EFFECT OF SIZE OF AGGREGATE ON SELF COMPACTING CONCRETE

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National E-conference on "Research & Innovation, 2020

Sakshi Rajiv Burade, Prof. M. R. Bhatkar 1

EFFECT OF SIZE OF AGGREGATE ON SELF COMPACTING CONCRETE

Sakshi Rajiv Burade¹, Prof. M. R. Bhatkar²

1B.E. student of final year, Civil Engineering Department, Jagadambha College of Engineering &

Technology, Yavatmal.

Assistant Professor, Civil Engineering Department, Jagadambha College of ngineering &

Technology, Yavatmal.

ABSTRACT

Self compacting concrete (SCC) is an advanced concrete that does not require vibrations for placing and compaction. It is capable of filling the formwork completely under its self weight,even in the presence of congested reinforcements. Generally, SCC is made up of cement, fine aggregate, coarse aggregate, mineral admixtures, super plasticizers and viscosity modifying agents. The present investigation is aimed at the development of self compacting concrete of M40 grade. The Nan-Su mix design method is adopted for preparing the self compacting concrete of M40 grade.

The parameters of study include the effect of size of aggregate on self compacting concrete. In this study, coarse aggregates of sizes 10 mm, 12.5 mm and 20 mm are used. The SCC mixes are prepared by using fly ash as a mineral admixture and PERMA PLAST PC-101 as super plasticizer.

The characteristics of self compacting concrete such as filling ability, passing ability and segregation resistance have been verified using slump flow test, L-box test and V-funnel test. The compressive strength of mixes is determined at the ages of 7 days, 14 days, 21 days & 28 days.

Key words – self compacting concrete, coarse aggregate, strength.

[1] INTRODUCTION

Self compacting concrete can be defined as the fresh concrete that flows under its own weight and does not require external vibration to undergo compaction. It does not required any compaction by using external force from mechanical equipment such as an immersion vibrator. It is also known as flowable concrete or self consolidating concrete or non- vibration concrete. It is considered as the most revolutionary development in the concrete construction. Prof. Dr. Hajime Okamura developed the self compacting concrete in 1986 in Japan. He is also known as the father of SCC technology. The development of self compacting concrete is a very desirable achievement in the construction industry in overcoming the problems related to cast in place concrete. It is not affected by the skill of

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workers, shape and arrangement of reinforcing bars in the structure. This type of concrete provides greater workability, strength, durability and it resists segregation and it has a passing ability. The time required for construction will be less if we use the self compacting concrete and also enhances the quality and durability of concrete. Day by day, the popularity of using self compacting concrete in concrete construction has increased in many countries, as the SCC effectively reduces the need for skilled workers on the construction site.

[2] MIX DESIGN

For preparing the self compacting concrete of M40 grade, the Nan-su mix design method is adopted. The quantities of materials required for 1m³ of SCC is shown in the table.

Table No. 2.1

Quantities of materials required for 1m³ of SCC Cement

(kg/m³)

Fine Aggregate (kg/m³)

Coarse Aggregate (kg/m³)

Water (kg/m³)

436.32 881.34 703.28 172.64

1 2.09 1.61 0.4

Thus the Ratio for M40 is (1:2.09:1.61)

W/C Ratio = 0.4

[3] RESULTS AND DISCUSSION

Fresh properties of self compacting concrete :-

The fresh properties of self compacting concrete are filling ability, passing ability &

segregation resistance. To fulfil these fresh properties of self compacting concrete, the various tests such as slump flow test, L-box test & V-funnel tests are performed with Mix- A, Mix-B & Mix-C having different sizes of coarse aggregate i.e. 10 mm, 12.5 mm & 20 mm respectively.

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Figure No. 3.1 Slump flow test apparatus Figure No. 3.2 L-Box test apparatus

Figure No. 3.3 V-Funnel test apparatus

Table No. 3.1

Test results for fresh properties of self compacting concrete for different mixtures

Mixes Mix-A Mix-B Mix-C

Slump flow test 665 mm 655 mm 650 mm

L-box Test 0.97 0.90 0.86

V-funnel Test 7.2 sec 9.5 sec 11.8 sec

Chart No. 3.1 Slump flow test Chart No. 3.2 L-box test

665

655 650

640 645 650 655 660 665 670

MIX-A MIX-B MIX-C

Diameter in mm

SLUMP FLOW TEST

0.97

0.9

0.86

0.8 0.85 0.9 0.95 1

MIX-A MIX-B MIX-C

H2/H1ratio

L-BOX TEST

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Chart No. 3.3 V-funnel test

Hardened properties of self compacting concrete :-

The compressive strength is one of the hardened property of self compacting concrete.

The compressive strength test of cubes is performed on the compression testing machine with Mix-A, Mix-B & Mix-C having different sizes of coarse aggregate i.e. 10 mm, 12.5 mm & 20 mm respectively after 7 days, 14 days, 21 days & 28 days of curing.

Table No. 3.2

Test results for compressive strength of Mix-A, Mix-B & Mix-C Mixture No. Compressive Strength (N/mm²)

7 days 14 days 21 days 28 days Mix-A 20.23 33.11 42.45 56.45 Mix-B 19.56 32.23 40.45 54.23

Mix-C 18 30.23 39.78 52.89

Chart No.3.4 Comparison between compressive strength of Mix-A, Mix-B & Mix-C

7.2

9.5

11.8

0 5 10 15

MIX-A MIX-B MIX-C

Timeinseconds

V-FUNNEL TEST

0 20 40 60

Mix-A Mix-B Mix-C

20.23 19.56 18

33.11 32.23 30.23 42.45 40.45 39.78

56.45 54.23 52.89

Compressive strength in N/mm2

Mixtures

COMPRESSIVE STRENGTH

7 Days 14 Days 21 Days 28 Days

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Based on the systematic and detailed experimental study conducted on SCC mixes with an aim to develop performance mixes, the following are the conclusions arrived:

[1] The mixes are designed using the lower size of aggregate yielded better fresh properties than higher size of aggregates.

[2] As the strength of concrete increases, the effective size of aggregate has decreased.

[3] The optimum size of aggregate was 10 mm for standard self compacting concrete i.e.

M40 grade.

REFERENCES

[1] Hajime Okamura, Masahiro Ouchi, “Self-Compacting Concrete”, Journal of Advanced Concrete Technology Vol. 1, 5-15, April 2003.

[2] B. Chandraiah, C. Krishnama Raju, S. Talha Zaid, “Influence of Aggregate Size on SCC”, IJSRET, ISSN 2278-0882, Vol.8, Issue 3, March 2019.

[3] Hitesh, Mr.Sumit Kumar, “Effect of Size of Aggregate on Self Compacting Concrete”, IJERT, ISSN: 2278-0181.

[4] Rajesh Kumar Tiwari and G. Sahoo, “A New Methodology for Data Coding and Embedding for High Capacity Transmitting”, International Journal of Electronic Security and Digital Forensics, Vol. 3, No. 1, 2010 pp- 27-40.

[5] G. Sahoo and Rajesh Kumar Tiwari, “A Secure Image Transmission using Steganographic Methodologies”. International Journal of Multimedia Intelligence and Security (IJMIS) ", U.K Vol. 1, No. 2, 2010, pp-169-190.

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[6] Mayank Srivastava, Md. Qasim Rafiq and Rajesh Kumar Tiwari “A Robust and Secure Methodology for Network Communication” International Journal of Computer Science Issues Vol. 7, Issue 5, September 2010, pp- 135-141.

[7] The European guideline for self-compacting concrete, may 2005.

[8] M.S. Shetty. “Concrete technology” (theory and practice), S. Chand & Company LTD.

2002.