400
12 Experimental Study on the Residual Seismic Resistance of UHPCC …
direct tensile test was conducted under the displacement control scheme with the
speed of 2 mm/min via the MTS 810 hydro-servo machine (Fig. 12.1b). The stressstrain curve was then obtained as reported in Fig. 12.1c, and the average yield and
ultimate tensile strength of the steel tube material are found to be 318.5 MPa and
497 MPa, respectively. From the tensile test results, it was found that the average
elongation of the steel at break was 26%, and the elastic modulus and Poisson’s ratio
of the steel was 201 GPa and 0.3, respectively. It should be noted that, the mechanical
treatment during the fabricating process caused the internal damage in specimens 2,
3 and 4, which led to the premature break of these specimens in the direct tension
test. Hence, the average values of five samples were adopted.
12.2.2 UHPCC
The mix proportion of UHPCC is given in Table 12.1. The strength control specimens were cured at room temperature of 21.0 ± 2 °C with the relative humidity of
98.4% for 28 days and then tested for the axial compressive and tensile strength. The
100 mm
3 cubic compressive strength of UHPCC was obtained as 135.1 MPa. The
corresponding axial stress strain curve of the 100 mm × 100 mm × 300 mm prism
specimen is shown in Fig. 12.2a, the axial compressive strength, the elastic modulus
and Poisson’s ratio of UHPCC could be determined as 121 MPa, 42.9 GPa and 0.20,
respectively. The stress strain response of the UHPCC derived from the direct tensile
Table 12.1 Mix proportion of UHPCC (kg/m 3 )
Cement Admixture (fly ash and ultra-fine slag) Sand Steel fiber Water reducer Water
700
250
1200 156
22.8
152
0.000
0.002
0.004
0.006
0.008
0.010
0
30
60
90
120
150
Strain
Axial compressive strength (MPa)
0.000
0.002
0.004
0.006
0.008
0.010
0
2
4
6
8
10
Axial tensile strength (MPa)
Strain
(a)
(b)
Fig. 12.2 Stress-strain curve of UHPCC a axial compressive test b direct tensile test, reprinted
from Wang et al. (2020a), copyright 2020, with permission from Elsevier
12 Experimental Study on the Residual Seismic Resistance of UHPCC …
direct tensile test was conducted under the displacement control scheme with the
speed of 2 mm/min via the MTS 810 hydro-servo machine (Fig. 12.1b). The stressstrain curve was then obtained as reported in Fig. 12.1c, and the average yield and
ultimate tensile strength of the steel tube material are found to be 318.5 MPa and
497 MPa, respectively. From the tensile test results, it was found that the average
elongation of the steel at break was 26%, and the elastic modulus and Poisson’s ratio
of the steel was 201 GPa and 0.3, respectively. It should be noted that, the mechanical
treatment during the fabricating process caused the internal damage in specimens 2,
3 and 4, which led to the premature break of these specimens in the direct tension
test. Hence, the average values of five samples were adopted.
12.2.2 UHPCC
The mix proportion of UHPCC is given in Table 12.1. The strength control specimens were cured at room temperature of 21.0 ± 2 °C with the relative humidity of
98.4% for 28 days and then tested for the axial compressive and tensile strength. The
100 mm
3 cubic compressive strength of UHPCC was obtained as 135.1 MPa. The
corresponding axial stress strain curve of the 100 mm × 100 mm × 300 mm prism
specimen is shown in Fig. 12.2a, the axial compressive strength, the elastic modulus
and Poisson’s ratio of UHPCC could be determined as 121 MPa, 42.9 GPa and 0.20,
respectively. The stress strain response of the UHPCC derived from the direct tensile
Table 12.1 Mix proportion of UHPCC (kg/m 3 )
Cement Admixture (fly ash and ultra-fine slag) Sand Steel fiber Water reducer Water
700
250
1200 156
22.8
152
0.000
0.002
0.004
0.006
0.008
0.010
0
30
60
90
120
150
Strain
Axial compressive strength (MPa)
0.000
0.002
0.004
0.006
0.008
0.010
0
2
4
6
8
10
Axial tensile strength (MPa)
Strain
(a)
(b)
Fig. 12.2 Stress-strain curve of UHPCC a axial compressive test b direct tensile test, reprinted
from Wang et al. (2020a), copyright 2020, with permission from Elsevier