Dhanya SCC

7/29/2019 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

Documents

Dhanya SCC