r - The Hong Kong Polytechnic University

and a corresponding shear strain of 6.20×10 -3 . At the onset of panel failure, the applied load gradually declined
and the major cracks opened up slowly. The failure of the panel was dictated by an aggregate interlock failure as
there was no indication of concrete crushing or reinforcement rupture.
Figure 3 The shear stress - shear strain response of SCHPFRC panel
The comparison of crack pattern of SCHPFRC and control panels (Susetyo 2009) at failure is shown in Figure 4.
It is noted that the control panel (f’ c = 66MPa), which was made of conventional concrete, has higher
reinforcement ratios (x-direction: reinforcement area of 2061 mm², ρ x = 3.31%; y-direction: reinforcement area
of 260 mm²,ρ y = 0.42% ) compared to the SCHPFRC panel. It was also observed that the failure of the
SCHPFRC panel was caused by the inability of the concrete to transmit the load across the cracks (coarse
aggregate interlock failure) instead of the yielding or fracture of the transverse reinforcement in the conventional
concrete panel. The cracks in SCHPFRC panel were significantly fine and well distributed across the face of the
panel, with crack spacing smaller than those observed in the control panel.
Figure 4 Crack patterns at failure of SCHPFRC (left) and conventional concrete (right) panels
The principal tensile stress-strain relationships of SCHPFRC and conventional concrete are conducted based on
Mohr’s circle method and shown in Figure 5. Due to higher compressive strength of conventional concrete, the
-497-