Experimental Study of Artificial Sand Concrete

M. R. Chitlange, Head,

Applied Mechanics Dept., Government Polytechnic,

Aurangabad. mrchitlange1@rediffmail.com

Dr. P. S. Pajgade, Prof. & Head, Civil Engg. Dept.,

Prof. Ram Meghe Institute of Technology & Research,

Badnera, Amravati. ati_ppajgade@sancharnet.in

Dr. P. B. Nagarnaik, Prof. & Head,

Civil Engineering Dept., G. H. Raisoni College of Engineering,

Nagpur. pbnagarnaik@rediffmail.com

Abstract Conventionally concrete is a mix of cement, sand and aggregate. There is a large variation in the strength of concrete due to variation in the strength of aggregates used. There is scarcity of natural sand due to heavy demand in growing construction activities which forces to find the suitable substitute. The cheapest and the easiest way of getting substitute for natural sand is by crushing natural stone to get artificial sand of desired size and grade which would be free from all impurities. This paper presents the feasibility of the usage of artificial sand obtained by crushing basalt over natural sand considering technical, environmental and commercial factors. For the purpose of experimentation concrete mixes are designed for M20, M30 and M40 grades by 100% replacement of natural sand to artificial sand. Compressive and flexural tests are conducted to study the strength of concrete using artificial sand and the results are compared with that of natural sand concrete. Key Words - Natural sand, Artificial sand, Concrete mix, Super plasticizer, Compressive strength, Flexural strength. 1. Introduction

Concrete is the most widely used versatile building material all over the world. Concrete technology has made significant advances in recent years which results in economical improvement of the strength of concrete. This economical development depends up on the intelligent use of the locally available materials. One of the important constituent of conventional concrete is natural sand, which is expensive and scarce. In the process of producing widely used 20 mm and 10 mm nominal size of aggregate, a significant amount of crusher dust and stone chips in the size range of 2 to 6 mm are obtained. The modern

crushers specially designed for producing cubical, comparatively smooth textured, well graded sand are good enough to replace natural sand partially or fully.

Tests were conducted on cubes and beams to study the strength of concrete made of quarry rock dust and results were compared with the natural sand concrete.

2. Literature review

It was found that the compressive flexural strength and durability studies of concrete made of quarry rock dust were nearly 10% more than those of conventional concrete(1). It was reported the significant increase in compressive strength, tensile strength, and modulus of rupture for M20 and M30 concrete mixes with 20% and 40% replacement of natural sand with stone dust. The workability of the concrete mixes decreased with an increase in percentage of stone dust.(2) Concrete with stone crusher dust was reported to show 17%, 7%, 20% higher compressive, tensile, flexural strengths respectively than those of conventional concrete. The differences in the strengths were possibly due to the sharp edges of stone dust providing stronger bond with cement compared to the rounded shape of river sand. (3) In another study the concrete made of stone dust of about 48 MPa strength showed 10%, 24%, and 26% higher strength in compression, tension, and flexural tension respectively over the controlled concrete(4). It was tried experimentally to explore the use of crusher dust, stone chips and fly ash in self compacting concrete. Test results indicated that for SCC sufficiently low water to powder ratio can be attained even with the use of crusher dust, leading to high compressive strength. (5) It indicates that water requirement is higher in such concrete to maintain desired workability. The compressive, flexural and bond strength were improved in with partial replacement of natural sand by crusher rock dust but slump value of fresh concrete was significantly reduced(6).

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It is seen from the above studies, there is a large variation in the strength enhancement of the concrete made from artificial sand. This variation may be due to the type and strength of the parent rock, the size and shape of the particle, the dust content, etc. To encourage the use of locally available artificial sand, promotes the study to check its suitability in the concrete. 3. Materials 3.1 Cement

Ordinary Portland Cement Birla Super of 53 grade confirming to IS 12269 1987 was used. The physical properties are tabulated in table 1.

Table 1

Physical properties of Cement No. Property Value 1 Specific gravity 3.10 2 Fineness m2/kg 297 3 Normal consistency 30.50 % 4 Initial setting time 164 minute 5 Final setting time 244 minute 6 Soundness 0.90 mm 7 7 days Compressive strength 49.2 MPa 3.2 Fine aggregate

Natural sand obtained from the river and normally available in the market was used. The artificial sand obtained from local crusher was used. The physical properties of natural and artificial sands are listed in table 2. The sieve analysis details are given in table 3. Both types of fine aggregates are confirming to zone II of IS 383-1970. Details of sieve analysis are shown in figure 1. 3.3 Coarse aggregate

Crushed natural rock stone aggregate of nominal size up to 25 mm (A1) and aggregate passing 12.5 mm (A2) were used. The aggregates A1 and A2 are proportioned by trial in the mixes. The physical properties of these coarse aggregates are listed in table 4. The sieve analysis details of (A1) 25 mm and (A2) 12.5 mm coarse aggregate are shown in table 5 and in figure 2. 4. Concrete Mix Design

Concrete mixes were designed in accordance with IS 10262-1982 and IS 456-2000 by assuming good degree of quality control and moderate exposure

conditions. The mixes are designed for M20, M30 and M40 concrete with 100% replacement of natural sand by artificial sand. For comparison of behavior of natural and artificial sand, the natural sand was sieved and used in the same proportion as the percentages of fractions observed in artificial sand. All other ingredients of concrete i.e. cement, coarse aggregate, water cement ratio were kept same. To restrict the water cement ratio to 0.5 with desired workability, accelerating super plasticizer was used as admixture in the percentage of cement weight. The adopted mixes proportions by weight batching method are summarized in table 6.

Table 2

Physical properties of fine aggregate Property Natural sand Artificial

sand Specific gravity 2.60 2.73 Bulk density kg/m3 1560 1762 Fineness modulus 2.66 3.01

Table 3

Sieve analysis details of Natural and Artificial Sand Percentage Passing IS Sieve

Designation Natural sand Artificial sand 4.75 mm 100 100 2.36 mm 85.25 76.70 1.18 mm 70.62 51.40 600 micron 54.80 35.20 300 micron 18.2 20.70 150 micron 5.00 15.00

Table No. 4

Physical properties of coarse aggregate No. Property Value

1 Specific gravity 2.96 2 Bulk density kg/m3 1620 3 Fineness modulus 25mm (A1) 7.57 4 Fineness modulus 12.5mm (A2) 6.13

Table 5

Details of sieve analysis of Coarse Aggregate Percentage Passing IS Sieve

Designation 25 mm (A1) 12.5mm (A2) 40 mm 100 --- 20 mm 42.42 100 10 mm 0.30 83.0

4.75 mm 0.24 3.4 2.36 mm -- 0.1 1.18 mm -- --

600 micron -- -- 300 micron -- -- 150 micron -- --

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Table 6 Concrete Mix Proportions (kg)

Material M20 M30 M40 Cement 310 385 450 Artificial sand 612 590 556 Coarse aggregate A1 520 504 480 Coarse aggregate A2 780 755 720 Water 155 174 180 Super plasticizer (Lit) 3.1 3.85 4.5 Slump value (mm) 90 75 55 Compaction factor 0.90 0.87 0.87 Water / Cement ratio 0.50 0.45 0.40 Cement/Aggregate ratio 1:6.16 1:4.80 1:3.90

5. Experimentation

The exact amount of concrete ingredients were weighed and mixed thoroughly in laboratory concrete mixer till the consistent mix was achieved. The workability of fresh concrete was measured in terms slump value and compaction factor. The standard cubes of 150 mm size and beams of 100x100x500 were cast in steel moulds and compacted on a vibrating table. Six cubes and six beams of each grade with natural and artificial sand were cast for testing. The specimens were cured in water for 7 and 28 days by immersion. The cubes were tested after 7 and 28 days curing and the average strength was calculated. The acceptance criteria using IS 456-2000 is followed. The results are tabulated in table 7 and plotted in figure 3 and figure 4. The beam specimens were tested under two point loads for flexural strength after 7 and 28 days of curing. The average values are listed in table 8 and shown in figure 5.

6. Conclusions

From the above results, following conclusions are drawn. 1. It is observed from the figure 3, that the

compressive strength of M20, M30 and M40 grade concrete at 7 days, using artificial sand is marginally but consistently higher than the conventional concrete using natural sand. The percentage increase is 3.07% for M20, 1.92% for M30 and 1.64% for M40 grade concrete, respectively.

2. From figure 4, the compressive strength of M20, M30 and M40 grade concrete at 28 days using artificial sand again consistently higher than the conventional concrete using natural sand. The percentage increase is 5.08%, 4.56% and 3.78% for M20, M30 and M40 grade concrete respectively.

Table 7

Compressive strength of concrete Avg. 7days

strength in MPa Avg. 28 days

strength in MPa Grade

Natural Sand

Artificial Sand

Natural Sand

Artificial Sand

M20 21.20 21.85 37.04 38.92 M30 26.15 26.65 41.85 43.76 M40 29.86 30.35 47.84 49.65

Table 8

Flexural strength of concrete Avg. 7 days

strength MPa Avg. 28 days strength MPa

Grade

Natural Sand

Artificial Sand

Natural Sand

Artificial Sand

M20 3.05 3.25 4.83 5.15 M30 3.35 3.55 5.05 5.43 M40 3.63 3.86 5.41 5.85

3. The percentage increase in flexural strength at the

end of 7 days for artificial sand concrete is 6.55%, 5.97% and 6.33% for M20, M30 and M40 grades of concrete respectively over natural sand concrete.

4. The percentage increase in flexural strength at the end of 28 days for artificial sand concrete is 6.62%, 7.52% and 8.13% for M20, M30 and M40 grades of concrete respectively over natural sand concrete.

5. It is observed that use of admixture is necessary in all grades of concrete to restrict water cement ratio to 0.5 and below.

6. The excessive bleeding of concrete is reduced by using artificial sand.

7. It can be seen that mixes with artificial sand as fine aggregate gives consistently higher strength than the mixes with natural sand. The sharp edges of the particles in artificial sand provide better bond with cement than the rounded particles of natural sand resulting in higher strength.

8. The purchase cost of artificial sand is about 70% to that of natural sand and considering cost of screening, washing and wastage due to oversize particles of natural sand, the artificial sand concrete may be 20% cheaper than that of natural sand concrete.

9. The test results obtained from well planed and carefully performed experimental programme encourages the full replacement of natural sand by artificial sand considering the technical, environmental and commercial factors.

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0102030405060708090

100

0.15mm 0.30mm 0.60mm 1.18mm 2.36mm 4.75mm

IS sieve designations

Perc

enta

ge p

assi

ng

Natural sandArtificial sand

Fig. 1 Sieve analysis of Fine Aggregates

0102030405060708090

100

1.18mm 2.36mm 4.75mm 10mm 20mm 40mm

IS sieve designations

Perc

enta

ge p

assi

ng

A1 (25mm)

A2 (12.5mm)

Fig. 2 Sieve analysis of Coarse Aggregates

21.2 21.85

26.15 26.6529.86 30.35

0

10

20

30

Natural sand Artificial sand

Com

pres

ive

Stre

ngth

MP

a

M20M30M40

Fig. 3 - Compressive strength at 7 days

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37.04 38.9241.85 43.76

47.84 49.65

0

10

20

30

40

50

60

Natural sand Artificial sand

Com

pres

ive

Stre

ngth

MPa

M20M30M40

Fig. 4 - Compressive strength at 28 days

3.05 3.25

4.83 5.15

3.35 3.55

5.055.43

3.63 3.86

5.415.85

0

1

2

3

4

5

6

7

N.S. 7 days A.S. 7 days N. S. 28 days A.S. 28 days

Flex

ural

stre

ngth

MPa

M20M30M40

Fig. 5 Flexural strength at 28 days

REFERENCES - 1) Ilangovan R., Nagamani K., Gopal Samy P.,

Recycling of quarry waste as an alternative material in concrete manufacturing, Indian Construction, Vol 40, No. 2, pp. 7-12, Feb. 2007.

2) Sahu A. K., Kumar Sunil and Sachin A. K., Crushed stone waste as fine aggragate for concrete, The Indian Concrete Journal,, Vol-77, No.1, pp. 845-847, January 2003.

3) Prakash Rao D. S. & Giridhar kumar V., Investigation on concrete with stone crusher dust as fine aggregate, The Indian Concrete Journal, Vol-78, No. 7, pp. 45-50, August 2004.

4) Dr. Kode V. R., Murty D.S.R., Swarna Kumar P., Appraisal of Crushed Stone Dust, as Fine Aggregate in Structural Concrete, Civil Engineering & Construction Review, Vol. No. 7, pp. 52-58, July 2007.

5) Pravin kumar, Kaushik S. K., SCC with crusher dust, fly ash and micro silica, The

Indian Concrete Journal, Vol-79, No. 8, pp. 32-37, August 2005.

6) Ahmed E. Ahmed & Ahemed A. El-Kourd, Properties of concrete incorporating natural and crushed stone very fine sand, ACI Material journal, Vol-86, No. 4, pp. 417-424, July-August 1989.

7) M. S. Shetty, Concrete Technology Theory and Practice, (Fifth revised edition, 2002, S. Chand & Company limited, New Delhi).

8) ______ Code Of Practice for Plain & Reinforced Concrete IS 456: 2000, Bureau of Indian Standards, New Delhi.

9) ______ Recommended Guidelines for concrete mix Design, IS 10262: 1982, Bureau of Indian Standards, New Delhi.

10) ______ Specification for 53 Grade ordinary Portland cement, IS 12269: 1987, Bureau of Indian Standards, New Delhi.

11) ______ Coarse and fine aggregate from natural sources for concrete, (2nd revision), IS 383: 1970, Bureau of Indian Standards, New Delhi.

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