2
1 Static Mechanical Properties of UHPCC
2014) (1.0 ~ 4.0% by volume) have studied the influence of steel fiber content on the
compressive and flexural behaviors of UHPFRC, respectively. The results indicated
that, with the increase of steel fiber content, the compressive strength gradually
increased, while the flexural strength, deflection and CMOD (crack mouth opening
displacement) at peak load pseudo-linearly increased correspondingly, and the steel
fiber content had no noticeable influence on the first crack flexural strength and the
corresponding deflection/CMOD.
As for the existing works on the influence of steel fiber type on the static behavior
of UHPCC, Wille et al. (2014) also experimentally studied the effect of steel fiber type
(smooth, hooked and twisted) on the tensile properties of UHPFRC, which showed
that the tensile strength and the corresponding strain as well as the energy absorption
capacity were less affected by the steel fiber type. Liu et al. (2016) also studied the
effect of steel fiber type (smooth, spiral and hooked micro-fibers as well as hooked
macro-fiber) on the tensile properties of UHPC with coarse aggregates. The results
showed that the micro-hooked steel fiber had the most significant effect on the first
crack tensile strength and the fiber-bridging stress. Wu et al. (2016) also investigated
the effects of three typical steel fibers (straight, corrugated and hooked-end) on the
compressive and flexural properties of UHPC. It was concluded that the steel fiber
type had little influence on the first crack flexural strength and the corresponding
deflection, and the UHPC with hooked-end steel fiber had the highest compressive
and flexural strengths.
Generally, considering the time and economic cost, limited works were performed
to systematically assess the effects of steel fiber content and type on the static
strengths as well as the full stress–strain curves and flexural load–deflection/CMOD
curves of UHPCC. In the present chapter, a series of cubic/axial compressive, direct
tensile, four-point and three-point flexural tests on UHPCC specimens are conducted,
in which two typical steel fibers (micro-straight and hooked) with six volume fractions of 0 ~ 2.5% are considered. The systematical full compressive and tensile
stress–strain curves as well as the flexural load–deflection and flexural load-CMOD
curves are obtained. The effects of steel fiber content and type on the cubic and
axial compressive strengths, compressive elastic modulus and Poisson’s ratio, direct
tensile strength, flexural strength, load carrying capacity, energy absorption capacity,
fracture toughness and fracture energy are comprehensively discussed. The present
work is fundamental and the derived conclusions could provide helpful references
for the analysis and design of the UHPCC structures.
1.2 Test Program
1.2.1 Raw Materials and Mixture Proportions
UHPCC was prepared in the State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Research Institute of Building Science in China, and the
1 Static Mechanical Properties of UHPCC
2014) (1.0 ~ 4.0% by volume) have studied the influence of steel fiber content on the
compressive and flexural behaviors of UHPFRC, respectively. The results indicated
that, with the increase of steel fiber content, the compressive strength gradually
increased, while the flexural strength, deflection and CMOD (crack mouth opening
displacement) at peak load pseudo-linearly increased correspondingly, and the steel
fiber content had no noticeable influence on the first crack flexural strength and the
corresponding deflection/CMOD.
As for the existing works on the influence of steel fiber type on the static behavior
of UHPCC, Wille et al. (2014) also experimentally studied the effect of steel fiber type
(smooth, hooked and twisted) on the tensile properties of UHPFRC, which showed
that the tensile strength and the corresponding strain as well as the energy absorption
capacity were less affected by the steel fiber type. Liu et al. (2016) also studied the
effect of steel fiber type (smooth, spiral and hooked micro-fibers as well as hooked
macro-fiber) on the tensile properties of UHPC with coarse aggregates. The results
showed that the micro-hooked steel fiber had the most significant effect on the first
crack tensile strength and the fiber-bridging stress. Wu et al. (2016) also investigated
the effects of three typical steel fibers (straight, corrugated and hooked-end) on the
compressive and flexural properties of UHPC. It was concluded that the steel fiber
type had little influence on the first crack flexural strength and the corresponding
deflection, and the UHPC with hooked-end steel fiber had the highest compressive
and flexural strengths.
Generally, considering the time and economic cost, limited works were performed
to systematically assess the effects of steel fiber content and type on the static
strengths as well as the full stress–strain curves and flexural load–deflection/CMOD
curves of UHPCC. In the present chapter, a series of cubic/axial compressive, direct
tensile, four-point and three-point flexural tests on UHPCC specimens are conducted,
in which two typical steel fibers (micro-straight and hooked) with six volume fractions of 0 ~ 2.5% are considered. The systematical full compressive and tensile
stress–strain curves as well as the flexural load–deflection and flexural load-CMOD
curves are obtained. The effects of steel fiber content and type on the cubic and
axial compressive strengths, compressive elastic modulus and Poisson’s ratio, direct
tensile strength, flexural strength, load carrying capacity, energy absorption capacity,
fracture toughness and fracture energy are comprehensively discussed. The present
work is fundamental and the derived conclusions could provide helpful references
for the analysis and design of the UHPCC structures.
1.2 Test Program
1.2.1 Raw Materials and Mixture Proportions
UHPCC was prepared in the State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Research Institute of Building Science in China, and the