2. BETON MUTU TINGGI Pertemuan 11
Matakuliah : S0793 – Teknologi Bahan Konstruksi
Tahun : 2009
BETON MUTU TINGGI Pertemuan 11

3. Learning Outcome
Mahasiswa dapat menjelaskan persyaratan dan tata cara pembuatan beton mutu tinggi
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4. Outline Materi Defenisi Beton Mutu Tinggi Aplikasi Beton Mutu Tinggi
Persyaratan Bahan Beton Mutu Tinggi
Cara Pembuatan Beton Mutu Tinggi
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5. 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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6. 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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7. Ultra High Strength Concrete
How High?
Strengths of MPa 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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8. 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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9. Bina Nusantara University

10. Bina Nusantara University

11. 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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12. 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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13. · “Bridge Views” – http://www.cement.org/bridges/br_newsletter.asp
Information on H.P.C.
· “Bridge Views” –
· “High-Performance Concretes, a State-of-Art Report ( )” -
· “A State-of-the-Art Review of High Performance Concrete Structures Built in Canada: ” -
· “Building a New Generation of Bridges: A Strategic Perspective for the Nation” -
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14. 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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15. 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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16. 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: ”
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17. AS 5100 raised maximum strength to 65 MPa
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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18. Economics of High Strength Concrete
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19. 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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20. Economics of High Strength Concrete
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21. Maximum compressive strength; 65 MPa
AS 5100 Provisions for HSC
Maximum compressive strength; 65 MPa
Cl Alternative materials permitted
Cl MPa fatigue limit on compressive stress - conservative for HSC
Cl Part 2 - Deflection limits may become critical
Cl Tensile strength - may be derived from tests
Cl 6.1.7, Creep and shrinkage provisions conservative for HSC, but may be derived from test.
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22. AS 5100 and DR 05252
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23. · Shear strength of concrete capped at Grade 65.
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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24. Concrete strength: 50 MPa to 100 MPa
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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25. · Compressive strength at transfer = 0.7f’c.
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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26. Case Studies
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27. Bina Nusantara University

28. Bina Nusantara University

29. Grade 65 concrete with standard girders.
Case Studies - Summary
· Significant savings in concrete quantities and/or construction depth.
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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30. Strength-weight ratio becomes comparable to steel:
Future Developments
Strength-weight ratio becomes comparable to steel:
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31. Future Developments
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32. Improved durability the original motivation for HPC use.
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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33. 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 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 and/or reduced slab depth.
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34. Review of international best practice
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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35. 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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