Matakuliah
Tahun
: S0793 – Teknologi Bahan Konstruksi
: 2009
BETON MUTU TINGGI
Pertemuan 11
Learning Outcome
• Mahasiswa dapat menjelaskan persyaratan dan tata
cara pembuatan beton mutu tinggi
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Outline Materi
•
•
•
•
Defenisi Beton Mutu Tinggi
Aplikasi Beton Mutu Tinggi
Persyaratan Bahan Beton Mutu Tinggi
Cara Pembuatan Beton Mutu Tinggi
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High Performance Concrete
Concrete may be regarded as high performance for several
different reasons:
• high strength,
• high workability
• high durability
– and perhaps also improved visual appearance.
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High Performance Concrete
• High strength concrete (HSC) might be regarded as concrete with
a strength in excess of 60MPa and such concrete can be
produced as relatively normal concrete with a higher cement
content and a normal water-reducing admixture.
• However ultra high performance concrete (UHPC) will more
usually contain cement replacement materials and a high-range
water-reducer (HRWR) or superplasticiser(SP) (different names
for the same thing).
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Ultra High Strength Concrete
• How High?
• Strengths of 150-200MPa were reported in several
papers at a recent symposium
• How is it done?
• Using only fine sand as an aggregate, a high content of
cement and silica fume, a high dosage of HRWR
admixture plus steel fibres
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Ultra High Strength Concrete
• In what kind of structures?
• Thin shell roofing (2cm thick) and “bulb” double and
single tees were reported
• Both insitu and precast applications
• Flexural and tensile strengths also high, allowing
omission of secondary reinft.
• Concrete in tees was generally self- compacting
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Overview
• What is High Performance Concrete?
• International use of HPC in bridges
• Use of HPC in Australia
• Economics of High Strength Concrete
• HSC in AS 5100 and DR 05252
• Case Studies
• Future developments
• Recommendations
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What is High Performance Concrete?
"A high performance concrete is a concrete in which
certain characteristics are developed for a particular
application and environments:
• Ease of placement
• Compaction without segregation
• Early-age strength
• Long term mechanical properties
• Permeability
• Durability
• Heat of hydration
• Toughness
• Volume stability
• Long life in severe environments
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Information on H.P.C.
 “Bridge Views” – http://www.cement.org/bridges/br_newsletter.asp
 “High-Performance Concretes, a State-of-Art Report (1989-1994)”
- http://www.tfhrc.gov/structur/hpc/hpc2/contnt.htm
 “A State-of-the-Art Review of High Performance Concrete
Structures Built in Canada: 1990-2000” http://www.cement.org/bridges/SOA_HPC.pdf
 “Building a New Generation of Bridges: A Strategic Perspective for
the Nation” http://www.cement.org/hp/
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International Use of H.P.C.
• Used for particular applications for well over 20 years.
• First international conference in Norway in 1987
• Early developments in Northern Europe; longer span
bridges and high rise buildings.
• More general use became mandatory in some countries
in the 1990’s.
• Actively promoted for short to medium span bridges in N
America over the last 10 years.
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International Use of H.P.C.
• Scandinavia
• Norway
– Climatic conditions, long coastline, N. Sea oil
– HPC mandatory since 1989
– Widespread use of lightweight concrete
• Denmark/Sweden
– Great Belt project
– Focus on specified requirements
• France
• Use of HPC back to 1983
• Useage mainly in bridges rather than buildings
• Joint government/industry group, BHP 2000
• 70-80 MPa concrete now common in France
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International Use of H.P.C.
• North America
• HPC history over 30 years
• Use of HPC in bridges actively encouraged by owner
organisation/industry group partnerships.
• “Lead State” programme, 1996.
• HPC “Bridge Views” newsletter.
• Canadian “Centres of Excellence” Programme, 1990
• “A State-of-the-Art Review of High Performance
Concrete Structures Built in Canada: 1990-2000”
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Use of H.P.C. in Australia
• Maximum concrete strength limited to 50 MPa until the
introduction of AS 5100.
• Use of HPC in bridges mainly limited to structures in
particularly aggressive environments.
• AS 5100 raised maximum strength to 65 MPa
• Recently released draft revision to AS 3600 covers
concrete up to 100 MPa
INDONESIA?
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Economics of High Strength Concrete
Spacing, m
Section
AAASHTO
Type I
AAASHTO
Type II
AAASHTO
Type III
AAASHTO
Type IV
NU1100
3.4
NU1350
0.6 in diameter strands
2.1
2.7
1.5
3.4
0.5 in diameter strands
2.1
2.7
1.5
90
83
83
83
76
76
69
69
90
90
90
83
76
76
76
76
83
83
83
76
76
69
69
62
83
83
83
83
62
62
62
62
83
76
76
76
62
62
62
62
83
76
69
69
62
62
62
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Table 1 Maximum effective girder compressive strength, after Kahn and Saber (34)
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Economics of High Strength Concrete
• Compressive strength at transfer the most significant
property, allowable tension at service minor impact.
• Maximum spans increased up to 45 percent
• Use of 15.2 mm strand for higher strengths.
• Strength of the composite deck had little impact.
• HSC allowed longer spans, fewer girder lines, or
shallower sections.
• Maximum useful strengths:
• I girders with 12.7 mm strand - 69 MPa
• I girders with 15.2 mm strand - 83 MPa
• U girders with 15.2 mm strand - 97 MPa
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Economics of High Strength Concrete
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AS 5100 Provisions for HSC
• Maximum compressive strength; 65 MPa
• Cl. 1.5.1 - Alternative materials permitted
• Cl 2.5.2 - 18 MPa fatigue limit on compressive stress conservative for HSC
• Cl 6.11 - Part 2 - Deflection limits may become critical
• Cl 6.1.1 - Tensile strength - may be derived from tests
• Cl 6.1.7, 6.1.8 - Creep and shrinkage provisions
conservative for HSC, but may be derived from test.
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AS 5100 and DR 05252
Clause
Subject
Provisions
AS 5100 DR 05252
AS 5100
DR 05252
1.1.2
1.1.2 Concrete srength and
25-65 MPa, 2100-2800 kg/m3
20-100 MPa, 1800-2800 kg/m3
density range
1.5.1
Use of alternative materials Alternatives allowed
Clause removed
2.2
2.2
2.5.2
-
6.1.1
(b,c)
Phi reduced for ku > 0.4
Fatigue provisions
Maximum stress under fatigue
Not included
loading = 18 MPa
From compressive strength or tests From flexural or tensile tests,
upper and lower bound factors
applied if compressive strength
used
Proportional to square root fc
Revised for higher strength grades
Default basic shrinkage strain
Autogeneous and drying shrinkage
independent of concrete strength calculated separately, both related
to concrete strength
Basic creep factor constant for f'c Basic creep factor increased for f'c
>= 50 MPa
= 40, 50 MPa; reduced for f'c >=
80 MPa
Default creep factor uses prestress Default creep factor reduced to
force before time-dependent
80% of AS 5100 value
losses.
Stress = 0.85f'c
Stress = (1.0-0.003f'c)f'c with limits
of 0.67 and 0.85
Shear strength proportional to f'c1/3 f'c1/3 limited to 4 Mpa, ie no
increase in shear strength for f'c >
64 MPa
Independent of concrete strength Increased area for f'c > 36 MPa
3.1.1.2(b) Tensile strength
6.1.2
6.1.7
3.1.2
3.1.7
Modulus of elasticity
Shrinkage
6.1.8
3.1.8
Creep
6.4.3.3
3.4.3.3
Loss of prestress due to
creep
8.1.2.2
8.1.3
Rectangular stress block
8.2.7.1
8.2.7.1
Shear strength of beams
excluding shear
reinforcement
8.2.8
8.2.8
8.6.1(a)
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Strength reduction factors
9.1.1
Minimum shear
reinforcement
8.6.1(a) Minimum steel area in
tensile zone
9.1.1 Minimum tensile steel in
slabs
3ks(Act/fs)
Independent of concrete strength
Phi reduced for ku > 0.375
Cl 8.1.4.1 (minimum strength
requirements) applied
Increased area for f'c > 30 MPa
approx
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AS 5100 and DR 05252
Main Changes:
• Changes to the concrete stress block parameters for
ultimate moment capacity to allow for higher strength
grades.
 More detailed calculation of shrinkage and creep
deformations, allowing advantage to be taken of the
better performance of higher strength concrete
 Shear strength of concrete capped at Grade 65.
 Minimum reinforcement requirements revised for higher
strength grades.
 Over-conservative requirement for minimum steel area
in tensile zones removed.
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Case Studies
• Concrete strength: 50 MPa to 100 MPa
• Maximum spans for typical 3 lane Super-T girder bridge
with M1600 loading
• Standard Type 1 to Type 5 girders
• Type 4 girder modified to allow higher pre-stress force:

Increase bottom flange width by 200 mm (Type 4A)
 Increase bottom flange depth by 50 mm (Type 4B)
 Increase bottom flange depth by 100 mm (Type 4C)
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Case Studies
 Compressive strength at transfer = 0.7f’c.
 Steam curing applied (hence strand relaxation applied
at time of transfer)
 Strand stressed to 80% specified tensile strength.
 Creep, shrinkage, and temperature stresses in
accordance with AS 5100.
 In-situ concrete 40 MPa, 160 mm thick in all cases.
 Assumed girder spacing = 2.7 m.
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Case Studies
Type
1
2
3
4
5
4A
4B
4C
Depth
mm
750
1000
1200
1500
1800
1500
1500
1500
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Section Properties
A
mm2
454,084
491,409
531,021
573,592
616,426
680,172
592,772
618,612
Precast
I
mm4
3.280E+10
6.675E+10
1.043E+11
1.756E+11
2.658E+11
1.971E+11
1.798E+11
1.840E+11
Yc
mm
389
515
613
776
946
627
760
743
A
mm2
887,584
924,909
964,521
1,007,092
1,049,926
1,113,672
1,026,272
1,052,112
Composite
I
mm4
7.685E+10
1.412E+11
2.112E+11
3.357E+11
4.886E+11
4.383E+11
3.488E+11
3.632E+11
Max No
Strands
Yc
mm
604
779
913
1,122
1,331
998
1,106
1,088
50
50
50
50
50
82
62
74
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Super-T Maximum Span
55
50
Number of Strands
80 MPa
45
Type 1
Type 2
40
Type 3
Type 4
65 MPa
Type 5
35
50 MPa
30
25
18.00
20.00
22.00
24.00
26.00
28.00
30.00
32.00
34.00
36.00
38.00
Maximum Span, m
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Super-T Maximum Span
85
80
Number of Strands
75
70
Type 4
80 MPa
Type 4A
65
Type 4B
Type 4C
60
50 MPa
55
65 MPa
50
45
33
34
35
36
37
38
39
40
Maximum Span, m
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Case Studies - Summary
 Significant savings
construction depth.
in
concrete
quantities
and/or
• Grade 65 concrete with standard girders.
• Grade 80 concrete with modified girders and Type 1 and
2 standard girders.
• More substantial changes to beam cross section and
method of construction required for effective use of
Grade 100 concrete.
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Future Developments
• Strength-weight ratio becomes comparable to steel:
Strength-Weight Ratio
45
40
35
30
25
20
15
10
5
0
Structural steel
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Concrete
High strength
concrete
Lightweight HSC
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Future Developments
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Summary
 Clear correlation between government/industry
initiatives and useage of HPC in the bridge market.
• Improved durability the original motivation for HPC
use.
• Studies show direct economic benefits.
• HPC usage in Australia limited by code restrictions.
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Recommendations
 65 MPa to be considered the standard concrete grade
for use in precast pre-tensioned bridge girders and post
tensioned bridge decks.
 The use of 80-100 MPa concrete to be considered
where significant benefit can be shown.
 AS 5100 to be revised to allow strength grades up to
100 MPa as soon as possible.
 Optimisation of standard Super-T bridge girders for
higher strength grades to be investigated.
 Investigation of higher strength grades for bridge deck
slabs, using membrane action to achieve greater spans
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and/or reduced slab depth.
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Recommendations
 Active promotion of the use of high performance
concrete by government and industry bodies:
– Review of international best practice
– Review and revision of specifications and standards
– Education of designers, precasters and contractors
– Collect and share experience
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Pembuatan Beton Mutu Tinggi
• Faktor yang perlu diperhatikan:
– Faktor Air Semen (semakin rendah, kekuatan beton semakin
tinggi menyebabkan kesulitan pada pengerjaan).
– Kualitas Agregat Halus (agregat berbentuk bulat mempunyai
rongga udara minimum 33% lebih kecil dari rongga udara yang
dipunyai agregat berbentuk lainnya)
– Kualitas Agregat Kasar (pemilihan agregat kasar dengan
porositas rendah, butir maksimum, gradasi yang baik)
– Bahan tambahan (water reducing, super fly ash)
– Kontrol kualitas (pengambilan sample, pengujian, proses
penakaran)
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