Civil Engineering Reference
In-Depth Information
Table 4.7
Fitted parameters of regression equation
Constant
m
Constant
n
Constant
p
Correlation
coeffi cient
C
R
2
Serial number
PC (NCB0%
+
CF0%)
16.21
33.06
−
10.33
0.50033
NCB01 (NCB0.1%
+
CF0%)
32.31
47.48
−
21.05
0.82466
NCB02 (NCB0.2%
+
CF0%)
34.57
5.21
−
39.11
0.76742
NCB03 (NCB0.3%
+
CF0%)
56.89
85.79
−
44.85
0.92748
NCB04 (NCB0.4%
+
CF0%)
23.04
17.57
−
25.56
0.90907
CF04 (NCB0%
+
CF0.4%)
27.87
13.00
−
29.74
0.79566
CF08 (NCB0%
+
CF0.8%)
20.83
19.26
−
21.25
0.83359
CF10 (NCB0%
+
CF1.0%)
25.55
12.39
−
27.41
0.97752
CF13 (NCB0%
+
CF1.3%)
12.39
14.84
−
11.00
0.9471
CF16 (NCB0%
+
CF1.6%)
42.96
15.75
−
52.68
0.82598
BF14 (NCB0.1%
+
CF0.4%)
14.88
95.04
−
12.56
0.95126
BF18 (NCB0.1%
+
CF0.8%)
106.63
83.70
−
82.74
0.77459
BF24 (NCB0.2%
+
CF0.4%)
12.98
34.94
−
15.24
0.90456
BF28 (NCB0.2%
+
CF0.8%)
13.45
68.90
−
16.11
0.8813
4.4.3 Sensitivity of conductive concrete
The ability of a structural material to sense its own strain (i.e., sensitivity)
is an attractive attribute of smart structures. The sensitivity of conductive
concrete may be characterized by the gauge factor (
) which is defi ned
as the fractional change in resistance per unit strain (Chung, 2012; Tian
and Hu, 2012). Hence
λ
λ
is equal to the slope of Eq. [4.1] and may be
expressed by:
m
(
)
λ =
001
.
Y
′ =
exp
−
Xn
[4.5]
100
n
where
m
and
n
are both constant parameters and the variable
X
is the strain
of the initial geometrical neutral axis (IGNA) as in Eq. [4.4].
It may be seen from Eq. [4.5] that the value of
decreases in terms of
exponential decay function as the strain IGNA increases, i.e., the develop-
ment of strain leads to a degradation of sensitivity in electric conductive
concrete.
λ
4.5
Strain and damage in concrete beams
(self-diagnosing of damage)
The damage done to a beam prior to the concrete cracking is discussed in
this section and is based on the theory of damage mechanics (Cai and Cai,
1999). The problem may be simplifi ed as uni-dimensional damage and only
Search WWH ::
Custom Search