dhanya scc
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SELF COMPACTING
CONCRETE
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INTRODUCTION
A special type of concrete of flowing
consistency.
Developed initially in Japan in 1980s to offsetthe growing shortage of skilled labour.
The composition in addition to cement and
water, consists of high amount of super
plasticizer, high powder content and a
viscosity modifying agent.
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REQUIREMENTS
For a mixture to have self compatibility, it shouldhave
Filling ability
Passing ability
Segregation resistance
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TESTING METHODS FOR FRESH
CONCRETE.- Specified by Japanese Society Of Civil
Engineers
1. Slump flow test
2. Funnel test
3. T50 test
4. U type and box type tests
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TEST METHOD PROPERTY
Slump flow Filling ability
T50cmSlump flow Filling ability
V funnel Filling ability
V funnel at 5 minutes Segregation resistance
L box Passing ability
U box Passing ability
Fill box Passing ability
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PROPERTIES OF HARDENED SCC.
Items SCC
1.Water-binder ratio 0.25 to 0.40
2. Air content(%) 4.5-6.0
Compressive strength (age: 28days) (MPa) 40 to 80
Compressive strength (age: 91
days) (MPa)
55 to 100
5. Splitting tensile strength
(age: 28 days) (MPa)
2.4 to 4.8
6. Elastic modulus (GPa) 30 to 36
7. Shrinkage strain (x 10-6) 600 to 800
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REQUIREMENTS OF
CONSTITUENT MATERIALSCEMENT
Type depends on the overall requirements for concrete such as
strength, durability, etc.
C3A content higher than 10% may cause poor workability retention.
Typical cement content 350 to 450 kg/m3.
Cement > 500kg/m3 cause increase in shrinkage.
Cement < 350kg/m3 demands other fine fillers such as flyash,pozzolan, etc.
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AGGREGATE
SANDS
All normal sands are suitable for SCC,
Fines less than 0.125mm - powder, veryimportant for SCC.
COARSE AGGREGATE
All types of aggregates are suitable forSCC,
Normal maximum size is generally 16
20mm, Crushed aggregates improve strengthwhile rounded aggregate improve flow.
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MIX PROPORTIONING FOR
ACHIEVING SELF COMPACTION. Changes in the coarse aggregate content.
Changes in the fine aggregate content.
Use of super plasticizers.
Combination of most suitable water
cement ratio and superplasticizer powder
ratio.
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Coarse aggregatecontent-50% of solidvolume.
Fine aggregatecontent-40% of mortar
volume.
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ROLE OF SUPERPLASTICIZERS.
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FLOW DIAGRAM OF MIXDESIGN
SYSTEM.
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ADVANTAGES OF SCC.
Faster construction
Reduction in site manpower
Better surface finishes
Easier placing
Improved durability
Greater freedom in design
Thinner concrete sections
Reduced noise levels, absence of vibration
Safer working environment.
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SELECTED CASE STUDY
Akashi-Straits Bridge
SCC was used in the construction of the two
anchorages of the bridge.
concrete was transported 200 meters throughpipes, with out segregation to the actual castingsite
. In the final analysis self-compacting concreteshortened the anchorage construction periodby20%.
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CONCLUSION.
Self-Compacting Concrete is considered
to be the most promising building material
for the expected revolutionary changes onthe job site.
We can create durable and reliable
concrete structures using SCC
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THANK YOU
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