Bond behaviour of high-strength concrete flexural member under low
cyclic fatigue loading
W. ABBASS
1
, Z. A. SIDDIQI
2
, F. ASLAM
1
, R. R. HUSSAIN
3
and S. AHMED
4
1
Civil Engineering Department, King Saud University, Riyadh, Saudi Arabia,
2
Civil Engineering Department, U.E.T., Lahore, Pakistan,
3
CoE-CRT,
Civil Engineering Department, College of Engineering, King Saud University, Riyadh, Saudi Arabia,
4
Civil Engineering Department, U.E.T., Lahore,
Pakistan
Received in final form 28 April 2012
ABSTRACT Use of high-strength concrete can lead to more economical design reducing the material
requirements, weight of structure and extended service life of structure. The effect of
fatigue loading is more prominent on the structures using high-strength concrete. Bond
between concrete and reinforcing bars is a major factor affecting the performance and
sustainability of reinforced concrete structures. Less research is available on the effect
of low cyclic fatigue loading on the bond strength of high-strength concrete. In this
research, reinforced concrete beams (1165 150 225 mm) were tested under low cyclic
loading with different stress range levels. It can be concluded that the bond strength of
high-strength concrete is more than for normal-strength concrete. Low-cyclic fatigue
loading decreased the bond strength under monotonic loading by about 43–45%. Energy
dissipation during cycling is found to be good. At higher cycles, energy dissipation
decreased because of local damages in front of bar ribs. With the increase in number
of cycles, change in slip behaviour was found.
Keywords bond strength; energy dissipation; fatigue loading; high-strength concrete;
monotonic loading; slip behaviour.
NOMENCLATURE d
b
= diameter of bar
E = Modulus of elasticity of steel
fc
0
= Ultimate compressive strength of concrete at 28 days
LVDT = Linear variable differential transducer
MPa = Mega Pascal
PD = circumference of the bar
Psi = pound per square inch
d = unidirectional stress in concrete
E = axial strain in steel (Micro strains)
INTRODUCTION
Bond between steel and concrete is the mechanism
through which forces are transferred between the two
materials. So, the bond between steel and concrete
is essential in checking the flexural performance of
reinforced concrete structures at the serviceability and
ultimate stages that also controls the deflection, the width
and distribution of cracks and the ultimate strength of
reinforced concrete member.
1
Mechanism of bond under
repeated loading was studied, and it was observed that
bond fatigue failure could occur for load ranges as low as
45% of the beam’s static capacity and that the load-life
behaviour was linear on a log–log scale. As the number
of cycles increased, the slip behaviour changed from a sta-
ble to an exponential increase.
2
Comparison between nor-
mal-strength concrete (NSC) and high-strength concrete
(HSC). The analysis made use of an experimentally derived
local bond stress-slip model and considered the progressive
bond deterioration along the development/splice length
with the increase in bar force.
3
The presence of steel
fibres increased the peak bond strength, reduced the
bond degradation or damage under cyclic loading and
resulted in substantially enhanced energy absorption Correspondence: R. R. Hussain. E-mail: raja386@hotmail.com
© 2013 Wiley Publishing Ltd. Fatigue Fract Engng Mater Struct, 2013, 36, 602–613 602
doi: 10.1111/ffe.12027