1 Introduction
2 Test Plan
2.1 Test Specimens
Specimen | Fiber volume fraction, V
f
(%) | Spacing of transverse bars, s (volumetric ratio, ρ
st
) | Wire-mesh |
---|---|---|---|
HCC1 | 1.5 | 100 mm (2.52%) | O |
HCC2 | 2.0 | 100 mm (2.52%) | O |
HCC3 | 1.5 | 200 mm (1.26%) | O |
HCC4 | 2.0 | 200 mm (1.26%) | O |
HCC5 | 1.5 | 100 mm (2.52%) | – |
2.2 Material Properties
2.2.1 Concrete Mixes and Mechanical Properties
Mix type | 1.5% V
f
UHPFRC | 2.0% V
f
UHPFRC |
---|---|---|
Portland cement | 769.8 kg/m3
| 766.9 kg/m3
|
Silica fume | 192.5 kg/m3
| 191.7 kg/m3
|
Silica flour | 231.0 kg/m3
| 230.1 kg/m3
|
Find sand | 846.8 kg/m3
| 843.6 kg/m3
|
Super-plasticizer | 30.8 kg/m3
| 30.7 kg/m3
|
Expansive agent | 3.8 kg/m3
| 3.8 kg/m3
|
Deforming agent | 3.8 kg/m3
| 3.8 kg/m3
|
Steel fibers | 89.5 kg/m3
| 118.9 kg/m3
|
Water (W/B)a
| 192.5 kg/m3
(0.2) | 191.7 kg/m3
(0.2) |
2.2.2 Reinforcement
Nominal diameter (mm) | Nominal area (mm2) | Modulus of elasticity (GPa) | Yield strength (MPa) | Yield strain (mm/mm) | Ultimate strength (MPa) |
---|---|---|---|---|---|
10 (trans. bars) | 78.54 | 218.02 | 381.97 | 0.00176 | 536.66 |
22 (longi. bars) | 380.13 | 228.26 | 263.07 | 0.00115 | 416.63 |
16 (threaded bars) | 201.06 | 182.18 | 397.89 | 0.00218 | 508.07 |
2.3 Production of Column Specimens
2.4 Test Setup and Instrumentation
3 Test Results
3.1 Failure Mode
3.2 Crack Patterns
HCC1 (control) | HCC2 (V
f
= 2.0%) | HCC3 (s = 200 mm) | HCC4 (V
f
= 2.0%, s = 200 mm) | HCC5 (no wire-mesh) | |||||
---|---|---|---|---|---|---|---|---|---|
Crack no. | Load range (kN) | Crack no. | Load range (kN) | Crack no. | Load range (kN) | Crack no. | Load range (kN) | Crack no. | Load range (kN) |
1–8 | 2100–2400 | 1–6 | 2400–2700 | 1–2 | 2000–2200 | 1–2 | 2300–2600 | 1–20 | 2100–2400 |
9–19 | 2400–2700 | 7–31 | 2700–2900 | 3–5 | 2200–2400 | 3–16 | 2600–2800 | 21–37 | 2400–2600 |
20–33 | 2700–3000 | 32–39 | 2900–3100 | 6–10 | 2400–2600 | 17–26 | 2800–3000 | 38–55 | 2600–2800 |
34–37 | 3000–3100 | 40–60 | 3100–3300 | 11–43 | 2600–2800 | 27–53 | 3000–3200 | 56–94 | 2800–3000 |
NM | 3100– | 61–79 | 3300–3500 | 44–71 | 2800–3000 | 54–95 | 3200–3500 | 95–129 | 3000–3200 |
80–126 | 3500–3700 | 72–95 | 3000–3200 | 96–106 | 3500–3600 | 130–173 | 3200–3300 | ||
NM | 3700– | 96–140 | 3200–3400 | NM | 3600– | NM | 3300– | ||
NM | 3400– |
3.3 Axial Load–Displacement Relationship
Specimen | 1st crack | Yield displacement | Peak load | Ultimate displacement | ||||
---|---|---|---|---|---|---|---|---|
P
cr
(kN) |
δ
cr
(mm) |
P
y
(kN) |
δ
y
(mm) |
P
p
(kN) |
δ
p
(mm) |
P
u
(kN) |
δ
u
(mm) | |
HCC1 (control) | 2190 | 0.7 | 2787 | 1.3 | 3369 | 2.6 | 2695 | 4.3 (3.3) |
HCC2 (V
f
= 2.0%) | 2416 | 0.7 | 3194 | 1.2 | 3729 | 2.9 | 2893 | 4.0 (3.2) |
HCC3 (s = 200 mm) | 2084 | 0.6 | 2944 | 1.1 | 3440 | 2.0 | 2754 | 2.9 (2.7) |
HCC4 (V
f
= 2.0%, s = 200 mm) | 2351 | 0.6 | 3199 | 1.0 | 3624 | 1.7 | 2899 | 3.1 (3.0) |
HCC5 (no wire-mesh) | 2100 | 0.6 | 3003 | 1.0 | 3370 | 1.7 | 2700 | 2.4 (2.4) |
Specimen | Test resultsa
| Predictions by design codeb
| ||||
---|---|---|---|---|---|---|
Non-composite (NSC core only) | Full-composite (UHPFRC Tube + NSC core) | |||||
k
i
(kN/mm) |
P
p
(kN) |
k
e
(kN/mm) |
P
o
(kN) |
k
e
(kN/mm) |
P
o
(kN) | |
HCC1 (control) | 3466 | 3369 | 2610 | 2926 | 3262 | 4930 |
HCC2 (V
f
= 2.0%) | 3776 | 3729 | 2610 | 2926 | 3534 | 6241 |
HCC3 (s = 200 mm) | 3318 | 3440 | 2610 | 2926 | 3262 | 4930 |
HCC4 (V
f
= 2.0%, s = 200 mm) | 3689 | 3624 | 2610 | 2926 | 3534 | 6241 |
HCC5 (no wire-mesh) | 3476 | 3370 | 2610 | 2926 | 3262 | 4930 |