Page 9 - Open-Access-Dec-2019

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TECHNICAL PAPER

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i  Figure 7 shows the typical failure mode of the R/FRCs and R/
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(4% (4% ECC prism specimens subject to four-point bending before and

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after accelerated corrosion. The failure modes are categorized

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(4% (4% into shear failure, bond failure, and bending failure as shown in

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iviV̈œ˜ ­““® iviV̈œ˜ ­““® Table 4. As can be seen, shear failure was the dominant failure

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œ>` ­Ž ® œ>` ­Ž ® (b) 2-d accelerated corrosion as major shear cracks were observed
mode for all pristine R/FRC prism specimens before and after

as shown in Figures 7a, 7b, 7d, 7e, 7g and 7h. With the increase
(4% (4% (4% of accelerated corrosion duration to 4 d, the failure mode

(4% (4% (4% changed from shear failure to bond failure in R/FRC specimens.
(4% (4% (4% This phenomenon was attributed to the failure of bonding

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of steel bar. For example, a visible wider longitudinal crack was

œ>` ­Ž ® œ>` ­Ž ® iviV̈œ˜ ­““® œ>` ­Ž ® iviV̈œ˜ ­““® found in R/FRC 1 and R/FRC 2 specimens after 4-d accelerated
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corrosion as shown in Figures 7c and 7f. The increase of fibre
dosage delays the change of failure mode in R/FRC specimens,
and bond failure was not observed in R/FRC 3 specimen (Figure
7i). R/ECC showed a consistent bending failure before and after

accelerated corrosion (Figures 7j, 7k and 7l) owning to the high
ductility and damage tolerance of the ECC cover. In a sense, the

strong confinement effect of ECC on steel bar can compromise
iviV̈œ˜ ­““® iviV̈œ˜ ­““® iviV̈œ˜ ­““® the sharp deterioration of bonding between corroded steel
(c) and ECC in comparison with FRCs. Multiple micro-cracks were
observed at the tension side (bottom surface) of the specimen,
Figure 5: Load-deflection curves of reinforced prisms (a) before, and (b) and the crack width was limited to be less than 150 mm in R/
after 2-d and (c) after 4-d accelerated corrosion. ECC specimens.
The IndIan ConCreTe Journal | deCember 2019 15