1

ByBy

CHANDRA SHEKARCHANDRA SHEKARVIII sem CivilVIII sem Civil

Bangalore Institute Of Bangalore Institute Of TechnologyTechnology

SELF COMPACTING CONCRETE

Under the guidance of prof:PARVATI ONISADIQUA ANJUM8TH SEMVDRIT HALIYAL.

2

INTRODUCTIONWHAT IS SCC ?HISTORY.MATERIALS. COMPARISION B/W SCC & NVC.TEST METHODS FOR COMPACTIBILITY.ADVANTAGES OF SCC.CONCLUSIONS.CASE STUDY.REFERENCES.

3

INTRODUCTIONINTRODUCTION

• HEAVILY CONGESTED REINFORCED MEMBERS

• UNDER WATER CONCRETING

• LACK OF SKILLED LABOUR

4

WHAT IS SCC ?

Self-compacting concrete (SCC) describes a concrete with the ability to compact itself only by means of its own weight without the requirement of vibration. Self-compacting concrete also known as Self-consolidating concrete or self levelling concrete.

5

HISTORY OF SCC FIRST DEVELOPED IN JAPAN IN LATE 1980’S

where the lack of uniform and complete compaction had been identified as the primary factor responsible for poor performance of concrete structures.

This led to the development of the first practicable SCC by researchers (Okamura, Ozawa et al.) at the University of Tokyo and the large Japanese contractors (e.g. Kajima, Maeda, Taisei etc.) quickly took up the idea.

Self-compacting concrete has been successfully used in France, Denmark, the Netherlands, UK, USA, and Germany apart from Japan.

6

MIX COMPOSITION OF SCC IN COMPARISON WITH NORMAL MIX COMPOSITION OF SCC IN COMPARISON WITH NORMAL

VIBRATED CONCRETE [Ref 4]VIBRATED CONCRETE [Ref 4]

7

MATERIALS The Materials used in SCC are the same as in

conventional concrete except that an excess of fine material and chemical admixtures are used.

Fly ash, silica fume, lime stone powder, glass filler(Mineral admixture).

A high-range water-reducing admixture (HRWRA) such as superplasticizer.

Viscosity-modifying agent (VMA) and ultra fine materials are used to reduce bleeding and segregation.(Chemical admixture).

8

MIX PROPORTIONING FOR ACHIEVING SELF COMPACTION:

Role of Super Plasticizers:

Fig Showing the optimum combination of the w/c ratio and Super plasticizer powder ratio

9

Aggregates:If the coarse aggregate contact exceeds a certain limit, then blockage will occur inspite of the moderate viscosity of the mortar. The limit value of coarse aggregate is around 50% of the solid volume.

if the fine aggregate content exceeds a certain figure, direct contact between sand particles results in a decrease in deformability, again in spite of the moderate viscosity of the paste. The limit value of fine aggregate content in mortar is around 40% .

10

11

TEST METHODS FOR COMPACTIBILITY

The various test equipment was fabricated for judging the following characteristics..

12FIG 1: U-TUBE TEST APPARATUSFIG 1: U-TUBE TEST APPARATUS

13FIG 2 : SLUMP FLOW APPARATUSFIG 2 : SLUMP FLOW APPARATUS

14

FIG 3 : V-FUNNEL TESTFIG 3 : V-FUNNEL TEST

15

FIG 4: J RING TEST

16FIG 5: L BOX TEST

17FIG 6: FILL BOX TEST

18

SL.no. method Properties evaluated by the test

Acceptance criteria.unit Min max

1. Slump flow

Filling ability, flowability, segregation and bleeding.

mm 650 800

2. Slump flow(T 50 cm)

Filling ability, consistency, cohesiveness

sec 2 5

3. J- ring Passing ability, flowing ability.

mm 0 10

T

Test methods, properties evaluated and acceptance criteria of SCC

19

4. V-funnel Filling ability, viscosity, segregation.

sec 6 12

5. V-funnel (T 5 min)

Segregation resistance

sec 0 +3

6. L-box Passing ability, flowability, blocking effects.

(h2/h1) 0.8 1.00

7. U-box Passing ability, filling ability, blocking effects.

(h2-h1) 0 30

8. Fill box Filling ability.

% 90 100

20

ADVANTAGES OF SCC1.Shortening of construction period2.It eliminates noise due to vibration: effective especially at concrete products plants3.Reduction in site man power4.Better surface finishes.5.Easier placing6.Improved durability7.Greater freedom in design8.Thinner sections9.High strength concrete10.higher strength concrete.

21

Properties Age, days SCC CVC

Compressive

strength

(MPa)

1

3

7

28

18.3

39.8

54.2

72.1

19.3

37.1

46.8

69.4

Tensile strength

(Mpa)

1

3

7

28

2.1

4.7

5.5

6.2

2.0

4.6

5.2

5.8

showing comparision between SCC and CVC Ref(3,7)

22

CONCLUSIONSCONCLUSIONS

Even though the initial cost of self compacting concrete is more than conventional concrete but the life span of the SCC structure is more than conventional concrete.

Self compacting concrete is ideal for concrete parts with complicated shapes and elements with high quality visible concrete.

23

The two anchorages of Akashi-Kaikyo (Straits) Bridge opened in April 1998, a suspension bridge with the longest span in the world (1,991 meters) (Fig. 6).

The volume of the cast concrete in the two anchorages amounted to 290,000 m3.

The concrete was mixed at the batcher plant beside the site, and was the pumped out of the plant.

It was transported 200 meters through pipes to the casting site, where the pipes were arranged in rows 3 to 5 meters apart.

In the final analysis, the use of self-compacting concrete shortened the anchorage construction period by 20%, from 2.5 to 2 years and reduced the no. of workers.

CASE STUDY

24

Fig.6 Anchorage of Fig.6 Anchorage of Akashi Kaikyo BAkashi Kaikyo Bridgeridge (Japan)(Japan)

25

Placement of SCC in a reinforced slab Placement of SCC in a reinforced slab foundation of skyscraper. ( commercial foundation of skyscraper. ( commercial

center in New York)center in New York)

26Congested reinforced columnCongested reinforced column

(master builders Inc. USA)

27SCC Poured in Heavily Reinforced WallSCC Poured in Heavily Reinforced Wall

28SCC Pumped into ColumnSCC Pumped into Column

29

REFERENCES:REFERENCES:

[1]. EFNRC, specification and guidelines for self-compacting concrete, February 2002.

[2]. European guideliness for self compacting concrete(2005).

[3]. MS SHETTY Concrete Technology ,Properties ,Materials AND Mix design,page no 618 to 625.

[4].Self Compacting Concrete – A revolutionary Building Material by chandra shekhar BIT college.

[5].MIX DESIGN PROCEDURE for self compacting concrete, Krishna murthy.N, Narasimha Rao A.V, Ramanna Reddy I.V and Vijaya Shekhar Reddy.M.[6]. Kochi University of T echnology Academic Resource Repository, Okamura, Hajime, Oichi, Masahiro.

30

[7] J.Annie Peter et al, Flexural behavior of R.C. beams using self compacting Concrete ,Indian Concrete Journal, june 2004.

31