Workability, Strength and Durability Properties of Concrete with Blended Cement and Different Types of Fine Aggregates

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Workability, Strength and Durability Properties of Concrete with Blended Cement and Different Types of Fine Aggregates

Gab Suresh

AGM, Concrete Technologist

Ramco Research and Development Centre (RRDC) A Division of The Ramco Cements Limited Chennai-India

Abstract:- The use of Manufactured Sand (M-Sand) and Crushed Stone Sand (CSS) is steadily growing due to scarcity of natural River Sand. Now-a- days the sand available in the river bed contains high percentage of silt and clay. Generally CSS and a few source of M- Sand samples contain higher percentage of Fine, Flaky, Elongated and rough texture particles and negligible clay content when compared to the River Sand. At the same mix proportions, concrete workability with river sand will be higher when compared to that with M-Sand or CSS concretes due to the spherical shape and smooth texture of river sand particles. The purpose of this research is to achieve the same workability, strength and durability properties of concrete by using appropriate proportion of River Sand, M Sand and CSS without changing cement content and free water cement ratio. From the test results it was ascertained that the concrete workability, strength and durability properties show more or less equal values which could be possible by designing the concrete mix proportions based on the gradation, fines content and other physical properties of fine aggregate.

KeywordsRiver Sand, Crushed Stone Sand, Manufactured Sand, Vertical Shaft Impact

INTRODUCTION

River sand is a product of natural weathering of rocks over a period of millions of years. Natural rocks are disintegrated by weathered process. The disintegrated particles are worn out by streams or glacial agencies and finally get deposited on the banks of the rivers and are called River Sand also called Uncrushed Sand. Now-a-days River sand is becoming a scarce product and hence exploring alternatives to it becomes imminent. Crushed Stone Sand (CSS) or Crushed Rock Fines (CRF) is produced by crushing hard granite stones and Crushed Gravel Sand(CGS) is produced by crushing natural gravel.

IS 383-2016 code stated that Manufactured Sand is manufactured from other than natural sources. Copper Slag, Iron Slag and Steel Slag materials are considered as Manufactured Aggregates. Recycled Concrete Aggregates also considered as Manufactured Aggregates. As per IS 383-2016 code, the utilization of Manufactured Aggregates in different concretes are given in Table 1. The limits of deleterious materials in the fine aggregate are given in Table 2 as specified in the same code.

Crusher Stone Sand / Crushed Rock Fines / Crusher Dust / Quarry Dust are the fine particles obtained as a by-product during the crushing of rocks to produce coarse aggregates. Jaw crusher or Cone crusher is used for crushing large size rocks to small size rocks. This material contains more fine particles, dust, flaky, and elongated particles. It shows high water demand for required workability and this may lead to develop more shrinkage cracks in concrete. Thus Crushed Stone Sand should be used only after proper testing and designing the concrete mix accordingly.

PRODUCTION TECHNOLOGY OF M-SAND / ROBO SAND / ECO SAND

To resolve the Crushed Stone Sand quality problems, the technology of processing to improve the particle shape and reduce the fines content has been developed. Rock crushed to the required grain size distribution is colloquially termed as manufactured sand (M-Sand). Generally M-Sand production involves crushing, screening and washing. M-Sand particles are cubical in shape and also some extent smooth texture. M-Sand is manufactured using technology like Rock-on-Metal and Rock-on-Rock process which is synonymous to that of natural process undergoing in river sand formation.

M-Sand is produced by feeding hard stones of varying sizes to primary and secondary crushers (Jaw crusher and Cone crusher), for size reduction and these crushed stones are further crushed in Vertical Shaft Impact (VSI) crusher to attain the required grain size distribution and shape to that of River Sand. The VSI crusher by its unique design and action of attrition produces well shaped fine aggregate particles that are cubical angular particles. Generally the real M-Sand or Robo Sand quality is better than the River Sand. The comparisons between River Sand and M-Sand are given in Table 4.

The VSI machine is shown in Fig. 1. In the production process of M-Sand it is a challenge to avoid generating of a high percentage of fines. Very fine particles will be removed by washing. However, the latest development of equipment combined dry screening

with air classification to govern the grading curve very precisely, including the finest part. The River Sand, CSS and M-Sand fine aggregates colour and coarse particles properties are shown in Fig.2. The quality of M-Sand samples which were collected from different suppliers in Tamil Nadu are shown in Table 3

LITERATURE

Prof.Venkatarama Reddy et. al. (2012)(7) investigated that the mortar workability, compressive strength, modulus of rupture, modulus of elasticity, bond strength properties are superior by using M-Sand when compared to those of natural River Sand. Saeed Ahmad et al. (2008)(11) found that concrete compressive strength increased and workability decreased with increasing proportion of M-Sand. Balamurugan et.al.(2013)(8) ascertained that quarry dust can be utilized in concrete mixtures as a good substitute for river sand with higher strength at 50% replacement. Adams et.al.(2013)(9) found that the replacement of 50% fine aggregate by M-Sand induced higher compressive strength, split tensile strength, flexural strength and durability. Priyanka et.al. (2013)(10) determined that the compressive strength of cement mortar with 50% replacement of river sand by M-Sand reveals higher strengths as compared to 100% River sand mix.

EXPERIMENTS

In this research physical properties such as sieve analysis, particle shape, specific gravity, water absorption, fines and silt content, bulk density etc of different types of fine aggregates were studied and the effect of using these materials on the performance of concrete are investigated. From the sieve analysis results it was observed that River Sand and M-Sand are coarse sand and Crusher Stone Sand is fine sand. The sieve analyses and other physical properties of aggregates are presented in Table 5 and Table 6 respectively.

The main objective of this research is to establish the data to achieve more or less equal concrete workability, strength and durability properties by fixing appropriate fine aggregate proportion in the total aggregate. Nominal and Design mix concrete trials were carried out by using Ramco Super Grade cement (PPC) and different types of fine aggregates i.e. River sand, M-Sand and CSS. Basically the percentage of fine aggregate in the total aggregate was fixed based on the fine aggregate gradation, fines content (<75microns) and other physical properties. Concrete trials were also carried out with blending of coarser and finer fine aggregates. The River sand & CSS and M-Sand & CSS were blended 50:50 and 55:45 ratios by volume respectively and these blending gradation curves are shown in Fig.3. The test results of workability, strength and durability obtained for the nominal mix and design concretes are presented in Table 7 and Table 8 respectively.

From the test results of nominal and design mix concretes it was ascertained that at the same cement content and free water cement ratio, all concretes were attained relatively equal slump, flow, compressive strength and duraility properties by fixing appropriate proportion of River Sand, CSS and M-Sand in total aggregate based on the gradation, fines content and other physical properties of fine aggregate. This methodology is not only helpful to obtain relatively equal rheological, strength and durability properties of concrete with different quality of River Sand, CSS and M-Sand, it will be also useful to minimise the plastic shrinkage and plastic settlement cracks in the structures. The nominal mix concretes slump tests photographs are shown in Fig. 4 .

Concrete trials were also carried out at different percentages of replacing River Sand with Crushed Stone Sand considering relatively same workability, strength and durability of all concretes. Crushed Stone Sand was added for replacement of River Sand from 0% to 100% in the increment of 10% and the percentage of total fine aggregate proportion by volume gradually decreased from 45 % to 36% in the total aggregate volume. The River Sand and CSS blend concretes design mix proportions are given in Table 9. For all these mixes were also maintained constant cement content and free water cement ratio. The fine particles (150, 300 and 600 microns) content per one cubic meter concrete for different proportions of River Sand, CSS and blended River Sand & CSS fine aggregates are presented in Fig.5. From the graph it was observed that 300 to 600 microns particles content is gradually decreased, below 150 microns particles content gradually increased and 150 to 300 microns particles content slightly increased by gradually replacing River Sand with Crushed Stone Sand. Due to this phenomenon all concretes have attained more or less equal slump, flow, compressive strength and durability properties. The photographs of flow tests of the concretes containing the blends of River Sand and CSS are shown in Fig.6, and Fig. 7shows the results of their workability, strength and durability.

CONCLUSIONS

  1. By fixing appropriate weight of fine aggregate in total aggregate weight, Nominal Mix Concretes attained more or less equal slump, flow, strength and durability properties with River Sand (44%), M-Sand (39%) and Crushed Stone Sand (36%) without changing the cement content and free water cement ratio.

  2. With fixing proper volume of fine aggregate in total aggregate volume, Design Mix Concretes attained more or less equal slump, flow, strength and durability properties with River Sand (45%), M-Sand (40%) and Crushed Stone Sand (36%) without changing cement content and free water cement ratio.

  3. As a result of blending suitable ratios of different type of fine aggregates River sand & CSS (50:50) and M-Sand & CSS (55:45) concretes also achieved good rheological, strength and durability properties.

  4. With the higher percentage of CSS (43%) in the total aggregate (Table 8), the water demand is increased for getting required workability and it decreased the strength and durability.

  5. By gradually increasing of CSS and proportionally decreasing the River Sand in total volume of fine aggregate and gradually decreasing the volume of total Fine aggregate in the total aggregate volume, concretes achieved almost equal slump, flow, strength and durability properties.

    The above conclusions indicate that by fixing appropriate Fine and Coarse Aggregate Proportions based on Fine Aggregate Gradation, Fines content and coarser particles properties, one can make the concrete by using River Sand, M-Sand and Crushed Stone Sand or with the combination of these fine aggregates and get the almost same workability, strength and durability properties without changing the cement content and free water cement ratio.

    ACKNOWLEDGEMENTS

    The author gratefully acknowledges the initiative of The Ramco Cements Limited for providing the state-of-the-art research facilities at Ramco Research and Development Centre (RRDC), Chennai. The author is extremely grateful to The Ramco Cements Limited and Technical and non-Technical Staff of the RRDC.

    REFERENCES:

    1. IS 383 : 2016 Coarse and Fine Aggregate for Concrete Specification

    2. IS 516 Methods of tests for strength of concrete

    3. IS 2386 (Part I – VIII) Methods of test for aggregate for concrete

    4. IS 10262 2009 Concrete Mix Proportioning Guidelines

    5. IS 456 2000 Plain and Reinforced Concrete Code of Practice

    6. ASTM C 1202- 19 Standard Test Method for Electrical Indication of Concretes Ability to Resist Chloride Ion Penetration

    7. Prof. Venkatarama Reddy (2012) Suitability of Manufactured sand (M-Sand) as fine aggregate in Mortars and Concrete Project Review Article, Dept. of Civil Engg., Indian Institute of Science, Bangalore.

    8. Balamurugan G and Perumal P (2013) Use of quarry dust to replace sand in concrete-An experimental study Int. Journal of Scientific and Research Publications, Vol. 3, Issue 12, Dec. 2013.

    9. .Adams A Joe, Maria A Rajesh, Brightson P, PremAnand M (2013) Experimental Investigation on the effect of M-Sand in high performance concrete

      American Journal of Engineering Research, Vol.02, Issue-12, pp-46-51

    10. Priyanka A. Jadhav and Dilip K. Kulkarni (2013) Effect of replacement of natural sand by manufactured sand on the properties of cement mortar Int. J. of Civil and Structural Engineering, Vol. 3, No.3, 2013

    11. Saeed Ahmad and ShahidMahmood (2008) Effects of Crushed and Natural Sand on the properties of Fresh and Hardened Concrete 33rd Conference on our World in Concrete &Structures, Singapore, pp. 25-27

Table 1: As per IS 383:2016 Utilization of Manufactured Aggregates in Different Concretes

Type of Aggregate

Plain Concrete (%)

Reinforced Concrete (%)

Lean Concrete (<M15) (%)

Coarse aggregate

(a) Iron Slag Aggregate

50

25

100

(b) Steel Slag Aggregate

25

Nil

100

(c) Recycled Concrete Aggregate

25

20 (<M25)

100

(d) Recycled Aggregate

Nil

Nil

100

(e) Bottom Ash from thermal power plant

Nil

Nil

25

Fine Aggregate

(a) Iron Slag Aggregate

50

25

100

(b) Steel Slag Aggregate

25

Nil

100

(c) Copper Slag Aggregate

40

35

50

(d) Recycled Concrete Aggregate

25

20 (<M25)

100

Table 2: As per IS 383: 2016 Limits of Deleterious Materials in the Fine Aggregate

td>

5.0

Sl. No

Deleterious Substance

Uncrushed Sand (River Sand)

Crushed Sand (CSS)

Manufactured Sand

1

Coal and lignite, Max (%)

1.0

1.0

1.0

2

Clay lumps, Max. %

1.0

1.0

1.0

3

Material finer than 75 µm IS sieve, Max %

3.0

15

10

4

Mica, Max (%)

1.0

1.0

1.0

5

Deleterious materials (Max. %)

2.0

2.0

Table 3: The quality of M-Sand samples which were collected from different suppliers in Tamil Nadu

IS Sieve (mm)

Cumulative Percentage Pass

Sample-1

Sample-2

Sample-3

Sample-4

Sample-5

Sample-6

10.0

100

100

100

100

100

100

4.75

99.9

98.1

99.8

100

99.4

100

2.36

75.0

82.9

68.6

71.3

79.5

87.7

1.18

44.7

62.7

41.6

45.8

58.1

64.7

0.60

29.5

50.1

29.8

34.7

46.4

51.7

0.30

17.4

36.1

22.2

24.8

35.6

38.4

0.15

5.7

15.3

14.0

13.3

19.9

22.6

<75 µm

3.5

9.3

12.0

13.5

16.7

18.5

Zone

Zone-I

Zone-II

Zone-I

Zone-I

Zone-II

Zone-II

Fineness Modulus

3.28

2.55

3.24

3.10

2.61

2.35

Type of Sand

Coarse Sand

Fine Sand

Coarse Sand

Coarse Sand

Medium Sand

Fine Sand

Particle Shape

Cubical Angular

Flaky & Elongated

More Cubical Angular

Cubical Angular

Medium Cubical

More Flaky & Elongated

Table 4: Comparison between River Sand and M- Sand

Sl.No

Description

River Sand

M- Sand

1

Process

Naturally available on river banks

Manufactured in factory

2

Quality

No control over quality since it is naturally occurring.

Consistent quality since manufactured in a controlled environment (VSI)

3

Shape

Mostly sphere particles

Mostly cubical and angular particle ( rounded angular)

4

Below 75 microns

< 3 %

10 %

5

Surface texture

Smooth

Smooth

6

Clay and Organic impurities

Higher

Zero

7

Over Sized materials

May contains oversized materials ( like pebbles)

Zero

8

Marine Products

It contains shells etc

Zero

9

Workability

Better

River sand mix

(If adjust mix proportions based on fines and particle shapes)

10

Strength

Good

River sand or slightly higher

11

Eco friendly

Harmful to environment. ECO imbalance, reduce ground water level and rivers water gets dried up.

Less damage to environment as compared to river sand

12

Gradation

It may vary load to load

Maintain good gradation

13

Applications

Recommended for RCC, Masonry and Plastering

Recommended for RCC, Masonry and Plastering (M- Sand with low fines and less flaky& elongated particles and smooth texture is suitable for plastering works).

14

Adulteration

Probability of adulteration is more (filtered sand). As a rule, supply shortage always brings adulterer products to the market.

Probability of adulteration is less

15

Availability

In monsoon more scarcity. Diminishing of Natural Rivers or River beds, not available for future generations

Uninterrupted supply (since plenty of hills/rocks available)

16

Price

High

Low when compared to River sand

Table 5: Coarse and Fine Aggregates Sieve Analysis

Coarse Aggregate (single sized aggregate)

Fine Aggregate

IS Sieve Size (mm)

Percentage Pass

IS Sieve Size (mm)

Percentage Pass

IS 383 Limits for

Zone – II

12.5 mm Agg.

IS 383

Limits

20mm Agg.

IS 383

Limits

River Sand

M-Sand

CSS

40

100

100

100

10

100

100

100

100

20

100

96.8

85 -100

4.75

99.9

100

100

90 – 100

16

100

100

55.2

2.36

93

91.7

87.6

75 100

12.5

98.7

85 – 100

17.8

1.18

66.3

60.2

70.9

55 – 90

10

58.4

0 – 45

2.17

0 – 20

0.60

35.1

29.5

52.3

35 59

4.75

0.27

0 – 10

0.07

0 – 5

0.30

11.2

16.0

39.2

8 – 30

0.15

1.9

8.6

21.1

0 10*

* Crushed stone sand, the permissible limit on 150 m IS Sieve is increased to 20 percent.

Table 6: Coarse and Fine Aggregates Physical Properties

table cellspacing=”0″>

Sl. No

Description

12mmAgg.

20mmAgg.

River Sand

CSS

M-Sand

1

Specific Gravity

SSD

2.78

2.75

2.64

2.67

2.67

True

2.77

2.74

2.61

2.60

2.62

2

Water Absorption (%)

0.51

0.46

0.94

2.43

1.73

3

Loose Bulk Density (kg/m3)

1404

1462

1528

1660

1619

4

Compacted Bulk Density (kg/m3)

1549

1623

1694

1924

1781

5

Flakiness Index (%)

22.7

11.4

6

Elongation Index (%)

20.3

14.4

7

Impact Value (%)

21.9

16.6

8

Crushing Value (%)

23.4

20.2

10

Angularity Number

8.11

5.06

11

< 75 microns (%)

(by wet sieve analysis)

0.90

20.2

6.0

12

Fine Aggregate Zone

I

II

I

13

Type of sand

Coarse

Fine

Coarse

Table 7: Nominal Mix Concrete proportions and its workability, Strength and Durability Properties with different type of Fine Aggregates

Description

Fine Aggregate % by weight in total aggregate

River Sand (44)

(MIX-NR)

M-Sand (39)

(Mix-NM)

Crushed Stone Sand (36)

(Mix-NC)

Mix Proportions

in Dry condition (kgs)

Ramco Super Grade (PPC)

350

350

350

Fine Agg.

790

700

638

20mm Agg.

1014

1098

1144

Total water

(including water absorption)

205

210

214

Free W/C

0.55

0.55

0.55

Initial Slump (mm)

98

90

73

Compressive Strength , MPa

1 -Day

9.2

9.4

10.6

3 – Days

14.0

14.6

15.0

7 – Days

19.1

19.7

19.1

28 – Days

31.6

31.2

30.0

RCPT

(Coulombs)

28 – Days

1177

1013

1182

Table 8: Design Mix Concrete proportions and its Workability, Strength and Durability Properties with different type of Fine Aggregates

Description

Fine Aggregate % by Volume in total aggregate

River Sand (45)

M-Sand (40)

CSS (36)

RS+CSS (50+50)

M-Sand + CSS (50+50)

CSS (43)

Mix Proportions per1m3 concrete in SSD (kgs)

Ramco Super Grade (PPC)

340

340

340

340

340

340

Fine Agg.

812

741

667

352+361

387+317

783

12.5mm Agg.

446

486

519

494

502

454

20mm Agg.

609

664

709

675

686

620

Water (Free W/C)

187 (0.55)

187

187

187

187

199 (0.585)

Initial Slump (mm)

64

60

59

75

72

78

Initial Flow Diameter (mm)

455

448

425

453

428

440

Compressive Strength , MPa

1 -Day

7.9

8.4

8.3

7.9

7.0

5.6

3 – Days

15.9

15.9

15.7

15.3

14.5

11.3

7 – Days

20.6

20.9

19.7

19.4

18.3

15.3

28 – Days

29.5

31.1

28.7

29.7

28.7

22.5

RCPT (Coulombs)

28 Days

1097

1285

1304

1174

1358

1613

Table 9 River Sand and CSS Blend Concretes Mix Proportions

Description

M- RC1

M- RC2

M- RC3

M- RC4

M- RC5

M- RC6

M- RC7

M- RC8

M- RC9

M- RC10

M- RC11

Fine Aggregates proportions in percentage (by Volume)

(45)* 100 RS

(44) RS+CSS 90+10

(43) RS+CSS 80+20

(42) RS+CSS 70+30

(41) RS+CSS 60+40

(40) RS+CRS 50+50

(39) RS+CSS 40+60

(38) RS+CRS 30+70

(37) RS+CSS 20+80

36.5) RS+CSS 10+9

(36) 100 CSS

Mix Proportions per 1m3 concrete in SSD(kgs)

Ramco PPC

350

350

350

350

350

350

350

350

350

350

350

River Sand

811

714

620

530

443

360

281

205

133

66

0

CSS (CRF)

0

80

157

230

300

366

428

487

541

601

659

12.5 mm

440

448

456

464

472

480

488

496

504

508

512

20 mm

601

612

623

634

645

656

667

678

688

694

699

Water

193

193

193

193

193

193

193

193

193

193

193

*The percentage of Total Fine Aggregate proportion by volume in total aggregate volume

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