Transcript Document

4.7.3 High Performance Concrete (HPC)
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Introduction
Characteristics
Techniques
Proportion ratio
Properties
Application
Introduction
• HPC refers to excellent materials made by
strict construction craftworks, It is convenient to
cast and compact with no segregate It is
steady in volume and mechanical property.
• ACI international conference first proposed that
high performance concrete can’t be made by
regular materials and technology to meet
synthetic properties and uniformity in 1990.
• It has good performance in toughness,
durability.
• It can be applied to high architectures, bridges
and those exposed in harsh environment.
Characteristics
• HPC is a new kind of concrete with great
feasibility, high strength and durability.
• Its characteristics are as follows:
– The concrete mixture has good performance in
mobility, self-impact and can ensure uniformity
and impact with slight vibration or without
vibration.
– The concrete mixture shows good cohesion,
water retentivity, plasticity, stability and pump
ability with no segregate in water.
– It can be used in mass concrete casting because
low hydration heat is produced in the process of
setting and hardening.
– It can keep volume steady and have small
shrinkage deformation after hardening, so there
are few defaults such as micro cracks inside
concrete and it forms a stable structure.
Characteristics
• Its characteristics are as follows:
– It has good protective ability of reinforced bars in
concrete in high solidity and strong resistance of
permeability of water, corrosive liquid and chlorineion.
– It contains little Ca(OH)2 and hydrated calcium
sulfate, which are easy to be eroded by sulfate and
magnesium to ensure the resistance to seawater
corrosion.
– Concrete has excellent permeability and proper
content of gas with even and impact bubbles so it
has good performance in freeze-thaw resistance and
fastness to efflorescence. It is easy to be cast for the
concrete structure in the area which can be touched
by waves.
– It can be used in prefabricated concrete for its high
strength and lower content of binding material, which
is less than that in ordinary concrete.
Techniques
• Selection
Cement with medium heat, MDF, DSP; super fine
mineral admixture; superplasticizer;
Dmax<15mm.
• Parameter
W/ C<0.4, W<175; Sp=36-42%; binding
material=500-600
• Craft works control
Forced mixing, high frequent vibration; pumping
up, SL>200; protection in early days
Tab.4.7.2 Proportion Ratio
C60 Pumped
concrete
C70
Pumped
concrete
items
C30 Ordinary
concrete
C50 Pumped
concrete
amount of cement
（Kg/cm3）
460
357
357
400
amount of fly-ash in
Grade 1（Kg/cm3）
/
63
63
70
NSF-A silicon
/
50~63
76~88
103~112
Cement + fly-ash +
NSF-A silicon
460
474
502
578
amount of
water(Kg/cm3)
200
114~118
98~102
114~118
slump（cm）
20±2
20±2
20±2
20±2
content of gas（％）
/
2.6
2.4
2.1
compressive strength
after
39
58
69
79
28 days（MPa）
Properties
• Comparison of Properties
(Tab.4.7.3)
• Dry Shrinkage (Tab.4.7.4)
• Time and the Slump Loss
(Tab.4.7.5)
Tab.4.7.3 Comparison of Properties
properties
C30OPC
C50HPC
C60HPC
compressive
strength(MPa)
39
58
69
bending
strength(MPa)
5.1
7
5.4
axial tensile
strength(MPa)
3.1
4.7
5.2
compressive elastic
modulus(GPa)
27.8
34.3
35.9
Loss ratio of
resistance to
impact(%)
7.1
3.2
2.5
Tab.4.7.4 Dry Shrinkage
kinds of
concrete
shrinkage ratio(×10-6)
2d
7d
14d
28d
60d
90d
C30
109
200
286
431
577
621
C50
109
172
239
345
433
475
C60
55
622
163
124
121
442
C70
96
170
232
326
430
466
Tab.4.7.5 Time and the Slump Loss
Slump loss
C50
C60
C70
beginning
23
20.7
21.4
1 hour
23
20.5
17
2 hours
20.4
20
15
2.5 hours
19.8
20
14
Application
In foreign countries:
• German concrete structure design has reached
to C110
• In Norway C105, HPC in 85～90 is widely used
in road construction
• Denmark Belt-connection between tunnels and
bridges
• Designed for 100 years
• Applied in tower structure, prefabricated beam
and block
• Japan
• Super strength and high performance concrete
for apartment buildings
• Super durable concrete over 500 years has
been developed
Application
In China：
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Shanghai Jin Mao Tower C60
Beijing West Railway Station C60
Beijing Jing’an Center C80
Liaoning Goods and Material Mansion C80
Nanjing Posts and Telecommunications Center C60
Changchun International C55
Guangzhou Humen Bridge C50
Shanghai Yangpu Bridge C50
Steel concrete for Changjiang River Bridge Wanxian
County C60