Design & Cost Analysis of Self-Compacting Concrete For Mivan Shuttering

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International Journal of Recent Advances in Engineering & Technology (IJRAET)

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Design & Cost Analysis of Self-Compacting Concrete For Mivan Shuttering

1Syed Mehdi Abbas, ²Dada Patil, ³Sanjeev Raje

1,2Civil Eng. Dept. - AIKTC, Panvel, ³V.P Technical (N.C.C)

Abstract—This paper summarizes the research work performed to design a self-compacting concrete for Mivan/Aluminum shuttering and analyzing per cum cost of the designed concrete. High grade SCC was designed using mineral and chemical admixtures. Workability tests such as Flow table test, V funnel test and U box tests were conducted. Compressive Strength test was carried out on hardened 150mm concrete cubes after 3, 7, & 28 days curing in water. The output of the research work was a highly workable concrete which could be used for densely reinforced sections of Mivan shuttering.

Index Terms—Self-Compacting Concrete, Mivan shuttering, Micro Silica, Super plasticizer, Workability, Compressive strength.

I. INTRODUCTION

Self-consolidating concrete or self-compacting concrete (SCC) is a flow able concrete mixture that is able to compact under its self-weight. It is a high-performance concrete that can spread easily and fill congested sections as well as congested reinforcement structures without the need of mechanical compaction and without undergoing any significant separation of material constituents or segregation. SCC was conceptualized in 1986 by Prof.

Okamura at Ouchi. It is an emerging class of concrete materials that offers great potential for improved ease of placement, increased rate of construction, and reduced cost through reduced time and labor. Even though concept of SCC was introduced in 1986 by Hajime Okamura, its first Prototype was developed in 1989 by Prof. Ozwa of University of Tokyo.

The Mivan Technology System was developed by Mivan Company Ltd from Malaysia late 1990s as a system for constructing mass housing project. The units were to be of cast-in-place concrete, with load bearing walls using a formwork of aluminum panels. To be erected by the hundreds, of a repetitive design, the system ensured a fast

and economical method of construction

II. SCC FOR MIVAN SHUTTERING.

Mivan/Aluminum shuttering is an advanced construction technique for constructing mass housing project. Mivan shuttering is most effective formwork system in today’s scenario. It gives a boost to the speed of construction.

Some of the sections of Mivan shuttering are very densely reinforced and therefore Self-Compacting Concrete becomes the requirement at site. The concrete mix should be designed in such a way that the designed concrete could be pumped at high elevations and also fill the congested sections.

III. MATERIALS AND METHODS

A. Materials

1. Cement- Ambuja OPC 53 grade of cement was used.

2. Flyash- Ashtech (India) Class F Flyash was used.

3. Micro Silica- Micro Silica was obtained from Bhutan.

4. Coarse Aggregate- Coarse Aggregates of size 10mm was used for this research work. It was sourced from a quarry in Turbe in Mumbai, India.

5. Fine Aggregate- Fine Aggregates used for this research work was crushed sand (VSI). It was sourced from a quarry in Turbe in Mumbai, India.

6. Water- Water was obtained from a boring. . It conformed to IS 456-2000 requirements.

7. Admixture- A highly effective superplasticizer Sikaviscocrete5210NS was being used.

B. Mix Design

In this Experimental Work Department of Environment (DOE) Method of Mix Design was used for

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manufacturing concrete of grade M60. DOE method is standard British method of concrete mix design.

Table 1- Trail Number 1.

Trail Number 1

M60 SCC 1 CUM

Cement 74.38%

Flyash 21.49%

Micro Silica 4.13%

C/Sand 45.70%

C.A 1 54.30%

A/C 2.79

W/C 0.28

Admixture 0.90%

Table 2- Workability test results of trail 1.

Time Actual Required 1 Flow table Test

Initial 570mm Greater then 600mm 1 hour 520mm Greater then 600mm 2 hour 480mm Greater then 600mm 2 ) V Funnel test

T0 15 sec 8-12 Sec T5 20 sec 11-15 sec 3) U box Test

h1-h2 37mm Less than or equal to 30mm The tests on fresh concrete indicate that the mix is not much workable as required. The mix was cohesive but not workable. The workability tests were done on fresh concrete and was found to be non-satisfactory. So change in the mix design was needed to suit the site requirement.

So to increase the workability of the concrete, the percentage Flyash was from 21.49% to 23.39% in the next trail and minor modifications were also done. So the total cementitious material got increased from 605 kg/Cum to 620kg/Cum. Only Flyash content was increased keeping Micro Silica and OPC content unchanged. 9 cubes of size 150 mm were casted for compressive strength test.

Trail Number 2

M60 SCC 1 CUM

Cement 72.58%

Flyash 23.39%

Micro Silica 4.03%

C/Sand 51.99%

C.A 1 48.01%

A/C 2.72

W/C 0.28

Admixture 0.90%

h1-h2 33mm Less than or equal to 30mm The increase in the Flyash content increased the workability to some extent. The tests on fresh concrete indicate that again the mix is not much workable as required. The workability tests were done on fresh concrete and was found to be non-satisfactory but better than previous trial. So change in the mix design was needed accordingly. 9 cubes of size 150 mm were casted for compressive strength test. After 3 days and 7 days compressive strength test results, it was found that the initial strength gain was not up to the mark. Therefore to increase the initial strength of the concrete, Micro Silica and OPC content was increased. Also to increase workability, Flyash content was slightly increased.

So for early strength gain, Micro Silica content was directly increased from 4.03% to 5.43% in the next trail.

Therefore the total cementitious material got increased from 620 kg/Cum to 645kg/Cum.

Also the water cement ratio was decreased from 0.28 to 0.26 to give a boost to compressive strength.

Table 5- Trail Number3.

Trail Number 3

M60 SCC 1 CUM

Cement 71.32%

Flyash 23.26%

Micro Silica 5.43%

C/Sand 50.00%

C.A 1 50.00%

A/C 2.51

W/C 0.26

Admixture 0.95%

Initial 700mm Greater then 600mm 1 hour 520mm Greater then 600mm 2 hour 470mm Greater then 600mm

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2 ) V Funnel test

h1-h2 27mm Less than or equal to 30mm Concrete mix design was revised and as shown in table 5, 50% fine and 50% coarse aggregates of the total aggregate.. The workability test results shows that initially the workability was good but, there was no retention and therefore there was a need to revise the mix. The flow of the concrete drastically fell down from 700mm initial to 520mm after 1 hour, this shows that there was not much retention. 9 cubes of size 150 mm were casted for compressive strength test. The compressive strength test results of 3 days and 7 days were excellent because of increase in total cementitious materials, this allows slight reduction in Micro Silica content.

Therefore Micro Silica content was decreased from 5.43% to 4.58%. Reduction in Micro Silica content reduced the overall cost of per Cum of concrete. Also Flyash content was increased from 23.26% to 25.19% to increase the workability of the concrete. Total cementitious material got increased 645kg/Cum to 645kg/Cum.

Trail Number 4

M60 SCC 1 CUM

Cement 70.23%

Flyash 25.19%

Micro Silica 4.58%

C/Sand 47.53%

C.A 1 52.47%

A/C 2.47

W/C 0.26

Admixture 0.80

T0 8 sec 8-12 Sec

T5 10 sec 11-15 sec 3) U box Test

h1-h2 25mm Less than or equal to 30mm

The revised mix was very much workable and cohesive.

The workability test results shows that the mix is very much suitable for site conditions and also shows good retention even after 2 hours. The percentage of crushed sand was decreased from 50% to 47.53% and the percentage of 10mm aggregate was increased from 50%

to 52.47%. This change in the percentages of aggregate and addition of Flyash increased the workability of the concrete. Also optimal use of Micro Silica resulted in cost optimization. 9 cubes of size 150 mm were casted for compressive strength test after 3, 7 and 28 days of curing in water. The compressive strength test results were also up to the mark.

Trail number 4 was found to most suitable concrete mix for site condition so therefore this mix was finalized.

IV. RESULTS & COST ANALYSIS

Compressive Strength test was carried out on hardened 150mm concrete cubes after 3, 7, & 28 days curing in water. Following are the results of compressive strength of all trails.

Figure 1- Compressive strength test results As shown in figure 1, the compressive strength of trail number 2 and 3 were not up to the mark. Therefore the water cement ratio was decreased and cementitious materials were increased. Also compressive strength of trail number 3 is was very high. Because of this, the cememtitious materials were reduced in trail number 4.

Trail number 4 shows good compressive strength and optimal use of cementitious material.

Following are the current unit rates of the ingredients of concrete.

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Table 9- Unit rates.

Materials Rates (Rs) Unit

Cement 6 Per Kg

Flyash 2.273 Per Kg

MicroSilca 33.75 Per Kg

c/sand 4600 Per Brass

10mm 3350 Per Brass

20mm 3350 Per Brass

Water 0.2 Per Kg

Sikaviscocrete 5210 NS 163.18 Per Kg

Figure 2- Cost Analysis

Total cost per cubic meter of the concrete is shown Figure 2. Trail number 1 and 2 were very economical as compared to other trails, but due to strength criteria these trails were discarded. The total cost of trail number 3 was highest among all the trails therefore modifications in the next trail lead to optimum use of cementitous materials and cost minimization was done. Trail number 4 was very economical as there was optimum use of OPC and Micro Silica. This is how cost optimization was done.

V. CONCLUSION

Micro Silica content in per cubic meter of concrete increases the compressive strength but it also increases the overall cost of concrete as it is most expensive cementitious material used. Therefore optimum use of Micro Silica has to be done for economical concrete mix.

Use of crushed sand directly affects the workability of concrete. High percentage of fines in crushed sand i.e.

high percentage of 75 micron passing crushed sand would result in cohesive mix but it won’t be workable and low

percentage of crushed sand would result in high workability along with initial bleeding. Therefore the percentage calculation of crushed sand must be very accurate for desirable workability.

The mix has to be cohesive and therefore the amount of fines in the concrete must be sufficient.

Workability is the governing factor of self compacting concrete. Workability has to be adjusted in such a way that it meets the site requirement.

One of the most important site requirement is that the deshuttering of the section has to be done within 24 hours, therefore the initial compressive strength must be high.

Therefore cementitious content in the concrete mix must be on higher side.

VI. ACKNOWLEDGEMENT

We would take this opportunity to thank all those people who helped us to execute this research work. We would extend our special thanks to Navdeep Construction Company for providing their Lab and Lab staffs for various trials.

REFERENCES

[1] Hajime Okamura and Masahiro (2003).

“Self-Compacting Concrete”. Journal Of Advanced Concrete Technology vol 1, No 1, 5-15 April 2003.

[2] B.H.V. Pai, M. Nandy, A. Krishnamoorthy, P.K.Sarkar and C. Pramukh Ganapathy (2014).

“EXPERIMENTAL STUDY ON

SELFCOMPACTING CONCRETE

CONTAINING INDUSTRIAL

BY-PRODUCTS” European Scientific Journal April 2014 edition vol.10, No.12 ISSN: 1857 – 7881.

[3] Dr.Needhidasan Santhanam, Manoj Nallanathel, and Monirupa Ananya (2014). “Self Compacting Concrete – A Boon To Construction Industry”

(2014). Global Journal To Research Analysis Volume-3, Issue-9, Sept-2014 • ISSN No 2277 – 8160.

[4] Komas K.Sideris (2007) “Mechanical Characteristics of Self-Compacting Concrete Exposed to Elevated Temperatures”

10.1061/(ASCE)0899-1561(2007)19:8(648).

[5] Philippe Turcry, Ahmed Loukili, Khalil Haidar, Gilles Pijuadier-Cabot and Abdeldjelil Belarbi (2006). “Cracking Tendency Of Self-Compacting

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_______________________________________________________________________________________________

Concrete Subjected To Restrained Shrinkage”

10.1061/(ASCE)0899-1561(2006)18:1(46).

[6] Mohammed Ibrahim Khan “Design and Evaluation of M50 Grade Concrete (H.P.C &

S.C.C) using Ferro Alloy Silicon Slag as Fine Aggregate” International Journal of Engineering Innovation & Research Volume 3, Issue6, ISSN:

2277–5668.

[7] Kushal Patil, Ajitkumar Jadhav and Nikhil Shingate (2015) “Mivan Technology” . International Journal of Engineering and

Technical Research (IJETR) ISSN: 2321-0869, Volume-3, Issue-6, June 2015.

[8] Shankar Bimal Banerjee, Pawan Dilip Barhate and Vipul Pradip Jaiswal (2015) “MIVAN

TECHNOLOGY” INTERNATIONAL

JOURNAL OF INNOVATIONS IN

ENGINEERING RESEARCH AND

TECHNOLOGY [IJIERT] ISSN: 2394-3696 VOLUME 2, ISSUE 3 MARCH2015.

[9] Mr.C.M.Dordi (2004) “SELF COMPACTING

CONCRETE”. AMBUJA TECHNICAL

LITERATURE SERIES 98.

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