164
6 Impact Resistance of Basalt Aggregated UHP-SFRC/Fabric …
maximum aggregate diameter (5–16 mm), the grading curve of the coarse aggregates
as well as binder content on the impact resistances of the HSC panels (90–130 MPa)
impacted by the 7.62 mm hardcore bullet. Recently, Sovják et al. (2013, 2015) and
Máca et al. (2014) conducted the deformable (Pb core) and non-deformable (steel
core) 7.92 mm bullet impacting tests on the traditional no coarse aggregated UHPSFRC (148–164 MPa), HSC (69–130 MPa), fiber reinforced concrete (FRC, 37–
38 MPa), ultra-high performance concrete (UHPC, 110–141.9 MPa) and normal
strength concrete (NSC, 43 MPa) slabs with the striking velocity at 691–720 m/s.
The excellent impact resistance of UHP-SFRC was validated and the influences of
steel fiber volumetric fractions (1–3%) on the depth of penetration (DOP), the impact
crater size and debris fragment mass were studied, respectively.
Furthermore, aiming to reduce the damage degree of the concrete panels and block
the high-speed ejecting fragments from the rear face of the concrete slab, compared
with the rear attached steel liner (Kojima 1991; Tetsuo et al. 1997; Siddiqui et al.
2014; Wu et al. 2015c), pasting fabric on the rear face of the concrete panel is more
practical for both operation and interior decoration. Vossoughi et al. (2007) conducted
12.7 mm conical-nosed projectile impact test on the normal strength concrete (30–
43 MPa) panels with the front and/or rear Polypropylene or Zylon fabric liner. It is
found that the rear scabbing of the fabric protected concrete panel was considerably
reduced and the debris was contained by the fabric. Recently, Almusallam et al.
(2015) presented the responses of rear CFRP strengthened RC panels (49 MPa,
90 mm thick) impacted by the hemispherical nosed projectile (40 mm in diameter,
striking velocity at 92–158 m/s). It indicated that the rear strengthened CFRP fabric
could increase the ballistic limit (the minimum initial impact velocity of the projectile
to perforate the target with given thickness) by about 18%, reduce the front crater
damage and block the fragments from the rear face of the panel.
The resistance of concrete panel under projectile impact depends mainly on the
compressive strength of the target as well as the size and strength (hardness) of the
coarse aggregate (Zhang et al. 2005; Dancygier et al. 2007, 2014; Wu et al. 2015a).
Because the improvement of the strength needs decreasing or even eliminating the
ingredients sizes in order to improve the homogeneity and density of the composite,
there are few coarse aggregates mixed into UHP-SFRC (Graybeal 2006; Farnam
et al. 2010; Habel and Gauvreau 2008; Sovják et al. 2013, 2015; Máca et al. 2014),
and the impact resistance of coarse aggregates are neglected. For the optimization
design of the mixing proportions of concrete target, (i) compressive strength of the
target, Wu et al. (2015a) and Zhang et al. (2005) have found that DOPs of the
projectiles are no longer decreasing obviously when the compressive strength of the
target are larger than ~100 MPa; (ii) sizes of the high strength coarse aggregates,
Bludau et al. (2006) proposed that the existence of coarse aggregates with size equal
to or larger than the projectile’s diameter would obtain a larger impact resistance, and
basalt as well as quartzite aggregates give a good ratio between costs of production
and anti-strike resistance. Also, Wu et al. (2015a) suggested that the average size
of the coarse aggregates should be larger than 1.5 times of the projectile shank
diameter for the constructions of protective structures; (iii) type, dimension and
volumetric ratio of incorporating fibers, Wu et al. (2015a), Sovják et al. (2013, 2015)
6 Impact Resistance of Basalt Aggregated UHP-SFRC/Fabric …
maximum aggregate diameter (5–16 mm), the grading curve of the coarse aggregates
as well as binder content on the impact resistances of the HSC panels (90–130 MPa)
impacted by the 7.62 mm hardcore bullet. Recently, Sovják et al. (2013, 2015) and
Máca et al. (2014) conducted the deformable (Pb core) and non-deformable (steel
core) 7.92 mm bullet impacting tests on the traditional no coarse aggregated UHPSFRC (148–164 MPa), HSC (69–130 MPa), fiber reinforced concrete (FRC, 37–
38 MPa), ultra-high performance concrete (UHPC, 110–141.9 MPa) and normal
strength concrete (NSC, 43 MPa) slabs with the striking velocity at 691–720 m/s.
The excellent impact resistance of UHP-SFRC was validated and the influences of
steel fiber volumetric fractions (1–3%) on the depth of penetration (DOP), the impact
crater size and debris fragment mass were studied, respectively.
Furthermore, aiming to reduce the damage degree of the concrete panels and block
the high-speed ejecting fragments from the rear face of the concrete slab, compared
with the rear attached steel liner (Kojima 1991; Tetsuo et al. 1997; Siddiqui et al.
2014; Wu et al. 2015c), pasting fabric on the rear face of the concrete panel is more
practical for both operation and interior decoration. Vossoughi et al. (2007) conducted
12.7 mm conical-nosed projectile impact test on the normal strength concrete (30–
43 MPa) panels with the front and/or rear Polypropylene or Zylon fabric liner. It is
found that the rear scabbing of the fabric protected concrete panel was considerably
reduced and the debris was contained by the fabric. Recently, Almusallam et al.
(2015) presented the responses of rear CFRP strengthened RC panels (49 MPa,
90 mm thick) impacted by the hemispherical nosed projectile (40 mm in diameter,
striking velocity at 92–158 m/s). It indicated that the rear strengthened CFRP fabric
could increase the ballistic limit (the minimum initial impact velocity of the projectile
to perforate the target with given thickness) by about 18%, reduce the front crater
damage and block the fragments from the rear face of the panel.
The resistance of concrete panel under projectile impact depends mainly on the
compressive strength of the target as well as the size and strength (hardness) of the
coarse aggregate (Zhang et al. 2005; Dancygier et al. 2007, 2014; Wu et al. 2015a).
Because the improvement of the strength needs decreasing or even eliminating the
ingredients sizes in order to improve the homogeneity and density of the composite,
there are few coarse aggregates mixed into UHP-SFRC (Graybeal 2006; Farnam
et al. 2010; Habel and Gauvreau 2008; Sovják et al. 2013, 2015; Máca et al. 2014),
and the impact resistance of coarse aggregates are neglected. For the optimization
design of the mixing proportions of concrete target, (i) compressive strength of the
target, Wu et al. (2015a) and Zhang et al. (2005) have found that DOPs of the
projectiles are no longer decreasing obviously when the compressive strength of the
target are larger than ~100 MPa; (ii) sizes of the high strength coarse aggregates,
Bludau et al. (2006) proposed that the existence of coarse aggregates with size equal
to or larger than the projectile’s diameter would obtain a larger impact resistance, and
basalt as well as quartzite aggregates give a good ratio between costs of production
and anti-strike resistance. Also, Wu et al. (2015a) suggested that the average size
of the coarse aggregates should be larger than 1.5 times of the projectile shank
diameter for the constructions of protective structures; (iii) type, dimension and
volumetric ratio of incorporating fibers, Wu et al. (2015a), Sovják et al. (2013, 2015)