lower than that of the deformed bars given equal structural characteristics and details. Averagely, plain bars appeared to develop only 18.3% of the bond stress of deformed bars. Differing from the bond strength of plain steel bars, which is based primarily on chemical adhesion and friction force, the bond stress of aluminium alloy bars is mainly experienced by chemical adhesion and about 0.21~0.56 MPa, which is just one-tenth of that of plain steel bars. Based on the test results, a bond-slip model at the interface between concrete and plain bars is put forward.

Bond of steel reinforcement with microwave cured concrete repair mortars

“…The relationship between bond strength and compressive strength of concrete is more complex with deformed reinforcement bars which are normally used in modern concrete. In this case, the strength of concrete provides additional bond through mechanical interlock of deformed bars [47] whereas bond strength of plain steel bars is composed of adhesive stress and friction [17]. A non-linear relationship of bond and compressive strength is often used, with the fib code of practice [22] relating bond to the square root of strength.…”

“…Plain steel bars provide a true bond failure mechanism with concrete, which includes chemical adhesion and frictional resistance. The pull out strength of deformed reinforcement bars overestimates the basic bond strength by including the mechanical interlock strength of the concrete [17]. The simple pull-out mechanism of the plain rebar embedded in concrete is made more complex by the bursting forces generated by the wedge action of ribs on the rebar which is confined to different degrees by the concrete cover and confining reinforcement [18,19].…”

Experimental and Numerical Study of Nano-Silica Additions on the Local Bond of Ultra-High Performance Concrete and Steel Reinforcing Bar

“…Xing G. et.al. (2015) performed the pullout test to determine the bond stress between ultra-high performance concrete and steel reinforcement [8]. Guizani, L. et.…”

Experimental Study on Bond Stress between Ultra High Performance Concrete and Steel Reinforcement

“…Xing G. et.al. (2015) performed pull out testing to determine the bond stress between ultra-high performance concrete and steel reinforcement [8]. Guizani, L. et.…”