240
8 Response of UHPCC-FST Subjected to Low-Velocity Impact
Table 8.2 Chemical composition of cement and silica fume (%)
Composition
CaO
SiO
MgO
Fe 2 O 3
Al 2 O 3
SO 3
LOI
Cement
61.80
20.00
5.31
3.46
4.64
3.15
2.44
Silica fume
1.00
93.10
0.65
2.44
0.76
0.12
1.04
Table 8.3 Material properties of steel fiber
Fiber type
Length
(mm)
Diameter
(mm)
Aspect
ratio
Density
(g/cm 3 )
Tensile
strength
(MPa)
Elastic
modulus
(GPa)
Micro-straight
13
0.2
65
7.8
2800
210
micro-straight steel fiber is incorporated with the volume fraction of 2.0% and the
corresponding material properties are given in Table 8.3. The slump and spread of
the present UHPCC were about 230 mm and 610 mm respectively, which guarantees
the workability requirements of on-site constructions.
The control specimens of UHPCC including three cubes of 100 mm × 100 mm
× 100 mm and three prisms of 100 mm × 100 mm × 300 mm were cast and
tested according to the Chinese standard GB/T 50081–2002 (2003). The average
quasi-static compressive strength, elastic modulus and Poisson’s ratio of UHPCC
are 141.5 MPa, 43.8GPa and 0.23, respectively.
The outer steel tubes are made from 20# steel, and the material properties of
which are determined from the standard static tensile coupon test. The coupons were
cut from the longitudinal direction of the tube and a total of five standard coupons
were tested according to the Chinese standard GB/T 228.1–2010 (2003). Figure 8.1
illustrates the experimental tensile stress–strain curves of 20# steel coupons 1 ~ 5.
The engineering yield stress, ultimate tensile stress and rupture strain of the coupons
can be derived and listed in Table 8.4. Besides, the elastic modulus and Poisson’s
ratio of 20# steel are taken as 206GPa and 0.3 according to the Chinese standard GB
50,017–2017 (2017).
Five large-sized circular UHPCC-FSTs were fabricated. As shown in Fig. 8.2,
the thickness of steel tube is 6 mm, the length and outer diameters of the specimen
are 2000 mm and 203 mm, respectively. A 20 mm thick and 400 mm × 400 mm
sized square steel plate was welded on the bottom of the specimen to guarantee the
preparation and stability of the column.
8.2.2 Axial Compression Test
As shown in Fig. 8.3, the axial compression test was conducted by using a 1000t
hydraulic testing machine and two UHPCC-FSTs were tested to analyze their axial
load bearing capacities. The load was applied at the top of each specimen with the
8 Response of UHPCC-FST Subjected to Low-Velocity Impact
Table 8.2 Chemical composition of cement and silica fume (%)
Composition
CaO
SiO
MgO
Fe 2 O 3
Al 2 O 3
SO 3
LOI
Cement
61.80
20.00
5.31
3.46
4.64
3.15
2.44
Silica fume
1.00
93.10
0.65
2.44
0.76
0.12
1.04
Table 8.3 Material properties of steel fiber
Fiber type
Length
(mm)
Diameter
(mm)
Aspect
ratio
Density
(g/cm 3 )
Tensile
strength
(MPa)
Elastic
modulus
(GPa)
Micro-straight
13
0.2
65
7.8
2800
210
micro-straight steel fiber is incorporated with the volume fraction of 2.0% and the
corresponding material properties are given in Table 8.3. The slump and spread of
the present UHPCC were about 230 mm and 610 mm respectively, which guarantees
the workability requirements of on-site constructions.
The control specimens of UHPCC including three cubes of 100 mm × 100 mm
× 100 mm and three prisms of 100 mm × 100 mm × 300 mm were cast and
tested according to the Chinese standard GB/T 50081–2002 (2003). The average
quasi-static compressive strength, elastic modulus and Poisson’s ratio of UHPCC
are 141.5 MPa, 43.8GPa and 0.23, respectively.
The outer steel tubes are made from 20# steel, and the material properties of
which are determined from the standard static tensile coupon test. The coupons were
cut from the longitudinal direction of the tube and a total of five standard coupons
were tested according to the Chinese standard GB/T 228.1–2010 (2003). Figure 8.1
illustrates the experimental tensile stress–strain curves of 20# steel coupons 1 ~ 5.
The engineering yield stress, ultimate tensile stress and rupture strain of the coupons
can be derived and listed in Table 8.4. Besides, the elastic modulus and Poisson’s
ratio of 20# steel are taken as 206GPa and 0.3 according to the Chinese standard GB
50,017–2017 (2017).
Five large-sized circular UHPCC-FSTs were fabricated. As shown in Fig. 8.2,
the thickness of steel tube is 6 mm, the length and outer diameters of the specimen
are 2000 mm and 203 mm, respectively. A 20 mm thick and 400 mm × 400 mm
sized square steel plate was welded on the bottom of the specimen to guarantee the
preparation and stability of the column.
8.2.2 Axial Compression Test
As shown in Fig. 8.3, the axial compression test was conducted by using a 1000t
hydraulic testing machine and two UHPCC-FSTs were tested to analyze their axial
load bearing capacities. The load was applied at the top of each specimen with the