1.4 Test Results and Discussion
23
0.0
0.5
1.0
1.5
2.0
2.5
3.0
5
10
15
20
25
Steel fiber content (%)
Micro-straight fiber
Hooked fiber
Maximum
flexural strength (MPa)
Fig. 1.21 Effects of steel fiber content and type on the maximum flexural strength of UHPCC, Ren
et al. (2018), copyright 2020, with permission from Elsevier
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
5
10
15
20
25
0%
0.5%
1.0%
1.5%
2.0%
2.5%
CMOD (mm)
Load (kN)
(a)
(b)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
5
10
15
20
25
30
CMOD (mm)
Load (kN)
0%
0.5%
1.0%
1.5%
2.0%
2.5%
Fig. 1.22 Representative three-point flexural load-CMOD curves of UHPCC with a micro-straight
fiber b hooked fiber, Ren et al. (2018), copyright 2020, with permission from Elsevier
1.4.4.2 Fracture Toughness
Fracture toughness K IC represents the critical stress intensity value when the fracture
failure of materials occurs. For the present non-standard three point bending concrete
beam, a modified calculation formula suggested by Fan et al. (2012) is adopted to
derive the fracture toughness of UHPCC, which is expressed as
K IC =
3(F un + 0.5m 1 g × 10
−3
)L × 10
−3
2bh 2
√
h × k β (α)
(1.3)