The most critical drawback in currently used steel reinforcement in reinforced concrete (RC) structures is susceptibility to accumulation of plastic deformation under excessive loads. Many concrete structures due to damaged (yielded) steel reinforcement have undergone costly repairs and replacements. This research presents a new type of shape memory alloy (SMA)-based composite reinforcement with ability to withstand high elongation while exhibiting pseudo-elastic behavior. In this study, small diameter SMA wires are embedded in thermoset resin matrix with or without additional glass fibers to develop composite reinforcement. Manufacturing technique of new proposed composite is validated using microscopy images. The proposed SMA-FRP composite square rebars are first fabricated and then embedded in small scale concrete T-beam. 3-point bending test is conducted on manufactured RC beam using a cyclic displacement controlled regime until failure. It is found that the SMA-FRP composite reinforcement is able to enhance the performance of concrete member by providing re-centering and crack closing capability.
forward transformation / yielding- Austenite to Martensite start
1.96
3.69
0.87
G
end of loading phase-Cycle 2
2.33
3.44
1.19
unloading
H
end of 2nd Cycle
1.01
0
0.5
3
loading
I
forward transformation / yielding
1.99
3.55
0.88
J
peak loading
2.2
3.73
1.05
K
end of loading phase-Cycle 3
3.37
3.62
2.14
unloading
L
reverse transformation- Martensite to Austenite start
2.92
1.89
1.84
M
phase transformation- Martensite to Austenite finish
1.98
1.58
0.93
N
end of 3rd Cycle
1.21
0
0.56
4
loading
O
widening of shear cracks
2.53
3.5
1.13
P
complete shear failure
3.94
2.33
0.86
Tab.4
cycles
phase
point
description
force /kN
SG-1/%
SG-2/%
SG-3/%
1
loading
A
uncracked extending from zero load
0
0
0
0
B
initiation of flexural crack
1.31
7.46
1.01
-0.008
C
initiation of shear crack
2.63
peaked out
7.46
-0.024
D
end of loading phase-Cycle 1
3.05
peaked out
-0.036
unloading
E
end of 1st Cycle
0
-0.019
2
loading
F
forward transformation / yielding- Austenite to mMartensite start
3.69
-0.087
G
end of loading phase-Cycle2
3.44
-0.33
unloading
H
end of 2nd Cycle
0
-0.21
3
loading
I
forward transformation/ yielding
3.55
-0.23
J
peak loading
3.73
-0.298
K
end of loading phase-Cycle 3
3.62
-4
unloading
L
reverse transformation- martensite to Austenite start
1.89
-4
M
phase transformation- martensite to Austenite finish
1.58
-1.44
N
end of 3rd Cycle
0
-0.57
Tab.5
1
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