msand research paper

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International Journal of Mechanics and Solids

ISSN 0973-1881 Volume 4, Number 1 (2009), pp. 95-104

Research India Publications

http://www.ripublication.com/ijms.htm

Workability and Strength characteristics of Cement

Concrete with Partial Replacement of River Sand by

Manufactured Fine aggregate

V.R.K. Narasinha Raju1

andT. Appa Reddy

2

1Professor of Civil EngineeringKakatiya Institute of Technology And Sciences

Warangal 505 012, INDIA.

2Professor of Civil Engineering

AU College of Engineering Andhra University,

Visakhapatnam 530 003, INDIA.

Abstract

Artificial sand is a fine aggregate processed from quarried stone that is

crushed and classified to obtain a controlled gradation and a cubical to angular

particle shape. Statistics from the Bureau of Mines substantiate the growing

popularity of stone sand. In 1983, 13 million tons of stone sand was produced

in the U.S. By 1991, the number had grown to 45 million tons presently the

requirement would have reached above 100 million tons. This artificial sand

here after will be referred as Manufactured Sand of Manufactured Fine

Aggregate. An experimental study has been conducted for different concrete

mix proportions at different percentage replacement levels of river sand by

MFA. The results indicated that replacement of river sand by MFA is

beneficial from strength as well as workability viewpoint.

Need for Manufactured SandAs the supplies of suitable natural sand near the point of consumption are becoming

exhausted, the cost of this sand is increasing. In addition to this, the turbulence

created by dredging sand near the estuaries could damage the fragile ecosystem along

the coast. Thus a replacement material to the natural sand was sought, and the fines

from crushing operations were identified as a possible substitute material. Early

attempts by the quarry industry to market this material as manufactured sand resulted

in failure. This was due to the material having been produced as a waste product; no


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96 V.R.K. Narasinha Rajuand

T. Appa Reddy

thought having been given to the properties that are crucial to its performance in

concrete. The manufactured sand also failed due to noncompliance with the existing

sand specifications. Criteria such as misshapen particles increasing the water demand,

gradation not falling within the prescribed envelope, micro fines (material passing a

75micron sieve) content too high, sand equivalent and fineness modulus out of

specification; to name but a few, have limited the general acceptance of manufactured

sand. Attempts to modify the properties of the manufactured sand to conform to the

specifications brought with them new problem such as increased production costs and

disposal of the waste micro fines from the washing process. These problems were

recognized by the aggregate and concrete industries and together with the specifying

authorities, revised the sand specifications to include manufactured sand as a

construction material in its own right. However, since manufactured sand is so

different to natural sand, new testing sand proportioning methods need to bedeveloped. One of the main causes is the limit being placed on the amounts of

material finer than 75micron is allowed in the aggregates and sand. Most countries

have recognized manufactured sand as a unique material, as compared to natural sand.

More and more countries recognize that the recovery of sand from riverine deposits

has an ecological price tag attached. In addition, sources of sand suitable for use in

concrete are fast being depleted, and many of the remaining sources are situated far

from the point of consumption. Brazil has introduced a specification for crushed fines

allowing higher levels micro fines. In some areas of India the use of natural sand in

concrete is banned, thus forcing concrete manufacturers to use manufactured sand

with high amounts of micro fines (IS 383-1972, 20% passing 150 micron sieve).

Need of the present studyThe challenge before a construction engineer is that, with the available knowledge of

Concrete Technology, can a structurally sound concrete can be developed using eco-

friendly materials economically. To answer this, the present investigation has been

focused on effective utilization manufactured sand in place river sand in concrete.

A detailed review of literature reveals that there is need for the study of strength

aspects of concrete when conventional river sand is partially / totally replaced with

manufactured sand. MFA is a fine aggregate processed from quarried stone that is

crushed and classified to obtain a controlled gradation and a cubical to angular

particle shape. The first commercial use of MFA was made in the early 1930s.Current usage of MFA is over 100 times the amount utilized in 1930s and represents

approximately 20% of total concrete fine aggregate requirements. This percentage is

expected to increase in the years ahead. MFA differs from natural sands in gradation,

particle shape and texture. Each of these characteristics has some influence on

mixture design and influences cement requirements, water requirements, additive

requirements, workability, and finishing characteristics of the concrete. This material

completely passes through 4.75mm sieve and retains on 150m sieve. In this phase ofstudy, river sand used in concreting is replaced partially with the manufactured fine

aggregates and the properties at green state and hardened state of such concrete were

studied.


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Workability and Strength characteristics of Cement Concrete 97

Experimental Program: Experimental program consists of workability and

strength tests on concrete with partially replacing river sand by MFA. . For the

determination of properties at green stage of concrete, workability, slump test has

been preferred as it is more convenient for field works than any other workability test.

For the evaluation of strength properties of concrete with MFA as partial replacement

to sand, tests on cubes, cylinders and prisms were adopted. The variations in this

phase of study include the partial replacement of river sand by MFA at regular

intervals of 20% from 0% to 100%.

Designation of mixes:In total, 6mixes for each grade, thus studies on 18 mixes

were done in this part of the investigation. Each mix is designated by the letter M

followed by the designed cube compressive strength and a letter A-F indicating the

replacement of fine aggregate by Manufactured sand at regular intervals of 20%. For

example M20D indicates that the mix is of M20grade concrete with 60% natural riversand replaced by manufactured sand. M40A denotes mix is of M40 grade concrete

without any replacement of natural sand. M30F indicates, the M30 grade concrete

with manufactured sand in place of natural sand (100% replacement)

MaterialsCement: The ordinary Portland cement of 43 Grade is used for the production of

concrete. Standard Consistency, specific gravity and fineness as percentage retained

on 90microns sieve were found to be 30%, 3.12 and 4.3% respectively.

Fine Aggregate: The fine Aggregate used in this investigation is natural river

sand and it has a fineness modulus of 2.67. The specific gravity and unit weight arefound to be 2.30 and 1510kg/cu.m. respectively. The sieve analysis of the fine

aggregate is presented in Table.4.1. The sieve analysis revealed that the fine aggregate

falls in the Zone II of IS 383:1972. The fineness modulus of the fine aggregate is

found be 2.68.

Coarse Aggregate: The nominal maximum size of the coarse aggregate is of

20mm. The sieve analysis of the coarse aggregates is presented in Table.4.1. The

Specific gravity and fineness modulus of the Coarse Aggregate was 2.78 and 6.89

respectively.

Manufactured Fine Aggregate: The specific gravity of MFA is found to be 2.50.

The sieve analysis of this aggregate is presented in Table.4.2. The fineness modulus is

found to be 2.64. This sand falls in the Zone II category of IS: 383-1972. The bulkdensity is 1450kg/cum. The percentage bulking is observed to be 33.33% at 5% of

water content. The bulking characteristics of MFA are presented in Fig.4.1. A

comparison of the sieve analysis of River sand and MFA is presented in Fig.4.2.

Water: Portable water is used for concreting and curing purpose.

Tests for workability and compressive strengthThree grades of concrete namely M20, M30 and M40 were designed using river sand

as fine aggregate. The Fine aggregate (river sand) is partially replaced with MFA to

the tune of 100% with 20% replacement as increment. Thus 6 mixes were prepared


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Sieve Analysis of River Sand and MFA

0

10

20

30

40

50

60

70

80

90

100

804020104.752.361.180.60.30.15

Size (mm)

Percentage

Passing

MFA

River Sand

Figure 2:A comparison of the sieve analysis of River sand and MFA.

Variation of Compressive strength with Partial Replacement ofNatural sand by MFA

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

0 10 20 30 40 50 60 70 80 90 100

Percentage replacement of Natural Sand by MFA

CubeCom

pressivestrength(Mpa)

M20

M30

M40

Figure 3: Variation of Compressive strength for different levels of replacement of

River sand by Manufactured Fine Aggregate.


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T. Appa Reddy

Variation of Workability (Slump) with Partial Replacement of

Natural sand by MFA

0

10

20

30

40

50

60

70

80

90

0 10 20 30 40 50 60 70 80 90 100

Percentage replacement of Natural Sand by MFA

Slump(mm)

M20

M30

M40

Figure 4:Variation of workability for different levels of replacement of River sand

by Manufactured Fine Aggregate.

Table 1: Sieve Analysis of River Sand and Coarse aggregates.

Coarse Aggregates Fine aggregatesSieve Size

Percentage

retained

Percentage

Passing

Percentage

retained

Percentage

Passing

80mm 0 100 0 100

40mm 0 100 0 100

20mm 13.90 86.10 0 100

10mm 78.60 21.40 0 100

4.75mm 96.44 3.56 0 1002.36mm 100 0 0 100

1.18mm 100 0 20.14 79.86

600m 100 0 56.25 43.75

300m 100 0 91.65 8.35

150m 100 0 100 0


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Table 2: Sieve analysis of Manufactured Fine Aggregates.

Manufactured Fine aggregatesSieve Size

Percentage retained Percentage Passing

80mm 0 100

40mm 0 100

20mm 0 100

10mm 0 100

4.75mm 0 100

2.36mm 11.0 89

1.18mm 20.87 79.13600m 48.52 51.48

300m 84.14 15.86

150m 100 0

Table 3: Mix Proportions adopted for different grades of concrete.

Fine Aggregate (kg)Mix

Designation

(Grade)

Water/

binder

Cement

(kg)

Water

(kg) Natural

sand

Manufactured

Fine

Aggregate

Coarse

aggregate

(kg)

Slump

(mm)

M20A 0.58 327.59 190 675 0 1400 65

M20B 0.58 327.59 190 540 135 1400 70

M20C 0.58 327.59 190 405 270 1400 75

M20D 0.58 327.59 190 270 405 1400 80

M20E 0.58 327.59 190 135 540 1400 70

M20F 0.58 327.59 190 0 675 1400 60

M30A 0.52 355.77 185 700 0 1300 50

M30B 0.52 355.77 185 560 140 1300 55

M30C 0.52 355.77 185 420 280 1300 60

M30D 0.52 355.77 185 280 420 1300 65

M30E 0.52 355.77 185 140 560 1300 65

M30F 0.52 355.77 185 0 700 1300 50

M40A 0.45 400.00 180 820 0 1150 45

M40B 0.45 400.00 180 656 164 1150 50

M40C 0.45 400.00 180 492 328 1150 50

M40D 0.45 400.00 180 328 492 1150 60

M40E 0.45 400.00 180 164 656 1150 60

M40F 0.45 400.00 180 0 820 1150 45


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T. Appa Reddy

Table 4: Cube Compressive strength variation for different percentage replacements

of river sand by MFA for different grades of concrete.

Natural

Sand

(%)

Manufactured

sand (%)

Compressive

strength(Mpa)

M20

Compressive

strength

(Mpa) M30

Compressive

strength

(Mpa) M40

100 0 28.00 38.72 46.80

80 20 34.00 39.11 48.51

60 40 38.07 51.63 53.08

40 60 40.11 54.21 55.82

20 80 36.04 47.83 52.51

0 100 31.97 42.35 50.22

Table 5: Split tensile strength variation for different percentage replacements of river

sand by MFA for different grades of concrete.

Natural

Sand

(%)

Manufactured

sand (%)

Split tensile

strength(Mpa)

M20

Split tensile

strength(Mpa)

M30

Split tensile

strength(Mpa)

M40

100 0 3.21 3.66 4.05

80 20 3.50 3.78 4.20

60 40 3.78 4.05 4.34

40 60 3.80 4.10 4.54

20 80 3.20 4.00 4.28

0 100 3.10 3.68 4.20

Table 6: Rebound hammer values of different grades of Concrete mix for different

percentage replacements of Natural sand by MFA.

At 7 day curing At 14 day curing At 28 day curingMix

Designation(Grade) Rebound

Value

Compressive

Strength

(MPa)

Rebound

Value

Compressive

Strength

(MPa)

Rebound

Value

Compressive

Strength

(MPa)

M20A 14.7 17.7 24.3 23.1 29.2 26.61

M20B 15.5 18.5 25.6 24.1 30.8 27.816

M20C 16.1 19.1 26.5 24.8 31.8 28.62

M20D 15.9 18.9 26.3 24.6 31.6 28.419

M20E 15.3 18.3 25.2 23.8 30.2 27.414

M20F 14.9 17.9 24.5 23.2 29.4 26.811

M30A 22.8 25.8 37.6 33.5 45.1 38.67

M30B 24.1 27.1 39.8 35.3 47.7 40.68

M30C 25.5 28.5 42.0 37.0 50.4 42.69


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M30D 24.1 27.1 39.8 35.3 47.7 40.68

M30E 24.1 27.1 39.8 35.3 47.7 40.68

M30F 23.5 26.5 38.7 34.4 46.4 39.675M40A 32.2 35.2 53.0 45.7 63.7 52.74

M40B 32.8 35.8 54.2 46.6 65.0 53.745

M40C 33.9 36.9 55.9 48.0 67.1 55.353

M40D 34.2 37.2 56.4 48.3 67.6 55.755

M40E 33.5 36.5 55.3 47.5 66.3 54.75

M40F 33.1 36.1 54.6 46.9 65.5 54.147

Table 7: Ultrasonic Pulse Velocity values of different grades of Concrete mix for

different percentage replacements of Natural sand by MFA.

At 7 day curing At 14 day curing At 28 day curingMix

Designation

(Grade)US Pulse

speed

(kM/Sec)

Dynamic

Modulus

US Pulse

speed

(kM/Sec)

Dynamic

Modulus

US Pulse

speed

(kM/Sec)

Dynamic

Modulus

M20A 3.50 24320 3.55 255848 3.57 26403

M20B 3.59 25497 3.64 268419 3.66 27707

M20C 3.68 26763 3.73 281939 3.75 29109

M20D 3.87 29593 3.93 312234 3.95 32254

M20E 3.77 28124 3.83 296507 3.85 30621

M20F 3.68 26763 3.73 281939 3.75 29109

M30A 3.35 22197 3.39 233219 3.41 24057

M30B 3.42 23222 3.47 244141 3.49 25189

M30C 3.59 25497 3.64 268419 3.66 27707

M30D 3.68 26763 3.73 281939 3.75 29109

M30E 3.68 26763 3.73 281939 3.75 29109

M30F 3.87 29593 3.93 312234 3.95 32254

M40A 3.42 23222 3.47 244141 3.49 25189

M40B 3.59 25497 3.64 268419 3.66 27707

M40C 3.68 26763 3.73 281939 3.75 29109

M40D 3.87 29593 3.93 312234 3.95 32254

M40E 3.87 29593 3.93 312234 3.95 32254M40F 3.77 28124 3.83 296507 3.85 30621

ConclusionsBased on the experimental results in this part of the research work the following

conclusions were drawn.

(1)Replacement of Natural sand by Manufactured Fine Aggregate improves the

workability of the matrix.

(2)Replacement of Natural sand by Manufactured Fine Aggregate improves the

cube compressive strength of the matrix.


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T. Appa Reddy

(3)Increase in the workability and the strength of the Concrete with MFA over

Concrete with natural sand is mainly due to the presence of material passing

through 75 micron sieve present in the MFA.

(4)The dynamic modulus, ultrasonic pulse velocity increase with the age of

concrete.

AcknowledgementsAuthors are highly thankful to the authorities of Kakatiya Institute of Technology and

Sciences, Warangal, for providing necessary materials and equipment for the

experimental program.

Reference

[1] ACI Committee 221, Guide for use of normal weight and heavyweight

aggregates in concrete, ACI 221R-96, American Concrete Institute, p. 29,

1997

[2] ACI Committee 309, Behaviour of fresh concrete during vibration, ACI

Journal, Vol. 78, No. 1, pp. 36-53, 1981 Alexander, K. M. et al, Discussion on

Effects of aggregate size on properties of concrete, ACI Journal, Vol. 32,

No. 9, pp. 1201-1258, 1961

[3] Backstrom J. E., Mielenz R. C., Wolkodoff V. E., Falck H.L., Origin,

evolution and effects of the air void system in concrete. Part 2. Influence of

type and amount of airentraining agent, ACI Journal, Vol. 30, No. 2, pp. 261-

272, 1958

[4] Backstrom J. E., Mielenz R. C., Wolkodoff V. E., Falck H.L., Origin,

evolution and effects of the air void system in concrete. Part 3. Influence of

water-cement ratio and compaction, ACI Journal, Vol. 30, No. 3, pp. 359-

375, 1958

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