1.4 Test Results and Discussion
21
0.0
0.5
1.0
1.5
2.0
2.5
3.0
8
10
12
14
16
18
Steel fiber content (%)
Flexural strength at
LOP (MPa)
Micro-straight fiber
Hooked fiber
0.5
1.0
1.5
2.0
2.5
3.0
4
8
12
16
20
24
Steel fiber content (%)
Flexural strength at
MOR (MPa)
Micro-straight fiber
Hooked fiber
(a)
(b)
(c)
(d)
0.5
1.0
1.5
2.0
2.5
3.0
0
5
10
15
20
25
30
Steel fiber content (%)
Flexural strength at L/600 (MPa)
Micro-straight fiber
Hooked fiber
0.5
1.0
1.5
2.0
2.5
3.0
0
3
6
9
12
15
Steel fiber content (%)
Flexural strength at L/150 (MPa)
Micro-straight fiber
Hooked fiber
Fig. 1.19 Effects of steel fiber content and type on the load carrying capacity of UHPCC at a LOP
b MOR c L/ 600 d L/ 150, Ren et al. (2018), copyright 2020, with permission from Elsevier
UHPCC with hooked steel fiber, when the steel fiber content is 1.5%, the flexural
strength reaches the maximum value. With incorporating 2.5% micro-straight steel
fibers and 1.5% hooked steel fibers, the maximum flexural strengths of UHPCC has
increased by 48.4% and 28.6% compared to the corresponding value of plain UHPCC
(12.6 MPa).
1.4.4 Three-Point Flexure Test
1.4.4.1 Three-Point Flexural Load-CMOD/deflection Curves
The representative three-point flexural load-CMOD and flexural load–deflection
curves of UHPCC are shown in Figs. 1.22 and 1.23, respectively. As can be seen,
except for the three-point flexural load–deflection curve of UHPCC with 0.5% microstraight steel fibers, all the other curves exhibit the deflection hardening behavior.
Figure 1.24 shows the crack pattern of UHPCC specimens, which is similar with that