192
7 Impact Resistance of Armor Steel/Ceramic/UHPCC Layered …
Table 7.3 Physical properties of SiC ceramic
Density (g/cm 3 ) Vickers hardness Compressive
strength (MPa)
Thermal
conductivity
(Cal/cm·s·°C)
Coefficient of
thermal expansion
(1/K)
3.2
2500
>3000
0.3
4.3 × 10 –6
The corresponding front and back faces of the 10CrNi3MoV21A armor steel/SiC
ceramic composite plate are also shown in Fig. 7.2c.
(4) UHPCC target
UHPCC is developed by Jiangsu Research Institute of Building Science in China,
which is prefabricated by mixing the Chinese standard Graded 52.5 P.II type Portland
cement, silica fume, ultra-fine mineral admixture which consists of fly ash and ultrafine slag, the natural river sand with a maximal diameter of 2.5 mm, polycarboxylic
type high-range-water-reducer (HRWR) and 2% (volume fraction) straight brasscoated steel fiber. The corresponding mixing proportions of the UHPCC and material
properties of steel fiber are listed in Tables 7.4 and 7.5, respectively.
The casting process as well as the UHPCC target with 10CrNi3MoV21A armor
steel/SiC ceramic composite plate are shown in Fig. 7.3. The cylindrical UHPCC
target was firstly cast into a 5 mm-thick steel hoop with the height and diameter of
500 mm and 700 mm, respectively. The fluidity of UHPCC was then significantly
weakened after curing atmospherically for about 4 ~ 5 h, after which, the composite
plates were embedded into the UHPCC targets at the centre of front faces (the front
surface of the plate was guaranteed in the same plane with the UHPCC target, as
depicted in Fig. 7.3b). It should be noted that, all the UHPCC targets were cured in
the air for 30 days before the impact tests. The average 30-d unconfined compressive
strength of the UHPCC was about 135 MPa, which was tested on cylinder specimens
with the dimensions of 75 × 150 mm.
7.2.1.2 Test Setup
Seven different target configurations were designed in the present tests, i.e., NSC
(35 MPa), UHPCC, 5 mm armor steel/UHPCC, 10 mm armor steel/UHPCC,
Table 7.4 Mix proportions of UHPCC (kg/m 3 )
Cement Silica fume Viscosity reducing
admixture
River sand Water Superplasticizer Steel fiber
700
140
110
1200
152
22.8
156
Table 7.5 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
7 Impact Resistance of Armor Steel/Ceramic/UHPCC Layered …
Table 7.3 Physical properties of SiC ceramic
Density (g/cm 3 ) Vickers hardness Compressive
strength (MPa)
Thermal
conductivity
(Cal/cm·s·°C)
Coefficient of
thermal expansion
(1/K)
3.2
2500
>3000
0.3
4.3 × 10 –6
The corresponding front and back faces of the 10CrNi3MoV21A armor steel/SiC
ceramic composite plate are also shown in Fig. 7.2c.
(4) UHPCC target
UHPCC is developed by Jiangsu Research Institute of Building Science in China,
which is prefabricated by mixing the Chinese standard Graded 52.5 P.II type Portland
cement, silica fume, ultra-fine mineral admixture which consists of fly ash and ultrafine slag, the natural river sand with a maximal diameter of 2.5 mm, polycarboxylic
type high-range-water-reducer (HRWR) and 2% (volume fraction) straight brasscoated steel fiber. The corresponding mixing proportions of the UHPCC and material
properties of steel fiber are listed in Tables 7.4 and 7.5, respectively.
The casting process as well as the UHPCC target with 10CrNi3MoV21A armor
steel/SiC ceramic composite plate are shown in Fig. 7.3. The cylindrical UHPCC
target was firstly cast into a 5 mm-thick steel hoop with the height and diameter of
500 mm and 700 mm, respectively. The fluidity of UHPCC was then significantly
weakened after curing atmospherically for about 4 ~ 5 h, after which, the composite
plates were embedded into the UHPCC targets at the centre of front faces (the front
surface of the plate was guaranteed in the same plane with the UHPCC target, as
depicted in Fig. 7.3b). It should be noted that, all the UHPCC targets were cured in
the air for 30 days before the impact tests. The average 30-d unconfined compressive
strength of the UHPCC was about 135 MPa, which was tested on cylinder specimens
with the dimensions of 75 × 150 mm.
7.2.1.2 Test Setup
Seven different target configurations were designed in the present tests, i.e., NSC
(35 MPa), UHPCC, 5 mm armor steel/UHPCC, 10 mm armor steel/UHPCC,
Table 7.4 Mix proportions of UHPCC (kg/m 3 )
Cement Silica fume Viscosity reducing
admixture
River sand Water Superplasticizer Steel fiber
700
140
110
1200
152
22.8
156
Table 7.5 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